Synthesis of 3-methyl-4H-benzo[b][1,4]thiazine-2-carboxylates Using CAN as a Catalyst and Its Conversion Into Guanidines

Author(s): Dhanaji V. Jawale, Devendra Wagare, Dinesh L. Lingampalle, Prashant D. Netankar*

Journal Name: Current Organocatalysis

Volume 8 , Issue 2 , 2021


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Abstract:

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.

Keywords: Guanidine, 1, 4-Benzothiazine, CAN, 4H-benzo[b][1, 4]thiazine-2-carboxyguanidines, Synthesis, catalyst, disulphide.

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Article Details

VOLUME: 8
ISSUE: 2
Year: 2021
Published on: 28 December, 2020
Page: [258 - 263]
Pages: 6
DOI: 10.2174/2213337207999201228141906
Price: $25

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