Gabriel, Siegmund

The Gabriel synthesis is based on work carried out by Siegmund Gabriel at the Uni versity of Berlin in the 1880s A detailed discussion of each step in the Gabriel synthesis of benzylamine can be found in the October 1975 Journal of Chemical Education (pp 670-671)... 

Siegmund Gabriel (1851-1924) was bom in Berlin, Germany, and received his Pn.D. in 1874 at the University of Berlin, working with August von Hofmann. After further work with Robert Bunsen, he became professor of chemistry st the University 0 Berlin. 

In 1887, Siegmund Gabriel (at the University of Berlin) developed the Gabriel amine synthesis for making primary amines without danger of over-alkylation. He used the phthalimide anion as a protected form of ammonia that cannot alkylate more than once. Phthalimide has one acidic N—H proton (pKa 8.3) that is abstracted by potassium hydroxide to give the phthalimide anion. 

Siegmund Gabriel (Berlin ii November 1851-22 March 1924), professor in Berlin, synthesised isoquinoline, discovered a preparation of primary amines by the action of potassium phthalimide on halides and acid hydrolysis of the resulting ester of phthalylglycocoll, synthesised pyrrolidine from S-chlorobutylamine and piperidine from co-chloramylamine, pyrimidine from barbituric acid, and quinazoline. ... 

A successful variation of the simple alkylation synthesis involves a protected, disguised amine, and is called the Gabriel synthesis (Siegmund Gabriel, 1851-1924). In this procedure, bromomalomc ester is first treated with potassium phthalimide in an Sn2 displacement of bromide ion (Fig. 23.11). 

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