Efficient Synthesis of Cannabigerol, Grifolin, and Piperogalin via Alumina-Promoted Allylation.

The synthesis of three phenolic natural products has been accomplished with unprecedented efficiency using a new alumina-promoted regioselective aromatic allylation reaction. Cannabigerol and grifolin were prepared in one step from the inexpensive 5-alkyl-resorcinols olivetol and orcinol. Piperogalin was synthesized, for the first time, via two sequential allylations of orcinol with geraniol and prenol.

Sialidase inhibitory activity of diarylnonanoid and neolignan compounds extracted from the seeds of Myristica fragrans.

Sialidases are key virulence factors that remove sialic acid from host cell surface glycans, thus unmasking receptors to facilitate bacterial adherence and colonization. In this study, we report the isolation and characterization of novel inhibitors of the Streptococcus pneumoniae sialidases NanA, NanB, and NanC from Myristica fragrans seeds. Of the isolated compounds (1-12), malabaricone C showed the most pneumococcal sialidases inhibition (IC50 of 0.3µM for NanA, 3.6µM for NanB, and 2.9µM for NanC). These results suggested that malabaricone C and neolignans could be potential agents for combating S. pneumoniae infection agents.

Synthesis, structure, and binding properties of lipophilic cavitands based on a calix[4]pyrrole-resorcinarene hybrid scaffold.

We report the synthesis, structural characterization, and binding properties of a series of unprecedented cavitands based on a meso-dodecyl-calix[4]pyrrole-resorcin[4]arene hybrid scaffold. The reported structural and conformational features of the prepared cavitands are derived from results obtained in solution, solid state, and molecular modeling studies. In the solid state, these cavitands are exclusively observed in the kite C4 structure and as a racemic mixture of two cyclochiral conformers, which are interconverting fast on the (1)H NMR time scale, according to solution studies. In agreement, molecular modeling studies assign an energy preference for the kite conformer of the cavitands. The polar interior of the synthesized containers allows for the inclusion of a series of pyridine N-oxide derivatives. This results in the formation of 1:1 complexes that are kinetically and thermodynamically highly stable. The putative switching process between the vase and kite forms of these cavitands is investigated in solution by means of variable temperature (1)H NMR experiments. N-Oxide guests that are size and shape complementary to the volume of the cavity of the vase form are also employed to facilitate its emergence. All of the results obtained indicate the existence of a remarkable preference toward the kite conformation both in free and bound calix[4]pyrrole-based cavitands.

Hydrogen-bond driven assembly of a molecular capsule facilitated by supramolecular chelation.

Resorcinarene-based cavitands functionalized with acetamido groups capable of self-complementary hydrogen-bond interactions, were synthesized in order to construct supramolecular capsules. The 1,3-bifunctionalized cavitand produced a polymeric assembly, whereas the tetra-functionalized analogue yielded a discrete capsule held together via N-H···O hydrogen bonds. The ethynyl species attached to the rim of these host molecules deepen each cavitand and expands the volume of the resulting capsule.

Ardisiphenols A-C, novel antioxidants from the fruits of Ardisia colorata.

Novel alk(en)ylphenols, named ardisiphenols A--C (1--3) were isolated from the fruits of Ardisia colorata, together with known alk(en)ylresorcinols (4--6). Their structures were determined by the NMR and MS/MS analyses. All compounds showed scavenging activities towards 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and cytotoxicities against murine breast cancer cell line, FM3A.

Synthesis and nematocidal activity of diarylnonanoids related to malabaricones.

Twenty diarylnonanones were synthesized and their nematocidal activity was examined. Among those, the p-hydroxy compound 16 exhibited the strongest activity comparable to the natural diarylnonanoids, malabaricones A and C. Diarylundecanoid 57 also showed appreciable activity.