1,1'-(Diazomethylene)bis(benzene) → N-tert-butoxycarbonyl-trans-4-hydroxy-L-proline diphenylmethyl ester

HRID 51192

Reaction equation

HRID 51192 reaction equation
[C:1]([N:8]1[CH2:15][C@H:14]([OH:16])[CH2:13][C@H:9]1[C:10]([OH:12])=[O:11])([O:3][C:4]([CH3:7])([CH3:6])[CH3:5])=[O:2].[C:17]1([C:23]([C:26]2[CH:31]=[CH:30][CH:29]=[CH:28][CH:27]=2)=[N+]=[N-])[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1>C(OCC)(=O)C>[C:17]1([CH:23]([O:11][C:10](=[O:12])[C@@H:9]2[CH2:13][C@@H:14]([OH:16])[CH2:15][N:8]2[C:1]([O:3][C:4]([CH3:7])([CH3:6])[CH3:5])=[O:2])[C:26]2[CH:27]=[CH:28][CH:29]=[CH:30][CH:31]=2)[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1

Participants

4

Reactant 2

HCID 612301,1'-(Diazomethylene)bis(benzene)HCID 88804(2S,4R)-4-hydroxy-1-[(2-methylpropan-2-yl)oxycarbonyl]pyrrolidine-2-carboxylic acid

Product 1

HCID 21348449N-tert-butoxycarbonyl-trans-4-hydroxy-L-proline diphenylmethyl esterYield 91%

Reagents, catalysts & solvents 1

HCID 8857Ethyl AcetateSolvent2×

Procedure

To a solution of freshly prepared diphenyldiazomethane22 (3.50 g, 18.0 mmol) in ethyl acetate (20 ml) was added N-Boc-trans-4-hydroxy-L-proline (3.25 g, 14.0 mmol) in ethyl acetate (30 ml). Nitrogen gas was slowly evolved from the solution and the intense purple colour of diphenyldiazomethane was gradually discharged. The solution was stirred at room temperature overnight using a CaCl2 guard tube. Evaporation of the solvent followed by precipitation of the product from ethyl acetate-petroleum ether b.p. 40-60° C. gave a white solid, N-tert-butoxycarbonyl-trans-4-hydroxy-L-proline diphenylmethyl ester (2a), (5.10 g, 91%), m.p. 93-95° C. (lit.9 m.p. 103-104° C.), δH (200 MHz; CDCl3) 1.22 and 1.47 (9H, 2×s, Boc rotamers), 1.95-2.50 [3H, br m, CH2(3) and OH], 3.45-3.74 [2H, br m, CH2(5)], 4.40-4.65 [2H, br m, CH(2)and CH(4)], 6.95 (1H, br s, CHPh2), 7.25-7.55 (10H, br m, phenyl CH); νmax (KBr)/cm−1 3491br (O—H), 1728s (C═O ester), 1693s (C═O urethane); m/z (ES MS) 436 (M+K+, 55%), 420 (M+Na+, 100), 415 (M+NH4+, 15), 398 (M+H+, 72); [α]D25−54.3 (C=1.0, EtOH).

Workup

  1. customEvaporation of the solvent
  2. customfollowed by precipitation of the product from ethyl acetate-petroleum ether b.p. 40-60° C.

Sources & evidence

ORD record
ord-69c8cfbd21774ea0b20386ad05cc23fc
Source dataset
uspto-grants-2004_03
Patent number
US06713603B2

Linked notes

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