Multifunctional nucleic acid monomer

A multifunctional nucleic acid monomer having the structure

• wherein
• R.sup.1 is a base,stable acid-sensitive blocking group;
• R.sup.2 is a phosphorous derivative that enables addition of the nucleic acid to the 5'-position of an oligonucleotide chain during chemical synthesis;
• R.sup.3 is selected from the group consisting of hydrogen, methyl, I, Br and F;
• R.sup.4 is hydrogen or methyl;
• and
• R.sup.5 is selected from the group consisting of levulinyl, ##STR20## in which R' is hydrogen, aryl or aralkyl;
• the R.sub.i may be the same or different and are selected from the group consisting of amino, nitro, halogeno, hydroxyl, lower alkyl and lower alkoxy;
• the Rj may be the same or different and are selected from the group consisting of amino, nitro, halogeno, hydroxyl, lower alkyl and lower alkoxy;
• the R.sub.k may be the same or different and are selected from the group consisting of amino, nitro, halogeno, hydroxyl, lower alkyl and lower alkoxy;
• i is zero, 1, 2 or 3, j is zero, 1, 2, 3 or 4, and k is 0, 1, 2, 3 or 4;
• and
• Z is selected from the group consisting of ##STR21## wherein x and y are integers which may be the same or different and are integers in the range of 1 to 8.