The molecule is a 7,8-dihydrobiopterin in which the 1,2-dihydroxypropyl group has (1R,2S)-configuration; naturally occurring form. It is an enantiomer of a D-erythro-7,8-dihydrobiopterin.
2-amino-6-[(1R,2S)-1,2-dihydroxypropyl]-7,8-dihydro-3H-pteridin-4-one