1,4,5-Thiadiazepines—II

Phenacylsulfonylacetic esters — source for thiadiazoles, triazoles and oxadiazoles

“…When the methyl ester of phenacylsulfonylacetic acid (1) was treated with hydrazine hydrate instead of the expected (oxo-phenyl-ethanesulfonyl)-acetic acid hydrazide (2), a cyclic product 6-phenyl-4,7-dihydro-1H-1 6 , 4,5-thiadiazepin-1,1,3(2H)-trione (4) was obtained [4] (Scheme I). The structure of this compound was established by its spectral parameters.…”

“…White solid, Yield 0.27 g (90%), mp 98-100 °C; ir: 1150, 1327 (SO 2 ), 1632 (C=N), 1722 (C=O), 3339 (OH) cm -1 ; 1 H nmr (CDCl 3 ): H 3.69 (s, 3H, OCH 3 ), 4.38 (s, 2H, SO 2 -CH 2 ), 4.95 (s, 2H, CH 2 -SO 2 ), 7.22-7.41 (m, 4H, Ar-H), 12.26 (s, 1H, OH); 13 C nmr (CDCl 3 ): C 54.0 (OCH 3 ), 56.9 (SO 2 -CH 2 ), 58.6 (CH 2 -SO 2 ), 129. 4,130.7,134.8,, 166.9 (C=NOH), 169.6 (COOCH 3 ). Anal.…”

An unusual reaction of phenacylsulfonylacetic acid methyl ester and styrylsulfonylacetic acid methyl ester with hydrazine hydrate

“…Earlier it was reported the formation of 1,4,5-thiadiazepines from (phenacylthio)acetic acid derivatives by esterification followed by oxidation and treatment with hydrazine hydrate. 4 When the methyl ester of phenacylsulfonylacetic acid ( 1) is made to react with hydrazine hydrate instead of the expected acid hydrazide, a cyclic product (2) is obtained (Scheme 1). The 1 H NMR spectrum of this compound showed signals at δ H 4.25 and 4.89 for C 2 -H and C 7 -H and a broad singlet at δ H 10.65 for NH which disappeared on deuteration.…”

“…The 13 C NMR spectrum of this compound showed signals at δ C 67.2, 166.3, 154.8 and 61.2 for C-2, C-3, C-6 and C-7. Based on this, the structure of the cyclic compound is predicted as 1, 1-dioxo-6-phenyl-1,2,4,7-tetrahydro-1λ 6 - [1,4,5]thiadiazepin-3one (2a). Besides a molecular ion peak is observed at m/z 238, which is in agreement with its chemical composition.…”

“…It seems that the initially formed hydrazone undergoes intramolecular cyclocondensation to 2a. In order to confirm the methodology, the reaction was repeated with 4-methyl and 4-chlorophenacylsulfonylacetic acids where 1,1-dioxo-6-p-tolyl-1,2,4,7tetrahydro-1λ 6 - [1,4,5]thiadiazepin-3-one (2b) and 1,1-dioxo-6-(4-chlorophenyl)-1,2,4,7-tetrahydro-1λ 6 - [1,4,5]thiadiazepin-3one (2c) were obtained. The structures of these compounds are confirmed by spectral parameters.…”