D.H. Ripin, D.A. Evans pKa's of Inorganic and Oxo-Acids Chem 206

D.H. Ripin, D.A. Evans
pKa's of Nitrogen Acids
Chem 206
Substrate pKa H 2 O (DMSO) Substrate pKa H 2 O (DMSO) Substrate pKa H 2 O (DMSO) Substrate pKa H 2 O (DMSO)
+ 9.2 (10.5) HN 3 4.7 (7.9)
N H 4
EtN + NH
H 3
38 (41)
3
10.6
i-Pr 2 N + i-Pr 2 NH (36 THF))
H 2
11.05
TMS 2 NH 26(THF) (30)
Et 3 N + H
10.75 (9.00) PhNH 2
(30.6)
PhN + H 3
4.6 (3.6) Ph 2 NH
(25.0)
Ph 2 N + H 2 0.78
NH
(44)
2-napthal-N + Me
H 3 4.16
Me
PhN + (Me) 2 H 5.20 (2.50) NCNH 2 (16.9)
H 2 NN + H 3
8.12
HON + H 3 5.96
Quinuclidine 11.0 (9.80)
Morpholine O 8.36
N-Me morpholine 7.38
O 2 N
PROTONATED NITROGEN
DABCO
H
+ NH 3
+ NH 3
H 3 N + + NH 3
Proton Sponge
NO 2
+
N + H
N +
N + H N + H 2
NO 2
NH 3
-9.3
2.97, 8.82
(2.97, 8.93)
6.90, 9.95
-9.0, 12.0
(--, 7.50)
TMP
H 2 N
R= H
CH 3
Ph
CF 3
NH 2 (urea)
OEt
(24.1)
AMINES
15.1
(37)
(26.5)
AMIDES & CARBAMATES
R NH 2
Et
O
O
O
N
H
NH
Ph
N
NH
Me
Me
O
O
(23.5)
(25.5)
(23.3)
(17.2)
(26.9)
(24.8)
(21.6)
12 (20.5)
NH
IMIDES
Ac 2 NH (17.9)
8.88 (13.7)
(17.0)
PhCN + OH
H -10
Ph N
(NH)
Bn
N O
N
H
H
*Values 14 for water and >35 for DMSO were extrapolated using various methods.
8.30
SULFONAMIDE
(14.7)
MeSO 2 NH 2
(17.5)
CF 3 SO 2 NH 2 6.3 (9.7)
PhSO 2 NH 2
(16.1)
MeSO 2 NHPh (12.9)
GUANIDINIUM,
HYRDAZONES,- IDES, & -INES
(13.6)
(21.6)
Ph Me
O
(18.9)
Ph NHNH 2
PhSO 2 NHNH 2 (17.2)
PhNHNHPh (26.1)
O
O
NH
O
N + H 2
Me 2 N NMe 2
NNH 2
O
NH
O
HYDROXAMIC ACID
R
R=
DBU
DMAP
R
+
NH
AMIDINES
R= Me (17.3)
Ph (15.0)
PROTONATED HETEROCYCLES
Me 2 N
NSO 2 Ph
R
+
NH
+
N
H
9.2
(12) (estimate)
+
NH
6.95
H (PPTS) 5.21 (3.4)
t-Bu
4.95 (0.90)
Me 6.75 (4.46)
Cl, H 0.72
NH
NH 2
HETEROCYCLES
H
N
(23.0)
N
HN
HN
(20.95)
N
(18.6)
1,2,3 triazole
N
NH
(13.9)