✍ Scribed by Vladimir N. Belov; Viktor V. Sokolov; Boris D. Zlatopolskiy; Armin de Meijere
No coin nor oath required. For personal study only.
A new rearrangement of the cyclic L‐glutamine derivative(S)‐6‐carbamoylamino‐3‐(methylamino)‐2,3,4,5‐tetrahydropyridin‐2‐one (2) and its descarbamoyl analogue 10‐H was found to yield enantiomerically pure 5‐carbamoylimino‐1‐methyl‐L‐proline amide (12‐CONH~2~) and its descarbamoyl analogue 12‐H, respectively. Cyclic amidines 2 and 10‐H were generated from the amide N^2^‐ZGlnOEt 3 in seven and six steps, respectively. Deprotection of (S)‐6‐amino‐3‐[(N‐benzyloxycarbonyl‐N‐methyl)amino]‐2,3,4,5‐tetrahydropyridin‐2‐one (8) led directly to 5‐iminoproline amide 12‐H (via 10‐H and the bicyclic orthoamidine 11‐H) in 66 % overall yield from 3. Carbamoylation of 8 with ZNCO (Z = PhCH~2~OCO) followed by hydrolytic removal of both Z groups gave 5‐(carbamoylimino)proline amide 12‐CONH~2~ (via 2 and orthoamidine 11‐CONH~2~) in 70 % overall yield from 3.
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