Background:
Solvent- and catalyst-free synthesis of 1,4-dihydropyridines (1,4-DHPs) under microwave radiation is directly dealt with the concept of green chemistry. They are the class of pharmacological agents and drugs used as Ca2+ channel blockers, and they behave as the photoelectronic functional materials to exhibit fluorescence because of the electron donating and withdrawing groups present in them.
Objective:
An efficient and rapid microwave assisted synthesis of 4-(3-bromo-4-hydroxy-5-methoxyphenyl)-3,5-dicarbmethoxy-2,6-dimethyl-1,4-dihydropyridine (4) has been achieved under solvent- and catalyst-free conditions using three components 3-bromo-4-hydroxy-5-methoxybenzaldehyde, 3-oxobutanoic acid methyl ester, and ammonium carbonate in 25 minutes, which was then subjected to spectroscopic characterization, single-crystal X-ray and fluorescence study.
Methods:
The characterization methods were 1H and 13C NMR, FT-IR, LC-MS, and elemental analysis. The single-crystal structure was developed using a mixture of Methanol: Tetrahydrofuran and was determined by single-crystal X-ray diffraction method. The fluorescence study was accomplished in a spectrofluorometer by taking cresyl violet as a reference with two organic solvents, methanol and chloroform.
Results:
The crystal structure is monoclinic, space group P21/n with a = 11.0557(3) Å, b = 7.3544(2) Å, c = 22.4852(7) Å and β = 104.107(2)°. The used single-crystal size is 0.200 × 0.200 × 0.200 mm3. The NH....O type intermolecular hydrogen bond is observed between N(1) and O(2) atoms. The absorption and fluorescence spectra were found to depend on the chemical nature of the substituents available on C(4), C(2), and C(3) atoms of the 1,4-DHP ring and solvent properties.
Separation, Detection, and Functional Materials. Solid-phase preconcentration/tristimulus colorimetry of trace cobalt(II), nickel(II) and iron(II,III) by using the L*a*b* chromaticity diagram system.