Herbicidal oxazine ethers

A compound selected from ##STR19## wherein:

• R.sup.1 is C.sub.1 -C.sub.6 alkyl optionally substituted with a substituent selected from halogen, phenyl and C.sub.1 -C.sub.3 alkoxy optionally substituted with 1-3 halogens;
• C.sub.3 -C.sub.6 cycloalkyl;
• phenyl optionally substituted with one to two groups selected from halogen, SCH.sub.3, CN, C.sub.1 -C.sub.2 alkyl optionally substituted with 1-3 halogens and C.sub.1 -C.sub.2 alkoxy optionally substituted with 1-3 halogens;
• and CR.sup.9 R.sup.10 X;
• X is CN, CO.sub.2 R.sup.13, C(O)R.sup.14, CHO, OR.sup.15 or CR.sup.11 R.sup.12 Y;
• Y is OR.sup.16 ;
• R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.13, R.sup.14, R.sup.15, R.sup.16, R.sup.20 and R.sup.21 are independently H or C.sub.1 -C.sub.3 alkyl;
• R.sup.6 is H, C.sub.1 -C.sub.3 alkyl or C.sub.2 -C.sub.4 alkenyl;
• R.sup.1 and R.sup.2 may be taken together to form a 5-6 membered ring substituted with R.sup.20 and R.sup.21 and optionally fused to a benzene ring;
• R.sup.9 and R.sup.11 are independently H or CH.sub.3 ;
• R.sup.10 and R.sup.12 are independently H, CH.sub.3 or OCH.sub.3 ;
• Q is CH.sub.2 W;
• and
• W is phenyl optionally substituted with 1-3 substituents selected from halogen, C.sub.1 -C.sub.3 alkyl, C.sub.1 -C.sub.3 alkoxy, OH, CN, C.sub.1 -C.sub.3 haloalkyl, C.sub.1 -C.sub.3 haloalkoxy, C.sub.1 -C.sub.3 alkylthio, C.sub.2 -C.sub.4 alkenyl and C.sub.2 -C.sub.4 alkynyl.