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Taxol is a clinically used drug for the treatment of various types of cancers. Its 6/8/6/4‐membered ring (ABCD‐ring) system is substituted by eight oxygen functional groups and flanked by four acyl groups, including a β‐amino acid side chain. Here we report a 34‐step total synthesis of this unusually oxygenated and intricately fused structure. Inter‐ and intramolecular radical coupling reactions connected the A‐ and C‐ring fragments and cyclized the B‐ring, respectively. Functional groups of the A‐ and C‐rings were then efficiently decorated by employing newly developed chemo‐, regio‐, and stereoselective reactions. Finally, construction of the D‐ring and conjugation with the β‐amino acid delivered taxol. The powerful coupling reactions and functional group manipulations implemented in the present synthesis provide new valuable information for designing multistep target‐oriented syntheses of diverse bioactive natural products. [ABSTRACT FROM AUTHOR]

The polysaccharide capsule surrounding bacterial cell plays an important role in pathogenesis of infections caused by the opportunistic pathogen Acinetobacter baumannii by providing protection from external factors. The structures of the capsular polysaccharide (CPS) produced by A. baumannii isolates and the corresponding CPS biosynthesis gene clusters are highly diverse, although many of them are related. Many types of A. baumannii CPSs contain isomers of 5,7-diamino-3,5,7,9-tetradeoxynon-2-ulosonic acid (DTNA). Three of these isomers, namely acinetaminic acid (l-glycero-l-altro isomer), 8-epiacinetaminic acid (d-glycero-l-altro isomer), and 8-epipseudaminic acid (d-glycero-l-manno isomer), have not been found so far in naturally occurring carbohydrates from other species. In A. baumannii CPSs, DTNAs carry N-acyl substituents at positions 5 and 7; in some CPSs, both N-acetyl and N-(3-hydroxybutanoyl) groups are present. Remarkably, pseudaminic acid carries the (R)-isomer and legionaminic acid carries the (S)-isomer of the 3-hydroxybutanoyl group. The review addresses the structure and genetics of biosynthesis of A. baumannii CPSs containing di-N-acyl derivatives of DTNA. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) are recyclable, non-volatile, and can dissolve cellulose, a natural polymer that is insoluble in versatile solvents. Therefore, ILs have been used to modify cellulose. However, 1-ethyl-3-methylimidazolium acetate (EmimOAc), a commercially available IL often used to dissolve and modify cellulose to prepare cellulose-based materials, causes the undesired introduction of an acetyl group derived from the acetate anion of EmimOAc onto the hydroxy group of cellulose during esterification. In this study, for cellulose esterification, we prepared aryloxy ILs as non-carboxylate-type and basic ILs, which can theoretically prevent the undesired introduction of an acyl group from the IL onto the hydroxy group of cellulose. The optimized 1-ethyl-3-methylimidazolium 2-pyridinolate (Emim2OPy) and mixed solvent system achieved rapid cellulose esterification (within 30 min) with an excellent degree of substitution (DS) value (up to >2.9) derived from the employed low-reactive vinyl esters and bio-based unsaturated aldehydes, without any undesired substituent introduction from side reactions. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Group B Streptococcus (GBS) is the major pathogen that causes invasive infectious diseases in neonates and infants. The development of preventive and therapeutic strategies against GBS infection has been becoming the most pressing subject worldwide. Group B carbohydrate (GBC), the group B‐specific polysaccharide that distinguishes GBS with other streptococci species, has been identified as an attractive antigen for diagnosis and vaccine development because of its highly conservative tetra‐antennary structure. In this paper, a highly convergent [3 + 5] glycosylation strategy for efficient synthesis of an octasaccharide derivative related to GBC oligosaccharide unit II has been developed. In this synthesis, each glycosylation reaction was efficiently constructed with glycosyl imidates, especially trifluoroacetimidate, as donors, and each glycosidic bond was stereoselectively controlled via the neighboring group participation effect of acyl group on the 2‐O‐position of imidate donors or the solvent effect of Et2O. Furthermore, the aminoethylphosphate group was smoothly installed on the 6‐O‐position of d‐glucitol residue using the phosphoramidite method. After global deprotection, the target octasaccharide was successfully obtained from d‐glucitol in 29 steps with an overall yield of 1.37%. The free amino group installed on the aminoethylphosphate spacer of the target molecule enables its modification with functionalized biomolecules for further biological studies. [ABSTRACT FROM AUTHOR]

Organic chemical reactions have been used to functionalize preformed conducting polymers (CPs). The extensive work performed on polyaniline (PANI), polypyrrole (PPy), and polythiophene (PT) is described together with the more limited work on other CPs. Two approaches have been taken for the functionalization: (i) direct reactions on the CP chains and (ii) reaction with substituted CPs bearing reactive groups (e.g., ester). Electrophilic aromatic substitution, SEAr, is directly made on the non-conductive (reduced form) of the CPs. In PANI and PPy, the N-H can be electrophilically substituted. The nitrogen nucleophile could produce nucleophilic substitutions (SN) on alkyl or acyl groups. Another direct reaction is the nucleophilic conjugate addition on the oxidized form of the polymer (PANI, PPy or PT). In the case of PT, the main functionalization method was indirect, and the linking of functional groups via attachment to reactive groups was already present in the monomer. The same is the case for most other conducting polymers, such as poly(fluorene). The target properties which are improved by the functionalization of the different polymers is also discussed. [ABSTRACT FROM AUTHOR]

Herein, a three component Catellani‐type reaction catalyzed by the Palladium/Norbornene/CuI (Pd/NBE/CuI) cooperative system by using N‐acylph‐thalimides as acyl electrophiles is reported, which gives access to a series of aromatic ketones. The transformation is performable in the presence of water, albeit with decreased reaction yield. The additive CuI was crucial to facilitate the cleavage of C(O)−N bond of imide. This protocol showed broad substrate scope: both alkyl and aryl acyl groups could be installed at the ortho‐position of aryl iodides; alkenes and boronic acids can be used as termination reagents. [ABSTRACT FROM AUTHOR]

Green leaf volatiles (GLVs) are six-carbon volatile oxylipins ubiquitous in vascular plants. GLVs are produced from acyl groups in the biological membranes via oxygenation by a pathway-specific lipoxygenase (LOX) and a subsequent cleavage reaction by hydroperoxide lyase. Because of the universal distribution and ability to form GLVs, they have been anticipated to play a common role in vascular plants. While resting levels in intact plant tissues are low, GLVs are immediately synthesized de novo in response to stresses, such as insect herbivory, that disrupt the cell structure. This rapid GLV burst is one of the fastest responses of plants to cell-damaging stresses; therefore, GLVs are the first plant-derived compounds encountered by organisms that interact with plants irrespective of whether the interaction is competitive or friendly. GLVs should therefore be considered important mediators between plants and organisms that interact with them. GLVs can have direct effects by deterring herbivores and pathogens as well as indirect effects by attracting predators of herbivores, while other plants can recruit them to prepare their defenses in a process called priming. While the beneficial effects provided to plants by GLVs are often less dramatic and even complementary, the buildup of these tiny effects due to the multiple functions of GLVs can amass to levels that become substantially beneficial to plants. This review summarizes the current understanding of the spatiotemporal resolution of GLV biosynthesis and GLV functions and outlines how GLVs support the basic health of plants. [ABSTRACT FROM AUTHOR]

