Addition to Carbon-Oxygen Double Bonds
Of
H—C-e-C—H
H,0
O OH
II I
H—C—C—H
AH
CI OH
I I
Cl—C—C—H
A OH
o
(III) (IV)
(IV) is ninhydrin, the well-known colour reagent for the detection and
estimation of a-amino acids. The hydrates are probably further
stabilised by hydtagpn bonding between the hydroxyl groups and the
ele**»negative oxy§gn or chlorine atoms attached to the adjacent
a-carbon: u
</ \
II I
H—C- -C—H
I
OH
(ii) ROH
Aldehydes with alcohols, in the presence of dry hydrogen chloride,
yield acetals: H
O OH EOH
II ROH
R'—C—H *== R
H© |
-C—H ?== R'—C—H
OR
| -H«
R'—C—H ^=
I
OR
OR
- •
H
®OR
'AR
1-H,°
R'-
R OH e
H R—C—H
OR OR