摘要:
Two modified DNA 14-mers have been prepared, containing either a 2-deoxy-D-erythrose-derived adenosine analogue carrying a C(8)-CH2O group (deA*). or a 2-deoxy-D-erpthrose-derived uridine analogue, possessing a C(6)-CH2O group (deU*). These nucleosides are linked via a phosphinato group between O-C(3') (deA* and deU*) and O-C(5') of one neighbouring nucleotide, and between C(8)-CH2O (deA*),or C(6)-CH2O (deU*) and O-C(3') of the second neighbour. N-6-Benzoyl-9-(beta -D-erythrofuranosyl)adeine (3) and 1-(beta -D-erythrofuranosyl)uracil (4) were prepared from D-glucose, deoxygenated at C(2'), and converted into the required phosphoramidites 1 and 2. The modified tetradecamers 31 and 32 were prepared by solid-phase synthesis. Pairing studies show a decrease in the melting temperature of 7 to 8 degrees for the duplexes 31 30 and 32 29, as compared to the unmodified DNA duplex 29 30. A comparison with the pairing properties of tetradecamers similarly incorporating deoxyribose- instead of the deoxyerythrose-derived nucleotides evidences that the CH2OH substituent at C(4') has no significant effect on the pairing.