group a 1 methyl 2 propynyl group a 3 butynyl group and a 3 pentynyl group examples of the halogen atom represented by r 2 include a fluorine atom a chlorine atom and a bromine atom examples of the c1 c4 alkyl group represented by r 2 include a methyl group an ethyl group and a 1 1 dimethylethyl group examples of the c1 c4 haloalkyl group represented by r 2 include a trifluoromethyl group a difluoromethyl group and a pentafluoroethyl group examples of the c1 c4 alkoxy group represented by r 2 include a methoxy group and an ethoxy group examples of the c1 c4 haloalkoxy group represented by r 2 include a trifluoromethoxy group and a pentafluoroethoxy group examples of the c1 c4 alkylthio group represented by r 2 include a methylthio group and an ethylthio group examples of the cr 3 r 4 group represented by a include a ch 2 group a ch ch 3 group and examples of the nr 5 group represented by a include a nh group a nch 3 group a nc 2 h 5 group a nch 2 och 3 group a nch 2 oc 2 h 5 group and a nch 2 cn group examples of the compound of the present invention include a 1 2 4.