5-[[3,5-Bis(1,1-dimethylethyl)-4-hydroxyphenyl]methylene]-2-thioxo-4-thiazolidinone → 5-(3,5-Bis(tert-butyl)-4-hydroxyphenyl)methylene-4-thiazolidinone

Participants

Reaction Steps

A solution of 69.90 g of 5-[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methylene}-2-thioxo-4-thiazolidinone in 4 liters of ethanol was hydrogenated at 500 pounds per square inch (psi) in the presence of 200 g of 5% palladium on carbon overnight at 100° C. The reaction mixture was filtered and evaporated to dryness. In sections, the material was dissolved in 1 volume of hot ethyl acetate, diluted with 2 volumes of hexane, filtered, and loaded onto a silica gel chromatography column. Elution with 35% ethyl acetate in hexane provided various fractions which were combined according to the purities of the respective compounds. A total of 4.6 g of Compound B were isolated by chromatography. Fractions which were predominantly Compound B were crystallized from ethyl acetate/hexane providing a total yield of Compound B of 13.79 g. Rechromatography of fractions containing impure Compound C on silica eluting with 25% ethyl acetate in hexane provided 9.82 g of Compound C.

Provenance & Evidence