Imidazole 3-oxide ring from pyrimidines

C9H 3N50(, Mr 287.23, cryst., mp. 228-231 °C. Insecticidal nucleoside from the tawny funnel cap Clitocybe inverse, Basidiomycetes). The nitro group on the pyrimidine ring is an unusual feature it is presumably formed by oxidative cleavage from the imidazole ring of adenine. 

The synthesis of target imidazoles can be also realized by photoinduced ring-contraction of the pyrimidine nucleus. For example, significant yield of 4(or 5)-acetylimidazoles 64 are isolated from the photolysis, at 254 nm in methanol or benzene, of 4-substituted 2,6-dimethyl-pyrimidine-N-oxides 62 (Scheme 12.18) [43],... 

Indole contains a pyrrole ring fused with a benzene ring. Compounds derived from indole include the essential amino acid L-tryptophan (Section 27.1C) and the neurotransmitter serotonin. Purine contains a six-membered pyrimidine ring fused with a five-membered imidazole ring. Caffeine is a trimethyl derivative of an oxidized purine. Compounds derived from purine and pyrimidine are building blocks of deoxyribonucleic acids (DNA) and ribonucleic acids (RNA, Chapter 28). 

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