Dithiocarbamates, Thiocarbamic Esters, Dithiocarboimidates, Guanidines, Thioureas, Isothioureas, and Tetraazathiapentalene Derived from 2‐Aminobenzothiazole

Abstract

Keywords: 2-Aminobenzothiazole / Dibenzothiazolyltetraazathiapentalene / Electrophilic and nucleophilic sulfur atoms Reactions between CS 2 and the exocyclic amino groups of 2-aminobenzothiazoles gave series of molecules bearing thiourea, isothiourea, dithiocarbamate, dithiocarboimine, dimethyldithiocarbamate, methyldithiocarbamate, S-CH 3 and O-alkyl thiocarbamic ester, and guanidine groups. Preferred tautomers and conformers were determined. Most compounds present coordinative bonds between the endocyclic sulfur atom, which behaves as a Lewis acid, and oxygen, ni-

S-Methyl-(-N-aryl and -N-alkyl)isothioureas derived from 2-aminobenzothiazole

“…A detailed study and characterization of the intermediates involved in this reaction have been reported 6 . It has been demonstrated that the reactivity of compound 2 is due to the facility to displace two molecules of HSMe, as leaving group, when it reacts with o-XH substituted anilines in refluxing DMF to get NH-bisbenzazoles 4 8 , scheme 2.…”

“…In a previous work, 6 we tested the reactivity of compound 2 by using methyl-and ipropylamines as nucleophiles to prepare S-methyl, N-methyl and S-methyl, Nisopropylisothioureas, and N,N´-dimethylguanidine derivatives, when the reaction is carried out in refluxing ethanol. However, this reaction was not generalized to isolate the methylisothiourea intermediates when o-, m-, and p-XH-substituted anilines, ammonia, aniline, or cyclic amines are used.…”

“…Thirteen and eleven carbon signals were observed in 13 C NMR spectra for 3f and 3g, respectively. In a previous work, 6 it was reported that the reaction of compound 2 with one and two molar equivalents of methylamine afforded the isothioureidic compound 3h (R 1 = H, R 2 = CH 3 ) and the corresponding guanidine derivative 4h (R 1 = R 3 = H, R 2 = R 4 = CH 3 ) respectively, scheme 1. Characteristic NMR data from which it can be pointed out the chemical shift of C11 in 175.0 ppm in thiocarboimidate compound 2, 172.5 ppm in the respective isothioureidic compound 3h and 174.7 ppm in the corresponding guanidine compound 4h.…”

“…5 By this, in our currently investigations about biologically active 2-aminobenzothiazoles, 6 we are interested in the functionalization of these aromatic heterocycles to get guanidine derivatives, where the nitrogen atoms can be bonded to hydrogen, alkyl or aryl groups and one or two nitrogen atoms are part of five or six membered heterocycles. Herein we report the preparation and 1 H and 13 C NMR structural study of a series of Smethylisothioureas 3, scheme 1, obtained from 2-aminobenzothiazole 1 through dithiomethyl carboimidate 2 as intermediate compound 7 .…”

Synthesis and Structure of Sulfur Derivatives from 2-Aminobenzimidazole

“…In this context, we have reported a detailed study and characterization of the intermediates involved in the synthesis of dimethyl benzo[d]thiazol-2-carbonodithioimidate (2) [7], by the reaction of 2-aminobenzothiazole (1) with carbon disulfide in basic media, following the procedure reported by Merchand et al [8] (Scheme 1). Compound 2 reacts with ortho-XH substituted anilines in refluxing DMF to give NH-bisbenzazoles [9][10][11] due to the facility with which HSMe molecules are displaced.…”