Synthesis and pharmacological evaluation of imidazoline sites I1 and I2 selective ligands

Pyrrolo[1,2-a]pyrazines have a broad spectrum of biological activity [1,2]. The method widely used for synthesis of 1,6-dialkyl-substituted pyrrolo[1,2-a]pyrazines is based on the reaction of substituted 2-acylfurans with ethylenediamine [3].We proposed that exchange of the starting 2-acylfurans and ethylenediamine for the corresponding 2-furonitriles and diethylenetriamine respectively permit the preparation of more complex structures. Reaction of 2-furonitriles with ethylenediamine, however, gave only the 2-(2-furyl)-4,5-dihydro-1H-imidazoles 2a,b.The exchange of ethylenediamine for diethylenetriamine unexpectedly led to the preparation of tricyclic structures via refluxing a mixture of the 2-furonitrile (1a) or 5-methyl-2-furonitrile (1b) with diethylenetriamine for 10 h to give the corresponding 2,3,5,6-tetrahydroimidazo[2,1-c]pyrrolo[1,2-a]pyrazine (3a) or its 8-methyl analog 3b in 32 and 35% yields respectively. N N N R 1a,b (NH 2 CH 2 CH 2 ) 2 NH 3 a (32%), b (35%) 1, 3 a R = H, b R = Me

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“…Yield 4.76 g (72%); mp 180ºC (ethylenediamine). The spectroscopic data agreed with that reported in [4]. .…”

Section: -(2-furyl)-45-dihydro-1h-imidazole (2a)supporting

confidence: 91%

Unexpected tandem condensation of 2-furonitriles with diethylenetriamine

Теренин

Galkin

Kabanova

et al. 2010

Chem Heterocycl Comp

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“…[2] BFI is broadly used in hypertensive therapy because the activities of the furane ring increase when the benzyl group is incorporated into the structure. [5] So far, the structural requirements for imidazoline interaction with the mentioned sites are not clearly understood, and the understanding of the influence of the heterocyclic rings on the compound structure in connection to its relevance in the biological function is essential for the design and synthesis of selective imidazoline ligands. The aim of this work is to carry out an experimental and theoretical study on this compound with quantum chemical methods in order to better understand its structural and vibrational properties.…”

Section: Introductionmentioning

confidence: 99%

Structural and vibrational analyses of 2‐(2‐benzofuranyl)‐2‐imidazoline

Contreras

Montejo

González

et al. 2011

J Raman Spectroscopy

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We have studied 2-(2-benzofuranyl)-2-imidazoline (BFI) and characterized it by using infrared and Raman spectroscopies. The density functional theory (DFT) method together with Pople's basis set shows that two conformers exist for the title molecule as have been theoretically determined in the gas phase and that, probably, an average of both conformations is present in the solid phase. The harmonic vibrational wavenumbers for the optimized geometry of the latter conformer were calculated at the B3LYP/6-31G * level in the proximity of the isolated molecule. For a complete assignment of the IR and Raman spectra in the compound in the solid phase, DFT calculations were combined with Pulay's scaled quantum mechanics force field (SQMFF) methodology in order to fit the theoretical wavenumbers to the experimental ones.

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“…The 2-arylimidazoline derivatives are important compounds because of their pharmaceutical activity [2]. The methods described for their preparation in the literature are based on the condensation of ethylenediamine or its salt [3] with benzonitrile in the presence of ZnCl 2 and NH 4 Cl [4], P 2 S 5 [5], with ethyl benzoate [6], or with benzoic acid in the presence of Ph 3 P and Et 3 N [7].…”

Section: Resultsmentioning

confidence: 99%