Pfizer Corporation

Albert Shaw Wood

Laurence James Harris

Keith Michael DeVries

Philip Charles Levett

Joanna Teresa Negri

Mark Edward Bunnage

John Paul Mathias

Stephen Derek Albert Street

Peter James Dunn

David James Rawson

Charlotte Moira Norfor Allerton

Christopher Gordon Barber

Richard Anthony Storey

A process for the preparation of Compounds of the formula (1): wherein R, R, Rand Rare as defined or a pharmaceutically or veterinarily acceptable salt or polymorph thereof, or a pharmaceutically or veterinarily acceptable solvate or pro-drug thereof: are potent and selective inhibitors of type 5 cyclic guanosine 3',5&#x2032;-monophosphate phosphodiestbrase (cGMP PDE5) and have utility in the treatment of, inter alia, male erectile dysfunction (MED) and female sexual dysfunction (FSD).

Process for preparing pharmaceutically active compounds

Process for the preparation of pyrazolo&lsqb;4,3-d&rsqb;pyrimidin-7-one compounds and intermediates thereof

Pharmaceutically active compounds

A polymorph of 1-&lcub;6-ethoxy-5-&lsqb;3-ethyl-6,7-dihydro-2-(2-methoxyethyl)-7-oxo-2H-pyrazolo&lsqb;4,3-d&rsqb;pyrimidin-5-yl&rsqb;-3-pyridylsulfonyl&rcub;-4-ethylpiperazine.

Crystalline therapeutic agent

A process for the preparation of a compound of formula (I): ##STR1## which comprises cyclization of a compound of formula (II): ##STR2##

Process for preparing sildenafil

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Sandwich, United Kingdom

Albert Shaw Wood