Abdel-Rahman B. A. El-Gazzar^* and Hend N. Hafez

National Research Centre, Photochemistry Department (Heterocyclic & Nucleosides Unit), Dokki, 12622 Cairo, Egypt
* Corresponding author: E-mail: profelgazzar@yahoo.com

Abstract
A novel series of 7-amino-5-aryl-6-(benzothiazol-2-yl)-2-thioxopyrido[2,3-d]pyrimidin-4-one derivatives was prepared and their reactivity towards some reagents was studied. Transformations of aromatic aldehydes, halogens and some hydrazonoyl chlorides towards the corresponding poly-condensed heterocyclic compounds, such as 8-amino-7-(benzothiazol-2-yl)-[1,3]thiazolo[4,5-a]pyrido[2,3-d]pyrimidine-3,5-diones, 3,9-diarylisoazolo[5´,4´:4,5]thiazolo-[3,2-a]pyrido[ 2,3-d]pyrimidin-10-ones and 1,6-diaryl and 3-aryl- or 3-acetyl- or 3-ethylcarboxylate- derivatives of 7-(benzothiazol- 2-yl)-pyrido[2,3-d][1,2,4]triazolo[4,5-a]pyrimidin-5-ones were investigated. Compounds synthesized were screened in vitro for their antimicrobial activity against a variety of bacterial and fungal agents.

Keywords: 7-Amino-, 8-amino-, 6-(benzothiazole)isooxazolo[5´,4´:4,5]thiazolopyridopyrimidine, antimicrobial activities.