Diethylamine → Sodium 2-ethylhexanoate

Participants

Reaction Steps

To 300 ml. of anhydrous ethanol is added 100 g. (0.293 mole) of anhydrous 6-(1-aminocyclohexanecarboxamido)penicillanic acid followed by 23.6 g. (0.322 mole) of diethylamine at about 20°C. with stirring. After stirring of one half hour, the solution is clarified by filtration through diatomaceous earth and the filter cake is washed with 50 ml. of a 1:1 mixture of hexane and anhydrous ethanol. The resulting solution of diethylamine 6-(1-aminocyclohexanecarboxamido)penicillanate is diluted with 500 ml. of hexane. To the slowly stirred solution of the diethylamine salt is gradually added over a thirty minute period at from about 20°-23° C., a solution of sodium 2-ethylhexanoate (prepared by the reaction of 16.6 g. (0.309 mole) of sodium methoxide with 46.5 g. (0.322 mole) of 2-ethylhexanoic acid in 200 ml. of a 1:1 mixture of anhydrous ethanol and hexane at a temperature maintained below 30°C. followed by filtration and the addition of 15 ml. of a 1:1 mixture of hexane and anhydrous ethanol to wash the filter). After addition of about 75 ml. of the solution of sodium 2-ethylhexanoate, seed material of sodium 6-(1-aminocyclohexanecarboxamido)penicillanate separately formed, is added to the solution to initiate crystallization. After complete addition of the sodium 2-ethylhexanoate solution, stirring is continued for 1/2 hour, 200 ml. of hexane is added over a 30 minute period and stirring is continued for another half hour at from about 20°-23°C.

Provenance & Evidence