With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.185815-59-2,4-Isobutyldihydro-2H-pyran-2,6(3H)-dione,as a common compound, the synthetic route is as follows.
Example 11: Preparation of (3R)-5-methyl-3-(2-oxo-2{[(lR)-l-phenylethyl]amino}ethyl) hexanoic acid compound (24); [0085] A three-necked flask equipped with an addition funnel, thermometer pocket, drying tube and a mechanical stirrer, was charged with methyl isobutyl ketone (100 ml), (R)-(+)-phenylethylamine (35.58 g, 0.147mole) and 4-dimethylaminopyridine (0.18 g, 0.00147 mole). The mixture was cooled to a temperature of 0-50C, followed by addition of a solution of 3-isobutyl glutaric anhydride (25 g, 0.147 mole) in methyl isobutyl ketone (25 ml), over a period of 15-20 minutes, and stirring for additional 1.5-2 hours, at a temperature of 0-5 C. The solvent was stripped off and the residue was extracted with 2.5-3 percent aqueous solution OfNaHCO3 solution (500 ml), followed by washing the aqueous phase with toluene (1 x 100 ml and 1 x 50 ml). The pH of the aqueous phase was adjusted to 2-2.5 by adding a 1-12N solution of hydrochloric acid. The aqueous phase was further extracted with ethyl acetate (1 x 150 ml and 1 x 50 ml), followed by drying the combined ethyl acetates extracts over anhydrous sodium sulfate, and stripping off the solvents, to obtain a residue. The residue was crystallized from ethyl acetate and toluene mixture to get 25.2 g (58.9 percent yield) of a white solid of (3R)-5-methyl-3-(2-oxo-2-{[(lR)-l- phenylethyl] amino }ethyl)hexanoic acid with an optical purity of 99.3 percent, as measured by chiral HPLC.
The synthetic route of 185815-59-2 has been constantly updated, and we look forward to future research findings.
Reference£º
Patent; TEVA PHARMACEUTICAL INDUSTRIES LTD.; TEVA PHARMACEUTICALS USA, INC.; WO2007/35789; (2007); A1;,
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