Hydrogen Bromide → KOJIC ACID, 2-BROMOMETHYL ANALOG

Temperature

4 °C

In a 250 mL round-bottomed flask 5-hydroxy-2-(hydroxymethyl)-4H-pyran-4-one (10.0 g, 70.36 mmol) was added to concentrated H2SO4 (30 mL). The solution was cooled to 4° C. and bromohydric acid (40 mL) was added dropwise for 1.5 h. HBr vapors were trapped using a NaOH 0.5 N solution. The reaction was stirred at 70° C. for 18.5 h. After cooling ice (220 g) was added with continuous stirring for for 1.5 h to obtain a white precipitate. The solid was filtered off and dissolved in ethyl acetate and the solution was dried with MgSO4, filtered and evaporated. 2-(Bromomethyl)-5-hydroxy-4H-pyran-4-one 21 was obtained as a pale yellow solid (9.1 g, 63% yield).

1. additionwas added
2. stirringwith continuous stirring for for 1.5 h
3. customto obtain a white precipitate
4. filtrationThe solid was filtered off
5. dissolutiondissolved in ethyl acetate
6. dry with materialthe solution was dried with MgSO4
7. filtrationfiltered
8. customevaporated

ORD record

ord-e754d328d4a344649274103f436a75ce

Source dataset

uspto-grants-2009_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07514432B2