Propyl mercaptan → Methyl-4-(Propylthio)Butyrate

Into a 1 liter reaction flask equipped with electric stirrer, reflux condenser, thermometer, addition funnel and cooling bath are placed 68.2 grams (0.5 moles) of methyl-4-chlorobutyrate having the structure: ##STR129## The methyl-4-chlorobutyrate is cooled to 20° C. The mixture of sodium methoxide and n-propyl mercaptan is then poured into the addition funnel. Over a period of 30 minutes while maintaining the pot temperature at 20°-30° C. the premix of n-propyl mercaptan and sodium methoxide is added slowly to the methyl-4-chlorobutyrate reactant. The reaction is exothermic and requires cooling. At the end of the 0.5 hour period, the reaction mass is stirred for a period of 1 hour and the temperature of the reaction mass is permitted to rise to 43° C. The reaction mass is then combined with 500 ml water and transferred to a separatory funnel. The resulting product is then extracted with three 50 ml portions of methylene dichloride. The methylene dichloride extract is then dried over anhydrous sodium sulfate, filtered and distilled on a micro Vigreux column yielding the following fractions: