| abstract |
57 Compounds of formulan and stereoisomers thereof, wherein X is an oxygen or a sulphur atom; R1 ' R 2 and R 3 , which may be the same or different, are hydrogen atoms or alkyl, cycloalkyl, optionally substituted alkenyl, optionally substituted aryl, optionally substituted alkynyl, haloalkyl, optionally substituted aralkyl, or cycloalkylalkyl groups; and R 4 can be any of the groups as defined for R 1 , R 2 and R 3 , except that it is not a hydrogen atom; and metal complexes thereof. |