IUPAC Name: 4-butyl-1,2-diphenylpyrazolidine-3,5-dione 
Empirical Formula: C₁₉H₂₀N₂O₂
Molecular Weight: 308.3743g/mol
EINECS: 200-029-0 
Structure of 4-Butyl-1,2-diphenyl-3,5-dioxopyrazolidine (CAS NO.50-33-9):

Index of Refraction: 1.59
Molar Refractivity: 88.7 cm³
Molar Volume: 262.7 cm³
Polarizability: 35.16×10^-24cm³
Surface Tension: 47.3 dyne/cm
Density: 1.173 g/cm³
Flash Point: 174.3 °C
Enthalpy of Vaporization: 67.94 kJ/mol 
Melting Point: 104-107 °C
Boiling Point: 424.9 °C at 760 mmHg
Vapour Pressure: 2E-07 mmHg at 25°C 
Water Solubility: <0.1 g/100 mL at 23.5 ºC 
Stability: Stable. Incompatible with strong oxidizing agents, strong acids, strong bases. 
Product Categories: Intermediates & Fine Chemicals;Pharmaceuticals  
Canonical SMILES: CCCCC1C(=O)N(N(C1=O)C2=CC=CC=C2)C3=CC=CC=C3
InChI: InChI=1S/C19H20N2O2/c1-2-3-14-17-18(22)20(15-10-6-4-7-11-15)21(19(17)23)16-12-8-5-9-13-16/h4-13,17H,2-3,14H2,1H3
InChIKey: VYMDGNCVAMGZFE-UHFFFAOYSA-N

 4-Butyl-1,2-diphenyl-3,5-dioxopyrazolidine (50-33-9) is a non-steroidal anti-inflammatory compound. An inhibitor of cyclooxygenase that is also a substrate for peroxidation by cyclooxygenase.

IARC Cancer Review: Group 3 IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 7 (1987),p. 316.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) ; Human Inadequate Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 13 (1977),p. 183.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) . EPA Genetic Toxicology Program. Reported in EPA TSCA Inventory.

Hazard Codes: Xn,T
Risk Statements: 36/37/38-20/21/22-42/43-45
R36/37/38:Irritating to eyes, respiratory system and skin. 
R20/21/22:Harmful by inhalation, in contact with skin and if swallowed. 
R42/43:May cause sensitization by inhalation and skin contact. 
R45:May cause cancer.
Safety Statements: 36/37/39-26-45-22-53
S36/37/39:Wear suitable protective clothing, gloves and eye/face protection. 
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. 
S45:In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) 
S22:Do not breathe dust. 
S53:Avoid exposure - obtain special instructions before use.
RIDADR: 3249
RTECS: UQ8225000
HazardClass: 6.1(b)
PackingGroup: III
Hazardous Substances Data: 50-33-9(Hazardous Substances Data)
Suspected human carcinogen producing leukemia. A human poison by parenteral route. An experimental poison by ingestion, intraperitoneal, subcutaneous, intravenous, and intramuscular routes. Human systemic effects by ingestion and possibly other routes: fever, blood pressure increase, other unspecified vascular effects, damage to kidney tubules and glomeruli, decreased urine volume, blood in the urine, reduction in the number of white blood cells, and agranulocytosis. Experimental teratogenic and reproductive effects. Human mutation data reported. An eye irritant. An anti-inflammatory agent. When heated to decomposition it emits toxic fumes of NO_x.

  4-Butyl-1,2-diphenyl-3,5-dioxopyrazolidine , its cas register number is 50-33-9. It also can be called 'Esteve' ; 1,2-Diphenyl-3,5-dioxo-4-butylpyrazolidine ; 3,5-Dioxe-4 buty-1, diphenyl-pyrazolidine ; 5-24-05-00400 (Beilstein Handbook Reference) ; Alindor ; Alkabutazona ; Alqoverin ; Anerval ; Anpuzone ; Antadol ; Anuspiramin ; Arthrizon ; Artrizin ; 
 Artrizone ; Artropan ; Azobutyl ; Azolid ; Benzone ; Betazed ; Bizolin ; Bizolin 200 ; Bunetzone ; Busone ; Buta phen ;
 Butacompren ; Butacote ; Butadion ; Butadiona ; Butadione ; Butadionum ; Butagesic ; Butalgina ; Butalidon ; Butaluy ;
 Butaphen ; Butapirazol ; Butapirazole ; Butapyrazole ; Butarecbon ; Butartril ; Butartrina ; Butazina ; Butazolidin ; 
 Butazolidine ; Butazona ; Bute ; Butidiona ; Butiwas-simple ; Butone ; Butoz ; Butylpyrin ; Buvetzone ; Buzon ;
 Chembutazone ; Digibutina ; Diossidone ; Diozol ; Diphebuzol ; Diphenylbutazone ; Ecobutazone ; Elmedal ; Equi bute ;
 Equipalazone ; Eributazone ; Exrheudon N ; Febuzina ; Fenartil ; Fenibutal ; Fenibutasan ; Fenibutazona ; Fenibutol ;
 Fenilbutazona ; Fenilbutazone ; Fenilbutina ; Fenilbutine ; Fenilidina ; Fenotone ; Fenylbutazon ; Intalbut ; Intrabutazone ;
 Mephabutazon ; Phebuzin ; Phebuzine ; Phen-Buta-Vet ; Phenbutazol ; Phenopyrine ; Phenyl-mobuzon ; Pyrazolidin ;
 Scanbutazone ; Schemergen ; UNII-GN5P7K3T8S . 4-Butyl-1,2-diphenyl-3,5-dioxopyrazolidine (CAS NO.50-33-9) is a off-whtie Solid.