2-Aminothiazole → 4-Hydroxy-N-(2-thiazolyl)-2H-naphtho-[2,1-e]-1,2-thiazine-3-carboxamide-1,1-dioxide

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Reaction Steps

3.2 gm (0.01 mol) of 4-hydroxy-2H-naphtho[2,1-e]-1,2-thiazine-3-carboxylic acid methyl ester-1,1-dioxide and 1.5 gm (0.015 mol) of 2-amino-thiazole were heated for 16 hours in 200 ml of dry xylene analogous to Example 35. After cooling, the precipitate which had formed was suction-filtered off, and the mother liquor was evaporated in vacuo, whereby another crop of crude 4-hydroxy-N-(2-thiazolyl)-2H-naphtho[2,1-e]-1,2-thiazine-3-carboxamide-1,1-dioxide was obtained. The two crops of crude product were combined and recrystallized three times from acetonitrile, yielding 0.85 gm (23% of theory) of the desired compound, m.p. 238° C (decomp.).

Provenance & Evidence