HCID 86733275, compound → HCID 21402604, compound

Participants

Reaction Steps

A suspension of 12.05 parts of 8-allyl-5-(3-methyl-n-butoxy)-4-oxo-4H-1-benzopyran-2-carboxylic acid, ethyl ester in 225 parts of ethanol was treated with 0.2 parts of 5% palladium/charcoal catalyst and hydrogenated at a pressure of 4 atmospheres. After 30 minutes the hydrogen uptake ceased and the reaction mixture was filtered. The volume of the filtrate was reduced and then water was added. On standing 10.2 parts of 5-(3-methyl-n-butoxy)-8-n-propyl-4-oxo-4H-1-benzopyran-2-carboxylic acid, ethyl ester crystallised as yellow needles, melting point 64.5°-65°C. This material was stirred with a hot aqueous solution of sodium bicarbonate containing some ethanol for 2 hours. The resulting solution was cooled, washed with diethyl ether and acidified with dilute hydrochloric acid. The yellow precipitate was collected and crystallised from aqueous ethanol to give 7.2 parts of 5-(3-methyl-n-butoxy)-8-n-propyl-4-oxo-4H-1-benzopyran-2-carboxylic acid as yellow needles, melting point 166°-167°C.

Provenance & Evidence