Water → 3-amino-8-(2-oxopyrrolidin-1-yl)-1-(thiophen-3-ylmethyl)-3,4-dihydroquinolin-2(1H)-one

Participants

Reaction Conditions

Reaction Steps

Sulfuric acid (470.6 mL) was added to water (5.65 L) at room temperature, and N-(2-oxo-8-(2-oxopyrrolidin-1-yl)-1-(thiophen-3-ylmethyl)-1,2,3,4-tetrahydroquinolin-3-yl)acetamide (561.5 g) was added thereto at an internal temperature of 41-43° C. The mixture was heated at an internal temperature of 80 to 92° C. for four hours while being stirred. Under cooling on ice, 25% sodium hydroxide (2,715 g) was added dropwise to the reaction mixture at an internal temperature of 50° C. or lower, to thereby adjust the pH of the mixture to 7. Ethyl acetate (1.0 L) was added to the resultant mixture while being stirred, and 25% sodium hydroxide (300 g) was added thereto at an internal temperature of 50° C. or lower, to thereby adjust the pH of the mixture to 10. An additional ethyl acetate (1.83 L) was added to the mixture, and stirring was performed for five minutes, to thereby partition the mixture. Ethyl acetate (2.83 L) was added to the aqueous layer at an internal temperature of 30° C. or lower, and stirring was performed for five minutes, to thereby partition the mixture. An additional ethyl acetate (2.83 L) was added to the aqueous layer, and the above-described extraction procedure was repeated. The ethyl acetate layers were combined, and the combined ethyl acetate layer was concentrated under reduced pressure, to thereby evaporate ethyl acetate (6.8 L). The reaction mixture was left to stand overnight in a refrigerator, and the crystals that precipitated were recovered through filtration. The thus-recovered crystals were washed with ethyl acetate (566 mL). The thus-obtained solid was dried in air overnight and then at 60° C. under reduced pressure, whereby the title compound (389.2 g) was yielded as pale yellow crystals.

Provenance & Evidence