Disclosed is a compound represented by the general formula (I) below. This compound is useful as a polymerization inhibitor and the like. [chemical formula 1] (I) (In the formula (I), R1 and R2 independently represent a monovalent hydrocarbon group; R3 represents a hydrogen atom or an alkyl group having 1-4 carbon atoms; X represents a divalent hydrocarbon group; and R4, R5 and R6 independently represent a monovalent organic group or a group represented by the following formula (II). [chemical formula 2] (II) (In the formula (II), R7 and R8 independently represent a monovalent hydrocarbon group; and R9 represents a hydrogen atom or an alkyl group having 1-4 carbon atoms.) In this connection, R4 and R5 may combine together to form a divalent hydrocarbon group.)
