1,3-Dimethyl 1,3-cyclopentanedicarboxylate

A 5-L, 3-neck, roundbottom flask was equipped with a mechanical stirrer, a J-KEM temperature controller, and a reflux condenser. The flask was charged with cyclopentane-l, 3-dicarboxylic acid(357 g, 2.262 mol) and methanol (1.75 L). The solution was cooled to 7 °C using anice/water bath. Concentrated sulfuric acid (70 mL) was added dropwise over 30 minresulting in an exotherm up to 12 °C. The reaction mixture was heated to reflux andstirred for 16 h when TLC analysis (10 percent methanol/ethyl acetate) indicated that thereaction was complete. The reaction mixture was concentrated, redissolved in methyl- 179 -ATI-2514175vl tert-butyl ether, and washed with saturated aqueous sodium bicarbonate (2 x 150 mL) and brine (2 x 150 mL). The organic layer was dried over sodium sulfate, filtered, and concentrated. The resulting clear oil was dissolved in hexane (2 L) and treated with a 2 N aqueous sodium hydroxide solution (950 mL) until the pH ~ 10. The layers were separated and the aqueous layer was extracted with hexane (4 x 1 L). The organic layers were combined, dried over sodium sulfate, filtered, and concentrated to provide 360 g (100percent) of dimethyl cyclopentane-l, 3-dicarboxylate as a clear oil. 1H NMR (500 Hz, CDCls) δ ppm 3.67 (s, 6H), 2.75-2.83 (m, 2H), 2.20-2.26 (m, 1H), 2.05-2.12 (m, 1H), 1.90-2.0 (m, 4H).Step A: . A solution of cyclopentane-1, 3- dicarboxylic acid (70.0 g, 443 mmol) and anhydrous methanol (300 mL) was cooled to 0 °C in an ice water bath. Concentrated sulfuric acid (14 mL) was added dropwise, maintaining the temperature at < 15 °C. After the addition, the reaction was heated to 90 °C and stirred overnight. The reaction was cooled to room temperature and concentrated to dryness. Theresidue was treated with MTBE (500 mL) and H20 (100 mL). The aqueous layer was separated and extracted with MTBE (2 x 100 mL). The combined organic extracts were washed with saturated sodium bicarbonate (2 x 100 mL), brine (100 mL), dried over anhydrous Mg504, filtered, and concentrated to dryness to provide the title compound (72.5 g, 88percent) as a pale yellow oil. ‘HNMR(400 IVIFIz, CDC13) 3.65 (s, 6H), 2.84-2.72 (m, 2H), 2.26-2.17 (m, 1H), 2.11 -2.02(m, 1H), 1.96- 1.88(m, 4H).To a solution of the title compound from Step A above (11.2 g) in MeOH (250 mL) was added concentrated H

Molecular Weight:186.20
XLogP3:0.8
Hydrogen Bond Acceptor Count:4
Rotatable Bond Count:4
Exact Mass:186.08920892
Monoisotopic Mass:186.08920892
Topological Polar Surface Area:52.6
Heavy Atom Count:13
Complexity:190
Undefined Atom Stereocenter Count:2
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes