Showing papers by "Asher Mandelbaum published in 1992"
TL;DR: In this article, an arachidonylethanthanolamide (anandamide) was identified in a screen for endogenous ligands for the cannabinoid receptor and its structure was determined by mass spectrometry and nuclear magnetic resonance spectroscopy and confirmed by synthesis.
Abstract: Arachidonylethanolamide, an arachidonic acid derivative in porcine brain, was identified in a screen for endogenous ligands for the cannabinoid receptor. The structure of this compound, which has been named "anandamide," was determined by mass spectrometry and nuclear magnetic resonance spectroscopy and was confirmed by synthesis. Anandamide inhibited the specific binding of a radiolabeled cannabinoid probe to synaptosomal membranes in a manner typical of competitive ligands and produced a concentration-dependent inhibition of the electrically evoked twitch response to the mouse vas deferens, a characteristic effect of psychotropic cannabinoids. These properties suggest that anandamide may function as a natural ligand for the cannabinoid receptor.
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TL;DR: In this paper, it was shown that a hidden hydrogen transfer accompanied the elimination of the halogen atom from the molecular ions of 4-haloresorcinols, 4-Bromo- and 4-icdoresorcinol undergo elimination of halogen atoms followed by a very fast loss of CO under collisionally induced dissociation (CID) conditions, affording [M − Hal]+ ions of low abundance and highly abundant [M− Hal − CO]- ions.
Abstract: Mono, di- and trihaloresorcinols substituted by a halogen atom at position 2 exhibit a highly specific elimination of H2O on electron impact ionization and under conditions of collisionally induced dissociation (CID). The high isomer specificity suggests the intermediacy of a hydrogen transfer from one of the hydroxy groups to the adjacent halogen atom. A subsequent hydrogen migration to the other hydroxy group readily explains the facile elimination of H2O from the M+· ions of these particular isomers. An analogous three-step hydrogen transfer has not been observed in 2,3-dihalo-l,4-hydroquinones. 4-Bromo- and 4-icdoresorcinol undergo elimination of the halogen atom followed by a very fast loss of CO under CID conditions, affording [M − Hal]+ ions of low abundance and highly abundant[M − Hal − CO]+ ions. The elimination of CO is suppressed in the isomeric 5-haloresorcinols, resulting in very highly abundant [M − Hal]+ ions. This behavior suggests that a ‘hidden hydrogen transfer’ accompanies the elimination of the halogen atom from the molecular ions of 4-haloresorcinols.
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