Dimethylamine hydrochloride Dimethylaniline

This approach to the synthesis of the 4-dimethylaminobutyrate ester (50, R = (CH2)3NMe2) involved initial reaction of pristinamycin 11 with 4-chloro-butyroyl chloride in the presence of dimethylaniline yielding the 4-chlorobutyr-ate ester (50, R = (CH2)3C1, 32%), followed by reaction with dimethylamine in methanol at 40 °C. This did indeed provide the required semi-synthetic pristinamycin 11 derivative (50, R = (CH2)3NMe2), which was soluble in water as its hydrochloride salt, but the yield was low (5%). The use of alternative secondary amines in the final reaction did not result in any improvement in the yield. 

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