Abstract: Oxidizing compositions particularly for use in automated oligonucleotide synthesis containing a mixture of KI and I.sub.2 in solution, in equilibrium with KI.sub.3. One preferred composition contains 1.75% KI.sub.3 (providing 0.69% KI and 1.06% I.sub.2) in tetrahydrofuran/pyridine/water (93/5/2, v/v). These formulations enable synthesis of oligonucleotides of significantly higher quality than the currently employed formulation comprising 3% I.sub.2 in tetrahydrofuran/pyridine/water (74/21/2, v/v).

Abstract: Purification of synthesized oligonucleotides is achieved using novel processes and reagents. The novel processes involve adding certain salts to treated synthesized oligonucleotides prior to eluting the oligonucleotides from reverse phase purification cartridges. The novel processes also involve treating synthesized oligonucleotides using cleaving and deprotecting reagents containing methylamine and certain salts. Reagents comprising methylamine and certain salts can be used to rapidly cleave and deprotect oligonucleotides while obtaining high yields of purified oligonucleotides using reverse phase purification technologies.

Abstract: A compound of general formula ##STR1## wherein R is methyl R' is selected from the group consisting of trityl and pixyl, and R" is H or OMe. These compounds may advantageously be employed in the synthesis of oligonucleotides by conventional methods, such as automated solid phase synthesis. Use of ethylene diamine in the cleavage and deprotection procedure substantially eliminates the formation of undesirable side products.

Abstract: Disclosed herein are N.sup.4 protected deoxycytidines for use in the synthesis of oligonucleotides, the protecting groups being represented by the formula: --CO--(CH.sub.2).sub.0-9 --CH.sub.3. Preferred embodiments are N.sup.4 acetyl deoxycytidines and include N.sup.4 acetyl deoxycytidine phosphoramidites and N.sup.4 acetyl deoxycytidine H-phosphonates. When used to prepare oligonucleotides the protected deoxycytidine compounds provide high quality oligonucleotide products with little side product from cleavage and deprotection reactions carried out with alkyl amine compounds.

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.