Sulfur → ethyl 4-[[7-amino-1-[(4-fluorophenyl)-methyl]oxazolo[5,4-d]pyrimidin-2(1H)-yliden]amino]-1-piperidinecarboxylate

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Reaction Steps

A mixture of 88.8 parts of ethyl 4-[[[(4-amino-6-hydroxy-5-pyrimidinyl)[(4-fluorophenyl)methyl]amino]thioxomethyl]amino]-1-piperidinecarboxylate, 88 parts of mercury(II) oxide, 0.1 parts of sulfur and 1200 parts of ethanol was stirred overnight at reflux temperature. The reaction mixture was filtered over diatomaceous earth while hot and the filtrate was evaporated. The residue was purified by column chromatography over silica gel using a mixture of trichloromethane and methanol, saturated with ammonia, (95:5 by volume) as eluent. The pure fractions were collected and the eluent was evaporated. The residue was crystallized from ethyl acetate. The product was filtered off and dried, yielding 50.7 parts (66.1%) of ethyl 4-[[7-amino-1-[(4-fluorophenyl)methyl]oxazolo[5,4-d]-pyrimidin-2(1H)-yliden]amino]-1-piperidinecarboxylate; mp. 174.6° C. (compound 24).

Provenance & Evidence