ChemInform Abstract: Synthesis of Some New Hydrazide Hydrazones, Thiosemicarbazides, Thiadiazoles, Triazoles, and Their Derivatives as Possible Antimicrobials.

Abstract

The mercaptoimidazole (I) is coupled with the chloroacetic acids (II) to produce the sulfides (III).

Regioselective synthesis and biological evaluation of some novel thiophene-containing heterocyclic scaffolds as potential chemotherapeutic agents

“…This downfield NH resonance in the isolated product from the studied reaction can be rationalized in terms of the presence of the thione group attached to the nitrogen atom linked to the thioamide proton and as a result this proton is deshielded by the thione group and appears around that chemical shift value. This assignment is in line with literature assignments, that predict this signal would appear typically in the range δH ~ 13.00-14.00 ppm by analogy with related heterocyclic thioamides [31][32][33][34][35][36][37]. On the contrary, the isomeric structure 7, if isolated, would be expected to display an upfield shift for the NH proton due to the absence of deshielding thione group.…”

“…Such a downfield signal can be assigned only to the thioamide CS carbon atom, which was reported to appear at δC value greater than 169 ppm in related systems [37][38][39][40]. It is worthwhile to report here that the thione form is the stable form in which compound 8 mainly exists since its IR spectrum revealed no absorption band at around ν 2600-2550 cm -1 , which is indicative of the thiol form [35,36,[41][42][43]. In the 1 H NMR spectrum of 8, the absence of a signal due to the SH proton that would be expected to resonate in the range δH 1.6-4.0 ppm [35,37] also provided confirmatory evidence for thione formation.…”

“…It is worthwhile to report here that the thione form is the stable form in which compound 8 mainly exists since its IR spectrum revealed no absorption band at around ν 2600-2550 cm -1 , which is indicative of the thiol form [35,36,[41][42][43]. In the 1 H NMR spectrum of 8, the absence of a signal due to the SH proton that would be expected to resonate in the range δH 1.6-4.0 ppm [35,37] also provided confirmatory evidence for thione formation. The prevalence of the thione rather than the thiol form in a number of heterocyclic systems is well-established [44][45][46].…”

SYNTHESIS AND EVALUATION OF NEW IMIDAZO[2,1-b]THIAZOLES AS ANTITUBERCULOSIS AGENTS

“…The general procedure for the preparation of target compounds 3a-i were described in Scheme 1. This steric arrangement might be attributed to the hindered rotation of azomethine linkage (30). It is assumed that the N=CH double bond restricts rotation and gives rise to the formation of E and Z isomers.…”

Synthesis and anti-HIV activity evaluation of novel N′-arylidene-2-[1-(naphthalen-1-yl)-1H-tetrazol-5-ylthio]acetohydrazides

“…63-4.75 and 4.24-4.32, 11.54-12.16 and 11.48-12.06, respectively. It is assumed that the N=CH double bond restricts rotation and gives rise to the formation of E and Z isomers with the E isomer dominating (Gürsoy et al, 1990;Yildir et al, 1995;Gürsoy et al, 1997;Mamolo et al, 2001). The 13 C NMR spectra of 5a-t also revealed the presence of two isomers in DMSO-d6 as supported by the C=O, tetrazole-C, N=CH, and SCH 2 carbon atoms resonating as double singlets at approximately 168.…”