Chemistry Reference
In-Depth Information
O
n
-Bu
2
Sn
H
H
2
O
816
CO
2
H
2
N
H
815
O
n-
Bu
2
SnO
n
-Bu
2
Sn
O
819
H
O
O
O
817
H
818
Typical procedure. Synthesis of oxazolidinone 818 [606]:
The 1,2-amino alcohol (10.0
mmol), solvent (8.0 mL), and n-Bu
2
SnO (1.0 mmol) were placed in a 50 mL auto-
clave. CO
2
was then introduced at an initial pressure of 5 MPa, and the autoclave
was heated at 180
C for 16 h. The reaction solution obtained was then analyzed by
GLC. The products were isolated by fractional distillation of the reaction solution
under reduced pressure. When necessary, i.e. for characterization, they could be
further purified by preparative GLC. The products were identified by comparing
their FT-IR-, mass-, and
1
H NMR spectra with those of corresponding authentic
samples.
4.3.2.11
Sodium Nitrite/HCl
4-Amino-2-oxazolidinones 821 have been prepared by treating Cbz-protected amino
acid hydrazides 820 with sodium nitrite/HCl in glacial acetic acid [607].
Me
HN
Cbz
OH
O
NaNO
2
,aq.HCl
acetic acid, rt
NH
2
Me
H
NH
O
HN
Cbz
O
820
821
4.3.3
Carbonates
Two types of carbonates 822 can be produced in carbonylation reactions of alcohols
with phosgene or phosgene equivalents or substitutes, namely symmetrical (R
1
R
2
)
ΒΌ
and asymmetrical (R
1
0
R
2
).
O
R
1
= R
2
, alkyl, aralkyl, aryl
R
2
= alkyl, aralkyl, aryl
R
1
R
2
822
O
O
