反应详情

3-(α-((2S,5S)-2,5-Dimethyl-1-piperazinyl)-3-hydroxybenzyl)-N,N-diethylbenzamide was prepared as a mixture of epimers from 3-(3-((tert-butyldimethylsilyl)oxy)-α-chlorobenzyl)-N,N-diethylbenzamide (Example 1, infra) and (+)-(2S,5S)-2,5-dimethylpiperazine [prepared from L-Ala-L-Ala-diketopiperazine (Bachem Chemicals, Philadelphia, Pa.) as described by Jung and Rohloff (J. Org. Chem. 50, 4909-13 (1985))] according to the methods of Example 1. This material was then alkylated with allyl bromide by methods similar to that in Example 4 to give a mixture of diastereomers that was separated by chromatography on silica gel (Waters Prep 500A, 0.1% triethylamine in dichloromethane). The first isomer to elute was deprotected by the method in Example 4 to give 3-((αR or αS)-α-((2S,5S)-4-Allyl-2,5-dimethyl-1-piperazinyl)-3-hydroxybenzyl)-N,N-diethylbenzamide. NMR (DMSO-d6, 200 MHz): δ0.890 (d, J=5.6 Hz, 3H); 0.981 (d, J=6.4 Hz, 3H); 1.00-1.25 (m, 6H); 2.10-2.48 (m, 4H); 2.59 (d, J=11.1 Hz, 1H); 2.73 (dd, J1 =7.8 Hz, J2 =14.1 Hz, 1H); 2.90-3.60 (m, 6H); 4.54 (s, 1H); 5.13 (d, J=9.0 Hz, 1H); 5.19 (d, J=16.2 Hz, 1H); 5.84 (m, 1H); 6.58 (d, J=8.0 Hz, 1H); 6.86 (s, 1H); 6.88 (d, J=7.1 Hz, 1H); 7.08 (t, J=7.6 Hz, 1H); 7.14 (d, J=7.8 Hz, 1H); 7.34 (t, J=7.6 Hz, 1H); 7.43 (s, 1H); 7.48 (d, J=7.7 Hz, 1H); 9.32 (s, 1H).

1. customto give
2. additiona mixture of diastereomers that
3. customwas separated by chromatography on silica gel (Waters Prep 500A, 0.1% triethylamine in dichloromethane)
4. washThe first isomer to elute
5. customto give 3-((αR