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Updated: Jul 8, 2026

Facile Preparation of 4-Substituted Quinazoline Derivatives
Published on: February 15, 2016
N-(X-chlorophenyl)-4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide (with X = 2 and 4)
Waseeq Ahmad Siddiqui1, Saeed Ahmad, Muhammad Ilyas Tariq
1Department of Chemistry, University of Sargodha, Sargodha, Pakistan.
Abstract:
The structures of N-(2-chlorophenyl)-4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide and N-(4-chlorophenyl)-4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide, both C16H13ClN2O4S, are stabilized by extensive intramolecular hydrogen bonds. The 4-chloro derivative forms dimeric pairs of molecules lying about inversion centres as a result of intermolecular N-H...O hydrogen bonds, forming 14-membered rings representing an R2(2)(14) motif; the 2-chloro derivative is devoid of any such intermolecular hydrogen bonds. The heterocyclic thiazine rings in both structures adopt half-chair conformations.
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