Synthesis and structural characterisation of amides from picolinic acid and pyridine-2,6-dicarboxylic acid

Abstract

Coupling picolinic acid (pyridine-2-carboxylic acid) and pyridine-2,6-dicarboxylic acid with N-alkylanilines affords a range of mono- and bis-amides in good to moderate yields. These amides are of interest for potential applications in catalysis, coordination chemistry and molecular devices. The reaction of picolinic acid with thionyl chloride to generate the acid chloride in situ leads not only to the N-alkyl-N-phenylpicolinamides as expected but also the corresponding 4-chloro-N-alkyl-N-phenylpicolinamides in the one pot. The two products are readily separated by column chromatography. Chlorinated products are not observed from the corresponding reactions of pyridine-2,6-dicarboxylic acid. X-Ray crystal structures for six of these compounds are described. These structures reveal a general preference for cis amide geometry in which the aromatic groups (N-phenyl and pyridyl) are cis to each other and the pyridine nitrogen anti to the carbonyl oxygen. Variable temperature 1H NMR experiments provide a window on amide bond isomerisation in solution.

Novel DGT Configurations for the Assessment of Bioavailable Plutonium, Americium, and Uranium in Marine and Freshwater Environments

“…In this work, we used a modified procedure to obtain the ligand L 1 in a one-pot synthesis, as described by Devi et al for amide synthesis from picolinic acid. 42 This is quicker and more scalable than previously reported (Scheme 1). 37 Resin Gel Syntheses.…”

Ion-imprinted resin for use in an automated solid phase extraction system for determining 90Sr in environmental and human samples

“…The procedure involved isolating the ethyl ester, the amide substitute and the final product HL1, after hydrolysis. Here, we successfully produced HL1 in a one-pot synthesis by activating the dipicolinic acid with SOCl 2 , following previous work by Devi et al [17]. Hydrolysis of the acyl chloride took place during the isolation step of the final product.…”

Effect of Heterocyclic Ring on LnIII Coordination, Luminescence and Extraction of Diamides of 2,2′-Bipyridyl-6,6′-Dicarboxylic Acid

“…Aminopyridine rings are cis relative the oxygen atom of amidic group. The latter is fundamental difference of represented structure from N-alkylanilides of 2,2′-bipyridyl-6,6′-dicarboxylic acid [11,13] and N-alkylanilides of 2,6-pyridinedicarboxylic acid [16,17]. Contrary to the tertiary amides of 2,2′-bipyridyl-6,6′-dicarboxylic acid, the molecule of 2a is almost flat: the torsion angle N1-C6-C6′-N1′ is 180.0(1)°.…”

“…The angle between pyridine rings of bypyridyl moiety and aminopyridine groups is 23.19°. Torsion angle N1-C2-C1-N2 is 3.4(2)°, which evidenced the better conjugation between bipyridyl moiety and amidic group and aminopyridine aromatic ring when comparing with N-ethyl-derivatives [16,17]. The complexes with nitrates of lanthanum, samarium, europium, and dysprosium were synthesized by interaction of the ligands with nitrates of corresponding metals in acetonitrile (Scheme 4).…”