Cellular polynucleotides are alkylated by endogenous components, such as S-adenosylmethionine, or after reacting with two general classes of environmental and laboratory chemicals. SN1 chemical agents include alkylnitrosourea and N-alkyl-N-nitro-N-nitrosoguanidine that react with the N7 position of guanine, N3 of adenine, O6 of guanine, O2 or O4 of pyrimidines, and the non-phosphodiester oxygen atoms of the phosphate backbone. In contrast, SN2 chemical agents such as methyl methanesulfonate and dimethyl sulfate react primarily with the N1 position of adenine (1-Methyl-2'-deoxyadenosine) and N3 of cytosine. To avoid chain branching during synthesis when using DCI as activator, N6-Me-dA is offered with acetyl protection.
Coupling: No changes needed from standard method recommended by synthesizer manufacturer. |Monomers that allow for UltraMILD deprotection are recommended. (dA:10-1601-xx, dC: 10-1015-xx, dG: 10-1621-xx, dT: 10-1030-xx ). To avoid any exchange of the iPr-Pac group on the dG with acetyl, use the UltraMild Cap Mix A (40-4210-xx/ 40-4212-xx). 0.02M Iodine for oxidation is also recommended.
Deprotection: 2 M Ammonia in methanol, 24 hours at Room Temperature using UltraMILD amidites or 60 hours at Room Temperature if using standard amidites.