53439-15-9Relevant articles and documents
Anion-Accelerated Aromatic Oxy-Cope Rearrangement in Geranylation/Nerylation of Xanthone: Stereochemical Insights and Synthesis of Fuscaxanthone F
Fujimoto, Yuuki,Takahashi, Kanae,Kobayashi, Ryouma,Fukaya, Haruhiko,Yanai, Hikaru,Matsumoto, Takashi
, p. 1378 - 1383 (2020)
An efficient installation of a 3,7-dimethylocta-2,6-dien-1-yl (geranyl or neryl) side chain at the C(1) position of a xanthone core by utilizing an anion-accelerated aromatic oxy-Cope rearrangement is described. Experiments revealed that this uncommon rearrangement takes place in a stereospecific manner through a chair-like transition-state structure. An application to the syntheses of the natural xanthone fuscaxanthone F, possessing a geranyl side chain, and its neryl analogue is also described.
Deuterated pentazocine and preparation method, pharmaceutical composition and application thereof
-
Paragraph 0031-0038; 0064-0066, (2020/06/20)
The invention relates to deuterated pentazocine shown as formula I in the specification and pharmaceutically acceptable salts thereof. The invention also provides a novel compound serving as an analgesic for various acute and chronic pains, a preparation method, and a pharmaceutical composition containing the compound. Compared with undeuterated pentazocine, pharmacokinetics is improved, better metabolic stability is achieved, the half-life period of pentazocine is prolonged, and the bioavailability of pentazocine is improved.
Scalable synthesis of the aroma compounds d6-β-ionone and d6-β-cyclocitral for use as internal standards in stable isotope dilution assays
Mosaferi, Shabnam,Jelley, Rebecca E.,Fedrizzi, Bruno,Barker, David
supporting information, (2020/12/02)
C13 Norisoprenoids are important aroma compounds in wine, giving positive attributes to the overall wine aroma even when found at very low levels. β-Ionone is considered one of the most important aroma compounds giving violet, woody and raspberry aromas to wine, fruits and vegetables in which it is found. Due to its potent aroma at low levels, precise analytical methods are desired for its quantification. Stable isotope dilution assay (SIDA) is one of the most important of these methods but requires the use of isotopically labelled standards. Herein, we describe the scalable synthesis of d6-β-ionone and d6-β-cyclocitral, another aroma compound with smokey and fruity notes, starting from the relatively inexpensive deuterated starting material d6-acetone.
Preparation of polycyclic compounds by intramolecular photospirocyclization and photocycloaddition reactions of 4-alkenyl-1-cyanonaphthalene derivatives
Maeda, Hajime,Wada, Hidenori,Mukae, Hirofumi,Mizuno, Kazuhiko
, p. 29 - 41 (2016/11/16)
Photoreactions of 4-pentenyl-1-cyanonaphthalenes yield spirocyclic products along with [4?+?2] cycloadducts. Photoreactions of 5-phenyl derivatives produce a product having tricyclo[6.3.0.01,4]undecadiene skeleton. Formation of angular triquinanes takes place in photoreactions of cycloalkene-linked cyanonaphthalenes. The observation demonstrates that π–π arene ring interactions, steric hindrance, and suitable locations of reaction sites in syn and anti singlet exciplexes govern the modes followed in intramolecular photoreactions of 4-alkenyl-1-cyanonaphthalenes.
δ-deuterium isotope effects as probes for transition-state structures of isoprenoid substrates
Choi, Seoung-Ryoung,Breugst, Martin,Houk, Kendall N.,Poulter, C. Dale
supporting information, p. 3572 - 3580 (2014/05/06)
The biosynthetic pathways to isoprenoid compounds involve transfer of the prenyl moiety in allylic diphosphates to electron-rich (nucleophilic) acceptors. The acceptors can be many types of nucleophiles, while the allylic diphosphates only differ in the number of isoprene units and stereochemistry of the double bonds in the hydrocarbon moieties. Because of the wide range of nucleophilicities of naturally occurring acceptors, the mechanism for prenyltransfer reactions may be dissociative or associative with early to late transition states. We have measured δ-secondary kinetic isotope effects operating through four bonds for substitution reactions with dimethylallyl derivatives bearing deuterated methyl groups at the distal (C3) carbon atom in the double bond under dissociative and associative conditions. Computational studies with density functional theory indicate that the magnitudes of the isotope effects correlate with the extent of bond formation between the allylic moiety and the electron-rich acceptor in the transition state for alkylation and provide insights into the structures of the transition states for associative and dissociative alkylation reactions.
