Auxetilization

Auxetilization is a process of partial methylation of a base, commonly referring to the methylation of nucleosides. This process involves replacing the amino group of a base with a methyl group, resulting in a molecule with an additional methylated nitrogen atom and a reduced positive charge at physiological pH.

In the context of nucleosocide chemistry, auxetilization is a useful method for introducing a protective group on the amino group of a base, thereby facilitating the formation of nucleoside analogs and derivatives. The process typically involves the reaction of a nucleoside base with methyl iodide in the presence of a base such as triethylamine. The resulting auxiliary group is resistant to acid hydrolysis, allowing the removal of the protecting group without affecting the base.

The protecting group introduced during auxetilization acts as a stabilizing entity, preventing the naturally occurring chemical reactions that could potentially occur at the primary amino group. The attachment of a methyl group to the amino group also increases the chemical stability and a decreases the polarity of the base.

The biological activity of the base may be affected by the additional methyl group, allowing for the modification of various biological properties, such as the binding affinity and the hydrophilicity of the base. In some cases, auxetilization may influence the transport or the charged state of the base, thus modifying its biological activity. The degree of biological modification achieved by auxetilization is dependent on the size and position of the additional methyl group.