Lawesson's reagent → 7-methoxy-3-methyl-4,5-dihydro-1H-pyrido[2,3-b][1,4]diazepine-2(3H)-thione

Participants

Reaction Conditions

Reaction Steps

To a solution of 7-methoxy-3-methyl-4,5-dihydro-1H-pyrido[2,3-b][1,4]diazepin-2(3H)-one (2.7 g, 13.03 mmol) in anhydrous tetrahydrofuran (30 mL) was added Lawesson's Reagent (8.32 g, 20.60 mmol). The mixture was stirred at 80° C. for 12 hours. The reaction mixture was concentrated in vacuo and washed with brine (20 mL), and then the mixture was filtered through a celite pad. The filtrate was extracted with acetic ester (20 mL×3). The combined organic phase was dried by anhydrous sodium sulphate, and then filtered. The filtrate was concentrated and purified by column chromatograph silica gel (elute: dichloromethane/Methanol: 80:1→50:1→30:1) to give 7-methoxy-3-methyl-4,5-dihydro-1H-pyrido[2,3-b][1,4]diazepine-2(3H)-thione (1.8 g, 62%) as a yellow solid.

Provenance & Evidence