Chemistry Reference
In-Depth Information
Tab. 4.2.
Hydantoins 26 synthesized from non-commercially available alkyl and aryl
chloroformates prepared with triphosgene [24].
Alcohol (mmol)
Triphosgene
(mmol)
Pyridine
(mmol)
Yield of
hydantoins
26 (%)
2-Adamantanol (1.8)
0.61
2.0
58
1-Octanol (1.77)
0.61
2.0
82
4-Methoxyphenol (1.2)
0.44
1.29
85
4-Trifluoromethanol (1.3)
0.44
1.29
40
3,4-Dichlorophenol (1.3)
0.44
1.29
42
3-Bromophenol (0.9)
0.33
0.9
74
Phenetyl alcohol (2.37)
0.84
2.37
65-85
Phenyloxycarbonyl-hydantoins 26 were synthesized from the corresponding
imidazolidine-2,4-diones 24 and chloroformates 25 [24].
R
1
R
1
R
3
OCOCl
O
25
O
Et
3
N, THF, 0-24°C, 1-15 hrs
NH
N
O
N
N
R
3
R
2
R
2
O
O
O
40-95 %
24
26
A series of non-commercially available chloroformates (R
3
OCOCl) 25 (Table 4.2)
were claimed to be synthesized from the desired alcohol and triphosgene in the
presence of pyridine [24].
Diphosgene reacts with piperidinyl alcohol 27, which has a protected nitrogen
group, to give the corresponding chloroformate 28 [25].
N
N
CCl
3
OCOCl
* HCI
* HCI
MeCN
Cl
O
OH
27
28
O
O
O
(CCl
3
O)
2
CO
O l
OH
N
N
Et
3
N, CH
2
Cl
2
, 72 hrs
80 %
O
30
O
29
O
