72 
CHEMISTRY: T. B. JOHNSON 
to which we have assigned the name — polypeptide-hydantoins. The 
hydantoin derivatives of the polypeptides — glycylphenylalanine IX, 
phenylalanylglycine X, glycyltyrosine XI and tyrosineglycine XII are 
now being investigated. Their formulas are: 
(IX) NH2CH2CO • NHCH (CH2C6H5) COOH 
(X) NH2 • CH (CH2C6H5) • CONH . CH2COOH 
(XI) NH2 • CH2CONH . CH (CH2C6H4 • OH) COOH 
(XII) NH2CH (CH2C6H4OH) CONHCH2COOH. 
The polypeptide-hydantoin XV (m, 184-185°) has already been synthe- 
sized and two methods have been developed for its preparation which 
are apparently of general application: 
(1) Alkylation of 4-benzylhydantoin^ XIII with ethyl chloracetate 
with formation of the ester XIV (m. 157°), which is easily converted 
into the polypeptide-hydantoin XV by saponification. 
NH-CO 
CO 
C2H5OOC CH2N - CO 
CO 
NH - CHCH2C6H5 NH - CHCH2C6H5 
(XIII) (XIV) 
HOOCCH2.N - CO 
I 
CO 
I 
NH - CH CHsCeHe 
(2) Alkylation of 4-benzalhydantoin^ XVI, with ethyl chloracetate 
with formation of the ester XVII (m. 174°). The latter gives by 
saponification the unsaturated acid XVIII (m. 258°), which undergoes 
reduction smoothly giving the polypeptide-hydantoin XV. 
NH-CO 
I 
CO 
C2H5OOC • CH2N - CO 
CO 
NH 
C : CHCgHs 
(XVI) 
NH-C:CHC6Hb 
(XVII) 
