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Benzothiazinones are promising candidates in the fight against tuberculosis, the leading bacterial killer worldwide. We present an overview of recent developments in the field of antitubercular benzothiazinones and summarize our own contributions.

8-Nitro-1,3-benzothiazin-4-ones (BTZs) are known as potent antitubercular agents. BTZ043 as one of the most advanced compounds has reached clinical trials. The putative oxidation products of BTZ043, namely, the corresponding BTZ sulfoxide and sulfone, were reported in this journal (Tiwari et al. ACS Med. Chem Lett.2015, 6, 128-133). The molecular structures were later revised to the constitutionally isomeric benzisothiazolone and its 1-oxide, respectively. Here, we report two BTZ043-derived benzisothiazolinones (BITs) with in vitro activity against mycobacteria. The constitutionally isomeric O-acyl benzisothiazol-3-ols, in contrast, show little or no antimycobacterial activity in vitro. The structures of the four compounds were investigated by X-ray crystallography and NMR spectroscopy. Molecular covalent docking of the new compounds to Mycobacerium tuberculosis decaprenylphosphoryl-β-d-ribose 2′-epimerase (DprE1) suggests that the active BITs exert antimycobacterial activity through inhibition of DprE1 like BTZs.

Large Spin-Orbit Coupling (SOC) is an intrinsic property of the heavy-elements that directly affects the electronic structures of the compounds. Herein we report the synthesis and characterization of a mono-coordinate bismuthinidene featuring a rigid and bulky ligand. All magnetic measurements (SQUID, NMR) point to a diamagnetic compound. However, multiconfigurational quantum chemical calculations predict the ground state of the compound to be dominated (76%) by a spin-triplet. The apparent diamagnetism is explained by an extremely large SOC induced positive zero-field-splitting of more than 4500 cm −1 that leaves the M S = 0 magnetic sublevel thermally isolated in the electronic ground state.

The title compound, C16H16N4O3, was obtained as a side product during the synthesis of the previously reported antitubercular agent N-(2-fluoroethyl)-1-[(6-methoxy-5-methylpyrimidin-4-yl)methyl]-1H-benzo[d]imidazole-4-carboxamide and structurally characterized by X-ray crystallography and computational methods. In the crystal (space group P21/n, Z = 4), the title compound adopts a twisted conformation with a dihedral angle between the benzimidazole and pyrimidine mean planes of 84.11 (3)°. The carboxylate group and the 5-methyl group on the pyrimidine ring exhibit partial disorder. The DFT-optimized molecular structure resembles the structure of the minor component in the crystal.

Isolation and stabilization of main group diradical species have posed a synthetic challenge over the years due to their intrinsic high reactivity. Herein we report on a large-scale synthesis and isolation of a mono-coordinate bismuthinidene featuring a rigid and bulky ligand, which protects the Bi(I) center. The compound was characterized by its unique spectroscopic features (UV-vis and NMR), but more prominently, by its magnetic properties. Multiconfigurational quantum chemical calculations predict the ground state of the compound to be dominated by a spin-triplet. Further support for this electronic structure description was obtained through correlation of theory to experimental XRD, XAS, and UV-Vis data. However, all magnetic measurements (EPR, NMR and SQUID) point to a diamagnetic compound. This apparent discrepancy can be explained by an extremely large spin-orbit coupling (SOC) that leads to an unprecedented zero-field splitting of more than 8000 cm‒1, thus leaving a MS = 0 magnetic sublevel thermally isolated in the electronic ground state. The extremely large SOC effect is a result of the low-coordination number of the bismuth center in interplay with its heavy element nature.

