Molecular Structure:

Molecular Formula: C₂₈H₃₈N₆O₁₁S
Molecular Weight: 666.70
IUPAC Name: 5-[2-Ethoxy-5-(4-methylpiperazin-1-yl)sulfonylphenyl]-1-methyl-3-propyl-4H-pyrazolo[4,3-d]pyrimidin-7-one; 2-hydroxypropane-1,2,3-tricarboxylic acid
Synonyms of Sildenafil Citrate (CAS NO.171599-83-0): 1-((3-(6,7-Dihydro-1-methyl-7-oxo-3-propyl-1H-pyrazolo(4,3-d)pyrimidin-5-yl)-4-ethoxyphenyl)sulfonyl)-4-methylpiperazine citrate (1:1) ; Caverta ; Revatio ; Sildenafil citrate ; Viagra ; Piperazine, 1-((3-(6,7-dihydro-1-methyl-7-oxo-3-propyl-1H-pyrazolo(4,3-d)pyrimidin-5-yl)-4-ethoxyphenyl)sulfonyl)-4-methyl-, 2-hydroxy-1,2,3-propanetricarboxylate (1:1)
CAS NO: 171599-83-0
H bond acceptors: 10
H bond donors: 1
Freely Rotating Bonds: 7
Polar Surface Area: 108.72 Å²
Flash Point: 360.5 °C
Enthalpy of Vaporization: 98.77 kJ/mol
Boiling Point: 672.4 °C at 760 mmHg
Vapour Pressure: 6.1E-18 mmHg at 25°C
Melting Point: 187-189°C
Appearance: White Solid
SMILES: O=S(=O)(N1CCN(C)CC1)c4cc(C\2=N\C(=O)c3c(N/2)c(nn3C)CCC)c(OCC)cc4.O=C(O)C(O)(CC(=O)O)CC(=O)O
InChI: InChI=1/C22H30N6O4S.C6H8O7/c1-5-7-17-19-20(27(4)25-17)22(29)24-21(23-19)16-14-15(8-9-18(16)32-6-2)33(30,31)28-12-10-26(3)11-13-28;7-3(8)1-6(13,5(11)12)2-4(9)10/h8-9,14H,5-7,10-13H2,1-4H3,(H,23,24,29);13H,1-2H2,(H,7,8)(H,9,10)(H,11,12)
InChIKey: DEIYFTQMQPDXOT-UHFFFAOYAI
Std. InChI: InChI=1S/C22H30N6O4S.C6H8O7/c1-5-7-17-19-20(27(4)25-17)22(29)24-21(23-19)16-14-15(8-9-18(16)32-6-2)33(30,31)28-12-10-26(3)11-13-28;7-3(8)1-6(13,5(11)12)2-4(9)10/h8-9,14H,5-7,10-13H2,1-4H3,(H,23,24,29);13H,1-2H2,(H,7,8)(H,9,10)(H,11,12)
Std. InChIKey: DEIYFTQMQPDXOT-UHFFFAOYSA-N
Product Categories of Sildenafil Citrate (CAS NO.171599-83-0): Intermediates & Fine Chemicals;Pharmaceuticals;Sildenafil

  Sildenafil Citrate (CAS NO.171599-83-0) was synthesized by a group of pharmaceutical chemists working at Pfizer's Sandwich, Kent, research facility in England. It was initially studied for use in hypertension and angina pectoris. The first clinical trials were conducted in Morriston Hospital in Swansea. Phase I clinical trials under the direction of Ian Osterloh suggested that the drug had little effect on angina, but that it could induce marked penile erections.Pfizer therefore decided to market it for erectile dysfunction, rather than for angina. The drug was patented in 1996, approved for use in erectile dysfunction by the US Food and Drug Administration on March 27, 1998, becoming the first oral treatment approved to treat erectile dysfunction in the United States, and offered for sale in the United States later that year. It soon became a great success: annual sales of Viagra in the period 1999–2001 exceeded $1 billion.
Pfizer's worldwide patents on sildenafil citrate will expire in 2011–2013. The UK patent held by Pfizer on the use of PDE5 inhibitors as treatment of impotence was invalidated in 2000 because of obviousness; this decision was upheld on appeal in 2002.

 Sildenafil Citrate (CAS NO.171599-83-0) is used as an orally active selective type 5 cGMP phosphodiesterase inhibitor.

Risk Statements of Sildenafil Citrate (CAS NO.171599-83-0): 36/37/38
R36/37/38: Irritating to eyes, respiratory system and skin.