title: Biosynthesis of 2'-deoxycoformycin: evidence for ring expansion of the adenine moiety of adenosine to a tetrahydroimidazo[4,5-d][1,3]diazepine system.
abstract: 2'-Deoxycoformycin (2'-dCF), a nucleoside antitumor agent produced in trace quantities by Streptomyces antibioticus, has been shown in earlier work to originate from the intact carbon-nitrogen framework of adenosine. Additional experiments using 13C and two-dimensional Fourier transform NMR techniques, together with radiolabeling studies, identify the C-1 of D-ribose, and not the tetrahydrofolate "C-1 pool", as the source of the C-7 carbon in the aglycon of 2'-dCF. These results show that the adenine portion of adenosine (or a nucleotide thereof) undergoes a unique ring expansion, by insertion of a -CH2- unit between the N-1 and C-6 of the adenine ring, to furnish the 1,3-diazepine portion of 2'-dCF.
mesh_terms: D000241:Adenosine; D000970:Antineoplastic Agents / Q000138:chemical synthesis*; D002250:Carbon Radioisotopes; D003070:Coformycin / Q000031:analogs & derivatives / Q000138:chemical synthesis*; D007202:Indicators and Reagents; D007288:Inosine; D009682:Magnetic Resonance Spectroscopy; D015649:Pentostatin; D012263:Ribonucleosides / Q000138:chemical synthesis*
chemical_list: D000970:Antineoplastic Agents; D002250:Carbon Radioisotopes; D007202:Indicators and Reagents; D012263:Ribonucleosides; D003070:Coformycin; D015649:Pentostatin; D007288:Inosine; D000241:Adenosine