Several fused triazolo and ditriazoloquinoxaline derivatives such as 1-aryl-4-chloro-[1,2,4]triazolo[4,3-a]quinoxalines (3a-d), 4-alkoxy[1,2,4]triazolo[4,3-a]quinoxalines (4a,b), 4-substituted-amino-[1,2,4] triazolo[4,3-a]quinoxalines (5a-h), 1-(aryl)-[1,2,4]triazolo[4,3-a]quinoxalin-4(5H)-thione (6), 4-(arylidenehydrazino)1-phenyl-[1,2,4]triazolo[4,3-a]quinoxalines (10a-e) and [1,2,4]ditriazolo[4,3-a:3',4'-c]quinoxaline derivatives (11-13) have been synthesized and some of these derivatives were evaluated for antimicrobial and antifungal activity in vitro. It was found that compounds 3a and 9b possess potent antibacterial activity compared to the standard tetracycline.

In this study, certain 3‐substituted styrylquinoxalin‐2(1H)‐ones (2a‐d) and their 2‐chloro (3a‐d) and 2‐piperazinyl derivatives (4a‐g) were synthesized from 3‐methylquinoxalin‐2(1H)‐one (1). In addition, a series of 1‐alkyl‐3‐substituted styrylquinoxalin‐2(1H)‐ones (5a‐d) was also prepared. Moreover, 3‐(N2‐arylidenehydrazinocarbonyl)quinoxalin‐2(1H)‐ones (8a‐c) as well as their cyclized oxadiazolinyl derivatives (9a‐c) were prepared from 3‐hydrazinocarbonylquinoxalin‐2(1H)‐one (7). Furthermore, 3‐(5‐substituted thio‐1,3,4‐oxadiazol‐2‐yl)quinoxalin‐2(1H)‐ones (11a‐c) and (12a‐c) were obtained from the intermediate compound (10) ‐ previously obtained via cyclization of (7) with CS2. Likewise, 3‐(5‐oxo‐4,5‐dihydro‐(1,3,4‐oxadiazol‐2‐yl)quinoxalin‐2(1H)‐one (13), 3‐[5‐(4‐nitrophenyl)‐1,3,4‐oxadiazol‐2‐yl]‐quinoxalin‐2(1H)‐one (14) and its 2‐chloro derivative (15) were prepared from 3‐hydrazinocarbonylquinoxalin‐2(1H)‐one (7). Some of these derivatives were evaluated for antimicrobial activity in vitro and some of the tested compounds showed antibacterial or antifungal activity.

2-Amino-3-cyanothiophenes were successfully condensed with a number of cycloalkanones to afford tacrine analogues in a one-step reaction mediated with Lewis acid. The newly synthesized compounds have been tested for their ability to inhibit acetylcholine esterase (AChE) activity using tacrine as standard drug. Some of the tested compounds showed moderate inhibitory activity in comparison with tacrine, especially compounds 6a which displayed the highest inhibitory activity. Furthermore, molecular-modeling studies were performed in order to rationalize the obtained biological results.

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Gas liquid chromatographic analysis of the fatty acid methyl esters from eggs ofDermacentor andersoni Stiles (Ixodidae) revealed the presence of significant quantities (15% total fatty acids) of an unidentified component with a retention time between C18∶3−C22∶0 fatty acids. Smaller amounts of the unidentified component (ca. 5% total fatty acid) also were detected in host rabbit serum. Purified, the unidentified component's methyl ester collected from the tick eggs by preparative gas liquid chromatography was partially identified and characterized by chemical and spectroscopic analyses. The evidence suggests that the unidentified component is a methyl branched C15 tricarboxylic acid containing two vicinal carboxylic acid groups. Biosynthesis of the unidentified component by the tick is under investigation.

Design, Synthesis, and Molecular-Modeling Study of Aminothienopyridine Analogues of Tacrine for Alzheimer's Disease. -Starting compounds (I) are obtained by classical Gewald reaction. Condensation of (I) with a number of cycloalkanones affords several tacrine analogues in a one-step reaction mediated by Lewis acids. Some of the newly prepared compounds, e.g. (III), (Va), and (Vb), show significant AChE inhibition activity. (IIIb) is the most active derivative with an activity similar to that of tacrine. -(BADRAN, M. M.; HAKEEM*, M. A.; ABUEL-MAATY, S. M.; EL-MALAH, A.; SALAM, R. M. A.; Arch. Pharm. (Weinheim, Ger.) 343 (2010) 10, 590-601, http://dx.