反应详情

Sodium hydroxide (4 g, 100 mmol, 1.25 eq.) dissolved in 10 ml distalled water was added to a solution of 3-hydroxy-pyran-4(1H)-one (8.96 g, 80 mmol, 1 eq.) in 50 ml methanol and allowed to stir at room temperature for 5 minutes. 16 ml (200 mmol, 2.5 eq.) of 35% formaldehyde solution was added dropwise over 15 minutes and the solution was stirred overnight. After adjustment to pH 1 with 37% w/v hydrochloric acid, the reaction mixture was concentrated in vacuo to dryness and the resulting solid was extracted with 2×100 ml of isopropanol at 90° C. The isopropanol extracts were concentrated to yield the crude products. Recrystallisation from isopropanol afforded 9.7 g (85.4%) of the pure title product as a white crystalline solid. m.p. 154-156° C. [lit. 148-150° C. (Tate and Miller, 1964].

1. stirringthe solution was stirred overnight
2. concentrationAfter adjustment to pH 1 with 37% w/v hydrochloric acid, the reaction mixture was concentrated in vacuo to dryness
3. extractionthe resulting solid was extracted with 2×100 ml of isopropanol at 90° C
4. concentrationThe isopropanol extracts were concentrated
5. customto yield the crude products
6. customRecrystallisation from isopropanol