No abstract

A simple and convenient method has been developed for the synthesis of title compounds, 1-methyl-2-phenyl-1H-imidazo[4,5-f]quinoline and derivatives (5a-f) in reasonable yields. The commercially available 6-nitro-quinoline-5-amine (1) is used as raw material and it is reduced conveniently using SnCl 2 to give the initial intermediate, quinoline-5,6-diamine (2) in good yield. Compound 2 on consecutive steps when treated on condensation followed by cyclization generated the rest of intermediates, N 6benzylidene-quinoline-5,6-diamines (3a-f) and 2-phenyl-1H-imidazo[4,5-f]-quinolines (4a-f) respectively. The chemical structures of all newly prepared compounds were elucidated using infrared, 1 H NMR and mass spectral studies as well as elemental analysis. The output of this synthetic method has been provided a series of successful biologically important structures.

A convenient and simple method for the synthesis of novel 3,4‐dihydrofuran‐annulated coumarins, 3‐(hydroxymethyl)‐2H‐furo[3,2‐c]chromen‐4(3H)‐ones 5a, 5b, 5c, 5d, 5e, 5f, 5g, by combined Claisen rearrangement and intramolecular regioselective oxidative cyclization of 4‐O‐allyl coumarin intermediates 3a, 3b, 3c, 3d, 3e, 3f, 3g using inexpensive oxidizing agent m‐CPBA is described. The reaction proceeds smoothly by tandem epoxidation/regioselective 5‐exo‐tet‐intramolecular ring opening. The structures of synthesized compounds are established on the basis of spectral data including IR, 1H NMR, and mass and elemental analyses.

Combined Claisen Rearrangement and Oxidative Cyclization as a Route to Hydroxymethyl Dihydrofuran-Annulated Coumarins. -The title compounds are efficiently and conveniently obtained by a tandem epoxidation/5-exo-tet intramolecular ring opening of allyl-derivatives (I) using MCPBA as inexpensive oxidizing reagent. -(JAYAPRAKASH*, R. Y.; CHAKRAVARTHULA, V.; J. Heterocycl. Chem. 52 (2015) 4, 1014-1018, http://dx.