2-Hydroxy-2-methyl-4-pentenoic acid ethyl ester
2-Hydroxy-2-methyl-4-pentenoic acid ethyl ester ??
??
2-Hydroxy-2-methyl-4-pentenoic acid ethyl ester C??? ??, ??, ??
2-Hydroxy-2-methyl-4-pentenoic acid ethyl ester ?? ?? ? ???
???
?? ??
2-Hydroxy-2-methyl-4-pentenoic acid ethyl ester ?? ??
???( 0)?? ??