Abstract
In the present study, we report the synthesis of different condensed pyrimidine derivatives by the exploitation of addition reactions to π-deficient systems or active methylene building blocks. For instance, the Diels–Alder reaction of pyrimidinethione
1
and benzalacetophenone
2
yielded pyridopyrimidine
5
(Scheme
1
). On the other hand, the Michael addition of active methylene containing compounds to
1
produced derivatives
8
,
10
,
11
,
12
and
14
(Scheme
2
). The alkylation of
1
by ethylchloroacetate yielded
16
. Furthermore, a triazinoquinazoline
19
was obtained through the cyclic condensation reaction of
1
with benzilmonohydrazone (Scheme
3
). All reactions proceeded in good to moderate yields and the resulting compounds were characterized by different spectroscopic techniques.
Scheme 1
The synthesis of
5
by heterocyclization of pyrimidinethione
1
and benzalacetophenone
2
Scheme 2
Synthesis of quinazoline derivatives
8
,
10
,
11
,
12
and
14