Methyl propiolate → ethyl 2-oxo-2H-pyrimido[2,1-b]benzothiazole-8-acetate
Reaktionsgleichung
[NH2:1][C:2]1[S:3][C:4]2[CH:10]=[C:9]([CH2:11][C:12]([O:14][CH2:15][CH3:16])=[O:13])[CH:8]=[CH:7][C:5]=2[N:6]=1.[C:17](OC)(=[O:20])[C:18]#[CH:19]>C(O)C>[O:20]=[C:17]1[CH:18]=[CH:19][N:6]2[C:2]([S:3][C:4]3[CH:10]=[C:9]([CH2:11][C:12]([O:14][CH2:15][CH3:16])=[O:13])[CH:8]=[CH:7][C:5]=32)=[N:1]1Komponenten
4
Edukt 2
Produkt 1
Reagenzien, Katalysatoren, Lösungsmittel 1
Versuchsvorschrift
A stirred mixture of 5 g of ethyl 2-aminobenzothiazole-6-acetate [prepared according to Sawhney et al., Ind J. Chem., Vol. 16B p. 605 (1978)], 1.95 g of methyl propiolate and 30 ml of ethanol was heated under reflux for 2 hours and the mixture was allowed to cool. The crude product was collected and then recrystallized from n-butyl alcohol to obtain 2.88 g of ethyl 2-oxo-2H-pyrimido[2,1-b]benzothiazole-8-acetate as yellow needles (48% yield).