abstract |
Compounds of the general formulae IN WHICH R1 represents a straight or branched, optionally substituted alkyl, alkenyl or alkynyl radical; R2 stands for an optionally substituted phenyl radical; Y stands for oxygen, sulphur or a methylene radical; X stands for O or H2; their salts and esters and methods for their preparation. (From US3897476 A) [GB1406882A] |