Cyclisierungen mit Cyanthioacetamid in Gegenwart von Schwefel

Abstract

Cyclizations of Cyanothioacetamide in the Presence of Sulphur Cyanothioacetoamide 1 reacts with sulphur in the presence of triethylamine to form the 2,5‐diamino‐thiophene derivative 3 and in the presence of sodium ethoxide the 1,4‐dihydropyridine derivative 2, respectively. 3 easily undergoes ring opening to yield the butadiene derivative 6. Catalyzed by amine from 1, cyclic ketones, and sulphur the 2‐spiro[thieno[2,3‐d]pyrimidine‐4‐thiones] 8 arise. Analogously to other cyanoacetic acid derivatives 1 react with sulphur and isothiocyanates to form the 4‐amino‐Δ4‐thiazoline‐2‐thiones 9 and with sulphur and carbon disulfide to yield the 5‐amino‐1,2‐dithiol‐3‐thione derivative 12. Among the o‐amino‐thiocarboxamides 3, 9, 12 the compounds 3 and 9 can be converted into the 5,6‐heterocondensed pyrimidine‐4‐thiones 4 and 10.

A Facile Synthesis of Oxoindenothiazine and Dioxospiro(indene‐2,4′‐thiazine) Derivatives from (Substituted ethylidene)hydrazinecarbothioamides

“…From the IR of 8c, three sharp bands are shown at 2195, 1754, and 1630 cm À1 , because of the CN, C═O, and C═N groups, respectively, and a broad band at 3350-3295 cm . Thiazine-C-5′ and C-6′ resonated at δ C = 52.91 and 168.11 ppm, respectively, are in accordance with observed trends in δ values for C atoms in the Push-Pull alkenes [25,26]. The analytical data of 8 would also match other isomers of products 12-16.…”

Reactivity of 2-substituted hydrazinecarbothioamides towards tetracyanoethylene and convenient synthesis of (5-amino-2-diazenylthiazolylmethylene)malononitrile derivatives

“…In the (aminomethylene)malononitrile fragment, of 3a, the dicyanovinyl carbons C2 and C1 resonated at 164.4 and 61.6 ppm, respectively, and were in accord with the observed trends in the δ values for C-atoms in push-pull alkenes. 22,23 Further peaks at 115.6 (CN), besides the aromatic carbons support the assigned structure.…”

Synthesis of (3-Cyano-4, 5, 6, 7-Tetrahydrobenzo [B] Thiophen-2- Yl) Formamidine Derivatives as Effective Antimicrobial Agents

“…Compound 3 was synthesized by Gewald thiophene synthesis [23][24][25] The compound 7a was characterized as the IR spectrum of 7a showed stretching frequencies at 2198, 2935, 1766, 1620 cm −1 for CN, CH, C=N, C=C cm −1 respectively. The PMR of this compound showed singlet at δ 10.9 ,triplet at δ 1.85-2.59, quartet at δ 2.50, doublet at δ 7.67 and doublet at δ 3.10 were assigned to OH, CH 2 -CH 2, NH, CH,CH 2 groups respectively.…”