ethyl 4-(hydroxymethyl)-1H-pyrazole-5-carboxylate

prop-2-ynyl 4-chlorobenzenesulfonate

3-ethoxy-4-prop-2-ynoxycyclobut-3-ene-1,2-dione

3,4-bis(prop-2-ynoxy)cyclobut-3-ene-1,2-dione

甲基羧酸-2-丙炔基酯