Organic Communications Articles

A new series of 1,3-benzothiazol-2-yl)-1,3-thiazolan-4-one 5a-j has been synthesized by the reaction of 2-(4-methylphenyl)-3-(5,5,7-trimethyl-4,5,6,7-tetrahydro-1,3-benzothiazol-2-yl)-1,3-thiazolan-4-one 4 with aryl aldehydes. Chemical structures of all the new compounds were established by IR, 1H, 13C NMR, MS and elemental data. The compounds 5a-j were evaluated for their antibacterial activity against Gram-positive bacteria viz. Bacillus subtilis (MTCC 441), Bacillus sphaericus (MTCC 11), Staphylococcus aureus (MTCC 96) and Gram-negative bacteria viz. Pseudomonas aeruginosa (MTCC 741), Klebsiella aerogenes (MTCC 39), Chromobacterium violaceum (MTCC 2656). Amongst them, compounds containing [(4-chlorophenyl)methylidene] moiety 5b, [(3-nitrophenyl)methylidene] moiety 5d and [(2-thienyl)methylidene] moiety 5j showed significant antibacterial activity, almost equal/more than the activity of the standard drug Streptomycin. Further, the compounds 5a-j were also screened for their antifungal activity against Candida albicans (ATCC 10231), Aspergillus fumigatus (HIC 6094), Trichophyton rubrum (IFO 9185), and Trichophyton mentagrophytes (IFO 40996). Most of these new compounds showed appreciable activity against test bacteria and fungi and emerged as potential molecules for further development.

Chitosan catalyzed synthetic procedure has been developed for the synthesis of α-hydroxy phosphonates from different aromatic aldehydes and diethyl phosphite at 60 ºC. The title compounds are characterized by IR, 1H, 13C, 31P NMR and mass spectral data. All the title compounds 3a-j were tested for their invitro antioxidant activities by DPPH, Nitric Oxide and H2O2 scavenging methods.

A highly efficient, green and expeditious method is described for the synthesis of substituted 2-amino2-chromenes employing one pot three component condensation of aromatic aldehydes, malononitrile and activated phenol in presence of p-dimethylaminopyridine (10 mol %) as a catalyst under microwave irradiation. The present method is operationally simple and offers many advantages such as high yield, short reaction time and simple workup.

A series of poly substituted pyridines (3,11-disubstituted-7-aryl-5,6,8,9-tetrahydrodibenzo[c,h]acridines) were synthesized by the multicomponent condensation of 6-substituted-1-tetralone, aromatic aldehydes and ammonium acetate in ethanol using L-proline as an efficient organocatalyst. This methodology is mild, efficient, high yielding and the catalyst is inexpensive, easily recovered from the reaction mixture and reused for five times without losing its activity.

The absorption and fluorescence spectra of phenylcoumarin and cyanophenylbenzocoumarin-3- carboxylates 6a-f and 9a-e have been investigated in chloroform, acetonitrile and ethanol. The substituting groups with varying electron donating ability such as N,N-diethyl amine and morpholine at 7-position, in phenylcoumarin-3-carboxylate 6a-f exhibits fluorescence at a longer wavelength i.e. 420-460 nm in chloroform and 460-504 nm in acetonitrile. However the morpholine derivatives 6f-j did not show fluorescence in chloroform. In another series of cyanophenylbenzocoumarin-3-carboxylates 9a-e, the compound 9c exhibits fluorescence at 546 nm in ethanol and 256 nm in acetonitrile, and lower emission wavelength i.e. 356 nm in chloroform. Further the compounds 6e, 9b, 9d and 9e exhibited high quantum yield in ethanol i.e., ΦF = 0.79, 0.70, 0.80 and 0.74 respectively compare to Rhodamine B (ΦF = 0.24) in ethanol.

This article [1] has been retracted at the request of the editor as the authors have duplicated one of their articles that had already appeared in Russ. J. General Chem., 2012, 82:8,, 1464-1467 [2].