The starting materials, 2-amino-3-cyano-4-(3,4,5-trimethoxyphenyl)-4H-pyran0[3,2-hlquinoline
1 and ethyl-2-amino-4-(3,4,5-trimethoxyphenyl)-4H-pyrano [3,2-hlquinolin-3-carboxylate
2 were synthesised from 8-hydroxyquinoline and a-cyano-3,4,5-trimethoxycinnamonitrileand/or ethyl-a-cyano-3,4,5-trimethoxy-cinnamatre respectively. In order to construct a third heterocyclic ring
1 and
2were condensed with ethyl bromoacetate, formarnide, carbon disulfide to afford pyrrolo-, pyrimido- and thiazinopyranoquinolines
3
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The starting materials, 2-amino-3-cyano-4-(3,4,5-trimethoxyphenyl)-4H-pyran0[3,2-hlquinoline
1 and ethyl-2-amino-4-(3,4,5-trimethoxyphenyl)-4H-pyrano [3,2-hlquinolin-3-carboxylate
2 were synthesised from 8-hydroxyquinoline and a-cyano-3,4,5-trimethoxycinnamonitrileand/or ethyl-a-cyano-3,4,5-trimethoxy-cinnamatre respectively. In order to construct a third heterocyclic ring
1 and
2were condensed with ethyl bromoacetate, formarnide, carbon disulfide to afford pyrrolo-, pyrimido- and thiazinopyranoquinolines
3-
6respectively. The S-alkylated products
7 and
8 were obtained by the effect of chloroacetonitrile and/or ethyl chloroacetate on thiazinopyranoquinoline derivative
6. The attempt of cyanomethylation of the amino functional group of
1 to yield
10 with chloroacetonitrile in AcOHIAcONa failed and instead, pyridopyranoquinoline derivative
9 was obtained which is visualized to occur
via cyclization of the initially formed acetylarnino derivative by nucleophilic attack on the cyano group. Acetylation of
1 and
2 with acetic anhydride afforded the mono- and di-acetyl derivatives
11a and
11b respectively. A plausible explanation to form the mono-derivative with
1 and the di-derivative with
2 is the higher deactivating effect of the cyano function over that of the carboxyethyl group. Furoylation of
1 and
2 was achieved by furoyl chloride to give
12a and
12b respectively. The structural features of pyranoquinoline
2 were inferred from its microanalysis and spectral data such as IR,
1H-NMR and MS as well as its chemical reactions, as a bifunctional compound with carbon nucleophiles namely, phenyl isothiocyanate and nitrogen nucleophilic species namely, p-toluidine, benzylamine, aniline and hydrazine hydrate to give pyrimidopyranoquinoline derivative
13, carboxamides
14a-
c and carboxyhydrazide
15 respectively. When the hydrazide 15 was treated with carbon disulfide inpresence of KOH, it afforded the potassium salt
16 which was submitted to react with hydrazine hydrate at room temperature to give
17. The hydrazido group of
15was utilized to construct heterocyclic moieties attached to postion-3 of the pyranoquinoline structure. Thus, the reaction of the carboxyhydrazide
15 with phenyl isothiocyanate, acetylacetone, and benzoylacetone resulted in the formation of
18,
19a and
19b respectively. Ethyl carbazate as a typical mesophile reacted with
2 to afford a fused tetracyclic product triazepinopyranoquinoline
20 via cyclization of the initially formed hydrazide. Among sixteen compounds screened against
E. coli and
S. aureus respectively,compounds
2 and
14c show a high order of antibacterial activity against both bacteria.
12b is strongly potent against
Staphylococcus aureus.
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