Abstract
The refluxing of 3-amino-6,8-dibromo-2-thioxo-2,3-dihydro-1H-quinazolin-4-one (5) with ethyl chloroformate and/or ethyl chloroacetate afforded compounds
6
and
7
. The reaction of
5
with ethyl bromobutyrate, chloroacetyl chloride, phenacyl chloride, and phenyl isocyanate yielded compounds
8
,
9
,
11
, and
12
. The coupling of 5 with (2,3,4,6-tetra-O-acetyl-α -D-gluopyranosyl)bromide(
ABG
) in DMF at r.t. gave 3-amino-6,8-dibromo-2-(2′,3′,4′,6′-tetra-O-acetyl-β-D-glucopyranosyl)thioxo-2,3-dihydro-1H-quinazolin-4-one (
14
). The deblocking of
14
in sodium methoxide gave
5
. 3-Amino-6,8-dibromo-2-methylthio-3H-quinazolin-4-one (
16
) was prepared by stirring
5
with methyl iodide in methanol. The treatment of
16
with hydrazine hydrate afforded
4
. The condensation of
4
with aldehydes furnished 3,5-dibromo-2-arylaminobenzoic acid hydrazide (
18a-c
). The refluxing of
18a
with acetic anhydride gave 3-(benzylideneamino)-6,8-dibromo-2-methyl-3H-quinazolin-4-one (
19
). Hydrazones
20a-f
were prepared by the condensation of
4
with pentoses and/or hexoses. The acetylation of (
20a-f
) with acetic anhydride gave the acetyl derivatives
21a-f
.