- Degradation of a model naphthenic acid, cyclohexanoic acid, by vacuum UV (172 nm) and UV (254 nm)/H2O2
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The mechanism of hydroxyl radical initiated degradation of a typical oil sands process water (OSPW) alicyclic carboxylic acid was studied using cyclohexanoic acid (CHA) as a model compound. By use of vacuum ultraviolet irradiation (VUV, 172 nm) and ultraviolet irradiation in the presence of hydrogen peroxide UV(254 nm)/H2O2, it was established that CHA undergoes degradation through a peroxyl radical. In both processes the decay of the peroxyl radical leads predominantly to the formation of 4-oxo-CHA, and minor amounts of hydroxy-CHA (detected only in UV/H2O 2). In UV/H2O2, additional 4-oxo-CHA may also have been formed by direct reaction of the oxyl radical with H-O 2. The oxyl radical can be formed during decay of the peroxyl-CHA radical or reaction of hydroxy-CHA with hydroxyl radical. Oxo- and hydroxy-CHA further degraded to various dihydroxy-CHAs. Scission of the cyclohexane ring was also observed, on the basis of the observation of acyclic byproducts including heptadioic acid and various short-chain carboxylic acids. Overall, the hydroxyl radical induced degradation of CHA proceeded through several steps, involving more than one hydroxyl radical reaction, thus efficiency of the UV/H 2O2 reaction will depend on the rate of generation of hydroxyl radical throughout the process. In real applications to OSPW, concentrations of H2O2 will need to be carefully optimized and the environmental fate and effects of the various degradation products of naphthenic acids considered.
- Drzewicz, Przemyslaw,Afzal, Atefeh,El-Din, Mohamed Gamal,Martin, Jonathan W.
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Read Online
- New process for synthesizing 1-hydroxycyclohexanecarboxylic acid and application
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The invention discloses a new process for synthesizing 1-hydroxycyclohexanecarboxylic acid and an application. During the synthesis of the 1-hydroxycyclohexanecarboxylic acid, an anhydrous system is adopted. According to the process, due to an anhydrous r
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Paragraph 0030; 0031; 0033; 0034; 0035; 0036-0037; 0039-0040
(2019/01/14)
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- Anesthetic compounds and related methods of use
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Provided herein are compounds according to formula (I): Provided herein is also a pharmaceutical composition comprising a compound according to formula (I) and a pharmaceutically acceptable carrier, and a method for providing anesthesia in a subject by administering such a pharmaceutical composition.
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- ANESTHETIC COMPOUNDS AND RELATED METHODS OF USE
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Provided herein are compounds according to formula (I): Provided herein is also a pharmaceutical composition comprising a compound according to formula (I) and a pharmaceutically acceptable carrier, and a method for providing anesthesia in a subject by administering such a pharmaceutical composition.
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- Method for the efficient synthesis of highly-substituted oxetan- and azetidin-, dihydrofuran- and pyrrolidin-3-ones and its application to the synthesis of (±)-pseudodeflectusin
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Highly substituted four- and five-membered heterocycles were prepared starting with O,P- and N,P-acetals by using a one-pot method involving base induced cyclization and a Horner-Wadsworth-Emmons (HWE) olefination reaction. Divergent synthesis of various heterocycles was achieved by using this method and transformations of the alkenyl group in the products of these processes were exemplified. Finally, a short and efficient synthesis of (±)- pseudodeflectusin based on the new methodology was achieved.
- Maegawa, Tomohiro,Otake, Kazuki,Hirosawa, Keiichi,Goto, Akihiro,Fujioka, Hiromichi
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supporting information
p. 4798 - 4801
(2013/01/15)
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- A practical and inexpensive 'convertible' isonitrile for use in multicomponent reactions
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N-tert-Butylamides are readily converted into the corresponding carboxylic acids by simple nitrosation. The process, which occurs under mild nonaqueous conditions, leaves carboxylic esters untouched and transforms multicomponent reaction products into useful building blocks for further synthetic elaboration.
