Cyanoacetaldehyde ? New synthetic applications of an old compound syntheses with nitriles, XCI
摘要:
Various reactions of cyanoacetaldehyde (1), freshly prepared by ozonization of (E)-1,4-dicyano-2-butene or allylcyanide, are described. Thus, conversion of 1 with anilines gave beta-phenylaminoacrylonitriles 2a-e. Reaction of 1 with hydrazines led to the corresponding hydrazones 3a-e, which could be cyclized under alkaline conditions to 5-aminopyrazoles 4a-d. An aldol-type condensation product 5a could be obtained by reaction of 1 with sodiumphenoxide. Treatment of 1 with dimethylformamide-dimethylacetal led to the formation of (E)-3-dimethylamino-2-formylpropenenitrile (6), a very useful synthon in synthetic chemistry. For the determination of the structure of 6 the method of steady state differential NOEs was used. Reaction of 6 with hydrazines gave 1-substituted-4-cyanopyrazoles 7a-k.
Various reactions of cyanoacetaldehyde (1), freshly prepared by ozonization of (E)-1,4-dicyano-2-butene or allylcyanide, are described. Thus, conversion of 1 with anilines gave beta-phenylaminoacrylonitriles 2a-e. Reaction of 1 with hydrazines led to the corresponding hydrazones 3a-e, which could be cyclized under alkaline conditions to 5-aminopyrazoles 4a-d. An aldol-type condensation product 5a could be obtained by reaction of 1 with sodiumphenoxide. Treatment of 1 with dimethylformamide-dimethylacetal led to the formation of (E)-3-dimethylamino-2-formylpropenenitrile (6), a very useful synthon in synthetic chemistry. For the determination of the structure of 6 the method of steady state differential NOEs was used. Reaction of 6 with hydrazines gave 1-substituted-4-cyanopyrazoles 7a-k.