Lithium Hydroxide → HCID 59664680, compound

Participants

Reaction Steps

The faster eluting enantiomer of methyl 2-methyl-3-(1-trityl-1H-imidazol-4-yl)propanoate (0.186 g, 0.453 mmol) was saponified by stirring in THF (2 mL) and 1 N LiOH (0.45 mL) for 2 hours. HPLC analysis shows 50% conversion to product. Nearly complete conversion (97.5%) required two additional additions of 1 N LiOH (0.1 mL each) and stirring for a total of 36 hrs. After concentrating under reduced pressure and addition of water (20 mL), the aqueous phase was extracted with DCM (3×20 mL) and the combined DCM extracts were washed with water, saturated sodium chloride (each 1×20 mL) and dried over MgSO4. The DCM was removed and the resulting solid was dried in vacuo to yield 0.1728 g of 97% pure (+)-2-methyl-3-(1-trityl-1H-imidazol-4-yl)propanoic acid; retention time, 9.36 min.; column: YMC ODS-A (3 μm, 50×4.6 mm); gradient: 10% to 100% B in A over 15 min. at 1.25 mL/min. Solvent A: 0.1% TFA in water, solvent B: 0.1% TFA in AcCN. LC/MS: ESI (M+H)+=397.30, (M−H)-=395.30. Optical rotation, [α]D=+12.8° (c=1.03 in CHCl3). 1H-NMR (CD3OD, 500 MHz): δ 1.13 (d, 3H), 2.57-2.65 (m, 1H), 2.67-2.80 (m, 1H), 2.82-2.92 (m, 1H), 6.75 (s, 1H), 7.10-7.17 (m, 6H), 7.34-7.41 (m, 9H), 7.58 (s, 1H).

Provenance & Evidence