The present invention relates to novel compounds of formula (I) and their pharmaceutically acceptable salts, wherein ring “Ar1” represents a monocyclic or polycyclic aromatic or
partially saturated aromatic polycyclic, which may optionally contain up to 3 heteroatoms selected from N, S or O. The said monocyclic or polycyclic ring may be unsubstituted or have up to 4 substituents which may be identical or different; m and n independently represents an integer from 0 to 6; A represents O, S or bond; Y is selected from (CH2)p′(CH2)pB(CH2)q′(CH2)rB(CH2)pD(CH2)p′ where p, q and r each independently represents an integer from 0 to 6; B and D independently represents S, O, NR4 or a bond, with a proviso that when B and D represents hereto atom p is not zero; R4 represents
hydrogen,
alkyl, alkenyl, —S(O)2—R8 or —C(O)R8 where R8 is
alkyl, alkoxy; R5 and R6 independently represents
hydrogen,
alkyl, cycloalkyl or alkoxy; R5 and R6 together may form 3-8 membered cyclic ring which may optionally contains one or two hereto atoms selected from O, S or N; R7 represents
hydrogen, optionally substituted groups selected form alkyl, cycloalkyl, alkenyl or alkynyl. The present invention also relates to a process for preparation of compounds of formula (I), to pharmaceutical compositions containing compounds of formula (I) and their use in particular as antidiabetic, hypolipidemic, antiobesity and hypocholesterolemic agents.