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 3(i?)-3-(2-(Cinnamyloxy)-2-oxoethyl)-5-methylhexanoic acid, (III) Procedure BQuinine (28.7g, 88mmol) was suspended in toluene (38OmL). Cinnamyl alcohol (15.5 g, 115mmol) was added and the reaction mixture was cooled to -35 0C. The solution of 3- isobutylglutaric anhydride (15.0 g, 88 mmol) in toluene (1OmL) was added during 15 min and the reaction mixture was stirred at -35 0C for 24 hours. Toluene solution was washed with 5% HCl (250 + 5OmL), and than extracted with 2% K2CO3 solution (1000 + 25OmL). Aqueous extracts were washed with EtOAc (3x10OmL), acidified to pH 1 with cone. HCl and extracted with diisopropylether (150 + 5OmL). Combined extracts were warmed to 35 0C and (S)-alpha- phenylethylamine (9.7 g, 80 mmol) was added, followed by seed crystals (10 mg). Mixture was stirred for 4 hours at 25 C and filtered to obtain 24.8 g of (5)-alpha-phenylethylamine salt of (/?)-3-(2- (cinnamyloxy)-2-oxoethyl)-5-methylhexanoic acid. The salt was suspended in toluene (15OmL) and stirred with 3% HCl (10OmL) until clear solution was obtained. The aqueous acidic solution was separated and organic layer was washed once again with 3% HCl (30 mL). Evaporation of toluene afforded 17.3 g (66%) of monoester as viscous yellowish oil. HPLC analysis on Chiralpak AS column, hexane/EtOH/TFA=95/5/0.1 revealed 90.7 % ee., 185815-59-2
The synthetic route of 185815-59-2 has been constantly updated, and we look forward to future research findings.
Reference£º
Patent; PLIVA ISTRAZIVANJE I RAZVOJ D.O.O.; MCLEISH, Nicholas, Alistair, Maxwell; WO2008/9897; (2008); A1;,
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