Triphenylphosphine → 6-Bromomethylpteridine

Participants

Reaction Steps

Condensation of 2,4,5,6-tetraaminopyrimidine with dihydroxyacetone gave 6-hydroxymethylpteridine 1. Compound 1 was treated with bromine and triphenyl phosphine in dimethylacetamide to give the corresponding 6-bromomethylpteridine which was coupled in situ with 4-aminobenzoic acid to afford pteroylbenzoic acid 2. Purity of the crude product was about 85% as analyzed by HPLC. Due to the low solubility of this compound in most solvents, purification by recrystallization proved to be impractical. The corresponding sodium salt, however, was soluble in hot water and crystallized upon cooling. Although compound 2 decomposes in hot aqueous hydroxide, treatment of the crude product with dilute sodium bicarbonate gave the sodium salt without observable decomposition. Recrystallization of the salt from dilute aqueous bicarbonate raised product purity to 93% or above. The purified salt was then converted back to acid 2 by treatment with aqueous acetic acid.

Provenance & Evidence