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The synthesis and photochemistry of 4‐amino‐3‐cyanopyrazole
Author(s) -
Kagan Jacques,
Melnick Bennett
Publication year - 1979
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570160607
Subject(s) - chemistry , isomerization , photodissociation , photochemistry , imidazole , decomposition , cyanide , pyrimidine , hydrolysis , yield (engineering) , glycine , hydrogen cyanide , organic chemistry , stereochemistry , amino acid , catalysis , biochemistry , materials science , metallurgy
4‐Amino‐3‐cyanopyrazole ( 6 ) had once been considered to be a possible intermediate in the photochemical conversion at 350 nm of diaminomaleonitrile ( 1 ) into 4‐amino‐5‐cyanoimidazole ( 3 ), a precursor of adenine. The pyrazole was synthesized and irradiated at 350 nm. No isomerization into the imidazole was observed, even when the photolysis was carried out in the presence of an excess of 1 , where sensitization by this or one of its photolysis products might have operated. At 254 nm, complete decomposition of 6 was observed, with formation of polymeric products. At 300 nm, 6 underwent isomerization to 3 , as well as extensive decomposition. Hydrogen cyanide was probably produced, which reacted with the remaining starting material to yield 7‐aminopyrazolo[4,3‐ d ]pyrimidine ( 10 ), which did not isomerize into adenine under the photolysis conditions. A polymer was also obtained, from which glycine was identified after hydrolysis.