反应详情

温度

90 °C

A mixture of 8.2 g (0.042 mol) of 1-(5-carbethoxy-2-furanyl)-2-methyl-1-propene, 10.0 g of SeO2 (0.09 mol) and 120 mL of dioxane was degassed three times under argon and heated at 90° C. for 1.5 h. The reaction mixture was cooled, filtered through Celite and evaporated to remove most of the dioxane. The residue was filtered again and washed with 50 mL of dioxane. The filtrate and washings were concentrated to a small volume and chromatographed on 170 g of silica gel (25% Et2O/hexane) to give 3.9 g (44% yield) of a white solid. Recrystallization from EtOAc/hexane gave long white needles, mp 83° C.; IR (mull) 1740, 1690, 1650, 1320, 1280, 1240, 1200, 1040, 980, 780 cm-1 ; 1H NMR (CDCl3) δ1.43 (t, J=7 Hz, 3, CH2CH3), 2.18 (s, 3, C=CCH3), 4.48 (q, J=7 Hz, 2, CH2CH3), 6.88 and 7.35 (2d, J=4 Hz, 2, 3', 4'H), 7.15 (s, 1, C=CH), 9.60 (s, 1, CHO); MS calcd for C11H12O4 208.0736, found 208.0728.

1. customwas degassed three times under argon
2. temperatureThe reaction mixture was cooled
3. filtrationfiltered through Celite
4. customevaporated
5. customto remove most of the dioxane
6. filtrationThe residue was filtered again
7. washwashed with 50 mL of dioxane
8. concentrationThe filtrate and washings were concentrated to a small volume
9. customchromatographed on 170 g of silica gel (25% Et2O/hexane)