| abstract |
A compound of formula (I), or a salt or solvate thereof, in which R1 and R2 each independently represents hydrogen, alkyl, optionally substituted aryl or optionally substituted aralkyl; R3 represents alkyl, optionally substituted aryl or optionally substituted aralkyl and R4 represents alkyl or optionally substituted aryl; a process for preparing such compounds and the use of such compounds for resolving certain racemates. |