Preparation and properties of new antitubercular thioureas and thiosemicarbazides

Synthesis and Characterization of New 1‐(4‐Methylpiperazin‐1‐yl)thioureas as Potential Antitubercular Agents

“…This observed stability appears to be typical of the thioureas derived from these strongly nucleophilic bases. Similarly, we found no evidence for any contamination of our products with the thiourethanes (RNHCSOCH 2 CH 3 ) that would be formed by the side reaction of the isothiocyanates with the solvent ethanol . The results of reactions run in ethanol were identical to those run in toluene (see Experimental).…”

“…Under such circumstances, mixtures of products may be observed, and often the reaction is driven to completion by a LeChatelier effect towards the highly crystalline and relatively insoluble symmetrical thiourea (Scheme , Eqn. 2) . In the present reactions, however, we found that the aminoheterocycle was sufficiently nucleophilic to lead to rapid and irreversible formation of the 1‐(4‐methylpiperazin‐1‐yl)thioureas, with no tendency toward thermal fragmentations and their consequences.…”

Unclicking of thioureas: Base catalyzed elimination of anilines and isothiocyanates from thioureas

“…as a linker in nanoparticle and polymer functionalization [5]). The synthesis of thioureas is typically accomplished by mixing an appropriate isothiocyanate with an amine at ambient temperatures, although in the literature there are some procedures that are performed at elevated temperatures [6] (even at reflux [7]) in the presence of a base (e. g. Et 3 N). It should be noted that the yields reported in those cases were typically lower than obtained at milder temperatures.…”

Preparation and properties in vitro and in vivo of antitubercular pyrroles

“…4‐Aminosalicylic acid hydrazide (ASAH) was obtained (58%) in pure form from the hydrazinolysis of methyl 4‐aminosalicylate by a method that we have previously described in detail [37]. ASAH thus obtained (1.67 g, 10.0 mmoles) was weighed into a 100 mL round‐bottom flask fitted for reflux with a temperature‐controlled heating mantle, reflux condenser, and magnetic stirrer.…”