US Patent 7615619 Nucleoside analogues and oligonucleotide derivative comprising nucleotide analogue thereof

A nucleotide analogue compound represented by formula (1) and salts thereof. In formula (1), A represents a direct bond, C1-4 alkylene, etc.; B represents an optionally substituted aromatic heterocyclic groups; and R1, R2, R3 and R4 each represents hydrogen, an amino-protecting group, a hydroxyl-protecting group, a phosphate group, or —P(R7)R8, wherein R7 and R8 each represents hydroxyl, protected hydroxyl, mercapto, protected mercapto, etc. The compounds are useful as nucleotide analogues for producing oligonucleotide analogues useful in an antisense method and for producing intermediates thereof.