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Paper | Regular issue | Vol 53, No. 12, 2000, pp.2643-2652
Published online, 1st January, 1970
DOI: 10.3987/COM-00-9006
Synthesis and Properties of α-Thiagra. A Substituted 5-(2-Thienyl)pyrazolo[4,3-d]pyrimidin-7-one Bioisostere of Viagra®

Mustafa M. El-Abadelah,* Salim S. Sabri, Monther A. Khanfar, Wolfgang Voelter, Raid J. Abdel-Jalil, Cäcilia Maichle-Mössmer, and Yousef Al-Abed

*Chemistry Department , Faculty of Science, University of Jordan, Amman 11942, Jordan


For structure-activity manipulations, the compound α-thiagra (3) a thiophene bioisostere of viagra®, has been prepared and its X-Ray structure determined. The crystallographic data show that the thiophene and pyrazolo[4,3-d]pyrimidone hetero-ring systems are nearly coplanar by virtue of an adequate intramolecular hydrogen-bond between the pyrimidone NH and the oxygen lone pair of the 3’-ethoxy group.