[C:1]1([CH:7]([C:9]2[CH:17]=[CH:16][C:12]3[NH:13][N:14]=[N:15][C:11]=3[CH:10]=2)[OH:8])[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[H-].[Na+].[H][H].I[CH3:23]>CN(C)C=O>[CH3:23][N:15]1[C:11]2[CH:10]=[C:9]([CH:7]([C:1]3[CH:2]=[CH:3][CH:4]=[CH:5][CH:6]=3)[OH:8])[CH:17]=[CH:16][C:12]=2[N:13]=[N:14]1
A mixture of 22.5 parts of α-phenyl-1H-benzotriazole-5-methanol, 4.8 parts of a sodium hydride dispersion 50% and 90 parts of N,N-dimethylformamide was stirred till hydrogen production had ceased. After the addition of 14.2 parts of iodomethane, stirring was continued for 30 minutes at room temperature. The mixture was concentrated. The concentrate was taken up in 50 parts of water and the product was extracted with dichloromethane. The extract was dried, filtered and concentrated. The concentrate was purified by filtration over silica gel using a mixture of trichloromethane and methanol (99:1 by volume) as eluent. The desired fraction was collected and the eluent was evaporated. The two isomers were separated by crystallization from ethyl acetate. The first isomer was further purified by crystallisation from ethyl acetate. The product was filtered off and dried, yielding 3 parts (12.5%) of 1-methyl-α-phenyl-1H-benzotriazole-6-methanol; mp. 145° C. (int. 71).
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