Two new fluorescent heterocyclic perimidines: first syntheses, crystal structure, and spectral characterization

An efficient one-pot synthesis of two new heterocyclic perimidines 4-(2,3-dihydro-1H-perimidin-2-yl)-2-methoxyphenol and 2-(quinoxalin-2-yl)-2,3-dihydro-1H-perimidine in good yields is presented. This methodology provides a simple, straightforward synthetic route to these interesting classes of heterocycles. Crystal structure, solvatochromism, and antibacterial activity of these organic compounds are discussed.     

IR,Raman and SERS spectra of ethyl salicylate

The IR and Raman spectra of ethyl salicylate were recorded and analyzed. The surface enhanced Raman scattering (SERS) spectrum was recorded in a silver colloid. The vibrational wavenumbers of the compound have been computed using the Hartree‐Fock/6‐31G* basis. The direction of charge transfer contribution to SERS has been discussed from the frontier orbital theory. The presence of methyl modes in the SERS spectrum indicates the nearness of the methyl group to the metal surface and the presence of ring vibrations and out‐of‐plane ring modes in the SERS spectrum suggests a flat orientation of the molecule on the silver surface. The first hyperpolarizability is calculated and the calculated molecular geometry has been compared with the reported similar structures. Copyright © 2009 John Wiley & Sons, Ltd.     

Vibrational spectroscopic studies and DFT calculations of 4‐fluoro‐N‐(2‐hydroxy‐4‐nitrophenyl)benzamide

Fourier transform infrared (FT‐IR) and FT‐Raman spectra of 4‐fluoro‐N‐(2‐hydroxy‐4‐nitrophenyl)benzamide were recorded and analyzed. The vibrational wavenumbers and corresponding vibrational assignments were examined theoretically using the Gaussian03 set of quantum chemistry codes. The red‐shift of the NH‐stretching wavenumber in the infrared (IR) spectrum from the computed wavenumber indicates the weakening of the NH bond resulting in proton transfer to the neighboring oxygen atom. The simultaneous IR and Raman activation of the CO‐stretching mode gives the charge transfer interaction through a π‐conjugated path. Copyright © 2008 John Wiley & Sons, Ltd.     

Structure Analysis of Methyl‐3,4‐dihydro‐3‐(p‐methylphenyl)‐4‐oxo‐2‐quinazolinyl thiopropionate

The crystal structure of methyl‐3, 4‐dihydro‐3‐(p‐methylphenyl)‐4‐oxo‐2‐quinazolinyl thiopropionate (C₁₉H₁₈N₂O₃S) has been determined by X‐ray diffraction methods. The compound crystallizes in the triclinic space group P with unit cell parameters: a = 9.094(2), b = 9.428(3), c = 10.612(3) Å, α = 94.55(3), β = 95.44(2), γ = 106.75(3)° and Z = 2. The structure has been refined to an R‐value of 0.054 for 2533 observed reflections [F_o > 4σ(F_o)]. The quinazoline moiety and the methyl substituted phenyl ring is almost planar. The dihedral angle between these two moieties is 84.96(8)° . The crystal structure is stabilized by an intermolecular C‐H … O interaction.