N([O-])=O.[Na+].N[C:6]1[CH:7]=[CH:8][C:9]2[N:15]([CH3:16])[C:14](=[O:17])[CH:13]3[CH2:18][CH2:19][CH2:20][N:12]3[CH2:11][C:10]=2[CH:21]=1.Cl.[C:23](=O)([O-])[O-:24].[Na+].[Na+]>O.CO>[CH3:23][O:24][C:6]1[CH:7]=[CH:8][C:9]2[N:15]([CH3:16])[C:14](=[O:17])[CH:13]3[CH2:18][CH2:19][CH2:20][N:12]3[CH2:11][C:10]=2[CH:21]=1
A solution of 3.5 g. of sodium nitrite in 30 ml. of water is added over 1 hour at 48°-50°C. to a solution of 11.5 g. of 7-amino-1,2,3,5,10,11a-hexahydro-10-methyl-11H- pyrrolo[2,1-c] [1,4]benzodiazepin-11-one in 20 ml. of concentrated hydrochloric acid and 500 ml. of methanol. The reaction mixture is held at this temperature for 1 hour longer, diluted with an equal volume of water, neutralized with sodium carbonate and concentrated under reduced pressure to remove the methanol. The aqueous residue is extracted with benzene and the benzene layer is concentrated to remove the crude 1,2,3,5,10,11a-hexahydro-7-methoxy-10-methyl-11H- pyrrolo[2,1-c] [1,4]benzodiazepin-11-one. Further purification is by partition chromatography on a diatomaceous earth column using a heptane/methyl cellosolve solvent system.
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