Chemistry Reference
In-Depth Information
temperature until the evolution of hydrogen had ceased. Under ice-cooling, di-
phosgene (0.9 mL, 7.5 mmol) was added in a single portion to the reaction mix-
ture, which was stirred overnight at room temperature. After the addition of a so-
lution of t-butyl alcohol (1.11 g, 15 mmol) in pyridine (2.5 mL) under ice-cooling,
the reaction mixture was stirred for 3 h under ice-cooling, and then allowed to
stand overnight at room temperature. In order to decompose diphosgene, the re-
action mixture was stirred with powdered active charcoal (50 mg) for 1 h, and then
filtered. After removing the solvent from the filtrate by distillation in vacuo, the
resulting oil was dissolved in diethyl ether. The ether layer was washed successively
with 10% hydrochloric acid, 10% aqueous potassium hydroxide, and water, then
dried over sodium sulfate, and concentrated. The resulting oil was purified by dis-
tillation in vacuo to give the product as a colorless oil.
Mannich base 58 was e
ciently converted to the chloromethyl compound 59
with diphosgene [39].
Me
Me
Cl
H
H
CCl
3
OCOCl
N
O
O
4 eq
sym
-collidine
or
i
-Pr
2
NEt, CH
2
Cl
2
,
0-23°C, 6h
HO
Cl
O
O
O
e
O
O
e
Me
Me
58
59
Tropine hydrochloride 60 was transformed into the corresponding chloroformate
61 in 98% yield with diphosgene [40].
Cl
O
Cl
Cl
O
Cl
N
N
OH
O
O
MeCN; 1) 0°C, 30 min
2) rt, 24 h
* HCl
* HCI
Cl
98 %
60
61
(
)-8-Phenylmenthol 62 gave the corresponding chloroformate 63 upon treatment
with diphosgene in benzene [41].
O
Cl
OH
O
CCl
3
OCOCl
PhH; 1) 100°C, 13h
2) rt, 18 h
62
63
