Chemistry Reference
In-Depth Information
with diethyl ether (3
40 mL). The ethereal extracts were successively washed with
2 n HCl (2
20 mL), and saturated NaCl (30 mL), dried
with MgSO
4
, and filtered. Removal of the solvent under reduced pressure gave N-
phenyl-N
0
-n-octyl-urea as a white powder (0.84 g, 85%).
20 mL), 2 n NaOH (2
S,S-Dimethyldithiocarbonate (DMDTC)
S,S-Dimethyldithiocarbonate (DMDTC) 786 represents a mild and safely handled
reagent, structurally similar to phosgene, which is useful in the synthesis of ureas
(see also Section 4.3.2 ''Carbamates''). Tables 4.29, 4.30, and 4.31 illustrate various
symmetrical and unsymmetrical ureas prepared with DMDTC.
Tab. 4.29.
Preparation of symmetrical ureas by condensation of various amines with DMDTC
[577].
(MeS)
2
CO
2 RNH
2
+
RNHCONHR
Entry
Starting amine
Solvent
(conc.)
a
Product (yield, %)
b
N,N
0
-diisobutylurea (92)
1
isobutylamine
MeOH (1 M)
2
allylamine
MeOH (1 M)
N,N
0
-diallylurea (80)
N,N
0
-dibenzylurea (85)
3
benzylamine
MeOH (1 M)
4
1-methylpropylamine
no solvent
N,N
0
-bis(1-methylpropyl)urea (70)
N,N
0
-dicyclohexylurea (65)
5
cyclohexylamine
no solvent
O
6
MeOH (1 M)
(75)
NH
N
3
O
NH
2
N
H
N
H
7
MeOH (1 M)
H
2
N
H
2
N
NH
2
(55)
O
8
H
2
N
OH
+
HO
NH
CO
2
HN
O
MeOH (1 M)
70
30
MeOH (4.5 M)
90
10
no solvent
(70)
O
OH
9
HO
+
H
2
N
NH
CO
2
HN
O
MeOH (1 M)
5
95
no solvent
75(55)
25
a
Initial concentration of the starting amine.
b
Isolated yield.
