6-Chloro-7-hydroxy-3,4-dimethyl-2H-chromen-2-one synthesis

Yield:135065-47-3 81.1%

Reaction Conditions:

with sulfuric acid at 0;

Steps:

4.4.4. General Procedure for the Synthesis of 7-hydroxy-6-methyl-2,3-dihydrocyclopenta[c]chromen- 4(1H)-one (4)

General procedure: To a solution of 2-methylbenzene-1,3-diol (0.1 g) in alkylated ethyl acetoacetate, concentrated sulfuric acid (1 mL) was slowly added dropwise at 0 °C in an ice bath. The resulting solution was allowed to react at 0 °C for 5-6 h until the disappearance of starting material, as monitored by TLC (MeOH/DCM = 100:1). The reaction was quenched by adding 50 mL of ice water. The obtained crude solid was filtered, washed with water, dried, and recrystallized by 95% ethanol to give the desired compound (4) as a light yellow solid.

References:

Wang, Dong;Hong, Ren-Yuan;Guo, Mengyao;Liu, Yi;Chen, Nianhang;Li, Xun;Kong, De-Xin [Molecules,2019,vol. 24,# 21,art. no. 4003]