Trimethyl orthovalerate → 4-[[2'-(t-Butyoxycarbonyl)biphenyl-4-yl]methyl]-5-n-butyl-2,4-dihydro-3H-1,2,4-triazole-3-thione

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Reaction Steps

A solution of 1.11 g (3.1 mmole) of 4-[[2'-(t-butoxycarbonyl)biphenyl-4-yl]methyl]-3-thiosemicarbazide and 792 μl (745 mg, 4.6 mmole) of trimethyl orthovalerate in 10 ml of 2-methoxyethanol was stirred at reflux under N2 for 15 hours. The cooled solution was concentrated, and the residue was purified by column chromatography on silica gel (gradient elution with 0-1% methanol in CH2Cl2) to give a gum which could be crystallized by trituration with petroleum ether. The product (828 mg, 63%, mp 135°-137° C.) was homogeneous by TLC in 19:1 CH2Cl2 --MeOH; mass spectrum (FAB) m/e 424 (M+1).

Provenance & Evidence