Amino-Imino Tautomerization of N2-(4-n-Butylphenyl)-2'-deoxy-3,5'-cycloguanosine
摘要:
N-2-(4-n-Butylphenyl)-2'- deoxy-3,5'-cycloguanosine (cBuPdG) has been studied by one-dimensional 1H and 13C, two-dimensional TOCSY, HMQC, and HMBC, and long range selective INEPT NMR experiments. In DMF and DMSO solutions cBuPdG exists asa mixture of two isomers involved in a slow rate of interconversion which have been identified as N-2 amino-imino tautomers, while in chloroform only the imino tautomer is present. It has been proved that the tautomeric form of the parent nucleoside, N-2-(4-n-butylphenyl)-2'-deoxyguanosine (BuPdG), is N-2 amino. The selective INEPT experiment can be used efficiently in assignment of tautomeric structures of nucleosides.
Synthesis of the P1, P2-Methylene Analog of N2- (p-n-Butylphenyl)-2′- deoxyguanosine 5′-Triphosphate: A Non-substrate Inhibitor of DNA Polymerases
摘要:
N-2-(p-n-Butylphenyl)-2'-deoxyguanosine 5'-(P-1,P-2-methylene)-triphosphate (BuPdGMPCH(2)PP) has been synthesized. Displacement of the mesyloxy group of 5'-MesBuPdG by methanediphosphonate gave 30% of BuPdGMPCH(2)P, but 68% of 3,5'-cycloBuPdG. Reaction of the nucleoside BuPdG with methanediphosphonate and DCC gave 62% of BuPdGMPCH(2)PPCH(2)P, which was hydrolyzed to BuPdGMPCH(2)P in 77% yield. The title compound was obtained by reacting the imidazolide of BuPdGMPCH(2)P with orthophosphate. BuPdGMPCH(2)PP inhibited calf thymus DNA polymerase a with K-i = 9.5 nM, a potency only fivefold weaker than that of BuPdGTP itself.