Bracher F. A Novel Approach to Isomeric Part (+/-)-Methadone. Sci. Pharm 64(3/4)(1996)271-278
Only experimental part.
3-(2-Methyl-l,3-dioxolan-2-yl)-2,2-diphenylpropionitrile (1)1.92 g diphenylacetonitrile and 1.06 g sodium-tert-butoxide was heated until homogenous mix was obtained. To this mix 2.5 ml 2-ChlormethyI-2-methyl-1,3-dioxolan was added and the reaction was refluxed 16 hours. Water was added and mix was extracted with ethylacetat. Extract was dried with K2CO3 and solvent was stripped off in vacuo. Yield 1.46 g (50%) of red syrup.
4-0xo-2,2-diphenylvaleronitrile(2)1.46 g (0.005 mol)dioxolane (1) was stirred with mix of conc. HCL/water(1:3, 20 ml) and 20 ml petroleum ether during 24 hours. Organic layer was separated, water layer was extracted with ethylacetat. Extracts was dried with K2CO3, and solvent was evaporated in vacuo. The product was crystallized from petroleum ether/ethylacetat. Yield 0.98 g (79%) mp=107 °C
4-Dimethylamino-2,2-diphenylvaleronitrile0.25 g(0.001 mol) ketone(2) and 1 g dimethylamin hydrochloride were dissolved in 1 ml 33% solution of dimethylamine in MeOH and 4 ml of MeOH. After 2 h 0.2 g(0.0032 mol) NaCNBH3 was added and mix was stirred at RT. After 2 days 0.2 g NaCNBH3 was added and stirring was continued. After 8 days 2M solution of NaOH was added and mix was extracted with EtOAc. Organyc phase was extracted with 5M HCl and to the acid layer was added solid NaOH with cooling until pH became >12.
The mix was extracted with EtOAc and solvent was removed in vacuo. Yield 0.19 g (68%) white crystals mp=84 °C (lit: 90-92 °C).
I'm sorry for my English, I was forced to translate this article twice.
Edit: full-text version on German is available here: http://www.hyperlab.bravepages.com/SciPharm1996.djvu
. IMHO, this method is worse than standard one, because its total yield based on diphenylacetonitrile only 28.6%.