Catalytic 1,4-rhodium(III) migration enables 1,3-enynes to function as one-carbon oxidative annulation partners in C-H functionalizations
Burns, David J.,Lam, Hon Wai
supporting information, p. 9931 - 9935,5 (2014/10/15)
1,3-Enynes containing allylic hydrogens cis to the alkyne are shown to act as one-carbon partners, rather than two-carbon partners, in various rhodium-catalyzed oxidative annulations. The mechanism of these unexpected transformations is proposed to occur through double C-H activation, involving a hitherto rare example of the 1,4-migration of a RhIII species. This phenomenon is general across a variety of substrates, and provides a diverse range of heterocyclic products.
Development of an intramolecular aryne ene reaction and application to the formal synthesis of (±)-crinine
Candito, David A.,Dobrovolsky, Dennis,Lautens, Mark
supporting information, p. 15572 - 15580 (2012/11/07)
A general and high yielding annulation strategy for the synthesis of various carbo- and heterocycles, based on an intramolecular aryne ene reaction is described. It was found that the geometry of the olefin is crucial to the success of the reaction, with exclusive migration of the trans-allylic-H taking place. Furthermore, the electronic nature of the aryne was found to be important to the success of the reaction. Deuterium labeling studies and DFT calculations provided insight into the reaction mechanism. The data suggests a concerted asynchronous transition state, resembling a nucleophilic attack on the aryne. This strategy was successfully applied to the formal synthesis of the ethanophenanthridine alkaloid (±)-crinine.
Intramolecular aryne-ene reaction: Synthetic and mechanistic studies
Candito, David A.,Panteleev, Jane,Lautens, Mark
supporting information; experimental part, p. 14200 - 14203 (2011/10/31)
Although the chemistry of arynes is well developed, some challenges still remain. The ene reaction of arynes has not gained widespread use in synthesis as a result of poor yields and selectivity. A general, high yielding and selective intramolecular aryne-ene reaction is described providing various benzofused carbo- and heterocycles. Mechanistic data is presented, and a rationale for the resulting stereochemistry is discussed.
Stereochemistry of eudesmane cation formation during catalysis by aristolochene synthase from Penicillium roqueforti
Miller, David J.,Gao, Jiali,Truhlar, Donald G.,Young, Neil J.,Gonzalez, Veronica,Allemann, Rudolf K.
experimental part, p. 2346 - 2354 (2009/02/02)
The aristolochene synthase catalysed cyclisation of farnesyl diphosphate (1) has been postulated to proceed through (S)-germacrene A (3). However, the active site acid that reprotonates this neutral intermediate has so far proved difficult to identify and, based on high level ab initio molecular orbital and density functional theory calculations, a proton transfer mechanism has recently been proposed, in which proton transfer from C12 of germacryl cation to the C6,C7-double bond of germacryl cation (2) proceeds either directly or via a tightly bound water molecule. In this work, the stereochemistry of the elimination and protonation reactions was investigated by the analysis of the reaction products from incubation of 1 and of [12,12,12,13,13,13- 2H6]-farnesyl diphosphate (15) with aristolochene synthase from Penicillium roqueforti (PR-AS) in H2O and D2O. The results reveal proton loss from C12 during the reaction and incorporation of another proton from the solvent. Incubation of 1 with PR-AS in D2O led to the production of (6R)-[6-2H] aristolochene, indicating that protonation occurs from the face of the 10-membered germacrene ring opposite the isopropylidene group. Hence these results firmly exclude proton transfer from C12 to C6 of germacryl cation. We propose here Lys 206 as the general acid/base during PR-AS catalysis. This residue is part of a conserved network of hydrogen bonds, along which protons could be delivered from the solvent to the active site.
On the reduction of tertiary radicals by samarium diiodide (Sml2)
Nagashima, Tadamichi,Rivkin, Alexey,Curran, Dennis P.
, p. 791 - 799 (2007/10/03)
Reduction of o-iodopbeayl 3-methylbut-2-enyl ether with samarium diiodide generates mixtures of 3-isopropyl-2,3-dihydrobenzofuran and 3-(2-propenyl)-2-3-dihydrobenzofuran along with a small amount of dimer. If a source of deuterium is present during the r
