p-Toluenesulfonic acid → HCID 13924194, compound

Participants

Reaction Steps

To a three-necked flask provided with a magnetic stirring bar, dry-ice/acetone condenser and a gas inlet tube were charged 70 grams of 3-(5-t-butyl-3-isoxazolyl)-1-methyl-4-hydroxy-2-imidazolidinone, 5.0 grams of p-toluene sulfonic acid and 700 milliliters of t-butanol. A slow stream of gaseous mercaptomethanol was introduced into the stirred reaction mixture, a total 54 grams of mercaptomethanol being added over a 3 hour period. After 17 hours stirring at room temperature. HPLC and TLC analyses indicated unreacted starting material as the major component. Stirring was continued an additional 24 hours after which time HPLC analysis indicated about 50 percent conversion of starting material to desired product. The reaction mixture was then neutralized by the additiono of 10 grams of potassium carbonate in 15 milliliters of water and excess mercaptomethanol was removed by bubbling nitrogen gas through the reaction mixture. Evaporation of solvent, afforded a semi-solid gummy residue. The residue was dissolved in methylene chloride and adsorbed onto 840 grams of silica gel in a two liter sintered glass funnel. The silica gel was eluted with hexane:methylene chloride, methylene chloride and methylene chloride:methanol and the eluent fractions (about 500 milliliters) were analyzed by TLC or HPLC. Combination of appropriate fractions afforded 58 grams of material identified as the desired product.

Provenance & Evidence