Chemistry Reference
In-Depth Information
N
3
O
N
(COBr)
2
N
3
Br
1,2-addition
[3+2] cycloaddition
N
path A
path B
N
N
Br
N
Br
N
N
N
Br
-
+
N
2
Br
-
- N
2
- N
2
Br
retro [3+2]
cycloaddition
N
N
+
Br
-
anisole
bromoanisole
N
N
DBN (
2
)
Scheme 3.12 Proposed reaction mechanisms for the synthesis of bicyclic amidine from
haloiminium salt
3.2.4.4
Thioamide
Thioamides are used as more reactive precursors than amides for amidine synthesis. Lawesson
reagent is normally used for conversion of amide to thioamide. Preparation of an amidine-type
mannosidase inhibitor 6 is shown as a representative example [14] (Scheme 3.13).
