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Water (380 mL), 324 g of NaOH solution (30percent) were added to a 2000 mL reaction flask. The solution was cooled to 10-15° C. Cyclohexane 1,1-diacetic acid monoamide (II) (160 g) was added. The mixture was stirred until all solid dissolved, and the cooled to 0-5° C. NaClO solution (557 g, 11.3percent) was added dropwise at 0-5° C. The mixture was further stirred for 1.5 h at 5-10° C. The temperature was slowly raised to 35-40° C. in an hour and stirred at this temperature for 2 h. Sodium bisulfite (2-5 g) was added to destroy remaining NaClO. The pH was adjusted to 8.5+/-0.3 with HCl solution recycled from the hydrolysis of 3,3-pentamethylenebutyrolactam (IV). The mixture was reflux (100-105° C.) for 3 hours and then cooled to 60-65° C. The pH again was adjusted with 31percent HCl to 8.5+/-0.5. The mixture was extracted with toluene (400 mL.x.2). Toluene layer was evaporated to dryness, to obtain white crystalline 3,3-pentamethylenebutyrolactam (IV), 129 g, Yield: 104.8percent (due to the use of recycled HCl, which contained some 3,3-pentamethylenebutyrolactam (IV), the yield is higher than 100percent); purity, 99.9percent (HPLC).
93.8 - 95.9%
3,3-Pentamethylenebutyrolactam (IV). Water (380 mL), 324 g of NaOH solution (30percent) were added to a 2000 mL reaction flask. The solution was cooled to 10-20° C. Cyclohexane 1,1-diacetic acid monoamide (II) (160 g) was added. The mixture was stirred until all solid dissolved, and the cooled to 0-15° C. NaClO solution (557 g, 11.3percent) was added dropwise. The temperature was slowly raised to 40-50° C. and stirred at this temperature for 3 h. Sodium bisulfite was added to destroy remaining NaClO. The pH was adjusted to 11 to 12 with 31percent aqueous HCl solution. The mixture was refluxed (100-105° C.) for 3 hours and then cooled to 50-60° C. The mixture was extracted with toluene. Toluene layer was evaporated to dryness to afford white crystalline 3,3-pentamethylenebutyrolactam (IV), 118 g, Yield: 95.9percent; purity, 99.65percent (HPLC); 3,3-Pentamethylenebutyrolactam (IV). Water (420 L) and 420 kg of NaOH solution (30percent) were added to a 2000 L reaction vessel. The solution was cooled to 10-20° C. Cyclohexane 1,1-diacetic acid monoamide (II) (160 kg) was added. The mixture was stirred until all solid dissolved, and the cooled to 0-15° C. NaClO solution (630 kg, 11.3percent) was added dropwise at 0-5° C. The temperature was slowly raised to 40-50° C. and stirred at this temperature for 3 h. Sodium bisulfite was added to destroy remaining NaClO and starch-KI paper was used to assure that the excess NaClO was all destroyed. The pH was adjusted to 11 to 12 with 30percent aqueous HCl solution. The mixture was refluxed for 3 hours and then distilled and 300 to 400 L of water was distilled. The mixture was cooled to 0-5° C. and centrifuged. White crystalline product was obtained after toluene layer was evaporated the product was dried in vacuo, 115.5 kg, yield: 93.8percent; purity, 99.7percent, mp: 90-92° C.
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