| 摘要 |
<p>N-Acylamino acid polyethylene glycol esters are prepared by reacting polyethylene glycol in solvents suitable for peptide chemistry with N-acylamino acid active esters of the formula I <IMAGE> in which Ac is an amino-protecting group conventional in peptide chemistry, R is an amino acid side chain and Y is a di-, tri-, tetra- or pentachlorophenyl, nitrophenyl or chloronitrophenyl radical, and compounds of the formula II <IMAGE> in which A is the C=O or C=S group or a further nitrogen atom, and in which A and N are members of a 5- to 6-membered heterocyclic ring which is optionally fused to a benzene ring and/or contains 1 or 2 further heteroatoms and is optionally substituted by lower alkyl groups or halogen, and the benzene ring may be substituted by halogen, trifluoromethyl, nitro, sulphonamide, carboxamide, cyano, alkoxy or lower alkyl. The pK value of the compound II in 0.5 M solution in a mixture of 6 parts of diethylene glycol dimethyl ether and 4 parts of water at 30 DEG C is between 3.7 and 4.2. The acylamino esters obtained can be used for the synthesis of therapeutically valuable esters.</p> |