A novel protocol was developed for preparing functionalized chromeno[2,3-b]pyrrol-4(1H)-ones 3 (CMPOs) from 3-formylchromones with N-substituted glycine derivatives. The method entailed decarboxylative annulation of the acyl group of 3-formylchromones by simply heating a mixture of substrates 1–2 and toluene oxidized by 2-di-tert-butyl peroxide (DTBP) and catalyzed by CuBr. As a result, a series of CMPOs 3 were produced via a cascade reaction. This protocol can be used to synthesize functionalized CMPOs via combinatorial and parallel syntheses in a one-pot reaction rather than a tedious multi-step reaction. [ABSTRACT FROM AUTHOR]

Acid catalysis of weakly distorted or undistorted carboxamides in acyl-migration reactions proceeding through N-protonation is a process with low probability, in contrast to O-protonation. This circumstance makes the experimental study of the selective N-protonation path difficult or even impossible. However, such a problem can be solved by means of N-acyl-N,N,N-threemethylnaphtalenediamine (amide proton sponge, AmPS), which was synthesized back in 1999; after protonation, the relatively mobile NH proton of the dimethylamino group and amide nitrogen are in close proximity in this compound that significantly increases the probability of the N-protonation pathway. As was already shown, the noted structural peculiarity leads to remarkably high mobility of the acyl group in AmPS, but the details of this phenomenon were not explored previously. In this regard, a contribution of the N-protonation pathway to the reactivity of AmPS is of particular interest. In this study, for the first time, by means of quantum-chemical calculations, the energetic profiles for the reaction of AmPS with charged and uncharged nucleophiles have been established. A range of the similar AmPSs has been studied and the structural motifs promoting the decay of the amide bond and decreasing the Gibbs activation energy (ΔG‡) for nucleophilic attack have been determined. The most effective ways to achieve the desired effects are the additional withdrawal of the electron density from the amide nitrogen by means of substituents with negative mesomeric effect and a decrease in the steric constraints through aromatic core modification. The strengthening of the intramolecular hydrogen bond by the use of the buttressing effect shows a lesser extent of reduction in ΔG‡. The proposed structural modification of the classic AmPS can facilitate the design of a new acylation agent for practical use. [ABSTRACT FROM AUTHOR]

Unrestricted reproduction and spread of pest had caused great damage to the quality and yield of crops in recent years. Besides the use of traditional chemical pesticides, natural products also make a huge contribution against pests. Chasmanthinine, a diterpenoid alkaloid isolated from Aconitum franchetii var. villosulum, shown extremely antifeedant activity against Spodoptera exigua. Therefore, a series of novel Chasmanthinine derivatives were synthesized and their biological activity was studied in this work. Compound 33 showed the strongest antifeedant activity (EC50 = 0.10 mg/cm2) among all the test compounds. The mechanism research of 33 revealed that its antifeedant effect was related to the inhibition of carboxylesterase (CES), and proved the thiophene acyl group could form a strong binding effect with CES by molecular docking. Moreover, compound 10 exhibited the strongest cytotoxicity (IC50 = 12.87 μM) against Sf9 cell line and moderate contact toxicity. The mechanism research indicated that compound 10 could induce Sf9 cells apoptosis. In summary, the results lay a foundation for the application of diterpene alkaloids in plant protection. [ABSTRACT FROM AUTHOR]

Unrestricted reproduction and spread of pest had caused great damage to the quality and yield of crops in recent years. Besides the use of traditional chemical pesticides, natural products also make a huge contribution against pests. Chasmanthinine, a diterpenoid alkaloid isolated from Aconitum franchetii var. villosulum, shown extremely antifeedant activity against Spodoptera exigua. Therefore, a series of novel Chasmanthinine derivatives were synthesized and their biological activity was studied in this work. Compound 33 showed the strongest antifeedant activity (EC50 = 0.10 mg/cm2) among all the test compounds. The mechanism research of 33 revealed that its antifeedant effect was related to the inhibition of carboxylesterase (CES), and proved the thiophene acyl group could form a strong binding effect with CES by molecular docking. Moreover, compound 10 exhibited the strongest cytotoxicity (IC50 = 12.87 μM) against Sf9 cell line and moderate contact toxicity. The mechanism research indicated that compound 10 could induce Sf9 cells apoptosis. In summary, the results lay a foundation for the application of diterpene alkaloids in plant protection. [ABSTRACT FROM AUTHOR]

DHHC3 belongs to a family of DHHC palmitoyltransferase, which catalyzes the S-palmitoylation of target proteins by attaching a fatty acyl group to a cysteine. Recently, DHHC3 has been demonstrated to be a promising antitumor target in cancer therapeutics. However, the detailed structure and catalysis mechanism of DHHC3 remain elusive, considering its sequence diversity from the DHHC homologs with known crystal structures. Here, we described the expression and purification of human DHHC3 (hDHHC3) and truncated hDHHC3 with the flexible N-terminal domain (NTD) removed. Purified hDHHC3 proteins were used under various conditions for protein crystallization. LAMTOR1, one of the interacting proteins of hDHHC3 to facilitate the crystallization, was further identified by mass spectrometry and co-immunoprecipitation assay. The structural exploration using cryogenic electronic microscopy (cryo-EM) on the inactive hDHHS3 mutant showed a typical sideview of membrane proteins. These results provide a preliminary guidance for the structural determination of DHHC3. [ABSTRACT FROM AUTHOR]

The reaction of sodium ricinoleate with thiophosphoryl trichloride under various conditions was studied. At a high concentration of sodium ricinoleate, thiophosphoryl trichloride reacts primarily with the alcohol OH group, and the isolated compound contains a sodium acyl group, which was confirmed by IR, 1H, 13C, 31P NMR spectroscopy and elemental analysis data. When the salt solution is diluted 5 times, the reaction proceeds by the mechanism of nucleophilic substitution both on the carboxylate and on the alcohol group. According to gel chromatography data, the molecular weight of the reaction product is close to trisubstituted thiophosphate, the composition and structure of which are confirmed by elemental analysis and IR, 1Н, 13С, 31Р NMR spectroscopy and diffractometry data. During chromatography on silica gel, it decomposes, as during hydrolysis in a slightly acidic medium. [ABSTRACT FROM AUTHOR]