Synthesis and structural characterization of two heterodinuclear ZnII-LnIII complexes with the formula [ZnLn(HL)(µ-OAc)(NO3)2(H2O)x(MeOH)1-x]NO3 · n H2O · n MeOH [Ln = Pr (1), Nd (2)] and the crystal and molecular structure of [ZnNd(HL)(µ-OAc)(NO3)2(H2O)] [ZnNd(HL)(OAc)(NO3)2(H2O)](NO3)2 · n H2O · n MeOH (3) are reported. The asymmetrical compartmental ligand (E)-2-(1-(2-((2-hydroxy-3-methoxybenzylidene)amino)-ethyl)imidazolidin-2-yl)-6-methoxyphenol (H2L) is formed from N1,N3-bis(3-methoxysalicylidene)diethylenetriamine (H2valdien) through intramolecular aminal formation, resulting in a peripheral imidazoline ring. The structures of 1–3 were revealed by X-ray crystallography. The smaller ZnII ion occupies the inner N2O2 compartment of the ligand, whereas the larger and more oxophilic LnIII ions are found in the outer O2O2’ site. Graphic Abstract Synthesis and structural characterization of two heterodinuclear ZnII-LnIII complexes (Ln = Pr, Nd) bearing an asymmetrical compartmental ligand formed in situ from N1,N3-bis(3-methoxysalicylidene)diethylenetriamine (H2valdien) through intramolecular aminal formation are reported.

We leveraged the recent increase in synthetic accessibility of SF

Business confidence is a measure of optimism or pessimism that managers feel about the commercial prospects for their organizations. This paper uses later medieval high-value English credit data as a proxy gauge of merchants’ business confidence or uncertainty. It discusses whether mercantile restriction of credit during the fifteenth-century recession reflects uncertainty, whereby merchants became increasingly risk-averse and so reduced the amount of credit they extended to their customers. It discusses the chronological trends in English lending between 1353 and 1532. This paper examines medieval debt restructuring and argues that this might similarly reflect merchants’ commercial confidence or uncertainty. In contrasting two sample years (1375 and 1433), the paper seeks to identify the motivations and influences that lay behind medieval merchants’ business decisions more fully. It argues that merchants’ investment behavior was guided more by local commercial circumstances than it was by profound economic shocks, such as plague and bullion famine.

The synthesis and structural characterization of N-(6-methoxypyridin-3-yl)-4-(pyridin-2-yl)thiazol-2-amine mono-hydrobromide monohydrate (3) and N-(6-methoxypyridin-3-yl)-4-(pyrazin-2-yl)thiazol-2-amine mono-hydrobromide 0.35 methanol solvate (4) are reported. The crystal structures of 3 (monoclinic, space group P21/n, Z = 4) and 4 (monoclinic, space group, C2/c, Z = 8) feature N,4-diheteroaryl 2-aminothiazoles showing similar molecular conformations but different sites of protonation and thus distinctly different intermolecular hydrogen bonding patterns. In 3, Namine–H⋯Br−, N+pyridine–H⋯Owater, and Owater–H⋯Br− hydrogen bonds link protonated N-(6-methoxypyridin-3-yl)-4-(pyridin-2-yl)thiazol-2-amine and water molecules and bromide anions into a three-dimensional hydrogen-bonded network, whereas intermolecular N+methoxypyridine–H⋯Npyrazine hydrogen bonds result in hydrogen-bonded zigzag chains of protonated N-(6-methoxypyridin-3-yl)-4-(pyrazin-2-yl)thiazol-2-amine molecules in 4.

An approach for the possible production of novel bimetallic self-doped porphyrin-based compounds of potential interest in material science is reported. Heating Cu(II)tetraphenylporphyrin (TPPCu) with chromocene at 120°C in benzonitrile affords the crystalline multimetal porphyrin system TPPCu/TPPCr in good yield. The X-ray single crystal structural analysis reveals a random distribution of TPPCu and TPPCr, with a Cu:Cr ratio of 71(2):29(2)%. Exploratory DFT calculations of TPPCu/TPPCr indicate little if any electron transfer. In contrast, calculations of a hypothetical cationic TPPCu/TPPRu system indicates the possibility of self-doping.

