No abstract

The cyclocondensation reactions of 3,4‐diaminocoumarin (II), prepared by electrochemical reduction of 3‐nitro‐4‐aminocoumarin (I), with various carbonyl compounds are described.

3,4-Annelated coumarin-pyrimido-pyrimidine systems (7-imino-8-mercapto-7H-5oxa-7a,9,12-triaza-benzo[a]anthracen-6-one 2 and 8-hydroxy-7-imino-10-methyl-7H-5-oxa-7a,9,12-triaza-benzo[a]anthracen-6-one 3) were synthesized by the action of 4amino-2-mercapto-pyrimidine, 2-amino-4-hydroxy-6-methylpyrimidine, respectively, on 4-chlorocoumarin-3-carbonitrile 1. The synthesized compounds were examined for in vitro antibacterial activity against 4 bacterial cultures: Staphylococcus aureus, Streptococcus pneumonia, Escherichia coli, and Aeromonas Salmonicida. The antibacterial activity of synthesized compounds 2 and 3 was compared to antibacterial activity of novobiocin as a standard drug.

4‐(4′‐metoxy‐2‐Benzothiazolylamino)‐3‐nitro‐2H‐[1]‐benzopyran‐2‐one 4a, 4‐(6′‐nitro‐2‐Benzothiazolylamino)‐3‐nitro‐2H‐[1]‐benzopyran‐2‐one 4b, 4‐(6′‐fluoro‐2‐Benzothiazolylamino)‐3‐nitro‐2H‐[1]‐benzopyran‐2‐one 4c and substitued 4‐(1,2,4‐triazolyl‐3‐amino)‐3‐nitro‐2H‐[1]‐benzopyran‐2‐ones 4(d‐e) are synthetized by condensation of 4‐Chlor‐3‐nitro‐2H‐[1]‐benzopyran‐2‐one 2 and corresponding heteroarylamines 3(a–e) under the reflux reaction conditions. Alkali hydrolysis of 4(a–e) afforded the 2‐hydroxy‐ù‐nitroacetophenone 5. Microbiological activity of products 4(a–d) are investigated and results are submitted for their activities against Staphylococcus aureus, Escherichia coli and Clebsiella.