Cinnoline derivative, process for preparing the same and herbicidal composition containing the same

A cinnoline derivative having the formula (I): ##STR1## in which X is --OH, --O.sup.- M.sup.+, --OR.sup.1 or ##STR2## wherein M.sup.+ is an alkali metal cation, an alkaline earth metal cation or ##STR3## in which R.sup.4, R.sup.5 and R.sup.6 are the same or different and each is a hydrogen atom, a C.sub.1 -C.sub.6 alkyl group, a C.sub.3 -C.sub.4 alkenyl group, a C.sub.3 -C.sub.4 alkynyl group, a C.sub.3 -C.sub.8 cycloalkyl group, a benzyl group or a phenyl group; R.sup.1 is a C.sub.1 -C.sub.9 alkyl group, a C.sub.3 -C.sub.6 alkenyl group, a C.sub.3 -C.sub.4 alkynyl group, a C.sub.1 -C.sub.3 alkoxy(C.sub.1 -C.sub.4) alkyl group, a C.sub.1 -C.sub.3 haloalkyl group, a C.sub.3 -C.sub.8 cycloalkyl group, a benzyl group or a phenyl group; and R.sup.2 and R.sup.3 are the same or different and each is a hydrogen atom, a C.sub.1 -C.sub.6 alkyl group, a C.sub.3 -C.sub.4 alkenyl group, a C.sub.3 -C.sub.4 alkynyl group, a C.sub.3 -C.sub.8 cycloalkyl group, a benzyl group in which at most two of hydrogen atoms at the .alpha.-position thereof may be substituted by methyl group, a C.sub.2 -C.sub.3 hydroxyalkyl group or a phenyl group in which at most three of hydrogen atoms thereof may be substituted by the same or different C.sub.1 -C.sub.2 alkyl group or halogen atom; Y is a C.sub.1 -C.sub.4 haloalkyl group; A.sup.1 and A.sup.2 are the same or different and each is a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a trihalomethyl group, a C.sub.1 -C.sub.2 alkylthio group or a C.sub.1 -C.sub.2 haloalkoxy group, a process for preparing the same, and a herbicidal composition containing the same as an acitve ingredient, a method for controlling undesired weeds using the same, and use of the same as a herbicide.