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A racemic cyclopentannulated pyrrolidine derivative was synthesized utilizing ruthenium oxidation and borane reduction as the key steps. Ruthenium oxidation reaction of the 1,2-dibromoalkene moiety in an N-Boc-protected tetrabromonorbornyl derivative afforded a tricyclic α-hydroxy ketone, which on alkaline hydrogen peroxide cleavage furnished a bicyclic lactam in excellent yield. Borane reduction of the N-Boc-protected bicyclic lactam gave an unexpected product as a single diastereomer resulting from the reduction of not only the lactam and ester moieties but also the ketal to the corresponding methyl ether. A plausible mechanism involving an oxocarbenium ion is discussed. [ABSTRACT FROM AUTHOR]

Efficient reduction of mono- and disubstituted norbornyl a-diketones with zinc in [bmimBF4]:[H2O] to afford the corresponding acyloins in excellent yields and diastereoselectivities is described. In case of the monosubstituted norbornyl α-diketones, very high regioselectivities ranging from 90:10 to 100:0, in favor of diastereomer possessing endo-hydroxyl diagonal to endo-substituent were observed. [ABSTRACT FROM AUTHOR]

Abstract: Nucleophilic racemic amines have been synthesized utilizing a C7nC5x free-radical cascade reaction from a bis-allyl amine starting material. Being potentially useful organocatalytic bases as is evident from their screening in the Baylis–Hillman reaction, optically pure amines were also synthesized from optically pure aldehydes (−) or (+)-4. Bis-allyl amides under similar radical reaction condition resulted in C7n cyclized products. [Copyright &y& Elsevier]

Examines the method for easy access to γ-lactone-fused cyclopentanoids. Use of lead and alkaline to cleave the tricyclic α-keto hemiacetals; Elaboration of α-keto hemiacetal 3b to spiroepoxide derivative; Transformation of α-halo ester moiety.

Tyrosinase is a copper‐containing enzyme involved in the biosynthesis of melanin pigment. While the excess production of melanin causes hyperpigmentation of human skin, hypopigmentation results in medical conditions like vitiligo. Tyrosinase inhibitors could be used as efficient skin whitening agents and tyrosinase agonists could be used for enhanced melanin synthesis and skin protection from UV exposure. Among a wide range of tyrosinase‐regulating compounds, natural and synthetic derivatives of furochromenones, such as 8‐methoxypsoralen (8‐MOP), are known to both activate and inhibit tyrosinase. We recently reported a synthetic approach to generate a variety of dihydrofuro[3,2‐c]chromenones and furo[3,2‐c]chromenones in a metal‐free condition. In the present study, we investigated these compounds for their potential as antagonists or agonists of tyrosinase. Using fungal tyrosinase‐based in vitro biochemical assay, we obtained one compound (3k) which could inhibit tyrosinase activity, and the other compound (4f) that stimulated tyrosinase activity. The kinetic studies revealed that compound 3k caused 'mixed' type tyrosinase inhibition and 4f stimulated the catalytic efficiency. Studying the mechanisms of these compounds may provide a basis for the development of new effective tyrosinase inhibitors or activators. [ABSTRACT FROM AUTHOR]

Alkyl enol ethers (AEE) are versatile synthetic intermediates with a unique reactivity pattern. This review article summarizes the synthesis of AEE as well as its reactivity and how enol ether undergoes intermolecular reactions for various bond formation, leading to the construction of several useful organic molecules. The synthetic applications of alkyl enol ethers towards intermolecular bond‐forming reactions include metal‐catalyzed reactions, cycloaddition and heterocycle formation as well as rwactions in the field of natural products synthesis. The achievement of these impressive transformations prove the countless synthetic potential of AEE. The main objective of this review is to bring attentiveness among synthetic chemists to show how AEE extensively can be used to react with both electrophiles as well as nucleophiles, thereby behaving as an ambiphilic reactant. We trust that the unique reactivity pattern of alkyl enol ethers and the fundamental mechanistic idea can attract chemists in AEE chemistry. Exclusively, intermolecular reactions of AEE with other functionalized moieties have not been reviewed to the best of our knowledge. [ABSTRACT FROM AUTHOR]