Lignocellulose biorefinery depended on effective pretreatment strategies is of great significance for solving the current global crisis of ecosystem and energy security. This study proposes a novel approach combining seawater hydrothermal pretreatment (SHP) and microwave-assisted deep eutectic solvent (MD) pretreatment to achieve an effective fractionation of Pinus massoniana into high value-added products. The results indicated that complex ions (Mg2+, Ca2+, and Cl−) in natural seawater served as Lewis acids and dramatically promoted the depolymerization of mannose and xylan into oligosaccharides with 40.17 % and 75.43 % yields, respectively. Subsequent MD treatment realized a rapid and effective lignin fractionation (~90 %) while retaining cellulose. As a result, the integrated pretreatment yielded ~85 % of enzymatic glucose, indicating an eightfold increase compared with untreated pine. Because of the increased hydrophobicity induced by the formation of acyl groups during MD treatment, uniform lignin nanospheres were successfully recovered from the DES. It exhibited low dispersibility (PDI = 2.23), small molecular weight (1889 g/mol), and excellent oxidation resistance (RSI = 5.94), demonstrating promising applications in functional materials. The mechanism of lignin depolymerization was comprehensively elucidated via FTIR, 2D-HSQC NMR, and GPC analyses. Overall, this study provides a novel and environmentally friendly strategy for lignocellulose biorefinery and lignin valorization. [ABSTRACT FROM AUTHOR]

Rice and quinoa starches are modified with short-chain fatty acids (SCFA) with different SCFA acyl chain lengths and levels of modification. This work is aimed to investigate the impact of modifying rice and quinoa starches with short-chain fatty acids (SCFAs) on various physicochemical properties, including particle size, protein and amylose content, thermal behavior, pasting characteristics, and in vitro digestibility. Both native and SCFA-starches showed comparable particle sizes, with rice starches ranging from 1.58 to 2.22 μm and quinoa starches from 5.18 to 5.72 μm. SCFA modification led to lower protein content in both rice (0.218–0.255 %) and quinoa starches (0.537–0.619 %) compared to their native counterparts. Esterification led to the reduction of gelatinization and pasting temperatures as well as the hardness of the paste of SCFA-starches were reduced while paste clarity increased. The highest level of modification in SCFA-starch was associated with the highest amount of resistant starch fraction. Principal component analysis revealed that modification levels exerted a greater influence on starch properties than the types of SCFA used (acetyl, propionyl, and butyryl). These findings is importance in considering the degree of substitution or level of modification when tailoring starch properties through SCFA modification, with implications for various applications in food applications. [ABSTRACT FROM AUTHOR]

Nanofiltration plays a crucial role in antibiotic desalination from high salinity water, but the membranes often have low water permeability and insufficient selectivity between antibiotics and salts. In this study, a Gemini-type quaternary diethanolamine monomer (QTDEA) containing quaternary ammonium and hydroxyl groups was synthesized. This monomer had a hybrid spatial structure combining both rigid and flexible components, allowing it to covalently graft to the acyl chloride groups on the nascent polyamide (PA) film. The resulting modified PA-QTDEA membrane exhibited enhanced hydrophilicity, reduced negative charge, and a looser structure. It demonstrated a high water permeance of 18.2 L m−2 h−1·bar−1 for chlortetracycline hydrochloride (CTC) desalination from a NaCl solution of 10 g L−1, and the NaCl/CTC selectivity was 21.2. This research presents an efficient method for improving the performance of antibiotic desalination through surface modification using the novel QTDEA monomer. [Display omitted] • Novel Gemini-type monomer QTDEA is synthesized and used for the surface modification. • Grafting is achieved by the esterification of –OH in QTDEA with acyl chloride in TMC. • QTDEA with rigid and flexible hybrid structure increases the pore size of PA film. • Quaternary ammonium in QTDEA reduces membrane charge and Donnan exclusion. • Modified membrane improves both water permeability and antibiotics/salt selectivity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Trisarcglaboids A and B were new family lindenane sesquiterpenoid trimer. • Compound 1 was highly cytotoxic to five human cancer cell lines. • Compound 1 potentially induced apoptosis by blocking Akt phosphorylation. Trisarcglaboids A and B (1 and 2), representing the first example of lindenane sesquiterpenoid trimers repolymerized based on the classical [4 + 2] type dimer, together with known biogenic precursors chlorahololide D (3) and sarcandrolide A (4), were identified as chemical components of the root of Sarcandra glabra. The novel trimeric lindenane sesquiterpenoid skeletons, including their absolute configurations, were characterized using MS, NMR, ECD, and X-ray single crystal diffraction. The proposed Diels-Alder cycloaddition between Δ 2(3) of the tiglic acyl group of the classical [4 + 2] type dimer and Δ 15(4),5(6) of the third lindenane may serve as the key biogenic step. In addition, compound 1 exerted significant cytotoxicity against five human cancer cell lines with IC 50 values ranging from 1 to 7 μM, potentially through blocking Akt phosphorylation and activating the endogenous apoptosis pathway. [ABSTRACT FROM AUTHOR]

Newborn screening (NBS) for metachromatic leukodystrophy (MLD) is based on first-tier measurement of sulfatides in dried blood spots (DBS) followed by second-tier measurement of arylsulfatase A in the same DBS. This approach is very precise with 0–1 false positives per ∼30,000 newborns tested. Recent data reported here shows that the sulfatide molecular species with an α-hydroxyl, 16‑carbon, mono-unsaturated fatty acyl group (16:1-OH-sulfatide) is superior to the original biomarker 16:0-sulfatide in reducing the number of first-tier false positives. This result is consistent across 4 MLD NBS centers. By measuring 16:1-OH-sulfatide alone or together with 16:0-sulfatide, the estimated false positive rate is 0.048% and is reduced essentially to zero with second-tier arylsulfatase A activity assay. The false negative rate is predicted to be extremely low based on the demonstration that 40 out of 40 newborn DBS from clinically-confirmed MLD patients are detected with these methods. The work shows that NBS for MLD is extremely precise and ready for deployment. Furthermore, it can be multiplexed with several other inborn errors of metabolism already tested in NBS centers worldwide. [ABSTRACT FROM AUTHOR]

