[C:1]([C:3]([C@H:16]1[CH2:20][CH2:19][NH:18][CH2:17]1)([C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1)[C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1)#[N:2].[OH-:21].[Na+]>S(=O)(=O)(O)O.O>[C:1]([C:3]([C@H:16]1[CH2:20][CH2:19][NH:18][CH2:17]1)([C:10]1[CH:11]=[CH:12][CH:13]=[CH:14][CH:15]=1)[C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1)(=[O:21])[NH2:2]3-(R)-(-)-(1-cyano-1,1-diphenylmethyl)pyrrolidine (9.2 g-see Preparation 9(B)) was dissolved in 95% sulphuric acid (80 ml) and the mixture was heated at 80° C. for 4 hours and then at 90° C. for 1 hour. Ice (1 kg) was added and the mixture was basified (pH 12) by the addition of a cold solution of sodium hydroxide (120 g) in water (100 ml). The mixture was extracted with dichloromethane (4×100 ml) and the combined extracts were dried (MgSO4) then concentrated in vacuo to give a foam which was purified by column chromatography on alumina eluting with dichloromethane containing methanol (0% up to 10%). The product-containing fractions were combined and concentrated in vacuo to give the title compound as a foam, yield, 4.5 g, [α]D25 +16.9° (c 1.0, CH2Cl2).
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