The Effect of Esterification of the Carboxyl Groups of Collagen upon its

sufficieiit to prepare a n isolable quantity of the ketone. A few milligrams of the imine was hydrolyzed :rnd the product yielded a 2,4-dinitrophenylhydrazone, m.p. 138", calctl for C L ~ S ? 6 S 4 ON, 4 : 13.65; found: S , 13.50.

TABLE I11

c E-12'\

KETONES

I

H3C-- C--C 0-- I< /

,'

(CH,, )!CH----HC--- -C1Is C'arbon,

IZ n-Butyl Icobntyl s-Butyl Isoamyl Phenyla

" The

B.B.

" C . (mm.! 97-99 (1) 83-87 I I J

104

(ij)

1% -122 (6:

c;

I P ~ ii%i Calcd. Found 0.8793 1.4843 7 9 . 9 3 79.95 ,8763 1 . G 2 7 7!l.U:3 iS.53 .H791 I 4.53'1 7Ir.93 7!l 5 9 87ii9 1 80 29 $O.?(i

IJydrogen, I ' (