• Total synthesis of (±) aspidostomide B, C and regioisomeric N -methyl aspidostomide is reported. • An unusual Lewis acid-mediated regioselective epoxide opening is described. • Aspidostomide B, C was achieved in six steps with overall yields of 54.7 and 59.0% respectively. A full account of the total synthesis of aspidostomide B, C, their analogues and our synthetic efforts towards the synthesis of aspidostomide D, which led to the synthesis of regioisomeric N -methyl aspidostomide D, its analogues via epoxide opening strategy is presented. The synthesis of regioisomeric N -methyl aspidostomide D involves an efficient, five-step sequence, with 36.3% overall yield, starting from 3,4,5-tribromo-1H-pyrrole-2-carboxylic acid. The key features of this protocol are intramolecular cyclization, dehydration, oxidation, and a Lewis acid-mediated regioselective epoxide ring opening by C-3 position of 2,5-dibromo-1H-indole to furnish the title compounds. [ABSTRACT FROM AUTHOR]

Background: This study compared urinary and serum nerve growth factor levels and serum C-reactive protein levels in patients with overactive bladder, before and after treatment with antimuscarinic agents, to evaluate their diagnostic and therapeutic importance. Methods: This was a prospective case-control study conducted between February 2014 and December 2014 which included patients with a confirmed diagnosis of overactive bladder (overactive bladder group) and healthy controls (control group). All patients visiting urology out-patient department with urgency, frequency, and urge incontinence were assessed for overactive bladder and, if eligible, were enrolled in the study. Biomarkers were evaluated before in both groups and after antimuscarinic treatment in the overactive bladder group. Results: Overall, 80 participates were enrolled (overactive bladder, n = 40; control, n = 40). The mean age was not different between the two groups (overactive bladder, 48.6 years; control, 46.9 years [ P = 1.01]) and females were more in both the groups (60% and 55%, respectively). The majority (70%) of patients presented with frequency and urgency. After 3 months of treatment with antimuscarinics, the mean overactive bladder symptom score decreased significantly from 8.4 to 4.85 (P <.001). The mean urinary and serum nerve growth factor levels and serum C-reactive protein levels also decreased significantly from baseline after 3 months of treatment with antimuscarinics (24.78 pg/mL, 22.46 pg/mL, 0.89 mg/L, respectively; P <.0001). Conclusions: Measurement of urinary and serum nerve growth factor levels has diagnostic and therapeutic potential in patients with overactive bladder. [ABSTRACT FROM AUTHOR]

The first total synthesis of enisorine D, a natural product isolated from the marine sponge Iotrochota cf. iota , is described in 64% overall yield. The target molecule, which is an inhibitor of T3SS-dependent Yope secretion of Y. pseudotuberculosis , is achieved in seven linear steps from tyramine via simple and effective transformations that include bromination, acylation, alkylation, azidation, reduction and routine acid–amine coupling. A total of sixteen analogues are prepared by coupling with eight different cinnamic acids, two bromopyrrole carboxylic acids, five phenyl carboxylic acids and picolinic acid. [ABSTRACT FROM AUTHOR]

A general and catalyst-free protocol for the synthesis of pyrido-oxazepine-3-ols and benzo-oxazin-2-yl methanol via tandem epoxide opening followed by S N Ar reactions is reported. Oxirane derived from tribromopyridine undergoes epoxide opening followed by the S N Ar reaction, yielding seven-membered pyrido-oxazepine-3-ols. Predominantly 2-cyclized pyrido-oxazepine-3-ols observed in this reaction. Oxirane derived from tribromonitrobenzene undergoes epoxide opening followed by S N Ar reaction to produce six-membered benzo-oxazin-2-yl methanol. When oxirane treated with primary amine, mainly 2-cyclized benzo-oxazin-2-yl methanol is formed. furthermore, treatment of oxirane with secondary amine result in regio-selective 4-cyclized benzo-oxazin-2-yl methanol, accompanied by de-alkylation. A plausible reaction mechanism is proposed for the synthesis of benzo-oxazin-2-yl methanol, which proceeds via epoxide opening followed by a Smiles rearrangement. [Display omitted] [ABSTRACT FROM AUTHOR]

An abstract of the article "Aromaticity Driven 1,6-Conjugate Addition of Amines and Phenols to Cyclohexadienone Derivative" by Kaki Raveendra Babu and colleagues is presented.

