SYNTHESIS AND PROPERTIES OF 2'-DEOXY-1',2'-SECO-D-RIBOSYL (5'-]3')OLIGONUCLEOTIDES (EQUALS 1',2'-SECO-DNA) CONTAINING ADENINE AND THYMINE

Some 2'-deoxy-1',2'-seco-D-ribosyl (5' --> 3')oligonucleotides (= 1',2 '-seco-DNA). differing from natural DNA only by a bond scission betwee n the centers C(1') and C(2'), were synthesized and studied in order t o compare their structure properties and pairing behavior with those o f corresponding natural DNA and homo-DNA oligonucleotides (2',3'-dideo xy-beta-D-glucopyranosyl oligonucleotides). Starting from (-)-D-tartar ic acid, 2'-deoxy-1',2'-secoadenosine derivative 9a and 1',2'-secothym idine (9b) were obtained in pure crystalline form. Using the phosphora midite variant of the phosphite-triester method, a dinucleotide monoph osphate 1',2'-seco-d(T-2) was synthesized in solution, while oligonucl eotides 1',2'-seco-d[(AT)(6)], 1',2'-seco-d(A(10)) and 1',2'-seco-d(T- 10) were prepared on solid phase with either automated or manual techn iques. Results of UV-and CD-spectroscopic as well as gel-electrophoret ic studies indicated that neither adenine-thymine base pairing (as obs erved in natural DNA and homo-DNA), nor the adenine-adenine base pairi ng (as observed in homo-DNA) was effective in 1',2'-seco-DNA. Furtherm ore, hybrid pairing was observed neither between 1',2'-seco-DNA and na tural DNA nor between 1',2'-seco-DNA and homo-DNA.