Chemistry Reference
In-Depth Information
NH
2
NCO
CCl
3
OCOCl
charcoal, AcOEt
rt and then reflux
R
R
233
234
Polysubstituted aryl isocyanates 236 and 238 were obtained with diphosgene in
dioxane, ethyl acetate, or toluene from 3-fluoro-4-methoxyaniline 235 [164] and 3-
amino-2,6-dichloro-4-fluorophenyl methyl carbonate 237 [165], respectively. Table
4.8 summarizes the reported substituted aryl
isocyanate preparations with di-
phosgene.
F
NH
2
F
NCO
CCl
3
OCOCl
dioxane, 60 °C
MeO
MeO
235
236
F
F
NCO
NH
2
CCl
3
OCOCl
AcOEt, 2.5 h
Cl
Cl
OCOOMe
Cl
Cl
OCOOMe
237
238
Tab. 4.8.
Substituted aryl isocyanates prepared with diphosgene.
R in 234
Reaction conditions
References
H
EtOAc, charcoal, heating
Dioxane, heating
162, 166, 167
168
2-Me, 3-Me, 4-Me, 2-Et
EtOAc, charcoal, heating
EtOAc, 1) 40-50
C 1 h, 2) 80
C, 2 h
162, 167
169
3,5-dimethyl, 2,4,6-trimethyl
Charcoal, EtOAc, heating
EtOAc, 1) 40-50
C 1 h, 2) 80
C, 2 h
167
169
3-F, 3-Cl, 4-Cl
Dioxane, heating
168
4-F, 4-Cl, 4-Br, 4-I
EtOAc, charcoal, heating
162
2-I, 3-I, 4-I
Charcoal, EtOAc, rt and reflux
163
EtOAc, 1) 40-50
C 1 h, 2) 80
C, 2 h
4-COOEt
169
3-Ac, 4-Ac
EtOAc, charcoal, heating
167
2-CF
3
, 3-CF
3
, 4-CF
3
EtOAc, charcoal, heating
Dioxane, heating
162
168
4-NMe
2
EtOAc, charcoal, heating
162
4-OCF
3
EtOAc, charcoal, heating
162
4-allyloxy
1,2-DCE, 70
C, 1 h, 89%
170
4-NH
2
Dioxane
product: 1,4-diisocyanato-benzene
161
2-COOH
Dioxane, PCl
5
product: 2-isocyanato-benzoyl chloride
161
