N-Butyl propiolate → 5,6-Dihydro-5-oxopyrazolo[1,5-c]quinazoline-2-carboxylic acid, n-butyl ester
Reaktionsgleichung
[N+:1](=[C:3]1[C:11]2[C:6](=[CH:7][CH:8]=[CH:9][CH:10]=2)[NH:5][C:4]1=[O:12])=[N-:2].[C:13]([O:17][CH2:18][CH2:19][CH2:20][CH3:21])(=[O:16])[C:14]#[CH:15]>C1(C)C(C)=CC=CC=1>[O:12]=[C:4]1[N:1]2[N:2]=[C:14]([C:13]([O:17][CH2:18][CH2:19][CH2:20][CH3:21])=[O:16])[CH:15]=[C:3]2[C:11]2[CH:10]=[CH:9][CH:8]=[CH:7][C:6]=2[NH:5]1Komponenten
4
Edukt 2
Produkt 1
Reagenzien, Katalysatoren, Lösungsmittel 1
Versuchsvorschrift
2.0 g (0.126 mole) of 3-diazo-oxindole is taken up in xylene (85 ml), treated with 1.2 equivalents of n-butyl propiolate (1.9 g) and refluxed under a stream of nitrogen for 17 hours in an oil bath. The light coral-colored precipitates that form are cooled and filtered off and washed with ether. Yield: 3.0 g, m.p. 190°-195°; 83.57% crude yield. The crude product is taken up in boiling absolute ethanol (250 ml), treated with activated carbon, filtered and concentrated down on a steam bath to a volume of ~75 ml. After cooling, tan-colored precipitates are filtered off and dried in a vacuum oven at room temperature for 4 hours. Yield: 2.2 g, m.p. 198°-200°.