Chiral amines and alcohols are synthons of numerous pharmaceutically-relevant compounds. The previously developed enzymatic kinetic resolution approaches utilize a chiral racemic molecule and achiral acyl donor (or acyl acceptor). Thus, only one enantiodivergent step of the catalytic cycle is engaged, which does not fully exploit the enzyme's abilities. The first carbonate-mediated example of simultaneous double chemoselective kinetic resolution of chiral amines and alcohols is described. Herein, we established a biocatalytic approach towards four optically-pure compounds (>99% ee, Enantioselectivity: E > 200) via double enzymatic kinetic resolution, engaging chiral organic carbonates as acyl donors. High enantioselectivity was ensured by extraordinary chemoselectivity in lipase-catalyzed formation of unsymmetrical organic carbonates and engaged in a process applicable for the synthesis of enantiopure organic precursors of valuable compounds. This study focused not only on preparative synthesis, but additionally the catalytic mechanism was discussed and the clear impact of this rarely observed carbonate-derived acyl enzyme was shown. The presented protocol is characterized by atom efficiency, acyl donor sustainability, easy acyl group removal, mild reaction conditions, and biocatalyst recyclability, which significantly decreases the cost of the reported process. [ABSTRACT FROM AUTHOR]

Palladium(II) hydroxide on carbon is a catalyst routinely used for the cleavage of O‐benzyl groups by hydrogenolysis to obtain the corresponding parent organic compound. The work described in this article shows that allyl and benzyl phosphates, can be cleaved efficiently and selectively using palladium(II) hydroxide on carbon, under non‐hydrogenolytic and neutral conditions, precluding the migration of acyl groups. The utility of these cleavage reactions for the synthesis of diacylglycerol and phosphatidic acid, containing unsaturation, is demonstrated. These methods have high potential for the synthesis of a variety of phosphates and natural phospholipids. [ABSTRACT FROM AUTHOR]

A new set of cyclopentanone chalcone esters 2,5-bis-(4-alkanoyloxybenzylidene)cyclopentan-1-one (B2-B10) has been synthesized and monitored by TLC. Structures of these compounds were determined by spectroscopic techniques (FTIR, 1H NMR, and mass spectrometry). Differential scanning calorimetry (DSC) and polarized optical microscopy were used to evaluate their transition temperatures and mesophase properties (POM) throughout heating and cooling scans. The thermal data indicate that the compounds B5-B10 have mesomorphic properties with thermal stabilities; the data also reveal that the compounds B6-B10 are monotropic, whereas B5 is enantiotropic. B6, B7, and B9 only have a nematic phase, but B8 and B10 have a smectic phase followed by a nematic phase, and B5 only has a smectic phase. In addition, the study reveals that the inclusion of an acyl group as a terminal chain had the opposite effect on isotropization temperatures for compounds B6, B8, and B10, resulting in an increase in transition temperatures and a decrease in mesophase stability. The lack of a smectic phase in B7 and B9 compounds could be attributed to the narrow phase temperature range, which makes examination difficult, or to the molecules' lack of lateral attraction. [ABSTRACT FROM AUTHOR]

Novel reactive dyes with mono- and bi-acyl fluoride reactive groups have been designed and synthesized, which are obtained by using 2-amino-8-naphthol-6-sulfonic acid or 1-amino-8-naphthol-3,6-disulfonicacid as the coupling component and 4-aminobenzoyl fluoride (PABF) as the diazo component. Their structures have been defined by nuclear magnetic resonance spectroscopy and ultraviolet–visible spectra (UV—Vis). The novel reactive dyes were evaluated on cotton by using the exhaust dyeing method. The properties were examined in detail, and the results showed that the dye concentration of 4% (o.w.f), pH = 9, and salt-free was the most effective condition. The fixation of the novel reactive dyes on cotton was 60.27% and 64.13%, respectively. The micro-fluorine-containing reactive dyes have favorable dyeing properties owing to the covalent bond formed between the reactive group of dyes and the functional group of cotton fibers, which can achieve salt-free dyeing of cotton. [ABSTRACT FROM AUTHOR]

Acyl group migration affects the synthesis, isolation, manipulation and purification of all acylated organic compounds containing free hydroxyl groups, in particular carbohydrates. While several isolated studies on the migration phenomenon in different buffers have been reported, comprehensive insights into the overall migration process in different monosaccharides under similar conditions have been lacking. Here, we have studied the acyl migration in different monosaccharides using five different acyl groups by a combination of experimental, kinetic and theoretical tools. The results show that the anomeric configuration in the monosaccharide has a major influence on the migration rate, together with the relative configurations of the other hydroxyl groups and the nature of the migrating acyl group. Full mechanistic model, based on computations, demonstrates that the acyl migration proceeds through an anionic stepwise mechanism with linear dependence on the [OH−] and the pKa of the hydroxyl group toward which the acyl group is migrating. [ABSTRACT FROM AUTHOR]

Acyl phosphines (R2P–C(O)R) are the tertiary phosphorus compounds having a P–C(O) linkages. Though they are known historically, their literature is not exhaustive mainly due to the vulnerability of P–C(O) bonds toward nucleophilic substitution reactions. However, there is a renewed interest in the synthesis of acyl phosphines and di (acyl) phosphines, recently. Among the methods available for the synthesis, most involve nucleophilic substitutions at carbonyl carbon by phosphorus nucleophile as a customary step. The examples of phosphines possessing two acyl groups (R(O)C–RP–C(O)R) are found more frequently in the literature of late, and most of them are cyclic in nature. The transition‐metal complexes of acyl phosphines and di (acyl) phosphines are moderately explored in literature. However, their catalytic applications are meager. In the current review, the details of syntheses, reactivity, structural features, and catalytic activities of acyl phosphines and bis (acyl) phosphines reported in the last three decades are discussed. [ABSTRACT FROM AUTHOR]

Phloroglucinols of Dryopteris fragrans (L.) Schott plant show strong antifungal activity. In previous work, we isolated a wide range of phloroglucinols from the plant and found that pseudoaspidinol of D. fragrans and its structural modifications (methylphloroglucinol derivatives) showed stronger antifungal activity and confirmed that the butyryl group of these compounds accounted for this activity. In this study, we designed a series of phloroglucinol derivatives (A1–A9) and methylphloroglucinol derivatives (B1–B9) by introducing acyl groups with diverse carbon numbers in the C-2 position, synthesized these compounds, and evaluated the anti-dermatophyte activity of compounds A1–A5 and B1–B5 on Trichophyton rubrum and Trichophyton mentagrophytes fungal species. The results showed that compound A5 exhibited the strongest activity. These compounds can be used as leads for the development of new antifungal agents. [ABSTRACT FROM AUTHOR]

