| abstract |
Cpds. (I): (where each) of X1 and X2 are O or CH2; A is a 1-5 C satd. or unsatd. hydrocarbon chain opt. substd. by halogen or phenyl; m is 0 or 1; n is 1 or 2; R1 and R2 are each H or 1-4 C alkyl; R3 is 1-4 C alkyl, 3-7 C cycloalkyl, aryl, opt. substd. by 1-4 C alkyl, -alkoxy or -alkylthio, NO2, CN, CF3, methylene- or ethylene-dioxy or halogen, or a mono- or poly-alicyclic, satd. or unsatd. group opt. substd. by halogen, alkyl or phenyl or a fused to a benzene ring or alkyl substd. by the alicyclic group or a 5 or 6-membered heterocyclic residue contg. O, S or N opt. substd. by Me, Et or halogen; R4 is 1-4 C alkyl, H or M and M is a cation). |