X-ray crystal structure analysis of substituted 5-(2,3-dihydro-7-benzofuryl)-2-methylpyrazolo [4,3-d]pyrimidin-7-one (iso-Biagra)

摘要

X-ray crystal structure data for the substituted 5-(2,3-dihydro-7-benzofuryl)-2-methylpyrazolo[4,3-d]pyrimidin-7-one (3) reveal that the two bicyclic heteroaryl systems show no coplanarity along their joint C(5)-C(ll) axis with an interplanar angle of 9.6 degrees. Nonetheless, the spatial interatomic distance for O(17)-N(6), determined as 2.73 Angstrom, allows the formation of a relatively weak intramolecular hydrogen bond between the pyrimidinone N(6)-H and the O(17) lone pair of the dihydrobenzofuryl moiety. [References: 14]