Hydrogen Bromide → 1-[(1H-Pyrrol-2-yl)methylidene]pyrrolidin-1-ium bromide

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Reaction Steps

To a solution of 81.0 g (1.00 mole) of hydrogen bromide in 1000 ml of absolute chloroform is added dropwise with cooling and stirring a solution of 80.0 g (1.12 mole) of pyrrolidine in 100 ml of absolute chloroform. Then 95.1 g (1.00 mole) of pyrrole-2-carboxaldehyde is added to the above pyrrolidine hydrobromide solution along with 1 pound of Linde Molecular sieve 5A. The reaction mixture is stirred at ambient temperature for 3 hours, then is filtered through filter aid, washing well with chloroform. The combined filtrate and washings are evaporated in vacuo and the residue is recrystallized twice from acetonitrile to give 1-(pyrrol-2-ylmethylene)pyrrolidinium bromide; m.p. 113°-116° C.

Provenance & Evidence