Summary: The metabolic flux of fatty acyl‐CoAs determines lipopeptide biosynthesis efficiency, because acyl donor competition often occurs from polyketide biosynthesis and homologous pathways. We used A40926B0 as a model to investigate this mechanism. The lipopeptide A40926B0 with a fatty acyl group is the active precursor of dalbavancin, which is considered as a new lipoglycopeptide antibiotic. The biosynthetic pathway of fatty acyl‐CoAs in the A40926B0 producer Nonomuraea gerenzanensis L70 was efficiently engineered using endogenous replicon CRISPR (erCRISPR). A polyketide pathway and straight‐chain fatty acid biosynthesis were identified as major competitors in the malonyl‐CoA pool. Therefore, we modified both pathways to concentrate acyl donors for the production of the desired compound. Combined with multiple engineering approaches, including blockage of an acetylation side reaction, overexpression of acetyl‐CoA carboxylase, duplication of the dbv gene cluster and optimization of the fermentation parameters, the final strain produced 702.4 mg l‐1 of A40926B0, a 2.66‐fold increase, and the ratio was increased from 36.2% to 81.5%. Additionally, an efficient erCRISPR‐Cas9 editing system based on an endogenous replicon was specifically developed for L70, which increased conjugation efficiency by 660% and gene‐editing efficiency was up to 90%. Our strategy of redirecting acyl donor metabolic flux can be widely adopted for the metabolic engineering of lipopeptide biosynthesis. [ABSTRACT FROM AUTHOR]

Convergent, late-stage introduction of acylguanidine moieties is a useful strategy for the rapid development of novel compounds containing functionalised guanidines. As such, robust methodology for suitable acylguanidine building blocks is required. Here the synthesis of a range of 2-[2-(tert-butoxycarbonyl)-3-(acyl)- guanidino]ethylamine salts is reported using the reaction of readily prepared acyl substituted S-methylisothioureas with ethylenediamine then conversion of these aminoethylacylguanidines to salts (using HCl or MsOH). A wide range of acyl groups were tolerated, with the desired salts being isolated in good yields (52-86% over two steps). Introduction of one of the new acylguanidine reagents to an organic scaffold was readily accomplished to generate a new antimicrobial agent. [ABSTRACT FROM AUTHOR]

We developed a chiral symmetry breaking method for monoacylated meso diols. The X‐ray crystal structure analysis of monoacylated 1,4‐anhydroerythritols, meso cyclic diols with a cis configuration, revealed that the O‐(p‐anisoyl) derivative crystallized as a racemic conglomerate of the P212121 crystal system. It was confirmed that the substrate racemized by intramolecular transfer of the acyl group in the presence of a catalytic amount of base. Evaporating the solvent gradually from the solution or Viedma ripening to promote crystallization‐induced deracemization efficiently led to enantiomer crystals. These results provide the first successful example of asymmetric expression and amplification by deracemization of sugar derivatives without an external chemical chiral source. Furthermore, we applied this methodology to acyclic meso‐1,2‐diols. Three O‐monoacylated substrates were successfully deracemized to 99 % ee by Viedma ripening. We also developed asymmetric desymmetrization of meso‐1,2‐diols by combining acylation and crystallization‐induced deracemization. [ABSTRACT FROM AUTHOR]

We developed a chiral symmetry breaking method for monoacylated meso diols. The X‐ray crystal structure analysis of monoacylated 1,4‐anhydroerythritols, meso cyclic diols with a cis configuration, revealed that the O‐(p‐anisoyl) derivative crystallized as a racemic conglomerate of the P212121 crystal system. It was confirmed that the substrate racemized by intramolecular transfer of the acyl group in the presence of a catalytic amount of base. Evaporating the solvent gradually from the solution or Viedma ripening to promote crystallization‐induced deracemization efficiently led to enantiomer crystals. These results provide the first successful example of asymmetric expression and amplification by deracemization of sugar derivatives without an external chemical chiral source. Furthermore, we applied this methodology to acyclic meso‐1,2‐diols. Three O‐monoacylated substrates were successfully deracemized to 99 % ee by Viedma ripening. We also developed asymmetric desymmetrization of meso‐1,2‐diols by combining acylation and crystallization‐induced deracemization. [ABSTRACT FROM AUTHOR]

The mitochondrial carnitine/acylcarnitine carrier (CAC) transports short-, medium- and long-carbon chain acylcarnitines across the mitochondrial inner membrane in exchange for carnitine. How CAC recognizes the substrates with various fatty acyl groups, especially long-chain fatty acyl groups, remains unclear. Here, using nuclear magnetic resonance (NMR) technology, we have shown that the CAC protein reconstituted into a micelle system exhibits a typical six transmembrane structure of the mitochondrial carrier family. The chemical shift perturbation patterns of different fatty acylcarnitines suggested that the segment A76–G81 in CAC specifically responds to the long-chain fatty acylcarnitine. Molecular dynamics (MD) simulations of palmitoyl-L-carnitine inside the CAC channel showed the respective interaction and motion of the long-chain acylcarnitine in CAC at the cytosol-open state and matrix-open state. Our data provided a molecular-based understanding of CAC structure and transport mechanism. [ABSTRACT FROM AUTHOR]

Fluorination is a potent method to modulate chemical properties of glycans. Here, we study how C3‐ and C6‐fluorination of glucosyl building blocks influence the structure of the intermediate of the glycosylation reaction, the glycosyl cation. Using a combination of gas‐phase infrared spectroscopy and first‐principles theory, glycosyl cations generated from fluorinated and non‐fluorinated monosaccharides are structurally characterized. The results indicate that neighboring group participation of the C2‐benzoyl protecting group is the dominant structural motif for all building blocks, correlating with the β‐selectivity observed in glycosylation reactions. The infrared signatures indicate that participation of the benzoyl group in enhanced by resonance effects. Participation of remote acyl groups such as Fmoc or benzyl on the other hand is unfavored. The introduction of the less bulky fluorine leads to a change in the conformation of the ring pucker, whereas the structure of the active dioxolenium site remains unchanged. [ABSTRACT FROM AUTHOR]

An immunoadjuvant preparation (named Fraction B) was obtained from the aqueous extract of Quillaja brasiliensis leaves, and further fractionated by consecutive separations with silica flash MPLC and reverse phase HPLC. Two compounds were isolated, and their structures elucidated using a combination of NMR spectroscopy and mass spectrometry. One of these compounds is a previously undescribed triterpene saponin (Qb1), which is an isomer of QS-21, the unique adjuvant saponin employed in human vaccines. The other compound is a triterpene saponin previously isolated from Quillaja saponaria bark, known as S13. The structure of Qb1 consists of a quillaic acid residue substituted with a β-d-Galp-(1→2)-[β-d-Xylp-(1→3)]-β-d-GlcpA trisaccharide at C3, and a β-d-Xylp-(1→4)-α-l-Rhap-(1→2)-[α-l-Arap-(1→3)]-β-d-Fucp moiety at C28. The oligosaccharide at C28 was further substituted at O4 of the fucosyl residue with an acyl group capped with a β-d-Xylp residue. [ABSTRACT FROM AUTHOR]

