24979-69-9Relevant academic research and scientific papers
Synthesis of tsetse fly attractants from a cashew nut shell extract by isomerising metathesis
Baader,Podsiadly,Cole-Hamilton,Goossen
, p. 4885 - 4890 (2014)
Starting from a purified cashew nut shell extract containing mostly anacardic acid derivatives, the tsetse fly attractants 3-ethyl- and 3-propylphenol were selectively synthesised. The mixture was first converted into 3-(non-8-enyl)phenol in 98% purity via ethenolysis and distillation with concomitant decarboxylation. The olefinic side chain was then shortened by isomerising cross-metathesis with short-chain olefins in the presence of a [Pd(μ-Br)(tBu3P)]2 isomerisation catalyst and a second-generation Hoveyda-Grubbs catalyst, and the synthesis was completed by a hydrogenation step.
Pulsed Ultraviolet Laser Photolysis of Substituted Phenyl Diazosulphonates at 248 nm
Nomayo, M.,Wokaun, A.
, p. 1495 - 1503 (2007/10/02)
The photochemical decomposition of aqueous phenyl diazosulphonate solutions by KrF excimer laser pulses at 248 nm is investigated.The present study complements earlier investigations (Franzke et al. 1991, 1992) of the photochemistry of this class of compounds induced by irradiation at 308 nm (XeCl excimer laser), and in the 370-390 nm wavelength range (dye laser pulses).From the comparison, conclusions with regard to the wavelength dependent photolysis pathway are drawn.Phenyl diazosulphonates carrying methoxy- or ester-type substituents at the aromatic ring are observed to decompose in a two-step-reaction in aqueous solution: Photolysis proceeds via the phenyl diazonium ion as an intermediate, to yield the corresponding phenol as product.In contrast, the photolysis of 3-vinyl-phenyl diazosulphonate in aqueous solution at 248 nm results in a complex reaction involving via more than one intermediate.UV spectra recorded during photolysis show that products characterized by an absorption maximum at 272 nm are formed; these spectra are identical with those of final products from 308 nm photolysis, which are identified as 3-hydroxyethyl-phenols. - The photolysis pathway of 4-hydroxy-phenyl-diazosulphonate is found to proceed via the diazoquinone, instead of a diazonium ion.As a consequence of the high energy of 248 nm photons, the mentioned substituted phenols are not the final products of the photochemical reaction.These molecules are further decomposed by absorbing 248 nm photons; the quantum efficiency of these secondary photochemical reactions is lower by one to two orders of magnitude, as compared to the primary photolysis of the parent compounds. - Keywords: Light, Absorption / Materials Properties, Diazo Sulphonates / Photochemistry / Radicals / Spectroscopy, Ultraviolet
Acid-catalysed Aromatisation of Benzene cis-1,2-dihydrodiols: a Carbocation Transition State poorly stabilised by Resonance
Boyd, Derek R.,Blacker, John,Byrne, Briege,Dalton, Howard,Hand, Mark V.,et al.
, p. 313 - 314 (2007/10/02)
Acid-catalysed dehydration of 3-substituted benzene cis-1,2-dihydrodiols exhibits a Hammett plot with ρ=-8.2, consistent with reaction via a benzenonium ion-like intermediate; however, correlation of +M resonance substituents such as Me and MeO by ?p rather than ?+ constants indicates a marked imbalance between resonance and inductive stabilisation of the transition state.
Organomolybdenum and Organotungsten Reagents, III. Selective, Nonbasic Carbonylmethylenation Reagents from MoOCl3(THF)2 and MoOCl4: Formation, Thermolability, Structure
Kauffmann, Thomas,Fiegenbaum, Petra,Papenberg, Michael,Wieschollek, Raphael,Wingbermuehle, Dorothea
, p. 79 - 88 (2007/10/02)
From the family of more than 20 carbonylolefinating μ-methylene molybdenum and tungsten complexes the reagent "3", obtained in solution by treatment of MoOCl3(THF)2 with two equivalents of methyllithium, is probably the most favorable one for chemoselective carbonylolefination reactions.As judged by the 13C- and 1H-NMR spectra the reagent is not a single species, but a mixture of either isomeric 1,3-dioxo-1,3-dimolybda(V)cyclobutane complexes 3, differing in the position of the ligands Cl, O, and THF at the molybdenum atoms, or of oligomers of 3. - Treatment of MoOCl4 with two equivalents of methyllithium gave a carbonylolefinating reagent "4" which, according to NMR data, consists of isomeric or oligomeric 1,3-dioxo-1,3-dimolybda(VI)cyclobutane complexes 4.Both reagents are labile at room temperature, but differ from the classical carbonylolefinating reagents by an acidic rather than a basic character, resistance to hydroxy groups, and high selectivity. Key Words: Carbonylolefination / μ-Methylene complexes / Molybdenum reagent
