3-Methoxycarbonylmethylene-2-oxo-1,2,3,4-tetrahydroquinoxaline(7)을 hydrazine hydrate와 반응시켜 3-hydrazinocarbonylmethylene-2-oxo-1,2,3,4-tetrahydroquinoxaline(8)을 합성하였다. 화합물 8을 alkyl (ethoxymethylene)cyanoacetate류와 반응시켜 [(quinoxalin-2-ylidene)ethanoyl]-1H-pyrazole류(9)를 합성하였고, 화합물 9b를 N-alkylaniline류와 반응시켜 N-alkyl-(quinoxalin-2-ylidene)-N-phenylethanamide류(10)를 합성하였다. 얻어진 화합물 9, 10은 용액에서 enamine 형과 methylene imine 형 사이에 토토머화 현상을 나타내었는데, 이들의 토토머비를 $^1H$ NMR 로서 측정하였다.
The reaction of 3-methoxycarbonylmethylene-2-oxo-1,2,3,4-tetrahydroquinoxaline(7) with hydrazine hydrate gave 3-hydrazinocarbonylmethylene-2-oxo-1,2,3,4-tetrahydroquinoxaline(8). The reaction of compound 8 with alkyl (ethoxymethylene)cyanoacetates gave the [(quinoxalin-2-ylidene)ethanoyl]-1H-pyra-zoles(9). The reaction of compound 9b with N-alkylanilines provided the N-alkyl-(quinoxalin-2-ylidene)-N-phenylethanamides(10). Compounds 9 and 10 showed the tautomerism between the enamine and methylene imine forms in solution. The tautomer ratios were determined by the $^1H$ NMR.
