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1.
Org Lett ; 21(24): 10038-10042, 2019 Dec 20.
Article in English | MEDLINE | ID: mdl-31794237

ABSTRACT

A Cp*Co(III)-catalyzed γ-selective C-H allylation/hydroamination cascade toward the synthesis of 3,4-dihydroisoquinolines (DHIQs) has been successfully developed, starting from NH ketimines and allyl carbonates. Notably, highly efficient and γ-selective C-H allylations were accomplished using γ-substituted allyl reagents, thus overcoming the issues of poor α/γ selectivity and low reactivity of previous transition metal-catalyzed C-H allylations. The stereochemistry of allyl carbonates was a crucial factor, and synthesis of the DHIQs was achieved using (Z)-allyl carbonates.

2.
J Org Chem ; 79(19): 9253-61, 2014 Oct 03.
Article in English | MEDLINE | ID: mdl-25217006

ABSTRACT

The Pd-catalyzed oxidative olefin amination of the zinc bromide complex intermediate, formed by the sequential reaction of nitriles with a Reformatsky reagent and 1-alkynes, affords pyrrole derivatives in good to excellent yields. This tandem protocol provides a simple, efficient, and atom- and pot-economical way to quickly build polysubstituted NH-pyrroles starting from readily available reagents in a regiocontrolled manner with a broad substrate scope and high functional group tolerance. In contrast, the Pd-catalyzed oxidative olefin amination of an isolated α-vinyl-ß-enamino ester did not proceed effectively, but the reaction efficiency can be restored by addition of n-BuZnBr or Zn(OAc)2, indicating the crucial role of the zinc complex in this transformation. The synthetic utility of this protocol is exemplified by the rapid synthesis of pyrrolophenanthrenes and pyranopyrrolones through selective Pd- and Cu-catalyzed C-C and C-O bond-forming reactions.


Subject(s)
Bromides/chemistry , Palladium/chemistry , Pyrroles/chemical synthesis , Zinc Compounds/chemistry , Amination , Catalysis , Esters , Molecular Structure , Oxidation-Reduction , Pyrroles/chemistry
3.
Org Lett ; 14(24): 6358-61, 2012 Dec 21.
Article in English | MEDLINE | ID: mdl-23228166

ABSTRACT

A novel tandem Blaise/Pinner-type reaction for the one-pot synthesis of pyrimidin-4-ones is described. The Blaise reaction intermediate, formed by addition of a Reformatsky reagent to a nitrile, reacted with a second nitrile chemoselectively in the presence of a catalytic amount of Cu(OAc)(2) to afford pyrimidin-4-ones.

4.
Int Immunopharmacol ; 3(5): 713-21, 2003 May.
Article in English | MEDLINE | ID: mdl-12757740

ABSTRACT

Herbal medicine, Herba Taraxaci (Tarazacum mongolicum Hand.-Mazz.), was administered to mice with Behcet's disease (BD)-like symptoms induced by herpes simplex virus (HSV). BD is a chronic recurrent inflammatory disease. Herba Taraxaci (6 mg) was administered alone or in combination with 2 microg of colchicine to BD-like mice. Colchicine is a drug that is widely used as a medication for BD patients. The water extracts of Herba Taraxaci were administered orally once per day for 20 days. Eighty percent (8 of 10) of mice treated with Herba Taraxaci combined with colchicine showed improvement in mucocutaneous symptoms compared to 0% (0 of 10) of the nontreated group and 30% (3 of 10) treated with colchicine alone. Cytokine expression in spleen tissue collected from treated mice was analyzed by RT-PCR and FACS. Treatment with Herba Taraxaci induced IL-4 mRNA, and spleen from mice receiving the combined treatment (Herba Taraxaci and colchicines) showed an increased number of splenocytes staining with anti-IL-10 (46.8+/-6.80) compared to Herba Taraxaci (35.4+/-2.17) (p<0.05) or colchicine alone (26.2+/-4.47) (p<0.001). These results suggest that the Herba Taraxaci may be an effective complementary agent in the treatment of BD.


Subject(s)
Behcet Syndrome/drug therapy , Colchicine/therapeutic use , Cytokines/biosynthesis , Phytotherapy , Animals , Cells, Cultured , DNA Primers , Drug Therapy, Combination , Flow Cytometry , Interferon-gamma/biosynthesis , Interleukin-10/biosynthesis , Interleukin-4/biosynthesis , Male , Mice , Mice, Inbred ICR , Plant Extracts/therapeutic use , Plants, Medicinal/chemistry , Spleen/cytology , Spleen/drug effects
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