Metal-free synthesis of polysubstituted oxazoles via a decarboxylative cyclization from primary α-amino acids


Scheme 1

Control experiments.

The ubiquitous oxazoles have attracted more and more attention in both industrial and academic fields for decades. This interest arises from the fact that a variety of natural and synthetic compounds which contain the oxazole substructure exhibit significant biological activities and antiviral properties. Although various synthetic methodologies for synthesis of oxazols have been reported, the development of milder and more general procedure to access oxazoles is still desirable.

Initially, compound A, formed by the substitution reaction of 1a with 2a, which can be transformed following two pathways: (a) I+, generated by the oxidation of iodine, could oxidize A to radical intermediate B, which eliminates one molecular of CO2 to generate radical C, which is further oxidized to imine Dor its isomer E. Subsequently, F is obtained by intramolecular nucleophilic addition of E. Finally, the desired product…

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lei gong teng ,:雷公藤, Tripterygium wilfordii Hook F. for Rheumatoid Arthritis

New Drug Approvals

A Chinese herb called thunder god vine works better than a widely-prescribed pharmaceutical drug at easing rheumatoid arthritis, a new study has found.

Tripterygium regelii, Aizu area, Fukushima pref, Japan

The herb has long been used in China to treat this potentially crippling autoimmune disease, which typically strikes hand and foot joints. It is known in Mandarin as ‘lei gong teng’ and to botanists as Tripterygium wilfordii Hook F.

Extracts of the herb have already fired the interest of drug laboratories as they contain hundreds of compounds, including intriguing molecules called diterpenoids which are believed to ease inflammation and immune response.

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Researchers at the Johns Hopkins School of Medicine have discovered that a natural constituent isolated from a traditional Chinese medicinal herb, Triptergium wilfordii Hook F. (雷公藤, Lei Gong Teng, Thunder God Vine), used for hundreds of years to treat many conditions, works well by blocking gene control machinery in the…

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Eco-friendly synthesis of diverse and valuable 2-pyridones by catalyst- and solvent-free thermal multicomponent domino reaction


An efficient and highly eco-friendly synthesis of diverse and functionalized 2-pyridone derivatives in good yield via the thermal multicomponent reaction of 4-oxo-4H-chromene-3-carbaldehydes with 1,3-diketoesters and anilines or primary aliphatic amines under catalyst- and solvent-free conditions is described. This reaction proceeds via domino Knoevenagel condensation/Michael addition/ring opening/ring closure reactions.

Eco-friendly synthesis of diverse and valuable 2-pyridones by catalyst- and solvent-free thermal multicomponent domino reaction

Green Chem., 2015, 17,4579-4586
DOI: 10.1039/C5GC01526J, Paper
Tej Narayan Poudel, Yong Rok Lee, Sung Hong Kim!divAbstract
An eco-friendly protocol for diverse and functionalized 2-pyridone derivatives via a multicomponent reaction under catalyst- and solvent-free conditions has been developed.

nmr, structures