Tetrahydroisoquinoline derivatives, processes for producing the same and fungicides containing the same

A method of controlling fungal disease on plants comprising applying to the plants a fungicidally effective amount of a compound of formula [I] and acid addition salts thereof:

• ##STR144## wherein R.sup.1 represents C.sub.1 -C.sub.5 linear or branched alkyl, C.sub.2 -C.sub.5 linear or branched alkenyl, C.sub.2 -C.sub.5 linear or branched alkynyl;
• R.sup.2 R.sup.3 R.sup.4 R.sup.5 and R.sup.6 the same or different, represent hydrogen, C.sub.1 -C.sub.10 linear or branched alkyl, C.sub.3 -C.sub.10 linear or branched alkenyl, C.sub.2 -C.sub.10 linear or branched alkynyl, C.sub.1 -C.sub.10 linear or branched alkoxy, C.sub.2 -C.sub.10 linear or branched alkenyloxy, C.sub.2 -C.sub.10 linear or branched alkynyloxy, benzyloxy, hydroxy, haloalkyl, amino, mono- or di-substituted amino substituted with C.sub.1 -C.sub.4 linear or branched alkyl, phenyl or halogen;
• R.sup.2 and R.sup.3 may be bonded through a group of the formula --O--CH.sub.2).sub.m)-- wherein m represents an integer of 1 or 2 or --CH.dbd.CH).sub.2 to form a ring;
• and R.sup.4 and R.sup.5 may be bonded through a group of the formula --O--CH.sub.2).sub.m O-- wherein m represents an integer of 1 or 2 or --CH.dbd.CH).sub.2 to form a ring.