In oligonucleotide synthesis, the classic heterocyclic bases are dA, dC, dG, and dT.

UltraMILD deprotection

The classic heterocyclic base protection groups (Bz-dA, Bz- dC and iBu-dG) are routinely removed using ammonium hydroxide solution with heating. Unfortunately, many modifiers and labels used in oligonucleotide synthesis will not withstand prolonged exposure to such strongly alkaline conditions.

AMA deprotection is not recommended for use in the presence of sensitive labels such as cyanine or rhodamine (TAMRA) dyes, or where there are Bz-protected C nucleosides as this will result in transamidation with methylamine. dmf-dG works particularly well with tbutylamine/methanol/water (1:1:2) as used for rhodamine containing modifiers (e.g. TAMRA).