Thiazolyl-benzyl-piperazines for treating gastrointestinal disorders

Compounds of formula (I) wherein G is C-Y wherein Y is H or C1-4 alkyl; D is H, or a C1-10 alkyl or aryl group; E and F are each independently selected from H and methyl; R1 is a group of formula - CO-R3 wherein R3 is the residue of an optionally N-alkyl or - aryl substituted amino acid or a biolabile ester or salt thereof or R1 is a tetrazolyl group optionally substituted by R4; R2 is H or a C1-10 alkyl or aryl group; R4 is H, a group of formula R5-(CH2)m-Z-(CH2)n-, where m is 0, 1, 2 or 3, n is 1, 2 or 3, Z is a bond or O provided that when Z is O, m is 1, 2 or 3 and n is 2 or 3, and R5 is -CO2H or CO2(C1-C4 alkyl), or R4 is a group of formula -CH2-Ph-CO2R6 wherein Ph is a phenyl ring, the -CO2R6 group is at any position thereof and R6 is H or C Ü -C Ú alkyl; and salts thereof are useful for treating gastrointestinal disorders.