The title isomerizations of the substrates having disubstitution at benzylic position give different products depending on the nature of the substitution. [ABSTRACT FROM AUTHOR]

This unusual dimerization of substrates (I) proceeds via a dehydrohalogenation/1,6-conjugate addition/aromatization sequence. [ABSTRACT FROM AUTHOR]

We describe here the acid-catalysed reaction of anilines with activated indanol using the inexpensive catalyst p-toluenesulfonic acid (p-TSA). Various electron-donating as well as electron-withdrawing anilines are reacted with activated indanol. The reaction mechanism suggests the in-situ formation of a p-quinomethoxy methide intermediate, followed by the nucleophilic attack of the substituted or unsubstituted anilines. [ABSTRACT FROM AUTHOR]

Synthesis of brominated marine natural product amathamide F is described. Various strategies to construct the enamide functionality required for its synthesis have been explored. Finally, we succeeded in constructing the enamide moiety under a palladium-catalyzed condition. Facile transformation of 2,3,4-tribromo-5-methoxybenzaldehyde to the reported structure of amathamide F involved initial one-carbon-elongation of the aldehyde group followed by its conversion to corresponding enol acetate derivative prior to crucial Pd(II)-catalyzed cross-coupling with ( S )-1-methylpyrrolidine-2-carboxamide. However, due to nonconformity of its NMR spectral data to that of the reported natural isolate, we have confirmed its actual structure through a synthesis. [ABSTRACT FROM AUTHOR]

Curcumin, a popular herbal medicine derived from turmeric, blocks the synthesis of prostaglandins by inhibiting Cyclooxygenase-1 and 2 (COX-1 and COX2). We have recently reported an efficient method of synthesizing curcumin and synthesised analogues. In the present study, we have investigated sixteen novel analogues of curcumin for their ability to inhibit COX-1 and COX-2. We report here that most of the curcumin analogues display selective inhibition of COX-2, whereas a few suppress COX-1 activity. Further, we examined the binding of these inhibitors by molecular docking and observed that the compound with pronounced selectivity for COX-2 displayed better binding to COX-2 compared to curcumin. [Display omitted] [ABSTRACT FROM AUTHOR]

The mammalian AlkB homologue-3 (AlkBH3) is a member of the dioxygenase family of enzymes that in humans is involved in DNA dealkylation repair. Because of its role in promoting tumor cell proliferation and metastasis of cancer, extensive efforts are being directed in developing selective inhibitors for AlkBH3. Here we report synthesis, screening and evaluation of panel of arylated indenone derivatives as new class of inhibitors of AlkBH3 DNA repair activity. An efficient synthesis of 2,3-diaryl indenones from 2,3-dibromo indenones was achieved via Suzuki-Miyaura cross-coupling. Using a robust quantitative assay, we have obtained an AlkBH3 inhibitor that display specific binding and competitive mode of inhibition against DNA substrate. Finally, we established that this compound could prevent the proliferation of lung cancer cell line and enhance sensitivity to DNA damaging alkylating agent. [ABSTRACT FROM AUTHOR]

A regioselective synthesis of carbazole analogs belonging to both the categories of natural origin, viz., microorganisms and higher plant source is reported. The synthesis of carbazole derivatives possessing a methylester group at C-1 position has been achieved by Cadogan cyclization of nitro bi-phenyl derivatives, whereas, the carbazole analog possessing a methylester group at C-3 position was synthesized by Buchwald–Hartwig Pd-catalyzed cyclization of amino bi-phenyl derivatives. Suitably substituted bi-phenyl precursors were accessed from norbornyl α-diketones via Grob fragmentation, O-methylation and DBU aromatization reaction sequence. The reported carbazole derivatives possess structural features that are common with many carbazole natural products: mukonine, clausine-L, murrayafoline-A, and their sibling natural products. [ABSTRACT FROM AUTHOR]

