A nucleotide analogue compound represented by formula (1) and salts
thereof. In formula (1), A represents a direct bond, C.sub.1-4 alkylene,
etc.; B represents an optionally substituted aromatic heterocyclic
groups; and R.sub.1, R.sub.2, R.sub.3 and R.sub.4 each represents
hydrogen, an amino-protecting group, a hydroxyl-protecting group, a
phosphate group, or --P(R.sub.7)R.sub.8, wherein R.sub.7 and R.sub.8 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.