Synthesis, X‐ray crystal structure and optical properties of novel 2‐aryl‐3‐ethoxycarbonyl‐4‐phenylpyrido[1,2‐a]benzimidazoles

Abstract

A series of novel 2-aryl-3-ethoxycarbonyl-4-phenylpyrido[1,2-a]benzimidazole derivatives were synthesized by the tandem reaction of 2-benzoyl benzimidazole and (Z)-ethyl 4-bromo-3-arylbut-2-enoate in the presence of potassium carbonate. The compounds were characterized using IR, 1H-NMR, 13C-NMR, HRMS and the structure of 6f was further determined by X-ray crystallography. Both absorption and fluorescence spectra characteristics of the compounds were investigated in acetonitrile and dichloromethane. The results showed that the absorption maxima of the compounds varied from 220 to 284 nm, depending on the structure of 2-aryl group. The fluorescence results revealed that these compounds exhibited blue-green fluorescence (463-475 nm) in dilute solutions and showed acceptable fluorescence quantum yields (Ф(PL) = 0.13-0.73) in dichloromethane.

Indene Derived Phosphorus‐Thioether Ligands for the Ir‐Catalyzed Asymmetric Hydrogenation of Olefins with Diverse Substitution Patterns and Different Functional Groups

“…Phosphite/phosphinite‐thioether ligands L1 ‐ L8a ‐ f were prepared as previously reported [16] . Substrates S1 , [30] S2 , [12e] S3 – S4 , [30] S5 – S7 , [12g] S8 , [31] S9 – S10 , [32] S11 , [33] S12 , [32] S13 , [33] S14 , [34] S15 – S18 , [13b] S19 , [35] S20 , [13a] S21 , [36] S22 , [37] S28 , [6g] S29 , [38] S30 – S37 , [6g] S38 , [39] S39 – S43 , [22b] S44 , [40] S45 – S46 , [27j] S47 , [41] S48 , [27j] S49 , [27i] S50 [27a] were prepared following the reported procedures. 1 H, 13 C and 31 P NMR spectra were recorded using a 400 MHz spectrometer.…”

Phosphite‐thioether/selenoether Ligands from Carbohydrates: An Easily Accessible Ligand Library for the Asymmetric Hydrogenation of Functionalized and Unfunctionalized Olefins

“…Ligands L1 a , f , g , L11 a , f , g , L12 g , L14 g and L18 f , g and complexes [Rh(cod)( L14 g )]BF 4 and [Ir(cod)( L14 g )]BAr F were synthesized as previously reported . Substrates S1 , S2 , S5 , S6 – S7 , S8 , S9 , S10 – S11 , S12 – S14 , S17 – S23 , S24 , S25 , S26 , S31 , S33 – S38 , S39 – S43 , S44 – S45 and S46 were prepared following literature procedures. All other reagents are commercially available and were used as received.…”

Giving a Second Chance to Ir/Sulfoximine-Based Catalysts for the Asymmetric Hydrogenation of Olefins Containing Poorly Coordinative Groups

“…1 H, 13 C, and 31 P assignments were made on the basis of 1 H– 1 H gCOSY, 1 H– 13 C gHSQC, and 1 H– 31 P gHMBC experiments. Substrates S2 , S3 , S4 – S8 , S9 , S10 – S12 , S13 – S17 , S18 – S21 , and S24 were prepared following the reported procedures, whereas substrates S1 , S22 , and S23 were commercially available and used as received.…”