Sodium borohydride → 3-nitro-7-methylamino-6,7,8,9-tetrahydro [5H] benzocycloheptene-5-ol

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Reaction Steps

A solution of 125 g of sodium borohydride in 625 ml of water at 10° C. was added to a solution of 125 g of the product of Step C in 2 liters of ethanol kept at 25°-30° C. and the mixture was stirred for one hour and let stand for 12 hours. The mixture was concentrated to 0.5 liters and 0.5 liters of water was added thereto. The mixture was extracted 4 times with 250 ml of methylene chloride and the combined organic extracts were extracted 3 times with 200 ml of 2 N hydrochloric acid. The aqueous acid phase was washed with 200 ml of methylene chloride and made alkaline with excess ammonium hydroxide at 10° C. The mixture was extracted 5 times with 200 ml of methylene chloride and the combined organic phases was dried over sodium sulfate and evaporated to dryness to obtain 103 g of raw product. The latter was added to 1.5 liters of a 2-1 ether-ethyl acetate mixture and 10 g of activated carbon was added thereto. The mixture was filtered and the filtrate was evaporated to dryness under reduced pressure to obtain 95 g of 3-nitro-7-methylamino-6,7,8,9-tetrahydro [5H] benzocycloheptene-5-ol in the form of a brown resin.

Provenance & Evidence