A short and generally applicable synthesis of bioactive tetracyclic natural product paracaseolide A has been accomplished employing a ‘proposed’ biomimetic Diels–Alder reaction as the key strategic step. The Diels–Alder precursors for this purpose were readily assembled through a versatile Suzuki coupling on preformed α-halo butenolides. The mechanistic aspects of the ‘putative’ biomimetic Diels–Alder reaction have been probed using computational methods, which suggest that this [4+2]-cycloaddition proceeds through a step-wise process and product profile is thermodynamically governed. [ABSTRACT FROM AUTHOR]

[Display omitted] Marine sponges of the genus Suberea produce variety of brominated tyrosine alkaloids which display diverse range of biological activities including antiproliferative, antimicrobial and antimalarial activities. In continuation of our search for biologically active marine natural products for antibacterial compounds, we report here the synthesis and evaluation of biological activity of panel of ianthelliformisamines and subereamine analogues using the literature known acid-amine coupling reaction. Several derivatives of Ianthelliformisamine were achieved by the coupling of Boc-protected polyamine chain with brominated aromatic acrylic acid derivatives by varying the bromine substituents on aromatic acid derivatives, amine spacer as well as geometry of the double bond, and then Boc-deprotection using TFA. Similarly, subereamine analogues were also synthesized employing coupling reaction between various brominated phenyl acrylic acids with commercially available chiral amino ester derivatives followed by ester hydrolysis. We screened these synthetic analogues for antibacterial activity against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) strains. One of the compound 7c showed bactericidal activity against Staphylococcus aureus with an IC 50 value of 3.8 μM (MIC = 25 μM). [ABSTRACT FROM AUTHOR]

The first biomimetic and concise racemic total syntheses of renifolin F and antiarone K, accomplished in 8 and 7 linear steps, respectively, are presented in this article. Our synthetic approach commences with substituted aldehydes to produce prenylated aldol products followed by ene-type intramolecular cyclization affording a five-member core ring. This key step mediated by InCl 3 ·4H 2 O is a novel procedure first utilized in prenylated systems which directly culminates mainly into tertiary alcohols.

Herein, DFT studies corroborating experimental results revealed that the shortest intramolecular hydrogen bonding distance of cis/trans-oxaphosphetane (OPA) oxygen with the CH-hydrogen of a triphenylphosphine phenyl ring provides good evidence for the attained olefin Z/E-selectivity in Wittig olefination of the studied examples. 2-Nitrobenzaldehyde, 3-nitrobenzaldehyde, 2-nitro-3-bromobenzaldehyde, 2-nitro-5-bromobenzaldehyde and 2-nitro-5-arylbenzaldehydes provided Z-nitrostilbenes with (2-chloro-4-hydroxy-3-methoxy-5-(methoxycarbonyl)benzyl) triphenylphosphonium chloride as the major products. However, 4-nitrobenzaldehyde and 2-nitro-6-bromobenzaldehydes furnished E-nitrostilbenes as the major products in high yields. Furthermore, the DFT computed intramolecular CH1/CH2-hydrogen bond distances with Cl/NO 2 of selected stilbene derivatives were in good agreement with intramolecular hydrogen bond distances measured from single-crystal X-ray diffraction measurements., (© 2023 The Authors. ChemistryOpen published by Wiley-VCH GmbH.)

Herein, we report a novel and unexpected metal-free oxygenation of 2,3-diphenyl-1-indenones, under an oxygen atmosphere (air), to either 2,3-epoxy-2,3-diphenyl-1-indenone or 2-hydroxy-2,3-diphenyl-1-indanone, depending on the conditions. Several bioactive epoxy indenones and one-pot α-hydroxy indanones (α-acyloin) were synthesized from 2,3-diaryl dihydroindanone and 2,3-diarylindenone, respectively. A plausible reaction mechanism is also proposed, where oxygenation would take place at the α-position and further proton abstraction from the β-position leads to epoxy indenone derivatives. A one-pot cis -hydroxy indanone protocol is also achieved directly from biaryl indenone via reduction, epimerization, and oxygenation. The synthesized compounds were evaluated for inhibitory activity against the DNA repair protein AlkB. Among the screened (17 tested) compounds, one epoxide derivative was found to be a specific inhibitor of AlkB enzyme function.

