REACTIONS OF 5-SUBSTITUTED-2-THIOXO-4-OXO-1,3-THIAZOLIDINES WITH 4-METHOXYPHENYLAZIDE
作者:Mohamed T. Omar、Ahmed S.A. Youssef、Kamal A. Kandeel
DOI:10.1080/10426500008045217
日期:2000.7
4-Methoxyphenylazide cycloadds to the thiono function and undergoes nucleophilic attack at other electrophilic centers of 5-benzoylmethyl- (la) and E,Z-5-(4-bromobenzoylmethylene)- (E,2-2b) -2-thioxo-4-oxo-1,3-thiazolidines in non site selective reactions to afford variety of products. With la, the attack at the thiono as well as the hetero-ring carbonyl functions leads to the 5-benzoylmethylene-2-(4-methoxyphenylimino)- derivative (3) and the ring fission product 2-4. Similar treatment of E,Z-2b gives a mixture of the respective E,Z-2-(4-methoxyphenylimino)derivative (E,Z-5) containing 80% of the IE-configurated isomer (Z-5) and the ring enlarged thiazinonethione derivative (6), due to the attack at the thiono and exocyclic double bond functions, respectively. Rationalizations for the above mentioned conversions are given. Structures of all products are evidenced by microanalytical and spectral data,The chemistry of 4-thiazolidinones has been a subject of a series of publications(1-6) from this laboratory, Reactions of 2-thioxo-4-thiazolidinones with dipolar species in the literature are rather limited and treat the problem of alkylation of the 3-unsubstituted derivatives with diazomethane(7,8), and cycloaddition of nitrilimines to the thiono function of 5-aroylmethylene-3-phenyl-2-thioxo-4-oxo-1,3-thiazolidine(9). The present work aimed to study the reactivity of different functions in 5-alkyl- and 5-alkylidene substituted thiazolidones namely 3-phenyl-5-(2-phenyl-2-oxoethyl)-(1a) and E,Z-3-benzyl-5-(4-bromophenylmethylene)-(E,Z-2b)-4-oxo-2-thioxo-1,3-thiazolidines towards reaction with 4-methoxyphenylazide.