Acetylenic esters. II. Further addition reactions with sulfur- and nitrogen-containing compounds

Abstract

Substituted thiosemicarbazides react with dimethyl acetylenedicarboxylate to give 3-amino-2,3-dihydrothiazin-4-ones. Confirmation of the structures is provided by catalytic hydrogenation and by characteristic mass spectral fragmentations. 4-Substituted thiosemicarbazides react with methyl propiolate in the same way as monosubstituted hydrazines and hydrazides to give hydrazones, whereas I-substituted thiosemicarbazides undergo smooth removal of the sulfur with the production of an equal mixture of cis-trans and cis-cis dimethyl-6-thiodiacrylic esters. Bicyclic heterocyclic structures are formed by reaction of dimethyl acetylenedicarboxylate with imidazolidone thione and with 5,5-dimethyl-2-thiohydantoin. Substituted guanidines react with dimethyl acetylenedicarboxylate in an analogous fashion, yielding substituted 2,3-dihydrodiazinones. The high-resolution mass spectra of the latter show many similarities to the spectra of the sulfur analogues. Thioamides, despite previous claims to the contrary, react with dimethyl acetylenedicarboxylate to give thioethers of fumarate ester or 1,3-thiazin-4-ones. In contrast, thioamides react with methyl propiolate to give an equal mixture of cis-trans and cis-cis dimethyl-p-thiodiacrylic esters.

Utility of Acetylenedicarboxylate in Organic Synthesis

“…Lown et al , reported that, methyl 4‐oxo‐2‐phenyl‐4 H ‐1,3‐thiazine‐6‐carboxylate ( 191 ) was obtained by the reaction of N ‐methyl benzothioamide ( 190 ) with DMAD ( 1a ) in methanol at room temperature (Scheme ).…”

“…On the other hand, dimethyl 2‐[6‐(methoxycarbonyl)‐4‐oxo‐3,4‐dihydro‐2 H ‐1,3‐thiazin‐2‐ylimino]‐1,3‐dithiole‐4,5‐dicarboxylate ( 197a ) and ( E )‐dimethyl 2‐[6‐(methoxycarbonyl)‐4‐oxo‐3,4‐dihydro‐2 H ‐1,3‐thiazin‐2‐ylimino]‐3‐phenyl‐2,3‐dihydrothiazole‐4,5‐dicarboxylate ( 197b ) were formed via interactions between 5‐amino‐3 H ‐1,2,4‐dithiazole‐3‐thione ( 196a ) or 3‐(phenyl imino)‐3 H ‐1,2,4‐dithiazol‐5‐amine ( 196b ) and DMAD ( 1a ) in methanol at room temperature (Scheme ) .…”

Methyl (Z)-4-oxo-1,3-diphenyl-2-phenylimino-5-imidazolidinylideneacetate

“…The structure of the title compound was first reported by Ichikawa & Iitaka (1968 acetylenedicarboxylate (DMAD) have been given both the imidazolidin-4-one structure (1) (Sasaki, Sakata & Iwanami, 1964) and the pyrimid-4-one structure (2) (Ruhemann & Stapleton, 1900), although the structural assignments were often unsupported. Some chemical degradative evidence favours the fivemembered-ring structure (3) for the adduct from guanidine itself and DMAD (Katner & Zeige, 1971) but, in contrast, the adduct from 1,2,3-triphenylguanidine has been assigned the six-membered-ring structure (4), principally from its high-resolution mass (-c9 1980 International Union of Crystallography C24HI9N303 spectrum (Lown & Ma, 1967). The crystal structure of the adduct from 1,2,3-triphenylguanidine was therefore examined to gain some unambiguous information in this confused area.…”

“…The adduct was prepared in 71% yield from c(32) 1,2,3-triphenylguanidine and DMAD in methanol c(33) (Lown & Ma, 1967) (7) 0.2858 (5) 0.3328 (3) 7.1 0.5570 (7) 0.2553 (6) 0.3635 (2) 6.6 0.4751 (7) 0.1897 (6) Tables 2 and 3. The product from 1,2,3-triphenylguanidine and DMAD has in fact the five-membered ring structure (5) (Fig.…”

10.1007/s11176-008-2028-4

“…Reactions of thioamides with activated acetylenes normally involve the sulfur and nitrogen atoms and give rise to substituted 1,3-thiazolines [1,2] and 1,3thiazines [3,4]. It is also known that reactions of thioamides with acetylenedicarboxylic acid and its esters in benzene and acetonitrile form substituted 1,3thiazolin-4-ones [3,4].…”