The only recently discovered gem-hydrogenation of internal alkynes is a fundamentally new transformation, in which both H atoms of dihydrogen are transferred to the same C atom of a triple bond while the other position transforms into a discrete metal carbene complex. [Cp*RuCl]4 is presently the catalyst of choice: the resulting piano-stool ruthenium carbenes can engage a tethered alkene into either cyclopropanation or metathesis, and a prototypical example of such a reactive intermediate with an olefin ligated to the ruthenium center has been isolated and characterized by X-ray diffraction. It is the substitution pattern of the olefin that determines whether metathesis or cyclopropanation takes place: a systematic survey using alkenes of largely different character in combination with a computational study of the mechanism at the local coupled cluster level of theory allowed the preparative results to be sorted and an intuitive model with predictive power to be proposed. This model links the course of the reaction to the polarization of the double bond as well as to the stability of the secondary carbene complex formed, if metathesis were to take place. The first application of "hydrogenative metathesis" to the total synthesis of sinularones E and F concurred with this interpretation and allowed the proposed structure of these marine natural products to be confirmed. During this synthesis, it was found that gem-hydrogenation also provides opportunities for C-H functionalization. Moreover, silylated alkynes are shown to participate well in hydrogenative metathesis, which opens a new entry into valuable allylsilane building blocks. Crystallographic evidence suggests that the polarized [Ru-Cl] bond of the catalyst interacts with the neighboring R3Si group. Since attractive interligand Cl/R3Si contacts had already previously been invoked to explain the outcome of various ruthenium-catalyzed reactions, including trans-hydrosilylation, the experimental confirmation provided herein has implications beyond the present case.

Abstract Two polymorphic forms of 1-(4-methylpyridin-2-yl)thiourea (1) and the crystal and molecular structures of the 2-aminothiazoles N-(4-methylpyridin-2-yl)-4-(pyridin-2-yl)thiazol-2-amine (2) and N-(4-methylpyridin-2-yl)-4-(pyrazin-2-yl)thiazol-2-amine (3), derived from 1 and the respective α-bromoketone via the Hantzsch reaction, are described. Both polymorphic forms 1α (space group P21/c, Z = 4) and 1β (space group P21/n, Z = 8) crystallize in the monoclinic system but exhibit distinctly different intermolecular hydrogen bonding patterns. Compound 2 (orthorhombic, space group Pca21, Z = 8) forms polymeric N–H⋯N hydrogen-bonded zigzag tapes in the polar crystal structure, with a significant twisting between the thiazole and pyridine rings. In contrast, the crystal structure of 3 (monoclinic, space group P21/c, Z = 4) features nearly planar centrosymmetric N–H⋯N hydrogen-bonded dimers, which are laterally joined through long C–H⋯N contacts, affording a π⋯π stacked layered structure. Graphic Abstract Two polymorphs of 1-(4-methylpyridin-2-yl)thiourea and the crystal and molecular structures of two 2-aminothiazoles, derived from 1-(4-methylpyridin-2-yl)thiourea and α-bromoketones via Hantzsch reaction, are reported.

The crystal and mol­ecular structure of [2-chloro-3-nitro-5-(tri­fluoro­meth­yl)phen­yl](piperidin-1-yl)methanone, a side product in the synthesis of an 8-nitro-1,3-benzo­thia­zin-4-one, which belongs to a class of new anti-tuberculosis drug candidates, is reported., 1,3-Benzo­thia­zin-4-ones (BTZs) are a promising new class of anti-tuberculosis drug candidates, some of which have reached clinical trials. The title compound, the benzamide derivative [2-chloro-3-nitro-5-(tri­fluoro­meth­yl)phen­yl](piper­id­in-1-yl)methanone, C13H12ClF3N2O3, occurs as a side product as a result of competitive reaction pathways in the nucleophilic attack during the synthesis of the BTZ 8-nitro-2-(piperidin-1-yl)-6-(tri­fluoro­meth­yl)-1,3-benzo­thia­zin-4-one, following the original synthetic route, whereby the corresponding benzoyl iso­thio­cyanate is reacted with piperidine as secondary amine. In the title compound, the nitro group and the nearly planar amide group are significantly twisted out of the plane of the benzene ring. The piperidine ring adopts a chair conformation. The tri­fluoro­methyl group exhibits slight rotational disorder with a refined ratio of occupancies of 0.972 (2):0.028 (2). There is structural evidence for inter­molecular weak C—H⋯O hydrogen bonds.

