Reinvestigation of synthesis of halo-substituted 3-phenyl-1-(2-pyridyl)-2-propen-1-ones (azachalcones). A tandem reaction for formation of penta-substituted cyclohexanols

Halo-Substituted Chalcones and Azachalcones Inhibited Lipopolysaccharited-Stimulated Pro-Inflammatory Responses through the TLR4-Mediated Pathway

“…Azachalcones 9a – i were synthesized from 8 and corresponding 6a – h ( Figure 4 ) as reported recently [ 33 ]. The structures of synthetic chalcones 7a – i and azachalcones 9a – i are listed in Figure 5 .…”

“…The halo-substituted chalcones and azachalcones are not naturally occurring compounds [ 33 ]. The halogen substitution in ring B of chalcones alters the electron distribution owing to its high electronegativity and dipole moment, which can influence the biological activity.…”

Synthesis of Terpyridines: Simple Reactions—What Could Possibly Go Wrong?

“…A number of publications have provided overviews of the reaction space and the types of products that are to be expected. If the rates of the subsequent reactions are significantly faster than the initial ones leading to the enone, domino [32,33,34] or tandem [35] reactions are expected, leading to the selective formation of one (or more) of a range of potential reaction products. In this section, we present a comprehensive overview of the products other than terpyridines that have been obtained from Kröhnke and related syntheses.…”

“…In addition to the parent compound (Ar = Ar 1 = C 6 H 5 ) [39,40,41,42,43,44,45,46], a large number of derivatives with carbocyclic Ar and Ar 1 substituents have been obtained from reactions of substituted benzaldehydes and acetophenones [34,41,43,46,47,48,49,50,51,52,53]. Of most relevance to the chemistry reported in this manuscript, are compounds with heterocyclic substituents and, to date, examples with thiophen-2-yl [34,41,54,55,56], furan-2-yl [54,57], benzofuran-2-yl [33], benzofuran-3-yl [33], benzothiophen-2-yl [33], benzothiophen-3-yl [33], pyridin-2-yl [33,35,45,58,59,60,61,62,63,64,65,66] pyridin-3-yl [33,45,56] and pyridin-4-yl [16,20,33,45,56,67] groups have been reported. Cave and Raston have commented that reactions of 4-acetylpyridine with 4-alkoxybenzaldehydes in solution only yield the 3:2 products rather than the desired 4,2′:6′,4″-terpyridines [16,20].…”