Abstract
The hitherto unknown 3-amino-5-bromo-4, 6-dimethylthieno [2, 3-b] pyridine-2-carbonitrile (
4
) was condensed with p-anisaldehyde affording the Schiff base (
5
). Acylation of the thienopyridine derivative (
4
) using freshly distilled acetic anhydride gave a mixture of mono and diacetyl derivatives (
6
) and (
7
). Condensation of (
4
) with triethylorthoformate yielded the ethoxymethyleneamino derivative (
8
), which was treated with hydrazine hydrate to give the hydrazide derivative (
9
), which in turn was converted to a triazolopyrimidine derivative (
10
) upon treatment with freshly distilled acetic anhydride. Thiation of (
4
) with carbon disulfide afforded the pyrimidine dithione derivative (
11
), which was alkylated with ethyl iodide to give the di-s-ethylpyrimidine derivative (
12
).On the other hand, treatment of (
4
) with formamide yielded the aminopyrimidine derivative (
13
), whereas its treatment by formic acid produced the thienopyrimidinone derivative (1
4
). Chlorination of (1
4
) with a mixture of phosphorus pentachloride and phosphorus oxychloride gave the chloropyrimidine derivative (
15
), which in turn afforded the hydrazide derivative (
9
) upon treatment with hydrazine hydrate. Hydrazinolysis of ethyl-3-amino-5-bromo-4,6-dimethylthieno[2,3-b]pyridine-2-carboxylate (
17
) gave the hydrazino derivative (
18
), which in turn was converted to 8-bromo-7,9-dimethyl-3-formylaminopyrido[3′,2′:4,5]thieno[3,2-d]pyrimidin-4(3H)-one (
19
) and 8-bromo-3-diacetylamino-2,7,9-trimethylpyrido[3′,2′:4,5]thieno[3,2-d]pyrimidin-4(3H)-one (
20
) upon treatment with formic acid and freshly distilled acetic anhydride, respectively.