Molecule structure of 3-Methyl-5-ethyl-5-phenylhydantoin (CAS NO.50-12-4) :

IUPAC Name: 5-ethyl-3-methyl-5-phenylimidazolidine-2,4-dione 
Molecular Weight: 218.25176 g/mol
Molecular Formula: C₁₂H₁₄N₂O₂
Density: 1.154 g/cm³ 
Melting Point 135 deg C  
Storage Temp.: 2-8 °C
Index of Refraction: 1.541
Molar Refractivity: 59.39 cm³
Molar Volume: 188.9 cm³
Polarizability: 23.54810^-24 cm³
Surface Tension: 40.1 dyne/cm
pKa Dissociation Constant: 8.51 
log P (octanol-water): 1.69
Water Solubility: 1270 mg/L
Vapor Pressure: 3.80E-08 mm Hg 
Henry's Law Constant: 4.90E-10 atm-m³/mole
Atmospheric OH Rate Constant: 1.07E-11 cm³/molecule-sec
XLogP3-AA: 1.5
H-Bond Donor: 1
H-Bond Acceptor: 2
Rotatable Bond Count: 2
Tautomer Count: 2
Exact Mass: 218.105528
MonoIsotopic Mass: 218.105528
Topological Polar Surface Area: 49.4
Heavy Atom Count: 16
Complexity: 310
Canonical SMILES: CCC1(C(=O)N(C(=O)N1)C)C2=CC=CC=C2
InChI: InChI=1S/C12H14N2O2/c1-3-12(9-7-5-4-6-8-9)10(15)14(2)11(16)13-12/h4-8H,3H2,1-2H3,(H,13,16)
InChIKey: GMHKMTDVRCWUDX-UHFFFAOYSA-N
EINECS: 200-012-8

 3-Methyl-5-ethyl-5-phenylhydantoin (CAS NO.50-12-4) is used to be the anti-epileptic disease.

By benzene acetone cyclization, methylation derived. 1. Cyclization to ammonium carbonate, potassium cyanide, ammonia, benzene, acetone and ethanol followed by adding the mixture, heating the reaction, the reactant into the ice water, add diluted hydrochloric acid to pH = 5-6, analysis of the white powder. Filtration, the filtrate plus destruction of cyanide in aqueous solution of ferrous sulfate. Cake by washing to neutral, drying, may 5-ethyl-5-phenyl-hydantoin. 2. Methylation to 5-ethyl-5- phenyl-hydantoin dissolved in sodium hydroxide solution, slowly adding dimethyl sulfate, 2h at 12-15 °C reaction to the reaction solution neutral. Filtration, filter cake successively with 10% sodium hydroxide solution and water washing, drying may mephenytoin crude. Refined get the product.

Poison by ingestion and intraperitoneal routes. Human systemic effects by ingestion: somnolence, hemorrhage, changes in teeth and supporting structures. Human mutation data reported. An experimental teratogen. An FDA proprietary drug used as an anticonvulsant. When heated to decomposition it emits toxic fumes of NO_x.
Hazard Codes: Xn
Risk Statements: 22-36/37/38 
R22: Harmful if swallowed. 
R36/37/38: Irritating to eyes, respiratory system and skin.
Safety Statements: 26-36 
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. 
S36: Wear suitable protective clothing.
WGK Germany: 2

 3-Methyl-5-ethyl-5-phenylhydantoin (CAS NO.50-12-4) is also called (+-)-5-Ethyl-3-methyl-5-phenylhydantoin ; 2,4-Imidazolidinedione, 5-ethyl-3-methyl-5-phenyl- ; 2,4-Imidazolidinedione, 5-ethyl-3-methyl-5-phenyl-, (+-)- ; 3-Ethylnirvanol ; 3-Methyl-5,5-phenylethylhydantoin ; 5-24-08-00093 (Beilstein Handbook Reference) ; 5-Ethyl-3-methyl-5-phenyl-2,4(3H,5H)-imidazoledione ; 5-Ethyl-3-methyl-5-phenyl-2,4-imidazolidinedione ; 5-Ethyl-3-methyl-5-phenylhydantoin ; 5-Ethyl-3-methyl-5-phenylimidazolidin-2,4-dione ; 5-Ethyl-5-fenyl-3-methylhydantoin [Czech] ; Mefenitoina [INN-Spanish] ; Mephenytoine [INN-French] ; Mephenytoinum [INN-Latin] ; Phenylethylmethylhydantoin ; Sedantoinal ; Triantoin . 3-Methyl-5-ethyl-5-phenylhydantoin (CAS NO.50-12-4) is a white crystalline powder with odorless. It is soluble in chloroform, alcohol and ether, insoluble in water.