Trifluoroacetic acid → HCID 86590986, compound

Participants

Reaction Steps

To a cooled (0˜−5° C.) stirred solution of the tert-butyl ester 11 (0.469 g, 1.64 mmol) in CH2Cl2 (8 ml), a precooled (ca. 0° C.) trifluoroacetic acid (6.5 mL) was added portionwise. The reaction mixture was kept for 1.5 hours at room temperature and was evaporated in vacuo to dryness. Traces of trifluoroacetic acid were removed by repeated addition and evaporation of dry ether (3×15 mL). After drying in vacuo, 0.373 g (99%) of the product 12 was obtained as a yellowish semisolid. 1H NMR (400 MHz) in CDCl3 (J, Hz): δ 1.58 (3H, d, 3J=7.4, α-MeCH), 4.10-4.06 (1H, m, 5-H), 4.13 (1H, dd, 2J=−11.7, 3J=4.1 , 6-HA), 4.31 (1H, dd, 2J=−11.7, 3J=5.9, 6-HB), 4.43 (1H, d, 3J=7.4, 4-H), H), 5.12 (1H, q, 3J=7.4, α-CH), 6.51 (2H, br. s, OH, COOH). 13C (100 MHz) in CD3CN: δ 13.51, 54.74, 65.75, 71.38, 78.21, 167.55, 170.91. IR (film), cm−1: 3456, 2959, 2125, 1746, 1654, 1284. MS (CI, isobutane), m/Z: 231 (M++1). The compound was used in the next reaction without further purification.

Provenance & Evidence