Lawesson's reagent → 7-chloro-5-(2-pyridyl)-3H-1,4-benzodiazepine-2(1H)-thione

Participants

Reaction Conditions

Reaction Steps

A solution of 18.5 g of 7-chloro-5-(2-pyridyl)-3H-1,4-benzodiazepin-2(1H)-one (N. Ch. Hindley, T. M. McClymont & G. O. Chase; F. Hoffmann La Roche and Co., A. G., German Offenlegungsschrift 2,233,483, 1973) in 150 ml of pyridine was treated with 14.2 g of Lawesson reagent and the mixture was stirred at 100° C. for 2 h. After the addition of 1.0 g of Lawesson reagent the mixture was stirred at 100° C. for a further 0.5 h. and then evaporated in a vacuum. The residue was poured into 500 ml of saturated aqueous sodium hydrogen carbonate solution and the precipitate was filtered off (22 g). The red crystals were suspended in 100 ml of boiling methanol. After cooling 100 ml of diethyl ether were added and the crystals were filtered off. There were obtained 18.7 g of 7-chloro-5-(2-pyridyl)-3H-1,4-benzodiazepine-2(1H)-thione of m.p. 217-218° C.

Provenance & Evidence