Dhanaji V. Jawale, Devendra Wagare, Dinesh L. Lingampalle and Prashant D. Netankar* Pages 258 - 263 ( 6 )
Background: 1,4-benzothiazine carboxylates show wide application in the field of medicinal chemistry. Therefore, we have designed convenient and efficient method for the synthesis of 1,4-benzothiazine carboxylates.
Objective: Synthesis of 1,4-benzothiazine carboxylates and its guanidines by simple and facile method using efficient catalyst.
Methods: Derivatives of 1,4-benzothiazine carboxylates were synthesized by cyclocondensing β- keto esters with 2-aminobenzenethiols using CAN as a catalyst at room temperature. 1,4-benzothiazine carboxylate, condensed with guanidine hydrochloride in the presence of sodium methoxide in DMF to obtained new 3-substituted-l-4H-benzo[b][1,4]thiazine-2-carboxyguanidines (88-91%).
Results: All the products were obtained with good to excellent yields within 40 min. Here, CAN oxidizes aminothiophenol into disulfide and then nucleophilic attack of enolic form of β-ketoesters on the disulphide and 1, 4-benzothiazine acetates, were obtained with good yields.
Conclusion: We have designed convenient and efficient method for the synthesis of 1,4-benzothiazine carboxylates. Most remarkable features of this cyclocondensation such as use of efficient catalyst and non-volatile solvent under mild reaction condition to obtain excellent yield.
Guanidine, 1, 4-Benzothiazine, CAN, 4H-benzo[b][1, 4]thiazine-2-carboxyguanidines, Synthesis, catalyst, disulphide.
Department of Chemistry, R.D. and S.H. college and S.W.A. science college, Bandra West, Mumbai-400050, Maharashtra, Department of Chemistry, Vivekanand college, Aurangabad-431001, Department of Chemistry, Vivekanand college, Aurangabad-431001, PG Department of Maulana Azad College, Aurangabad-431001