Methyl 1,2,3-Triazole-4-carboxylate

Methyl 1,2,3-Triazole-4-carboxylate is catalogued as a heterocyclic entry: CAS 4967-77-5, formula C4H5N3O2, 127.10 g/mol.

Ring functionalisation is usually the selectivity problem here: the position that reacts first is set by the heteroatom and by whatever is already on the ring.

The formula C4H5N3O2 resolves to 4 carbons with 2 oxygens and 3 nitrogens. With 4 carbons the molecule is small enough to be lost to evaporation during a work-up, so the step is usually run closed.

Where this entry sits in a route

Methyl 1,2,3-triazole-4-carboxylate is the product side of a copper-catalysed azide-alkyne cycloaddition, and also a starting point in its own right: the ester is the handle for amidation or hydrolysis, and the triazole ring is a stable, planar amide bioisostere. It is bought both by groups building triazole libraries and by groups that need a pre-formed ring.

What the analysis covers

The lot is checked for the regioisomeric triazole, which is the main impurity from a non-selective cycloaddition, and for residual copper. Copper is the number that matters if the entry is going into a biological assay.

Handling and storage

Store closed, dry and dark. Ring oxidation and discolouration are the usual signs that a lot has been open too long.

Ordering

Quoted from stock in 1kg / 25kg / 100kg, or made to order where the lot has run down. Either way the same release testing applies. Where a specification has to be met on paper before shipment, it is agreed in writing and the lot is qualified against it rather than against the catalogue text.