Hydrogen Bromide → 2-Amino-5-bromo-1H-pyrrole-3,4-dicarbonitrile

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Reaction Steps

Tetracyanoethylene (1) is reacted with HBr followed by treatment with a base such as NaOH produced 2-amino-5-bromo-3,4-dicyanopyrrole (3). Treatment of 3 with triethyl orthoformate followed by the addition of sodium hydride and 1 equivalent of the appropriate alkylating agent, with a catalytic amount of tetrabutylammonium iodide, gives the intermediate (5). The synthetic route is dependent upon correctly placing the alkyl substituents on the N7 position. Alkylation of 5 before cyclization controls the regiochemistry. Reaction of 5 with methanolic ammonia affords the 7-alkylated-4-amino-6-bromo-5-cyanopyrrolo[2,3-d]pyrimidines (6). Thus, by selecting the appopriate alkyl substiuent, the desired 7-alkylated-4-amino-6-bromo-5-cyanopyrrolo[2,3-d]pyrimidines can be prepared.

Provenance & Evidence