abstract |
Compounds of the formula I ##STR1## where R is a polyethylene glycol radical of 3 to 60 chain members or a polypropylene glycol radical of 3 to 60 chain members or the radical of an ethylene oxide/propylene oxide block polymer of average molecular weight from 300 to 8,500, and R' is straight-chain or branched alkyl of 1 to 10 carbon atoms, or benzyl. |