The corrosion behavior of copper in 0.1 M aqueous sulfuric acid medium has been studied using potentiodynamic polarization measurements, quantum chemical calculations, and molecular dynamic simulations in the presence and absence of (2E,5E)-2,5-dibenzylidenecyclopentanone (M1) and (2E,5E)-bis[(4-dimethylamino)benzylidene]cyclopentanone (M2). The compounds were freshly prepared in high yields via the Claisen–Schmidt reaction between the cyclopentanone and the corresponding aryl aldehyde. The results from the potentiodynamic measurements imply that M1 and M2 act as mixed inhibitors due to their adsorption on the copper surface. The more pronounced corrosion inhibition performance of the M2 molecule in comparison to M1 was related to the fact that this molecule contains two basic nitrogen atoms (in 4-dimethylamino group).
Synthesis of a series of the substituted [(pyridinyl and pyrimidin-2-ylimino)-ethyl]-4-hydroxy-chromen-2-ones and their tetrazole derivates is presented in this study. By catalytic condensation of 4-hydroxy-3-acetylcoumarine 2 and 2-aminopyridines 3(a-d), 3-[(pyridin-2-ylimino)-ethyl]-4-hydroxy-chromen-2-ones 4(a-d) are synthesized in high yield. During the condensation reaction of 2 and 4-amino-2,6-dihydroxypyrimidine 3e, 3-[1-(2,6-Dihydroxy-pyrimidin-4-ylimino)-ethyl]-4-hydroxy-chromen-2-one 4e as condensation products is synthesized. In following series, by cyclization reactions of compounds 4 (a-e) with sodium azide, analogue 3-substituted pyridin-2-yl and pyrimidin-2-yl-5-methyl-2,5-dihydro-1H-tetrazol-5-yl]-4-hydroxy-chromen-2-one 5(a-e) are synthesized the products. Structural characterization of the synthesized products is done on the basis of spectrometric data. Antibacterial activity of the compounds 4(a-e) and 5(a-e) against S. aureus, E. coli and Klebsiella was examined by measuring the inhibition zones around the disks marked with the corresponding products solution. The impact of substitutions in antimicrobial is also explored. Compounds with polar groups have shown significant antibacterial activity against these microorganisms.
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.
Some new substitued 4‐(2‐benzithiazolylamino‐2H[1]‐pyran‐2‐ones are synthesized by condensation of 2H[1}‐pyran‐2‐ones and corresponding 2‐aminobenzothiazoles. Condensation of 4‐chloro‐6‐methyl‐2H[1]‐pyran‐2‐one 2 and 2‐aminobenzothiazoles 3(a‐c) gave corresponding 4‐(2‐benzothiazolylamino)‐6‐methyl‐2H[1]‐pyran‐2‐ones 4(a‐c). By condensation of 4‐chloro‐3‐nitro‐6‐methyl‐2H[1]‐pyran‐2‐one 6a and 2‐aminobenzothiazoles 3(ad) were synthesized 4‐(2‐benzothiazolylamino)‐3‐nitro‐6‐methyl‐2H[1]‐pyran‐2‐one 6a and 4‐(6‐ethoxy‐2‐benzothiazolylamino)‐3‐nitro‐6‐methyl‐2H[1]‐pyran‐2‐one 6c . The antibacterial activity of products 4(a‐d) against E. coli S. aureus and Clebsiella were investigated. Compounds 4(a‐d) showed light bactericide activity against E. coli, S. aureus and Clebsiella. Compounds 4b and 6d were more active against E. coli. Emphatic activity against S. aureus exhibited compounds 4c and 6d whereas compounds 6a and 6d exhibited the strongest activity against Clebsiella. In general there was a direct positive correlation between increasing concentration of the compound and antibacterial activity.
Novel derivatives of substituted bezopyran-2-ones are synthesized by catalytic reactions under refluxing conditions. 4-Hydrazinyl-3-nitrobenzopyran-2-one 4 is synthesized from 4-hydroxybenzopyran-2-one 1 via three steps reaction. By condensation reaction of 4-hydrazinyl-3-nitrobenzopyran-2-one 4 and aromatic aldehydes, corresponding 4-(Nbenzylidene-hydrazino)-3-nitrobenzopyran-2-ones 5(a-c) are obtained. Cyclization reaction of 4-hydroxybenzopyran-2-one 1 with aromatic aldehydes and malononitrile, in the presence of SDS, resulted by formation of 2-amino-5-oxo-4-phenyl-(4H, 5H) pyrano-[3,2-c]-chromen-3-carbonitrile derivatives 6(a-c), whereas by reacting of 4-hydroxybenzopyran-2-one 1 and aromatic aldehydes, in presence of SDS, corresponding 3,3'-(benzylidene)-bis-4-hydroxyibenzopyran-2-ones 7(a-c) are synthesized. The synthesized products are characterized on the basis of spectrometric data. Antimicrobial activity of products 5(a-c), 6(a-c) and 7(a-c) against S. aurous, E. coli and Klebsiella are investigated measuring of inhibition zones around the discs which are marked with their N, N-DMF solutions. Compounds of series 5 and 6 showed considerable antimicrobial activity against these microorganisms, whereas compounds of series 7 showed moderate activity. Impact of the substituents in antimicrobial activity also is investigated.
Nowel benzothiazol‐2‐yl‐benzylidene imines are synthesized by condensation of benzaldehydes and corresponding 2‐aminobenzothiazoles. Condensation of benzaldehyde 1a and 2‐aminobenzothiazoles 2(a,b) gave benzothiazol‐2‐yl‐benzylidene imines 3(a,b). By condensation of 3‐nitrobenzaldehyde 1b and 2‐aminobenzothiazoles 3(a,b) , corresponding benzothiazol‐yl‐3‐nitrobenzylidene imines 3(c, d) were synthesized. The antibacterial activity of products 4(a‐d) were investigated and results were submitted for their activities against E. coli, Clebsiella and S. aureus. Compound 3d showed light bactericide activity against S. aureus. Emphatic activity against E. coli exhibited compounds 3d and 3c , whereas 3d and 3b exhibited the strongest activity against Clebsiella. In general there was a direct positive correlation between increasing concentration of the compound and antibacterial activity.
Novel benzylideneimines, iminomethyl‐phenoles and iminoethyl‐benzopyran‐ 2‐ones were synthesized by condensation reactions of benzaldehyde analogues and acetyl‐benzopyran‐2‐one and heterocyclic amines. Condensation of 3‐acetylbenzopyran‐2‐one 1a and 2‐aminopyridines and 2‐aminopyrimidine 2(a‐c) resulted by synthesis of corresponding derivates of [2‐ylimino)‐ethyl]‐benzopyran‐2‐one 3(a‐c). By catalytic condensation of benzaldehyde and their analogues 1(b‐d) and 2‐amino‐5‐bromothiazole, 2‐aminobenzothiazoles and 2‐aminopyrimidines 2(d‐h), novel benzylideneimine derivatives 3(d‐h) were syntesized. The antibacterial activity of products 3(a‐h) against S. aureus, E. coli dhe Clebsiella were investigated and reported. Results of inhibition zones were indicated for considerable activity of these compounds against these microorganisms. Compounds 3f and 3c were more active against Staphylococcus aureus. Compounds 3c and 3g exhibited the strongest activity against Clebsiella, whereas 3d was more active against Escherichia coli. In general there was a driect positive correlation between increasing concentration of the compound and anitbacterial activity.
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