Water → 2,10-dimethyl-1,3,4,14b-tetrahydro-10H-pyrazino[1,2-a]pyrrolo[2,1-c][1,4]benzodiazepine

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Reaction Steps

To the solution of 2.5 g of 2-methyl-1,3,4,14b-tetrahydro-10H-pyrazino[1,2-a]pyrrolo[2,1-c][1,4]benzodiazepine (Example 1) in 25 ml of tetrahydrofran is added 4.5 ml of 2.45 molar n-butyl lithium in hexane at room temperature while stirring under nitrogen. The pale yellow solution rapidly becomes cherry-red and the temperature rises about 7°. The mixture is stirred for an additional 45 minutes, whereupon it is treated with methyl iodide until the color of the solution is discharged. After stirring for a further 30 minutes the mixture is poured into 100 ml of water, and the product is extracted with diethyl ether. The extract is washed successively with water and brine, evaporated and the residual oil chromatographed on silica gel, using 2% methanol-methylene chloride as eluent, to yield the 2,10-dimethyl-1,3,4,14b-tetrahydro-10H-pyrazino[1,2-a]pyrrolo[2,1-c][1,4]benzodiazepine which is converted to its mono maleate melting at 157°. The identical product is also obtainable according to the methods of Examples 1 and 15 by selecting o-nitro-α-methylbenzyl chloride or bromide respectively.

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