Regioselective synthesis of (E)-3-[2-(arylmethylene)-1-(arylsulfonyl)hydrazino]-2-propenoates via the reaction of arylsulfonyl hydrazones and alkyl propiolates in the presence of triphenylphosphine

New one-pot synthesis of anti-tuberculosis compounds inspired on isoniazid

A library of thirty N-substituted tosyl N'-acryl-hydrazones was prepared with p-toluenesulfonyl hydrazide, methyl propiolate and different aldehydes in a one-pot synthesis via an aza-Michael reaction. The scope of the reaction was studied, including aliphatic, isoprenylic, aromatic and carbocyclic aldehydes. The prepared collection was tested against Mycobacterium tuberculosis H37Rv. Nine analogs of the collection showed Minimum Inhibitory Concentration ≤10 μM, of which the most active members (MIC of 1.25 μM) were exclusively E isomers. In order to validate the mechanism of action of the most active acrylates, we tested their activity on a M. tuberculosis InhA over-expressing strain obtaining MIC that consistently doubled those obtained on the wild type strain. Additionally, the binding mode of those analogs on M. tuberculosis InhA was investigated by docking simulations. The results displayed a hydrogen bond interaction between the sulfonamide and Ile194 and the carbonyl of the methyl ester with Tyr 158 (both critical residues in the interaction with the fatty acyl chain substrate), where the main differences on the binding mode relays on the hydrophobicity of the nitrogen substituent. Additionally, chemoinformatic analysis was performed to evaluate in silico possible cytotoxicity risk and ADME-Tox profile. Based on their simple preparation and interesting antimycobacterial activity profile, the newly prepared aza-acrylates are promising candidates for antitubercular drug development.

Crystal structure and Hirshfeld surface analysis of two (E)-N'-(para-substituted benzyl-idene) 4-chloro-benzene-sulfono-hydrazides

Two (E)-N'-(p-substituted benzyl-idene)-4-chloro-benzene-sulfono-hydrazides, namely, (E)-4-chloro-N'-(4-chloro-benzyl-idene)benzene-sulfono-hydrazide, C13H10Cl2N2O2S, (I), and (E)-4-chloro-N'-(4-nitro-benzyl-idene)benzene-sulfono-hydrazide, C13H10ClN3O4S, (II), have been synthesized, characterized and their crystal structures studied to explore the effect of the nature of substituents on the structural parameters. Compound (II) crystallized with two independent mol-ecules [(IIA) and IIB)] in the asymmetric unit. In both compounds, the configuration around the C=N bond is E. The mol-ecules are twisted at the S atom with C-S-N-N torsion angles of -62.4 (2)° in (I), and -46.8 (2)° and 56.8 (2)° in the mol-ecules A and B of (II). The 4-chloro-phenyl-sulfonyl and 4-substituted benzyl-idene rings form dihedral angles of 81.0 (1)° in (I), 75.9 (1)° in (IIA) and 73.4 (1)° in (IIB). In the crystal of (I), mol-ecules are linked via pairs of N-H⋯O hydrogen bonds, forming inversion dimers with an R 2 2(8) ring motif. The dimers are linked by C-Cl⋯π inter-actions, forming a three-dimensional structure. In the crystal of (II), mol-ecules are linked by C-H⋯π inter-actions and N-H⋯O hydrogen bonds, forming -A-B-A-B- chains along the c-axis direction. The chains are linked via C-H⋯O and C-H⋯π inter-actions, forming layers parallel to the bc plane. Two-dimensional fingerprint plots show that the most significant contacts contributing to the Hirshfeld surface for (I) are H⋯H contacts (26.6%), followed by Cl⋯H/H⋯Cl (21.3%), O⋯H/H⋯O (15.5%) and Cl⋯C/C⋯Cl (10.7%), while for (II) the O⋯H/H⋯O contacts are dominant, with a contribution of 34.8%, followed by H⋯H (15.2%), C⋯H/H⋯C (14.0%) and Cl⋯H/H⋯Cl (10.0%) contacts.

Crystal structure and DFT studies of 4-methyl-N-(1-phenylethyl)-N′-(1-phenylethylidene)benzenesulfono-hydrazide: evidence of a carbene insertion in the formation of acetophenone azine from acetophenone p-toluensulfonylhydrazone

The crystal structure of 4-Methyl-N-(1-phenylethyl)-N′-(1-phenylethylidene) benzene sulfonohydrazide is disclosed, which is obtained from direct reaction between acetophenone tosylhydrazone and potassium tert-butoxide. Reaction mechanisms and the corresponding energy barriers were assessed through DFT calculations at the B3LYP/6-31G(d,p) level of theory and showed that this compound plays an important role as an intermediate in the formation of acetophenone azine from acetophenone p-toluensulfonylhydrazone through a carbene insertion on this last compound.