反应详情

A mixture of 5-(hydroxymethylene)-2,2-dimethyl-1,3-dioxane-4,6-dione (8.6 g, 50 mmole), described by Bihlmayer et al., supra, and mercaptoacetic acid methyl ester (13 g, 0.125 mole) in dry methanol (50 mL) was heated at reflux for 2 hr. Thereafter, the mixture was stirred for 18 hr at 20°-22° C., and then poured into ice-water. The resultant mixture was extracted with diethyl ether. The extract was dried (MgSO4) and concentrated to dryness under reduced pressure. The residue (8.0 g) was purified by chromatography on silica gel, using 30% ethyl acetate in hexane (v/v) as the eluant. The pure fractions were combined and the solvent removed under reduced pressure. Crystallization of the residue from ethyl acetate-hexane gave the title compound; mp 117°-118° C.; NMR (CDCl3) δ 1.7 (s, 6H), 3.65 (s, 2H), 3.75 (s, 3H), 8.95 (s, 1H); IR (CHCl3) 1735, 1700, 1535 cm-1 ; UVλmax (MeOH) 315 um (ε 8900), 260 (7950).

1. temperaturewas heated
2. temperatureat reflux for 2 hr
3. extractionThe resultant mixture was extracted with diethyl ether
4. dry with materialThe extract was dried (MgSO4)
5. concentrationconcentrated to dryness under reduced pressure
6. customThe residue (8.0 g) was purified by chromatography on silica gel
7. customthe solvent removed under reduced pressure
8. customCrystallization of the residue from ethyl acetate-hexane