| Popis: |
Substitution of 4-nitrophenoxy group at phosphorus atom of 5'-O-monomethoxytrityl-2'-deoxyadenosine 3'-O-¦ O-(4-nitrophenyl)-S-methyl-phosphorothioate¦( 4 )¦(Sp)- 4 : (Rp)- 4 =90:10 and (Sp)- 4 :(Rp)- 4 =30:70¦by base-activated 5'-hydroxyl function of 3'-O-tert-butyldimethylsilyl-2'-deoxyadenosine ( 5 ) gives fully protected P-chiral 2'-deoxyadenylyl(3',5') 2'-deoxyadenosine S-methylphosphorothioates ( 6 ), ¦(Sp)- 6 :(Rp)- 6 =92:8 and (Sp)- 6 :(Rp)- 6 -32:68 respectively ¦.Demethylation of internucleotide S-methylphosphorothioate group in 6 and deprotection of 3'- and 5'-hydroxyl functions lead to diastereoisomeric mixture of 2'-deoxyadenylyl (3',5') 2'-deoxyadenosine-O, O-phosphorothioates ( 7 ). |
