Preparation and antiviral properties of new acyclic, achiral nucleoside analogues: 1- or 9-[3-hydroxy-2-(hydroxymethyl)prop-1-enyl]nucleobases and 1- or 9-[2,3-dihydroxy-2-(hydroxymethyl)propyl]nucleobases.

Acyclic, achiral nucleoside derivatives 1b-e of adenine, cytosine, 5-methylcytosine, and guanine, containing a 3-hydroxy-2-(hydroxymethyl)prop-1-enyl group on N-1 or N-9, have been prepared analogously to the previously described thymine derivative 1a. In contrast to the adenine and guanine derivatives, the cytosine derivative 9 was unstable, and was obtained in a low yield due to side reactions. These include cleavage of the propenyl group from the base, and the formation of a bicyclic compound.

Preparation and properties of a new type of acyclic, achiral nucleoside analogue.

Preparation of the nucleoside analogues 1 and incorporation of 1, B = T, in deoxyribooligonucleotides by the phosphoramidite method is described. A two-step deprotection procedure was developed to reduce cleavage of the modified allylic unit. The binding properties of the modified oligonucleotides towards complementary DNA and RNA has been evaluated by Tm measurements showing a deltaTm of -2 to -6.

Oligonucleotides containing a new type of acyclic, achiral nucleoside analogue: 1-[3-hydroxy-2-(hydroxymethyl)prop-1-enyl]thymine.

An achiral, acyclic nucleoside analogue has been incorporated once or twice in oligodeoxyribonucleotides by the phosphoramidite method, and conditions found which allow deprotection of the oligonucleotides containing a sensitive modified allylic unit. The binding affinity of the modified oligonucleotides towards complementary DNA and RNA was reduced compared to unmodified DNA (DeltaT(m) -2 to -6.5 degrees C).