The 1,3-Isobenzofurandione, 3a,4,5,7a-tetrahydro-6-methyl- is an organic compound with the formula C₉H₁₀O₃. The systematic name of this product is 6-methyl-3a,4,5,7a-tetrahydro-2-benzofuran-1,3-dione. With the CAS registry number 19438-64-3, it is also named as Tetrahydro-4-methylphthalic anhydride.

The 1,3-Isobenzofurandione, 3a,4,5,7a-tetrahydro-6-methyl- has characteristics of  high purity, light color, low viscosity, good processing performance, long-term storage at room temperature, low freezing point, volatile small and low toxicity. It can be used as unsaturated polyester resin, epoxy resin curing agent, pesticide intermediates, casting dry-type transformers and so on.

The other characteristics of this product can be summarized as: (1)ACD/LogP: 0.67; (2)# of Rule of 5 Violations: 0; (3)ACD/LogD (pH 5.5): 0.67; (4)ACD/LogD (pH 7.4): 0.67; (5)ACD/BCF (pH 5.5): 1.9; (6)ACD/BCF (pH 7.4): 1.9; (7)ACD/KOC (pH 5.5): 55.19; (8)ACD/KOC (pH 7.4): 55.19; (9)#H bond acceptors: 3; (10)#H bond donors: 0; (11)#Freely Rotating Bonds: 0; (12)Index of Refraction: 1.516; (13)Molar Refractivity: 41.12 cm³; (14)Molar Volume: 136 cm³; (15)Polarizability: 16.3×10^-24 cm³; (16)Surface Tension: 39.9 dyne/cm; (17)Enthalpy of Vaporization: 54.96 kJ/mol; (18)Vapour Pressure: 0.000661 mmHg at 25°C.

People can use the following data to convert to the molecule structure.
1.SMILES: O=C1OC(=O)C2CCC(/C)=C\C12; 
2.InChI: InChI=1/C9H10O3/c1-5-2-3-6-7(4-5)9(11)12-8(6)10/h4,6-7H,2-3H2,1H3.