Acetone → Methylnaltrexone Bromide

Reaction equation

[CH2:1]1[CH:3]([CH2:4][N:5]2[C@@H:15]3[CH2:16][C:17]4[CH:22]=[CH:21][C:20]([OH:23])=[C:19]5[O:24][C@H:9]6[C:10]([CH2:12][CH2:13][C@:14]3([OH:25])[C@:8]6([C:18]=45)[CH2:7][CH2:6]2)=[O:11])[CH2:2]1.[CH3:26]C(C)=O.C[Br:31]>CN(C)C=O>[CH3:26][N+:5]1([CH2:4][CH:3]2[CH2:2][CH2:1]2)[C@@H:15]2[CH2:16][C:17]3[CH:22]=[CH:21][C:20]([OH:23])=[C:19]4[O:24][C@H:9]5[C:10]([CH2:12][CH2:13][C@:14]2([OH:25])[C@:8]5([C:18]=34)[CH2:7][CH2:6]1)=[O:11].[Br-:31]

Participants

Procedure

2.5 gm (7.35 millimols) of N-cyclopropylmethylnoroxymorphone were dissolved in a mixture consisting of 50 ml of absolute acetone and 0.5 ml of dimethylformamide, and the resulting solution was admixed with 4.25 gm (44.8 millimols) of methyl bromide. The reaction mixture was then allowed to stand for three weeks at room temperature in a sealed pressure vessel. Thereafter, the contents of the vessel were evaporated, and the residue was crystallized from methanol and recrystallized from methanol/ether, yielding 1.0 gm of the methobromide which had a melting point of 253° C.