Introduction: We share our experience of managing 15 cases of forgotten double-J (DJ) stent in our tertiary care center., Methods: This is a retrospective analysis of cases with forgotten DJ stent for a period of 2 years spanning from January 2017 to January 2019. The details included sex, age, literacy, socioeconomic status, stenting indication, duration of indwelling stent, presenting complaints, type of encrustations, various treatments given, intraoperative complications, and their management and eventual outcome., Results: The male-to-female ratio was 2:1, and the mean age was 39.5 years (17-65). The mean indwelling time was 31.7 months. The majority of patients had an education score of 1 out of 7 and belonged to lower socioeconomic class according to the modified Kuppuswamy scale. The most common presentation was irritative voiding symptom. The complicated and heavily encrusted stents were managed by combination of endourological procedures, and procedures were staged whenever deemed necessary. Majority of the stents were removed with simple retrograde cystoscopic removal. There was no mortality in our study., Conclusions: A forgotten DJ stent affects population having low education score and belonging to the lower end of the socioeconomic class. Endourological procedures are quite successful in managing a forgotten DJ stent, provided the treatment options are selected judiciously and meticulously. We also suggest some protocols to be followed in our study in order to prevent a forgotten DJ stent., Competing Interests: There are no conflicts of interest., (Copyright: © 2020 Urology Annals.)

Herein, we report a one-pot Lewis acid mediated synthesis of bi- and triarylpropanal derivatives and their corresponding isomeric ketones from aromatic enol ethers. This transformation takes place via nucleophilic attack of enol ethers to electron-rich benzyl alcohols. The substrate scope of this indicates that it might proceed via quinomethoxy methide as a key intermediate leading to propanal derivatives, and their Wagner-Meerwein rearrangement afforded isomeric ketones. Further, this methodology was applied for the synthesis of (±)-tetrahydronyasol, propterol A, and 1,3-diarylpropane.

The base-mediated formation of a bridgehead double bond in a bicyclo[2.2.1]heptane system (anit-Bredt molecules) is described. The synthesis of exocyclic norbornyl enones by Wittig reaction of α-diketones is reported. These enones and their Michael adducts are used as substrates for the generation of transient bridgehead enones and their trapping with MeOH and H2 O. Bridgehead alcohols are easily synthesized from norbornyl enones and are exploited for the diversity oriented synthesis of frameworks of natural and unnatural products., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

An unusual cascade rearrangement has been noticed as a competitive reaction during the treatment of norbornyl appended cyclopentanediols with a Lewis acid (LA): a BF3-Et2O mediated pinacol-pinacolone rearrangement. Deketalization and pinacolone rearrangement occur at two different sites in the molecule and are responsible for the observed cascade rearrangement product. However, deketalization appears to be triggering the cascade steps. The kinetically more stable pinacolone product with an exo-Me group was observed in the case of the bromo analogue, whereas, the thermodynamically more stable pinacolone product with an endo-Me group was observed in the case of the chloro analogue. Epimerization via tautomerization of one diastereomer to the other diastereomer under Lewis acid reflux conditions is possible. On the contrary, the diol equivalent epoxides provide only the diastereomeric mixture of pinacolone products under similar LA reaction conditions. The lower yields observed in the case of the epoxides are due to unwanted side reactions taking place between the two competitive reactive centers, namely, ketal and epoxide. Further, a sequence of elimination, nucleophilic substitution and Ritter type hydrolysis reactions of the epoxides resulted in unexpected elimination products. This transformation not only facilitates a regioselective epoxide opening, but also provides a new route for the preparation of allylic amides of the norbornyl appended cyclopentane ring system.