Track topics on Twitter Track topics that are important to you
The synthesis of 20 alkyl amides, including 15 naturally occurring polyunsaturated alkyl amides previously identified from Echinacea spp. (1-13 and 62) or from Achilla sp. (55) and five previously unknown geometric isomers (23, 28, 67, 73, and 80), is described. Importantly, these amides include all of the major alkyl amides present in commercially used Echinacea extracts. The syntheses demonstrate methodology used for constructing alkyl amides containing conjugated diyne and isomerically pure enyne and diene moieties and may be adapted easily for the preparation of other alkyl amides present in Echinacea spp. Terminal-conjugated diynes were prepared by a Cadiot-Chodkiewitz coupling/deprotection sequence utilizing a protected bromoacetylene, and methyl-substituted diynes were made via a base-catalyzed rearrangement of terminal-skipped diynes. Conjugated dienes were prepared conveniently and with high stereoselectivity by the reduction of enynes or diynes with Rieke zinc. With the exception of 1-2 and 11-12, the alkyl amides are synthesized here for the first time, and their NMR data are consistent with that of the reported isolated natural compounds.
School of Chemistry and Molecular Biosciences, The University of Queensland , Brisbane 4072, Australia.
This article was published in the following journal.
Name: The Journal of organic chemistry
The Cu-catalyzed synthesis of non-racemic 3-amino skipped diynes via an enantiodetermining C-C bond formation is described using StackPhos as ligand. Despite challenging issues of reactivity and stere...
A strategy for achieving diastereodivergent azidations of enynes has been developed, employing azide transfer from M-N3 complex to alkyl radicals. Following this concept, the diastereoselectivity has ...
An iridium-catalyzed enantioselective hydroalkynylation of α, β-unsaturated amides was described. The selectivity of this reaction is distinct from that observed in many catalytic hydroalkynylations...
2-Acylpyridines were prepared by iridium-catalyzed [2+2+2] cycloaddition of alpha,omega-diynes with acyl cyanides. [Ir(cod)Cl]2/rac-BINAP or F-DPPE is an efficient catalyst for this reaction. The scop...
Previous studies have shown that echinacea is among the most widely used herbal medicines during pregnancy in Western countries. Despite its frequent use, we know little about the safety of this herba...
This is a randomized trial to determine if echinacea is effective in shortening the length and/or lessening the severity of colds in children 2 through 11 years old.
The goal of this study is to determine if either of two, commercially available, Echinacea purpurea products stimulate the immune system. For the study, 60 healthy adults will be randomize...
The goal of the this study is to determine if Echinacea purpurea stimulates the immune system in children. For the study, 40 healthy children, 6-11 years old will be randomized to receive...
The purpose of this study is to determine whether three Echinacea preparations with different chemical compositions are effective for prevention or treatment of the common cold.
This study was designed to evaluate the efficacy of the herb Echinacea purpurea and of cranial osteopathic manipulative treatment to prevent otitis media (middle ear infections) in young c...
A genus of perennial herbs used topically and internally. It contains echinacoside, GLYCOSIDES; INULIN; isobutyl amides, resin, and SESQUITERPENES.
Amides composed of unsaturated aliphatic FATTY ACIDS linked with AMINES by an amide bond. They are most prominent in ASTERACEAE; PIPERACEAE; and RUTACEAE; and also found in ARISTOLOCHIACEAE; BRASSICACEAE; CONVOLVULACEAE; EUPHORBIACEAE; MENISPERMACEAE; POACEAE; and SOLANACEAE. They are recognized by their pungent taste and for causing numbing and salivation.
Organic compounds containing the -CO-NH2 radical. Amides are derived from acids by replacement of -OH by -NH2 or from ammonia by the replacement of H by an acyl group. (From Grant & Hackh's Chemical Dictionary, 5th ed)
Compounds with two triple bonds. Some of them are CYTOTOXINS.
A somewhat heterogeneous class of enzymes that catalyze the transfer of alkyl or related groups (excluding methyl groups). EC 2.5.