Abstract: Double stranded nucleic acid duplexes serve as universal harvestable and cleavable link systems in a variety of different types of immunoassays (e.g., sandwich, competitive, etc.). Depending upon the type of assay, at least one specific component involved in the assay system is attached to a first member of a pair of sequences forming a double stranded nucleic acid (i.e., two oligonucleotides comprising substantially complementary sequences). The assay is carried out in the presence of a support to which is attached an oligonucleotide which is the other member of the pair of sequences forming a double-stranded nucleic acid duplex under hybridization conditions. Upon the hybridization of the two complementary oligonucleotides to form a duplex, the component of the assay system to which the first member of the pair of oligonucleotides is attached may thereby be effectively removed from the solution phase and harvested onto the support.

Abstract: Deoxyribonucleotide and ribonucleotide derivatives of the general formula I ##STR1## wherein R.sup.1 represents --CR'R"--Ar, in which Ar is substituted aryl (as hereinafter defined) and R' and R" are independently selected from the group consisting of hydrogen and lower alkyl; one of --R.sup.2 and R.sup.3 is a hydroxyl-protecting group and the other is a group suitable for synthesis of polynucleotides or for attachment of the nucleotide to a solid support; R.sup.4 is selected from the group consisting of hydrogen, --OH and protected hydroxyl; and B represents a divalent radical corresponding to a purine or pyrimidine base. When synthesis is carried out using these derivatives, the deprotection procedure is reduced to an essentially instantaneous process. The derivatives have acceptable shelf life and are very stable to conventional DNA synthesis conditions. Particularly preferred are those compounds wherein Ar is mono- and dihalo-substituted phenyl.

Abstract: Disclosed herein are protecting groups for exocyclic amino groups of the base cytosine for use in the synthesis of oligonucleotides and oligonucleoside phosphorothioates, the protecting groups being represented by the formula: --CO--(CH.sub.2).sub.0-9 --CH.sub.3. In a particularly preferred embodiment, the base cytosine is protected with acetyl (--CO--CH.sub.3), and the oligonucleotide or oligonucleoside phosphorothioate incorporating the protected cytosine is subjected to a cleavage/deprotection reagent comprising methylamine and ammonia.

Abstract: A process for synthesizing oligonucleotides by phosphoramidite chemistry wherein the improvement is the use of substituted aryl carboxylic acids as the activators. These activators produce in situ nucleotide intermediates in which the substituted arylcarbonyl group has displaced the amidite moiety.