An efficient and straightforward methodology for the esterification of various N‐heteroarene methanols using benzoyl cyanides as acylating sources through a simply mixing conditions has been reported. The acyl groups were in‐situ generated via chemoselective C–CN bond cleavage to give the N‐heteroarenemethyl esters. This process features in readily accessible starting materials and offers an easy operational procedure, and broad substrate scope with excellent selectivity. [ABSTRACT FROM AUTHOR]

In this paper, chitosan/Fe3O4/graphene oxide hydrogel was synthesized then modified with 2,6-pyridinedicarbonyl dichloride to obtain a novel composite hydrogel. The modified hydrogel formed via interfacial polymerization crosslinking of amino groups of chitosan in chitosan/Fe3O4/graphene oxide hydrogel with acyl groups of 2,6-pyridinedicarbonyl dichloride. The synthesized hydrogels were characterized using different tools such as FT-IR, XRD, TGA, VSM, BET, HR-TEM, and FE-SEM instruments. The successful modification was demonstrated through FE-SEM where sphere and rod shapes were noticed due to the presence of Fe3O4/graphene oxide. The XRD diffraction peaks of the modified hydrogel were close to that of Fe3O4 without any changes in its structure. Also, there are no distinguishing XRD diffraction peaks due to the graphene oxide owing to the disorders that happen in graphene during the formation of the composite. The modified hydrogel was efficiently utilized for removing eriochrome black T and methylene blue dyes from aqueous media. The optimum pH for removing eriochrome black-T and methylene blue dyes is 2 and 8, respectively. Also, the optimum contact time and temperature for removing eriochrome black-T and methylene blue dyes are 140 min and 318 K, respectively. The maximum adsorption capacity of the modified hydrogel toward eriochrome black T and methylene blue dyes is 289.85 and 261.78 mg/g, respectively. The equilibrium and kinetic results were best fitted to the Langmuir isotherm and pseudo-second-order. The thermodynamic results confirmed that the adsorption process was spontaneous and endothermic. [ABSTRACT FROM AUTHOR]

Glycosphingolipids (GSLs) are a subclass of glycolipids made of a glycan and a ceramide that, in turn, is composed of a sphingoid base moiety and a fatty acyl group. GSLs represent the vast majority of glycolipids in eukaryotes, and as an essential component of the cell membrane, they play an important role in many biological and pathological processes. Therefore, they are useful targets for the development of novel diagnostic and therapeutic methods for human diseases. Since sphingosine was first described by J. L. Thudichum in 1884, several hundred GSL species, not including their diverse lipid forms that can further amplify the number of individual GSLs by many folds, have been isolated from natural sources and structurally characterized. This review tries to provide a comprehensive survey of the major GSL species, especially those with distinct glycan structures and modification patterns, and the ceramides with unique modifications of the lipid chains, that have been discovered to date. In particular, this review is focused on GSLs from eukaryotic species. This review has listed 251 GSL glycans with different linkages, 127 glycans with unique modifications, 46 sphingoids, and 43 fatty acyl groups. It should be helpful for scientists who are interested in GSLs, from isolation and structural analyses to chemical and enzymatic syntheses, as well as their biological studies and applications. [ABSTRACT FROM AUTHOR]

Acyl migration of alkyl and aromatic acyl groups from an alcohol to another alcohol or amine is a phenomenon that occurs in nature and can be a bane to some synthetic strategies. An acyl migration-dependent method was developed for the synthesis of ceramide and glucosyl ceramide derivatives, in which the desired fatty acyl moiety acts both as protecting and migrating group. Removal of the tetrachlorophthalimido (TCP) group with ethylenediamine as a mild base at room temperature resulted in subsequent intramolecular fatty acyl group migration from –O to –N, on sphingosine or per acetylated glucosyl sphingosine to yield the desired N-acylated products. Deacetylation reaction afforded the desired β-O-glucosylceramide derivatives. Thus, choice of the appropriate blocking group turns acyl migration into a tool for synthesis, rather than an impediment. [ABSTRACT FROM AUTHOR]

S-acylation, also known as palmitoylation, is the most abundant form of protein lipidation in humans. This reversible posttranslational modification, which targets thousands of proteins, is catalyzed by 23 members of the DHHC family of integral membrane enzymes. DHHC enzymes use fatty acyl-CoA as the ubiquitous fatty acyl donor and become autoacylated at a catalytic cysteine; this intermediate subsequently transfers the fatty acyl group to a cysteine in the target protein. Protein S-acylation intersects with almost all areas of human physiology, and several DHHC enzymes are considered as possible therapeutic targets against diseases such as cancer. These efforts would greatly benefit from a detailed understanding of the molecular basis for this crucial enzymatic reaction. Here, we combine X-ray crystallography with all-atom molecular dynamics simulations to elucidate the structure of the precatalytic complex of human DHHC20 in complex with palmitoyl CoA. The resulting structure reveals that the fatty acyl chain inserts into a hydrophobic pocket within the transmembrane spanning region of the protein, whereas the CoA headgroup is recognized by the cytosolic domain through polar and ionic interactions. Biochemical experiments corroborate the predictions from our structural model. We show, using both computational and experimental analyses, that palmitoyl CoA acts as a bivalent ligand where the interaction of the DHHC enzyme with both the fatty acyl chain and the CoA headgroup is important for catalytic chemistry to proceed. This bivalency explains how, in the presence of high concentrations of free CoA under physiological conditions, DHHC enzymes can efficiently use palmitoyl CoA as a substrate for autoacylation. [ABSTRACT FROM AUTHOR]

The stereoselective introduction of the glycosidic bond remains one of the main challenges in carbohydrate synthesis. Characterizing the reactive intermediates of this reaction is key to develop stereoselective glycosylation reactions. Herein we report the characterization of low‐populated, rapidly equilibrating mannosyl dioxanium ions that arise from participation of a C‐3 acyl group using chemical exchange saturation transfer (CEST) NMR spectroscopy. Dioxanium ion structure and equilibration kinetics were measured under relevant glycosylation conditions and highly α‐selective couplings were observed suggesting glycosylation took place via this elusive intermediate. [ABSTRACT FROM AUTHOR]

Acyltransferases (ATs) are important tailoring enzymes that contribute to the diversity of natural products. They catalyze the transfer of acyl groups to the skeleton, which improves the lipid solubility, stability, and pharmacological activity of natural compounds. In recent years, a number of ATs have been isolated from plants. In this review, we have summarized 141 biochemically characterized ATs during the period July 1997 to October 2020, including their function, heterologous expression systems, and catalytic mechanisms. Their catalytic performance and application potential has been further discussed. [ABSTRACT FROM AUTHOR]