The synthesis of ethyl 2-[(4-methylpyridin-2-yl)amino)-4-(pyridin-2-yl)thiazole- 5-carboxylateviathe Hantzsch reaction and partialin situtransesterification during recrystallization from methanol-d4to thed3-methyl ester, resulting in the title solid solution, ethyl 2-[(4-methylpyridin-2-yl)amino)-4-(pyridin-2-yl)thiazole-5-carboxylate–d3-methyl 2-[(4-methylpyridin-2-yl)amino)-4-(pyridin-2-yl)thiazole-5-carboxylate (0.88/0.12), 0.88C17H16N4O2S·0.12C16D3H11N4O2S, is reported. The refined ratio of ethyl tod3-methyl ester in the crystal is 0.880 (6):0.120 (6). The pyridine ring is significantly twisted out of the plane of the approximately planar picoline thiazole ester moiety. N—H...N hydrogen bonds between the secondary amino group and the pyridine nitrogen atom of an adjacent symmetry-related molecule link the molecules into polymeric hydrogen-bonded zigzag tapes extending by glide symmetry in the [001] direction. There is structural evidence for intramolecular N...S chalcogen bonding and intermolecular weak C—H...O hydrogen bonds between adjacent zigzag tapes.

Halogenated carboxylic acids have been important compounds in chemical synthesis and indispensable research tools in biochemical studies for decades. Nevertheless, the number of structurally characterized simple &alpha, brominated monocarboxylic acids is still limited. We herein report the crystallization and structural elucidation of (R)- and rac-2-bromo-3-methylbutyric acid (2-bromo-3-methylbutanoic acid, 1) to shed light on intermolecular interactions, in particular hydrogen bonding motifs, packing modes and preferred conformations in the solid-state. The crystal structures of (R)- and rac-1 are revealed by X-ray crystallography. Both compounds crystallize in the triclinic crystal system with Z = 2, (R)-1 exhibits two crystallographically distinct molecules. In the crystal, (R)-1 forms homochiral O&ndash, H&middot, &middot, O hydrogen-bonded carboxylic acid dimers with approximate non-crystallographic C2 symmetry. In contrast, rac-1 features centrosymmetric heterochiral dimers with the same carboxy syn&middot, syn homosynthon. The crystal packing of centrosymmetric rac-1 is denser than that of its enantiopure counterpart (R)-1. The molecules in both crystal structures adopt a virtually identical staggered conformation, despite different crystal environments, which indicates a preferred molecular structure of 1. Intermolecular interactions apart from classical O&ndash, O hydrogen bonds do not appear to have a crucial bearing on the solid-state structures of (R)- and rac-1.

8-Nitro-4H-benzo[e][1,3]thiazinones (BTZs) are potent in vitro antimycobacterial agents. New chemical transformations, viz. dearomatization and decarbonylation, of two BTZs and their influence on the compounds' antimycobacterial properties are described. Reactions of 8-nitro-2-(piperidin-1-yl)-6-(trifluoromethyl)-4H-benzo[e][1,3]thiazin-4-one and the clinical drug candidate BTZ043 with the Grignard reagent CH

This article examines English women who were engaged in wholesale long-distance or international trade in the later Middle Ages. These women made up only a small proportion of English merchants, averaging about 3 to 4 percent of the mercantile population, often working in partnership with their husbands. The article systematically quantifies, for the first time, women's penetration into this male-dominated trade and adds new perspectives to our understanding of women and trade in the Middle Ages by using both debt and customs records. It poses important questions about women's economic roles, the nature or distinctiveness of their businesses, and the ways that their actions fitted within mercantile activity more broadly. It examines the extent to which wives acted as equal economic partners with their husbands and also assesses the extent to which women's economic potential or agency in wholesale trade was shaped, or indeed constrained, by economic and patriarchal forces. It concludes by arguing that patriarchy certainly limited female access to wholesale markets, particularly after 1300, along with other linked features that also shaped women's economic trading endeavors. These features included status, access to capital, and the advantages to working within dynamic, extensive, and busy markets such as those found in later medieval London.

