Background:

Saccharin 1-methylimidazole (SMI) is a DNA and RNA synthesis activator.

Saccharin 1-methylimidazole (SMI) is the saccharin salt of 1-methylimidazole. 1-Methylimidazole or N-methylimidazole is identified as an aromatic heterocyclic organic agent with the formula CH3C3H3N2. 1-Methylimidazole is a colourless liquid that is used as a base, a specialty solvent, and as a precursor to some ionic liquids. 1-Methylimidazole is a fundamental nitrogen heterocycle and 1-methylimidazole mimics for a variety of nucleoside bases as well as histidine and histamine.

In vitro: Saccharin 1-methylimidazole was found to be able to perform very well for DNA and RNA synthesis. In addition, by using 3 minute, 6 minute, and 12 minute coupling times, saccharin 1-methylimidazole was evaluated in RNA synthesis using TBDMS phosphoramidites, and the results found that a 6 minute coupling time for saccharin 1-methylimidazole showed ETT at a 6 minute coupling time. In additio, it was found that longer coupling times for Saccharin 1-methylimidazole could result in even further improvements in RNA coupling efficiencies [1].

In vivo: So far, there is no animal in vivo data reported for saccharin 1-methylimidazole.

Clinical trial: Up to now, saccharin 1-methylimidazole is not used clinically.

Reference:
[1] Russell MA, Laws AP, Atherton JH, Page MI.  The mechanism of the phosphoramidite synthesis of polynucleotides. Org Biomol Chem. 2008 Sep 21;6(18):3270-5.