IUPAC Name:  2-[(5Z)-5-[(E)-2-Methyl-3-phenylprop-2-enylidene]-2,4-dioxo-1,3-thiazolidin-3-yl]acetic acid
Following is the structure of Epalrestat (82159-09-9):
             
Molecular Formula: C₁₅H₁₃NO₃S₂
Molecular Weight of Epalrestat (82159-09-9): 319.4 g/mol
RTECS: XJ5131855
Merck: 12,3640
Solubility: Soluble in water
Index of Refraction: 1.705 
Density: 1.43 g/cm³
Flash Point: 266.4 °C
Melting Point: 210-217 °C
Surface Tension: 75.3 dyne/cm
Enthalpy of Vaporization: 83.06 kJ/mol
Boiling Point of Epalrestat (82159-09-9): 516.8 °C at 760 mmHg
Vapour Pressure of Epalrestat (82159-09-9): 1.66E-11 mmHg at 25 °C 
Product Categories: Treatment of diabetic neuropathy; API's
Canonical SMILES: CC(=CC1=CC=CC=C1)C=C2C(=O)N(C(=S)S2)CC(=O)O
Isomeric SMILES: C/C(=C\C1=CC=CC=C1)/C=C\2/C(=O)N(C(=S)S2)CC(=O)O
InChI: InChI=1S/C15H13NO3S2/c1-10(7-11-5-3-2-4-6-11)8-12-14(19)16(9-13(17)18)15(20)21-12/h2-8H,9H2,1H3,(H,17,18)/b10-7+,12-8-
InChIKey: CHNUOJQWGUIOLD-NFZZJPOKSA-N

 Epalrestat (82159-09-9) is used as aldose reductase inhibitor, can reversibly inhibit the glucose into sorbitol and the role of aldose reductase. Obstacle for diabetic nerve endings caused by symptoms, vibration sense abnormalities, abnormal changes in heart rate improved.

 Benzene, formaldehyde, ethanol, sodium hydroxide and water mixture, 0 ~ 5 ℃ dropping propionaldehyde, dripping finished in 25 ~ 30 ℃ reaction. Add water, extracted with ether. Extract drying, vacuum distillation, collecting 148 ~ 151 ℃ / 5kPa distillate, may 2 - methyl -3 - phenyl-acrolein (Ⅰ), yield 83.5%.
Dioxane soluble in carbon disulfide, and concentrated ammonia, and stirring at -5 ℃, dropping sodium glycine response. Evaporated and after adding sodium chloroacetate solution at room temperature reaction. Evaporated, add water and concentrated hydrochloric acid, boiling water bath heating. Filter set crystal, recrystallized with ethanol, may 3 - carboxymethyl-rhodanine, the yield of 76.4%. 3 - carboxymethyl rhodanine, 2 - methyl -3 - phenyl-acrolein, anhydrous sodium acetate and glacial acetic acid with the return. Cool to room temperature, add water, refrigerator overnight. Filtration, ethanol recrystallization, were dark red needle-like crystals Epalrestat yield of 65%, melting point 210 ~ 217 ℃.

 Epalrestat , its cas register number is 82159-09-9. It also can be called {(5Z)-5-[(2E)-2-Methyl-3-phenylprop-2-en-1-ylidene]-4-oxo-2-thioxo-1,3-thiazolidin-3-yl}acetic acid ; 5-((Z,E)-beta-Methylcinnamylidene)-4-oxo-2-thioxo-3-thiazolidineacetic acid ; and Epalrestatum . Epalrestat (82159-09-9) should be stored in original container in a cool dark place.