Creating a gradient structure in a separation layer is an effective approach for enhancing separation performance of thin film composite membranes. Here we present the preparation of a positively charged nanofiltration membrane with a gradient structure. An inner layer consisting of a loose polyester separation layer with large pores was formed through the interfacial polymerization (IP) reaction between triethanolamine (TEA) and trimesoyl chloride (TMC). And a dense and thin top layer composed of a polyamide separation layer was obtained by secondary interfacial polymerization (SIP) reaction using polyethyleneimine (PEI) along with unreacted TMC and residual acyl chloride groups of IP reaction. The influences of TEA concentration, PEI concentration and SIP time on the physicochemical properties and separation performances of the membrane were systematically analyzed. Our results show that the presence of the gradient structure optimized mass transfer pathways and reduced mass transfer resistance, resulting in significantly improved permeability of 13.0 ± 0.5 L·m−2·h−1·bar−1 (over 3 times compared with control-PEI), high MgCl 2 rejection of 91.7 ± 0.6 %, and an excellent stability and anti-fouling performance. Our work provides valuable insights and guidance for developing high-performance positively charged NF membrane with gradient structures. • A positively charged nanofiltration membrane with gradient structure was designed and obtained. • The gradient structure significantly improves the permeability of the nanofiltration membrane (over 3 times). • The T0.2-P0.5–10 membrane exhibits excellent stability and anti-fouling performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Solvent-free and scalable food-grade KOP proliposomes are formulated with glycerol. • Glycerol in proliposomes unpacked the stacked chain acyl of phospholipids. • Hydration of proliposomes yielded stable multilayer nanoliposomes. • Nanoliposome formation remained stable during storage and environmental stresses. • Proliposomes enhanced in vitro bioaccessibility of phospholipids. This study presents a novel approach using polyol-based proliposome to produce marine phospholipids nanoliposomes. Proliposomes were formulated by blending glycerol with phospholipids across varying mass ratios (2:1 to 1:10) at room temperature. Analysis employing polarized light microscopy, FTIR, and DSC revealed that glycerol disrupted the stacked acyl groups within phospholipids, lowering the phase transition temperature (T m). Krill oil phospholipids (KOP) proliposomes exhibited superior performance in nanoliposomes formation, with a mean diameter of 125.60 ± 3.97 nm, attributed to the decreased T m (−7.64 and 7.00 °C) compared to soybean phospholipids, along with a correspondingly higher absolute zeta potential (−39.77 ± 1.18 mV). The resulting KOP proliposomes demonstrated liposomes formation stability over six months and under various environmental stresses (dilution, thermal, ionic strength, pH), coupled with in vitro absorption exceeding 90 %. This investigation elucidates the mechanism behind glycerol-formulated proliposomes and proposes innovative strategies for scalable, solvent-free nanoliposome production with implications for functional foods and pharmaceutical applications. [ABSTRACT FROM AUTHOR]

Due to the relatively low reactivity of hydroxyls with acyl chloride groups, the synthesized polyester (PE) membranes commonly have loose structures, only capable of removing large-molecule organics with low rejection of inorganic salts. In this study, the pore size reduction of the synthesized PE membrane was successfully achieved by optimizing the interfacial polymerization (IP) reaction between erythritol and trimesoyl chloride (TMC). The optimized membrane was able to maintain a high xylose rejection (∼60 %) and acceptable water permeance (7.85 L m−2 h−1 bar−1), which was suitable for drinking water treatment. Through comprehensive characterizations, a two-stage membrane formation process was demonstrated regarding the reaction between aqueous monomers with different reactive functional groups and TMC. The highly reactive primary hydroxyls more preferentially participated in the initial reaction stage, leading to a linear cross-linking pattern of polyester. When the molecular diffusion was inhibited, the participation of secondary hydroxyls made the reaction proceed toward partial or full cross-linking. The distinct roles of the two kinds of hydroxyl groups were further verified by the energy barrier differences obtained by density functional theory (DFT) calculation. The exploration of membrane-optimized preparation and formation mechanisms can promote the structural regulation and tailored synthesis of PE membranes for various applications. [Display omitted] • PE membrane preparation based on erythritol and TMC monomers was optimized. • High rejection capacity for small organic solutes was achieved by the PE membranes. • Membrane formation mechanisms were revealed by comprehensive characterizations. • A two-stage polymerization process was proposed and verified by DFT calculation. [ABSTRACT FROM AUTHOR]

Bighead carp head soup is a traditional Chinese cuisine with a pleasant aroma, but the effect of fish head phospholipids (FPLs) on the odorants is not fully understood. In this study, nuclear magnetic resonance (NMR), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and headspace solid-phase microextraction gas chromatography–mass spectrometry (HS-SPME–GC–MS) were used to monitor the oxidation products of phospholipids in fish head soup during the cooking process, and the fish head triglycerides (FTGs) were used as controls. In 1H NMR spectra, the signals of unsaturated acyl groups and the oxidation compounds in FPLs were significantly higher than those in FTGs. The results of FTIR showed that the changes of functional group absorptions of the oxidation compounds in FPLs were greater than FTGs. GC–MS demonstrated that FPLs samples produced more lipid-derived volatile compounds than FTGs samples. These results showed that FPLs were more prone to oxidation and could produce more lipid-derived odorants. Therefore, FPLs rather than FTGs, were the main precursor substance of lipid-derived odorants in bighead carp head soup. • NMR, ATR-FTIR and HS-SPME–GC–MS used to monitor phospholipid oxidation in fish head soup. • Unsaturated acyl groups and oxidation compounds in FPLs higher than those in FTGs. • FPLs samples produced more lipid-derived volatile compounds than FTGs samples. • FPLs were the main precursors of lipid-derived odorants in bighead carp head soup. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel HDACi were synthesized using a one-pot multi-component protocol as key step. • Compounds 8k and 8m were identified as highly selective HDAC6 inhibitors. • 8k and 8m showed significant inhibition of LPS-induced IL1B mRNA expression. Histone deacetylases (HDACs) are a class of enzymes that cleave acyl groups from lysine residues of histone and non-histone proteins. There are 18 human HDAC isoforms with different cellular targets and functions. Among them, HDAC6 was found to be overexpressed in different types of cancer. However, when used in monotherapy, HDAC6 inhibition by selective inhibitors fails to show pronounced anti-cancer effects. The HDAC6 enzyme also addresses non-histone proteins like α-tubulin and cortactin, making it important for cell migration and angiogenesis. Recently, the NLRP3 inflammasome was identified as an important regulator of inflammation and immune responses and, importantly, HDAC6 is critically involved the activation of the inflammasome. We herein report the design, synthesis and biological evaluation of a library of selective HDAC6 inhibitors. Starting from the previously published crystal structure of MAIP-032 in complex with CD2 of zHDAC6, we performed docking studies to evaluate additional possible interactions of the cap group with the L1-loop pocket. Based on the results we synthesized 13 novel HDAC6 inhibitors via the Groebke - Blackburn - Bienaymé three component reaction as the key step. Compounds 8k (HDAC1 IC 50 : 5.87 μM; HDAC6 IC 50 : 0.024 μM; selectivity factor (SF1/6): 245) and 8m (HDAC1 IC 50 : 3.07 μM; HDAC6 IC 50 : 0.026 μM; SF1/6: 118) emerged as the most potent and selective inhibitors of HDAC6 and outperformed the lead structure MAIP-032 (HDAC1 IC 50 : 2.20 μM; HDAC6 IC 50 : 0.058 μM; SF1/6: 38) both in terms of inhibitory potency and selectivity. Subsequent immunoblot analysis confirmed the high selectivity of 8k and 8m for HDAC6 in a cellular environment. While neither 8k and 8m nor the selectivity HDAC6 inhibitor tubastatin A showed antiproliferative effects in the U-87 MG glioblastoma cell line, compound 8m attenuated cell migration significantly in wound healing assays in U-87 MG cells. Moreover, in macrophages compounds 8k and 8m demonstrated significant inhibition of LPS-induced IL1B mRNA expression and TNF release. These findings suggest that our imidazo[1,2- a ]pyridine-capped HDAC6 inhibitors may serve as promising candidates for the development of drugs to effectively treat NLRP3 inflammasome-driven inflammatory diseases. [ABSTRACT FROM AUTHOR]

