sym-Homospermidine, a naturally occurring polyamine.
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Amines↗
Biomedical subjects
B Witkop
Publications and source records attributed to B Witkop.
Migration of substituents during Hydroxylation of aromatic substrates (NIH shift). Oxidations with peroxytrifluoroacetic acid.
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Anilides↗
Histrionicotoxins: roentgen-ray analysis of the novel allenic and acetylenie spiroalkaloids isolated from a Colombian frog, Dendrobates histrionicus.
The structures and absolute configuration of two unique alkaloids isolated from the Colombian frog, Dendrobates histrionicus, have been elucidated by Roentgen-ray (x-ray) crystallography. Histrionicotoxin is (2pR, 6S, 7pS, 8aS)-7-(cis-1-buten-3-ynyl)-8-hydroxy-2-(cis-2-penten-4- ynyl)-1-azaspiro[5.5] undecane, while in dihydro-isohistrionicotoxin the acetylenic 2-pentenynyl side chain is replaced by an allenic 2-(3,4 pentadienyl) substituent. Dendrobates histrionicus exhibits remarkable interpopulational variations in amounts and composition of skin toxins, in behavior, and in phenotypic characters, aspects of which are illustrated in a color plate. The histrionico-toxins are the third class of alkaloids isolated from the defensive skin secretions of Neotropical (Dendrobatidae) frogs.
Alkaloids↗
Batrachotoxin, an extremely active cardio- and neurotoxin from the Colombian arrow poison frog Phyllobates aurotaenia.
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Action Potentials↗
Photocyclization of pharmacodynamic amines. IV. Novel heterocycles from n-chloroacetyl-3,4-dimethoxyphenethylamine.
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Heterocyclic Compounds↗
Photocyclizations of pharmacodynamic amines. V. Unusual rearrangements of the mescaline skeleton.
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Heterocyclic Compounds↗
The structure of solaphyllidine, a novel 4-ketosteroidal alkaloid.
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Alkaloids↗
Enzymatic hydration of 8,9-indan oxide, Homoallylic addition of water.
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Chemical Phenomena↗
Cyclization of tryptophan and tryptamine derivatives to 2,3-dihydropyrrolo[2,3-b]indoles.
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Chemical Phenomena↗
1,2-naphthalene oxide as an intermediate in the microsomal hydroxylation of naphthalene.
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Animals↗
Selective cleavage and modification of peptides and proteins.
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Alanine↗
Sythesis of cis- and trans-4-mercapto-L-proline derivatives.
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Esters↗
Preparation and photochemistry of 5,6-cyclopropyluridines and of bicyclic isomers of thymines.
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Chemical Phenomena↗
Novel pyrimidine nucleoside oxosulfonium ylides and their photolysis to 2,2'-methylenecyclonucleosides.
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Chemical Phenomena↗
An unusual reaction of skatole with tetranitromethane.
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Alkanes↗
Selective photoreductions of nucleic acids and their building stones. 8. Photoreduction and dimerization of 1,3-dimethyluracil.
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Boron Compounds↗
Identification and characterization of natural and synthetic dihydroxyprolines.
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Chemical Phenomena↗
Photocyclizations of pharmacodynamic amines. 3. Three-dimensional structure of 7-hydroxy-1,9,10-trimethoxy-4-azabicyclo [5.2.2] undeca-8,10-dien-3-one from mescaline.
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Bridged-Ring Compounds↗