4-butoxy-1-chloro-1,1-difluorobut-3-en-2-one

ethyl 5-cyano-4,5-dihydro-1H-pyrazole-3-carboxylate

甲醇

4-乙氧基-2-氧代-3-丁酸乙酯

ethyl 2,4-dioxobutanoate