Reactions of cyclic anhydrides. Part XXII. Direct synthesis of N-aryl-α-(2,3,4,5-tetrahydro-2-imino-4-oxo-1,3-thiazoIe-5-yl) acetamides

Abstract

react with thiourea in refluxing ethanol to yield the corresponding N-aryl ct-(2,3,4,5-tetrahydro-4-oxo-l,3-thiazole-5-yl) acetamides (6a-j_') in 72-85~o. The spectral and analytical data are consistent with the assigned structures for 6a-j. Under similar conditions, isomalemides 3(~-_b and 3d--f) furnish the corresponding 6a-_b and 6d-f in 76-86~. While maleanilic acid (4_.a) itself failed to react with thiourea, 4b--e_, 4i and 4j yielded a mixture of the corresponding 6___~e, 6i and 6j in 2-50~o and fumaranilic acids (7b--e_, 7i and 7j) in 50-80~. Methyl maleanilates 5~, 5d-f and ~ gave 6b,6d-_f and 6i in 78-85~. The reaction course of Raney nickel desulphurisation of 6a-_b, ~ 6f and mass spectral fragmentation of 6b support the assigned structures.

An Efficient Ni(II) Laurate Promoted Heterocyclization of Symmetrical Thioureas with Maleic Anhydride and Mechanistic Approach toward Higher Substituted Thiazolidine‐4‐one‐5‐acetic Acids

“…As a continuation of the work carried out with maleic anhydride, we also examined the reaction of N , N ‐didodecyl thiourea with two stereoisomeric α,β‐unsaturated dicarboxylic acids such as maleic and fumaric acids under similar reaction conditions given in Table 1, entry 13. It is known from the literature that unsubstituted thiourea gives a successful heterocyclization reaction with these acids [38] . However, deispite our efforts the reactions of the thiourea derivative 1 c with these acids failed to occur in refluxing toluene.…”

“…It is known from the literature that unsubstituted thiourea gives a successful heterocyclization reaction with these acids. [38] However, deispite our efforts the reactions of the thiourea derivative 1 c with these acids failed to occur in refluxing toluene. In the case of using maleic acid as a substrate even after a long heating period, the desired product is obtained in a very low yield (20 %), while there is almost no conversion with fumaric acid (Table 2).…”

Heterocycle construction using the biomass-derived building block itaconic acid

“…Interestingly, when itaconic anhydride reacts with thiourea in acetic acid at reflux, as a mixture of 2-iminothiazo-Scheme 15 Scheme 16 lidine-4-ones 75 and 76 are obtained (Scheme 22). 70 One can envisage that upon hydrolysis of 2-iminothiazolidine-4-ones 75 and 76, thiazolidinediones would be obtained, the key heterocycle in a series of drugs known as glitazones used to treat type 2 diabetes mellitus. 72 4-Oxo-2-thioxo-1,3-thiazinanes ( 77) are accessible from the reaction between itaconic anhydride, carbon disulfide and primary amines.…”