Search results for "Ozono"
showing 8 items of 18 documents
Organocatalytic enantioselective synthesis of 2,5,5-trisubstituted piperidines bearing a quaternary stereocenter. Vinyl sulfonamide as a new amine pr…
2020
An organocatalytic desymmetrizing intramolecular aza-Michael reaction with vinyl sulfonamides as nucleophilic nitrogen source has been devised for the synthesis of a new family of 2,5,5-trisubstituted piperidines bearing a quaternary sterocenter. The process takes place with excellent levels of enantioselectivity and moderate to good diastereoselectivity. The vinyl sulfonamide moiety can be removed by means of an ozonolysis reaction.
Comparison of computational and experimental saturation vapor pressures of α-pinene + O<sub>3</sub> oxidation products
2021
Abstract. Accurate information on gas-to-particle partitioning is needed to model secondary organic aerosol formation. However, determining reliable saturation vapor pressures of atmospherically relevant multifunctional organic compounds is extremely difficult. We estimated saturation vapor pressures of α-pinene ozonolysis derived secondary organic aerosol constituents using FIGAERO-CIMS experiments and COSMO-RS theory. We found a good agreement between experimental and computational saturation vapor pressures for molecules with molar masses around 190 g mol−1 and higher, most within a factor of 3 comparing the average of the experimental vapor pressures and the COSMO-RS estimate of the iso…
Synthesis of (±)-(E)-2,6-dimethyl-6-hydroxyocta-2,7-dienoic acid and the corresponding amide (“acacialactam”)
1994
Abstract The total synthesis of the title compounds in racemic form is described. Linalool was used as the starting material and transformed into the target molecules in 6 steps. The synthetic amide displays spectral properties identical to those reported for the natural compound acacialactam, indicating that the structure proposed for the latter compound is not correct.
A Bioinspired Approach to Tri-nor-guaianes. Synthesis of (−)-Clavukerin A
2006
A bioinspired approach to tri-nor-guaianes by degradation of the C-7 side chain of related guaia-11-enes is described. In this approach (-)-clavukerin A (1) is obtained by selective ozonolysis-Criegge rearrangement of (+)-1alphaH,7alphaH,10alphaH-guaia-4,11-dien-3-one (4) to afford 7beta-hydroxy and 7beta-acetoxy tri-nor-guaiane derivatives 6 and 7, respectively, which after elimination and deoxygenation give the title compound. The starting guaiadienone is readily obtained from commercially available santonin or (+)-dihydrocarvone.
New tracer compounds for secondary organic aerosol formation from β-caryophyllene oxidation
2013
Abstract Five products from β-caryophyllene oxidation (β-caryophyllonic acid (I), 3,3-dimethyl-2-(3-oxobutyl)cyclobutanecarboxylic acid (βCA198) (II), β-nocaryophyllonic acid (III), β-caryophyllinic acid (IV), and 2-(2-carboxyethyl)-3,3-dimethylcyclobutanecarboxylic acid (βCA200) (V)) were synthesized and their structures confirmed by nuclear magnetic resonance spectroscopy. Reaction chamber experiments with β-caryophyllene at two different ozone mixing ratios were performed and the carboxylic acid oxidation products in the particle phase were characterized by APCI–MS and HPLC–ESI–MS. All five synthesized acids were found as β-caryophyllene oxidation products in the reaction chamber aerosol…
Synthesis of plagiochiline N from santonin.
2001
This article reports the transformation of O-acetylisophotosantonin, obtained by photochemical rearrangement of santonin, into plagiochiline N, an ent-2,3-secoaromadendrane isolated from Plagiochila ovalifolia. The synthesis was carried out in a sequence involving as the key steps (a) the substitution of the lactone moiety by a gem-dimethylcyclopropane ring through a synthetic intermediate having a C(6)-C(7) double bond and (b) the ozonolysis of the C(2)-C(3) bond followed by cyclization to the dihydropyran ring characteristic of plagiochiline N. Spectroscopic data of the synthetic product fully coincided with the reported data for the natural product.
Dienediolates of unsaturated carboxylic acids in synthesis. Aldehydes and ketones from alkyl halides, by ozonolysis of β,γ-unsaturated α-alkyl carbox…
1997
Abstract A convenient two-step procedure for a two carbon homologative conversion of alkyl halides into aldehydes and methyl ketones by α-alkylation of unsaturated carboxylic acids, followed by ozonolysis is developed and applied to the synthesis of ω-chloro aldehydes. Triethylamine is superior to dimethyl sulfide or triphenylphosphine for cleavage of the ozonides, except when aldol condensation side reactions require use of protic solvents and iodide salts. Cleavage of the ozonides by triethylamine is shown to occur mainly through a reductive process.
ChemInform Abstract: Synthesis of Plagiochiline N from Santonin.
2010
This article reports the transformation of O-acetylisophotosantonin, obtained by photochemical rearrangement of santonin, into plagiochiline N, an ent-2,3-secoaromadendrane isolated from Plagiochila ovalifolia. The synthesis was carried out in a sequence involving as the key steps (a) the substitution of the lactone moiety by a gem-dimethylcyclopropane ring through a synthetic intermediate having a C(6)-C(7) double bond and (b) the ozonolysis of the C(2)-C(3) bond followed by cyclization to the dihydropyran ring characteristic of plagiochiline N. Spectroscopic data of the synthetic product fully coincided with the reported data for the natural product.