[CH3:1][C:2]1[CH:19]=[CH:18][C:5]([CH2:6][CH:7]2[C:16]3[CH2:15][CH2:14][CH2:13][CH2:12][C:11]=3[CH2:10][CH2:9][N:8]2[CH3:17])=[CH:4][CH:3]=1.P(=O)(O)(O)O.N>O>[CH3:1][C:2]1[CH:19]=[CH:18][C:5]2[CH2:6][C@H:7]3[N:8]([CH3:17])[CH2:9][CH2:10][C@@:11]4([C:4]=2[CH:3]=1)[C@H:16]3[CH2:15][CH2:14][CH2:13][CH2:12]4(+)-1-p-methylbenzyl-2-methyl-1,2,3,4,5,6,7,8-octahydroisoquinoline (26.5 g) was added to 85% phosphoric acid (130 ml) and the mixture was heated to 130-140° C. for 72 h. After the reaction was complete, the reaction mixture was poured into ice-water and the solution was made strongly alkaline by the addition of conc. ammonia solution (about 300 ml) and diluted with water (500 ml). The solution was then extracted with ether (500 ml×2). The ether layers were combined and washed with water (200 ml), and dried (K2CO3), filtered and evaporated to yield an oil. The oil was immediately vacuum-distilled to produce a faint yellow oil (10 g; by 130-136° C./0.3 mm Hg) which was crystallized on standing. Recrystallization from acetone (˜10 ml) provided white prisms ((7.3 g) of (+)-3-methyl-17-methyl-morphinan; MS (ESI+): m/z 256 (M+1). This procedure is similar to the procedure in U.S. Pat. No. 3,786,054, incorporated by reference herein in its entirety.
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