Formation and Ring Contraction of Benzo[f][1,2]Thiazepine-1,1-Dioxides from and to Benzo[e][1,2]Thiazine-1,1-Dioxides |
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Authors: | Ali Khalaj Neda Adibpour |
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Institution: | 1. Department of Medicinal Chemistry, Faculty of Pharmacy , Tehran University of Medical Sciences , Tehran, Iran khalaj@ams.ac.ir;3. Department of Medicinal Chemistry, School of Pharmacy , Ahwaz Jundishapur University of Medical Sciences , Ahwaz, Iran |
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Abstract: | Alkoxide-promoted ring expansion of the novel ethyl 2-(6,7-dimethoxy-3-oxo-3,4-dihydrobenzoe]1,2]thiazine-1,1-dioxide-2-yl)acetate 3a and analogous 4,4-diethyl derivative 3b and cyclization of methyl 2-2-(phenylaminocarbonylmethyl sulfamoyl)-4,5-dimethoxyphenyl] acetate 9 to the corresponding new 3-carboxylates and 3-carboxanilide of 7,8-dimethoxy-4-hydroxy-2,5-dihydrobenzof]1,2]thiazepine-1,1-dioxide (5a,b and 10 respectively) is described. Compound 5a was deacylated upon treatment with sodium hydroxide followed by hydrochloric acid to give 7,8-dimethoxy-2,3-dihydrobenzof]1,2]thiazepine-1,1-dioxide-4 (5H)-one 8 and its N-ethyl derivative transferred to 6,7-dimethoxy-2-ethyl-3-oxo-3,4-dihydrobenzoe]1,2]thiazine-1,1-dioxide 7 by the reaction with ethyl methyl ketone in the presence of pyrrolidine. |
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Keywords: | 4-Hydroxy-2 5-dihydrobenzo[f][1 2] thiazepine-1 1-dioxides 3-oxo-3 4-dihydrobenzo[e][1 2]thiazine-1 1-dioxides ring contraction ring expansion |
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