Thiazolidine derivatives which contain a quinone group, their preparation and use in therapy.

ARE PRESENTED compounds of formula (I): endonde R1 is unsaturated; R2 and R3 are each an alkyl or alkoxide, or R2 and R3 together form a benzene ring optionally substituted Y, when R2 and R3 together form SAID benzene ring, R1 is hydrogen, halogen or alkyl; R4 and R5 both are hydrogen or JOINTS represent a single carbon-carbon bond; W is a single bond or alkylene; Z is hydrogen or a cation. The compounds have therapeutic and prophylactic evaluable ACTIVITY, INCLUDING antidiabetic activities.