Prebiotic adenine revisited: eutectics and photochemistry.
Recent studies support an earlier suggestion that, if adenine was formed prebiotically on the primitive earth, eutectic freezing of hydrogen cyanide solutions is likely to have been important. Here we revisit the suggestion that the synthesis of adenine may have involved the photochemical conversion of the tetramer of hydrogen cyanide in eutectic solution to 4-amino-5-cyano-imidazole. This would make possible a reaction sequence that does not require the presence of free ammonia. It is further suggested that the reaction of cyanoacetylene with cyanate in eutectic solution to give cytosine might have proceeded in parallel with adenine synthesis.
The Salk Institute for Biological Studies, San Diego, CA, USA. orgel@salk.edu
Leslie E
LE
Orgel
D000225:Adenine / Q000737:chemistry*; D005615:Freezing; D006856:Hydrogen Cyanide / Q000737:chemistry; D015394:Molecular Structure; D010777:Photochemistry; D011743:Pyrimidines / Q000096:biosynthesis; D012996:Solutions
D011743:Pyrimidines; D012996:Solutions; D006856:Hydrogen Cyanide; D000225:Adenine