Synthesis and Spectroscopy of New 4-Aryl-2(3h)- Thiazolethiones and Derived Thiazoles

Abstract

The optimized preparation of four new 4-aryl-2(3W)-thiazolethiones and three new phenacylthiothiazoles is described.Since the 2(3W)-thiazolethiones contain three functional groups in their ring: an enamine, a thiolactam, and a dithiolactone. their influence was studied by alkylation/aromatization reactions and by 'H-NMR experiments on deuterium exchange with DMSOd"/D,0. CDCi,/CF,COOD, CF,COOD and CF,C00D/D 2 0. Among these new compounds we have found intramolecular weak hydrogen bonding, as well as deuterium exchange involvingThe compounds under study have been registered in Chemical Abstracts as 4-thiazoline-2-thiones from 1951 to 1971, and as 2(3H)-thiazolethiones onwards. The earlier works considered these compounds as 2-mercapto-thiazoles.The papers related to these thioxo compounds have been reviewed several times (1-8).The reaction of an α-halo ketone with a dithiocarbamate (3) to obtain a 2(3W)-thiazolethione has been employed with rather simple ketone derivatives. We have prepared four new 4-aryl-2(3//)-thiazolethiones having di-or trisubstituted phenyl groups. Results and DiscussionWe tried the reaction of 2,4.5-trimethoxyphenacyl chloride (9), 1. with ammonium dithiocarbamate (10.11). A mixture dioxaneethanol (3:5) was employed as solvent due to the low solubility of the chloride 1 in FitOH. However, instead of the expected hcterocycle, bis(2,4.5-trimethoxyphenacyl) disulfide. 2. was formed via the α-mercaptoketone and air oxidation. The IR (KBr wafer) and 'H-NMR data (CDCh. 300 MHz) are given in Οις formulas.hydrogens bound to sp~ carbon atoms.