Cyclopropanation reactions of styrene derivatives with donor-acceptor carbenes formed in situ are significantly more enantioselective when catalyzed by the heterobimetallic bismuth-rhodium complex 5 a endowed with N-phthalimido tert-leucine paddlewheel ligands rather than by its homobimetallic dirhodium analogue 1 a. This virtue is likely the result of two synergizing factors: the conical shape of 5 a translates into a narrower calyx-like chiral binding site about the catalytically active Rh center; the Bi atom, although fully solvent exposed, does not decompose aryl diazoacetates and is hence incapable of promoting a racemic background reaction. Moreover, ligand variation proved that successful catalyst design mandates that the anisotropy of the conical heterobimetallic core be matched by proper directionality of the ligand sphere.

The crystal and molecular structures of the bio-based platform chemical furfural (1) and its derivatives furfurylamine (2), 2-furonitrile (3) and 2-methylfuran (4), which are all liquid at ambient temperature, have been determined by in situ cryocrystallography. Compound 1 crystallizes with three molecules in the asymmetric unit (Z′ = 3), which all adopt the syn conformation. Compound 2 crystallizes with two crystallographically distinct molecules in gauche and anti conformers, which are linked by N–H⋯N and N–H⋯O hydrogen bonds. The crystal structure of 3 is characterized by C–H⋯N interactions between C4 of the furan ring and the nitrile group. Compound 4 was found to crystallize in the non-centrosymmetric space group P42bc with a polar c axis. The molecular structures are compared with results from spectroscopic studies in the literature. Compounds 1–4 show a difference of ca. 14° between the external C–C–C and C–C–O angles to the substituent carbon atom in 2-position of the furan ring. Using this criterion as an indicator for the assignment of the oxygen atom in 2-substituted furan derivatives, a number of crystal structures in the Cambridge Structural Database (CSD) are called into question.

8-Nitro-1,3-benzothiazin-4-ones (BTZs), with BTZ043 and PBTZ169 as the most advanced compounds, represent a new class of potent antitubercular agents, which irreversibly inhibit decaprenylphosphoryl-β-d-ribose-2′-epimerase (DprE1), an enzyme crucial for cell wall synthesis in the pathogen Mycobacterium tuberculosis. Synthesis, structural characterization and in vitro testing against Mycobacterium aurum DSM 43999 and M. tuberculosis H37Rv of halogenated 2-(4-ethoxycarbonylpiperazin-1-yl)-1,3-benzothiazin-4-ones lacking a nitro group are reported. X-ray crystallography reveals that the structure of the BTZ scaffold can significantly deviate from planarity. In contrast to recent reports, the results of the present study indicate that further investigation of halogenated non-nitro BTZs for antitubercular activity is less than a promising approach.

The crystal and mol­ecular structures of 2-chloro-3-nitro-5-(tri­fluoro­meth­yl)benzoic acid and 2-chloro-3-nitro-5-(tri­fluoro­meth­yl)benzamide, two precursors for the synthesis of 8-nitro-1,3-benzo­thia­zin-4-ones, a promising class of new anti­tuberculosis drug candidates, are described., 8-Nitro-1,3-benzo­thia­zin-4-ones are a promising class of new anti­tubercular agents, two candidates of which, namely BTZ043 and PBTZ169 (INN: macozinone), have reached clinical trials. The crystal and mol­ecular structures of two synthetic precursors, 2-chloro-3-nitro-5-(tri­fluoro­meth­yl)benzoic acid, C8H3ClF3NO4 (1), and 2-chloro-3-nitro-5-(tri­fluoro­meth­yl)benzamide, C8H4ClF3N2O3 (2), are reported. In 1 and 2, the respective carb­oxy, carboxamide and the nitro groups are significantly twisted out of the plane of the benzene ring. In 1, the nitro group is oriented almost perpendicular to the benzene ring plane. In the crystal, 1 and 2 form O—H⋯O and N—H⋯O hydrogen-bonded dimers, respectively, which in 2 extend into primary amide tapes along the [101] direction. The tri­fluoro­methyl group in 2 exhibits rotational disorder with an occupancy ratio of 0.876 (3):0.124 (3).

