X-Ray Crystal Structures of a 1-(p-fluorophenyl)-2-(α-pyridyl)ethanol Intermediate and the 1-(p-fluorophenyl)-2-(α-pyridyl)ethene Dehydration Compound Obtained from the Condensation Reaction of 2-Methylpyridine and p-Fluorobenzaldehyde

Abstract

Abstract:The compound 1-(p-fluorophenyl)-2-( -pyridyl)ethanol and its corresponding dehydration compound 1-(pfluorophenyl)-2-( -pyridyl)ethene were obtained from the Knoevenagel condensation reaction between 2-methylpyridine with p-fluorobenzaldehyde. The X-ray structure determined for 1-(p-fluorophenyl)-2-( -pyridyl)ethanol reveals that the compound crystallizes in the monoclinic system space group, P2 1 /n, containing four molecules in each crystal unit cell [a = 5.3664 (15) (2)°. The molecular structure shows the p-fluorophenyl ring attached to the double bond and located trans to the pyridine ring. The crystallography data give evidence that the intermediary compound is actually the alcohol just before the dehydration process that yields the trans double bond of the 1-(p-fluorophenyl)-2-( -pyridyl)ethene.

Synthesis and molecular structure of the 1-phenyl-2-(2-pyridyl)ethanol intermediate obtained from the condensation reaction of 2-picoline and benzaldehyde

“…The X-ray structure refinement produced data to support the following observations: bond lengths and angles were in good agreement with values retrieved from [20]. The -CH 2 -CHOH moiety of the molecule showed the typical Csp 3 -Csp 3 distance for C(8)-C(7) = 1.526(3) Å , which is similar to 1.509(3), 1.508 (8), and 1.517(9) Å obtained for the intermediates 1-(p-fluorophenyl)-2-(apyridyl)ethanol, 1-phenyl-2-(4-pyridyl)ethanol, and 5-ethyl-2-(4-nitro-7-ol-styryl)-pyridine, respectively, as reported in the literature [8,11,13], whereas for a Csp 3 -O distance, C(7)-O(1) = 1.415(3) Å is a typical value for alcohols [20] (Table 3). Meanwhile, the carbon-carbon distances were representative of pyridyl and phenyl groups.…”

“…The method used has been important because is a straightforward and clean way to obtain different styrylpyridines [7] and interesting intermediates such as the 1-phenyl-2-(4-pyridyl)ethanol, 1-(p-fluorophenyl)-2-(a-pyridyl)ethanol, as well as 1-(p-fluorophenyl)-2-(2-pyridyl)ethene, 2-styrylpyridine, and 2,6-distyrylpyridine, which have been previously obtained and characterized by single crystal X-ray diffraction [8][9][10][11].…”

Synthesis and Characterization of Conjugated Pyridine-(N-diphenylamino) Acrylonitrile Derivatives: Photophysical Properties

“…The fluorescence quantum yield values in the solids were of 0.07, 0.08, 0.11 and 0.09 for I-IV, respectively. We also compared the fluorescence emissions of compounds I-IV with the fluorescence of compounds of the recently reported -N(CH 3 ) 2 analogues which only exhibit PL in the solid state ( Figure 5) (Percino, 2008). The dimethylamino derivatives showed PL emission maxima over a wider range of wavelengths, from 507-616 nm.…”

“…Some dyes with donor-acceptor structures have been formed in a Heck coupling reaction with palladium-catalysis (Patra, et al, 2002), while others have been formed in the Knoevenagel condensation (Knoevenagel, 1896). Our group previously has synthesized different conjugated compounds with the Knoevenagel condensation, without any catalyst and under solvent-free conditions (Percino, et al, 2007(Percino, et al, , 2008(Percino, et al, , 2006(Percino, et al, , 2010. This method was successfully used to synthesize α, (Percino, et al, 2010).…”

X-ray Structures of Precursors of Styrylpyridine-Derivatives Used to Obtain 4-((E)-2-(Pyridin-2-yl)vinyl)benzamido-TEMPO: Synthesis and Characterization

“…The introduction of a nitrogen atom into the ring noticeably affects the photophysical and photochemical behavior of stilbene. Our work has focused on model compounds with trans conformation distyrylbenzene (DSB) linked with pyridine moieties (styrylpyridines) which had been obtained without the need for catalyst and solvent [ 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 ]. We have also conducted studies to understand their effects on the optics and electronic properties from a theoretical perspective [ 52 ].…”