Surface lipids in plants include cutin, cuticular wax and suberin. sn -Glycerol-3-phosphate acyltransferases (GPATs) facilitate the acylation of sn -glycerol-3-phosphate (G3P) utilizing a fatty acyl group from acyl-coenzyme A (acyl-CoA) or acyl-acyl carrier protein (acyl-ACP) as substrates for the biosynthesis of plant extracellular lipids such as suberin and cutin. Here we found that Arabidopsis GPAT4 and GPAT8 are specifically expressed in endodermis cells of roots where suberin was accumulated. GPAT4 mutation significantly decreased the amounts of the C16 and C18 ω-oxidized suberin monomers, whereas the mutation of GPAT8 had little effect on the suberin production, and the functions of both were not redundant. Root suberin phenotype analysis of gpat4–1 and gpat6–1 single or double mutant revealed that GPAT4 and GPAT6 play redundant functions. Interestingly, the gpat4–1 gpat8–1 double mutant displayed a glossy stem phenotype since fewer wax crystals were accumulated. This phenotype was not shown in either parent. Further study showed that the amounts of most wax components were significantly decreased. Taken together, our findings revealed that GPAT4 has an additive effect with GPAT6 in the root suberin biosynthesis, and plays a redundant role in wax production with GPAT8. • GPAT4, expressed in root endodermis cells, contributes to C16/18 ω-oxidized suberin monomers formation in roots. • GPAT4 and GPAT6 are functionally redundant in the synthesis of root suberin. • GPAT4 and GPAT8 redundantly affect wax biosynthesis. [ABSTRACT FROM AUTHOR]

Glycosyl halides are historically one of the first glycosyl donors used in glycosylation reactions, and interest in glycosylation reactions involving this class of glycosyl donors is currently increasing. New methods for their activation have been proposed and effective syntheses of oligosaccharides with their participation have been developed. At the same time, the possibilities of using these approaches to the synthesis of sialosides are restricted by the limited diversity of known sialyl halides (previously, mainly sialyl chlorides, less often sialyl bromides and sialyl fluorides, with acetyl (Ac) groups at the oxygen atoms and AcNH, Ac 2 N and N 3 groups at C-5 were used). This work describes the synthesis of six new N -acetyl- and N -trifluoroacetyl-sialyl chlorides and bromides with O -chloroacetyl and O -trifluoroacetyl protective groups. Preparation of N , O -trifluoroacetyl protected derivatives was made possible due to development of the synthesis of sialic acid methyl ester pentaol with N -trifluoroacetyl group. [Display omitted] • New sialyl donors with different N - and O -acyl protective groups were prepared. • Six new N -acetyl and N -trifluoroacetyl sialyl chlorides and bromides were prepared. • Pure sialic acid methyl ester pentaol with N -trifluoroacetyl group was prepared. • Anomeric configuration was established by measuring 3 J C-1,H-3ax coupling constants. • Direct exchange of N -acetyl group with N -trifluoroacetyl group was studied. [ABSTRACT FROM AUTHOR]

Microbial fatty acid-producing strains are commonly engineered to improve their performance for industrial applications. However, it is challenging to efficiently and rapidly screen target strains for engineering. This study reported an in situ analytical platform using laser ablation electrospray ionization mass spectrometry (LAESI-MS) for fast profiling of triacylglycerols in cellular lipid droplets of Aurantiochytrium sp. colonies cultured on agar plates. LAESI-MS approach allowed for the direct acquisition of a colony cell's characteristic fingerprint mass spectrum and MS/MS facilitated the identification of triacylglycerol species containing three fatty acyl groups. The fatty acid contents of colony cells were calculated based on the intensities of triacylglycerols from their characteristic fingerprint mass spectrum. A Python package called TAFA-LEMS (Triacylglycerol to Fatty Acid by LAESI-MS) was also developed to process the high-throughput MS data and extract fatty acid contents in colony cells. The results demonstrated that the LAESI-MS platform is fast, stable, and reproducible, with a data acquisition rate of ≤2 s per sampling point and ≤13.69% RSDs of the relative contents of fatty acids. In addition, LAESI-MS was successfully performed on the analysis of P. tricornutum and Y lipolytica strains. This in situ MS platform has the potential to become a common biotechnology platform for microbial strain engineering. [Display omitted] • A high-throughput screening platform for fatty acid-producing strains. • A Python package for the rapid processing of MS data. • This platform exhibited high stability, speed, and reproducibility. • It can serve as the common platform for breeding engineering strains. [ABSTRACT FROM AUTHOR]

A formal carbene insertion into C(O)–S bonds to access α-quaternary pyridines was achieved via a rhodium(II)-catalyzed in situ formation of sulfonium ylides from pyridotriazoles with thioesters followed by acyl group migration. This protocol has enabled an efficient denitrogenative gem-acylthiolation of pyridotriazoles to incorporate an acyl, pyridyl, and sulfur-substituted quaternary carbon center with high selectivity, broad substrate scope, and good functional group tolerance. [ABSTRACT FROM AUTHOR]