Ethanol → HCID 86629019, compound

Participants

Reaction Steps

Following the general procedure for the preparation of carboxylic esters from carboxylic acids of Description 15, (2R)-4-{[3-(1,3-dioxobenzo[c]azolin-2-yl)propyl]sulfonyloxy}-3,3-dimethyl-2-(phenylmethoxy)butanoic acid (20) (0.8 g, 1.6 mmol) was dissolved in 20 mL of anhydrous dichloromethane (DCM) and reacted with 0.96 mL (1.92 mmol) of oxalyl chloride (2.0 M in DCM). After completion of the reaction, a solution of 2.0 mL (1.58 g, 34.3 mmol) of ethanol (EtOH) and 0.14 mL (0.127 g, 1.6 mmol) of pyridine in 10 mL of anhydrous dichloromethane (DCM) was added to the acid chloride. After work-up, the crude material was purified by silica gel column chromatography using a mixture of ethyl acetate (EtOAc) and hexane (Hxn) (EtOAc/Hxn=1:2) as eluent to provide 0.7 g (83% yield) of the title compound (22a) as a colorless oil. Rf=0.64 (EtOAc/Hxn=1:2). 1H NMR (400 MHz, CDCl3): δ=1.04 (s, 3H), 1.05 (s, 3H), 1.31 (t, J=6.8 Hz, 3H), 2.18-2.25 (m, 2H), 3.12-3.17 (m, 2H), 3.80 (t, J=6.8 Hz, 2H), 3.83 (s, 1H), 3.96 (d, J=8.8 Hz, 1H), 4.18-4.24 (m, 3H), 4.36 (d, J=11.2 Hz, 1H), 4.60 (d, J=11.6 Hz, 1H), 7.32-7.33 (m, 5H), 7.72-7.75 (m, 2H), 7.84-7.86 (m, 2H) ppm. MS (ESI) m/z 518.16 (M+H)+, 540.11 (M+Na)+. The analytical data was consistent with the proposed structure.

Provenance & Evidence