Hydrochloric Acid → Isopropyl 6-methyl-4-(3-nitrophenyl)-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate

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Reaction Steps

Sodium methoxide in methanol (1.6 ml, 7.5 mmol, 2 eq) was added to a solution of isomer B [described in Example 20, part B] of 1,2,3,4-tetrahydro-6-methyl-4-(3-nitrophenyl)-2-thioxo-3,5-pyrimidinecarboxylic acid, 5-(1-methylethyl)ester, 3-[(S)-5-methoxycarbonyl)-3-pyrrolidinyl]ester (2.04 g, 3.7 mmol) in methanol (18 ml). The reaction was allowed to stir at room temperature. After 16 hours, the pH was adjusted to 2 with ethereal hydrochloric acid and the mixture was cooled to 0° C. for six hours. The resulting solid was collected by filtration. Three further crops were collected from the mother liquors, which when combined afforded 1.12 g (89%). [α]D =+85° (c=0.5, dimethylsulfoxide).

Provenance & Evidence