反应详情

A solution of 5,6-dihydro-6-hydroxy-5,5-dimethyl-7-(2-oxopyrrolidin-1-yl)-7H-thieno[3,2-b]pyran (2.0 g, 7.48 mmol) and perchloric acid (70%, 10 drops) in acetic anhydride (20 mL) were stirred for 1 h at 0°-5° C. The solution was poured into ice water (100 mL). The product was extracted into dichloromethane, washed with water (4x), and evaporated in vacuo. The resultant oil was purified by flash chromatography, using 1% methanol in dichloromethane as the eluant, then crystallized from hexanes to give the product, 2.12 g (92%), as a colorless solid: mp 92°-93° C.; IR(KBr): 1745 and 1684 cm-1 ; MS: 310 (MH+); 1 1H NMR (CDCl3): w 1.37 (s, 3H), 1.38 (s, 3H), 1.98 (m, 2H), 2.10 (s, 3H), 2.37 (m, 2H), 3.24 (m, 1H), 3.40 (m, 1H), 5.15 (d, J=9.1 Hz, 1H), 5.44 (d, J=9.1 Hz, 1H), 6.58 (d, J=5.4 Hz, 1H) and 7.13 (d, J=5.4 Hz, 1H).

1. extractionThe product was extracted into dichloromethane
2. washwashed with water (4x)
3. customevaporated in vacuo
4. customThe resultant oil was purified by flash chromatography
5. customcrystallized from hexanes
6. customto give the product, 2.12 g (92%)