CH2PO3H2

CH2PO3H2 denotes the phosphonomethyl group, a functional motif consisting of a methylene unit (-CH2-) linked to a phosphonic acid moiety (-PO3H2). This group is a common building block in organophosphorus chemistry and is notable for its stability and ability to engage in hydrogen bonding and metal coordination.

Structure and terminology

The phosphonomethyl group is often described as a phosphonomethyl substituent or as a phosphonate-derived side chain. In molecules, it can be attached to nitrogen, carbon, or other heteroatoms, yielding a range of phosphonomethyl derivatives. The phosphonic acid portion contains a phosphorus center double-bonded to oxygen and bearing two hydroxyl groups, giving it strong acidic character.

Occurrence and examples

A prominent example of a molecule containing the phosphonomethyl moiety is glyphosate, scientifically known as N-(phosphonomethyl)glycine. In glyphosate, the phosphonomethyl group is attached to the amino nitrogen of glycine, producing HOOC-CH2-NH-CH2-PO3H2. Phosphonomethyl groups also appear in various pharmaceuticals and agrochemicals, where they are used to modulate biological activity, enhance metal binding, or improve pharmacokinetic properties.

Properties and reactions

Phosphonomethyl compounds typically feature two acidic protons from the phosphonic acid group, rendering them largely anionic at physiological pH. They can undergo esterification to form phosphonate esters, or coordinate with metal ions as bidentate ligands. Stability and polarity of the CH2PO3H2 unit influence the behavior of larger molecules into which it is incorporated.

Applications

The motif is valued in drug design and agrichemicals for mimicking phosphate groups, enabling interactions with enzymes and transporters, or serving as chelating and stabilizing groups. It also features in antiviral, anticancer, and herbicidal lead structures as a versatile phosphonate handle.

See also: phosphonate, glyphosate, phosphonic acid, bisphosphonates, phosphonomethyl group.