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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: mcdull1016 on July 17, 2005, 08:22:15 PM

Title: Synthesis of Lidocaine
Post by: mcdull1016 on July 17, 2005, 08:22:15 PM

1. Why do we use 3 mol of diethylamine with 1 mol of alpha-chloro-2,6-dimethylacetanile in the reaction?
ans i think: is it becoz to make sure the nucleophile is strong enough?

2. Why do we need to extract twice with pentane when isolating and purifying the product lidocaine?

Thanks in advance!! XD

Title: Re:Synthesis of Lidocaine
Post by: AWK on July 18, 2005, 05:00:49 AM

You need at least 2 moles of diethylamine
alpha-chloro-2,6-dimethylacetanile 2C4H11N = Lidocaine + C4H12NCl
Extraction is an equilibrium process, hence you need repeat the extraction a few times to increase practical yield. Lidocaine itsel is soluble in organic solvents, where us its hydrochloride is soluble in water together with diethylammonium chloride.