Heterobimetallic bismuth–rhodium paddlewheel complexes with phenylglycine ligands carrying TIPS-groups at the meta-positions of the aromatic ring exhibit outstanding levels of selectivity in reactions of donor/acceptor and donor/donor carbenes; at the same time, the reaction rates are much faster and the substrate scope is considerably wider than those of previous generations of chiral [BiRh] catalysts. As shown by a combined experimental, crystallographic, and computational study, the new catalysts draw their excellent application profile largely from the stabilization of the chiral ligand sphere by London dispersion (LD) interactions of the peripheral silyl substituents.

Heating Cu(II)tetraphenylporphyrin (TPPCu) with chromocene at 120 °C affords the crystalline self-doped multimetal porphyrin system TPPCu/TPPCr in good yield. The X-ray structural analysis reveals a random configuration of TPPCu and TPPCr with a Cu:Cr ratio of about 71:29 %. Exploratory DFT calculations indicate significant electron transfer in a hypothetical cationic TPPCu/TPPRu system, in contrast to TPPCu/TPPCr.

X-ray crystallography revealed the unintended formation of benziso­thia­zolinone 1-oxides from 1,3-benzo­thia­zin-4-ones through oxidation instead of the anti­cipated benzo­thia­zinone sulfones, which would be constitutional isomers., 1,3-Benzo­thia­zin-4-ones (BTZs) are a promising new class of drugs with activity against Mycobacterium tuberculosis, which have already reached clinical trials. A product obtained in low yield upon treatment of 8-nitro-2-(piperidin-1-yl)-6-(tri­fluoro­meth­yl)-4H-benzo­thia­zin-4-one with 3-chloro­perbenzoic acid, in ana­logy to a literature report describing the formation of sulfoxide and sulfone derived from BTZ043 [Tiwari et al. (2015 ▸). ACS Med. Chem. Lett. 6, 128–133], is a ring-contracted benziso­thia­zolinone (BIT) 1-oxide, namely, 7-nitro-2-(piperi­dine-1-carbon­yl)-5-(tri­fluoro­meth­yl)benzo[d]iso­thia­zol-3(2H)-one 1-oxide, C14H12F3N3O5S, as revealed by X-ray crystallography. Single-crystal X-ray analysis of the oxidation product originally assigned as BTZ043 sulfone provides clear evidence that the structure of the purported BTZ043 sulfone is likewise the corresponding BIT 1-oxide, namely, 2-[(S)-2-methyl-1,4-dioxa-8-aza­spiro­[4.5]decane-8-carbon­yl]-7-nitro-5-(tri­fluoro­meth­yl)benzo[d]iso­thia­zol-3(2H)-one 1-oxide, C17H16F3N3O7S. A possible mechanism for the ring contraction affording the BIT 1-oxides instead of the anti­cipated constitutionally isomeric BTZ sulfones and anti­mycobacterial activities thereof are discussed.

The synthesis and characterization through NMR and X-ray crystallography of a series of N-arylpyridiniophosphines and their corresponding Au(I)-derivatives are reported. Because of their acceptor properties, pyridiniophosphines efficiently enhance the electrophilicity of the Au atom in the complexes they form. In our study, this is translated into higher reactivity of the corresponding Au catalysts, which is demonstrated in two mechanistically differentiated cycloisomerizations. Moreover, the steric protection and probably also the electronic stabilization provided by the N-aryl substituents make the active Au-species more robust and slow down its rate of decay. This allows for an appreciable reduction of the catalyst loadings.