- Le, Hoang V.,Fan, Lijun,Ganem, Bruce
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supporting information; experimental part
p. 2209 - 2211
(2011/05/09)
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- Preparation and reactions of optically active cyanohydrins derived from 4-chlorobenzaldehyde, cyclohexanone and 2-methylcyclohexanone using the (R) hydroxynitrile lyase from Prunus amygdalus
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CYANURATION of 4-chlorobenzaldehyde (1), cyclohexanone (2a) and 2-methylcyclo-hexanone (2b) yielded the racemic 2-hydroxy-2-(4-chlorophenyl) ethanenitrile (R,S)-3, cyclohexanone cyanohydrin 21a and (R,S)-2- methylcyclohexanone cyanohydrin (R,S)-21b. The same reaction can be completed by using acetone cyanohydrin (4) as a transcyanating agent. The optically active cyanohydrins (R)-3 and (R)-21b could be respectively obtained by hydrocyanation of 1 and 2b using (R)-hydroxynitrile lyase (R) PaHNL [EC 4.1.2.10] from almonds (Prunus amygdalus) as a chiral catalyst. Cyanohydrins 3 and 21 in their racemic and optically active forms undergo a number of transformations which involve either the hydroxyl group or the cyanide function. Moreover, derivatization of 3 and 21b with (S)-Naproxen chloride (S)-7 gave the respective diastereoisomers 8 and 22b. The optical activities of (R)-3 and 21b as well as their derivatives were recorded. The postulated structures of the new products were supported with compatible elementary and spectroscopic (IR, 1H NMR, 13C NMR, MS and X-ray crystallography) analyses. The antitumor activity of some selected racemic new products and their respective optically active analogues were undertaken. The structure-activity relationship (SAR) was also discussed.
- Yosef,Elmasry,Ismael, Eman H. I.,Mahran
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p. 745 - 755
(2013/05/21)
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- One-step conversion of ketones to conjugated acids using bromoform
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Phase-transfer-catalyzed (PTC) reactions of ketones with bromoform and aqueous lithium hydroxide in alcoholic solvent result in the formation of ,-unsaturated carboxylic acids. The reaction was performed at room temperature for 24h. The corresponding conj
- Vitnik,Ivanovic,Vitnik,Orevic,Zizak,Juranic,Juranic
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body text
p. 1457 - 1471
(2009/09/26)
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- Bradykinin B1 receptor antagonists: An α-hydroxy amide with an improved metabolism profile
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A series of carbo- and heterocyclic α-hydroxy amide-derived bradykinin B1 antagonists was prepared and evaluated. A 4,4-difluorocyclohexyl α-hydroxy amide was incorporated along with a 2-methyl tetrazole in lieu of an oxadiazole to afford a suitable compound with good pharmacokinetic properties, CNS penetration, and clearance by multiple metabolic pathways.
- Kuduk, Scott D.,Chang, Ronald K.,DiPardo, Robert M.,Di Marco, Christina N.,Murphy, Kathy L.,Ransom, Richard W.,Reiss, Duane R.,Tang, Cuyue,Prueksaritanont, Thomayant,Pettibone, Douglas J.,Bock, Mark G.
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scheme or table
p. 5107 - 5110
(2009/05/26)
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- Decomposition of sodium trichloroacetate in the presence of quaternary ammonium under microwave irradiation: A convenient one-pot synthesis of α-hydroxy acids in water
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A good yielding phase-transfer-catalyzed procedure for one-pot preparation of α-hydroxy acids from carbonyl compounds and sodium trichloroacetate by in situ addition and hydrolysis under microwave irradiation is described. Decomposition of sodium trichloroacetate is strongly accelerated by the presence of quaternary ammonium. The reaction can be conducted in water. Copyright Taylor & Francis Group, LLC.
- Yu, Haitao,Fang, Yun,Xia, Yongmei,Wu, Jing
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p. 2421 - 2426
(2007/10/03)
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- Removal of estrogenic activity and formation of oxidation products during ozonation of 17α-ethinylestradiol
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This study investigated the oxidation of the oral contraceptive 17α-ethinylestradiol (EE2) during ozonation. First, the effect of ozone (O3) on the estrogenic activity of aqueous solutions of EE2 was studied using a yeast estrogen screen (YES). It could be shown that O 3 doses typically applied for the disinfection of drinking waters were sufficient to reduce estrogenicity by a factor of more than 200. However, it proved impossible to completely remove estrogenic activity due to the slow reappearance of 0.1-0.2% of the initial EE2 concentration after ozonation. Second, oxidation products formed during ozonation of EE2 were identified with LC-MS/MS and GC/MS and the help of the model compounds 5,6,7,8-tetrahydro-2- naphthol (THN) and 1-ethinyl-1-cyclohexanol (ECH), which represent the reactive phenolic moiety and the ethinyl group of EE2. Additionally, oxidation products of the natural steroid hormones 17β-estradiol (E2) and estrone (E1) were identified. The chemical structures of the oxidation products were significantly altered as compared to the parent compounds, explaining the diminished estrogenic activity after ozonation. Overall, the results demonstrate that ozonation is a promising tool for the control of EE2, E2, and E1 in drinking water and wastewater.
- Huber, Marc M.,Ternes, Thomas A.,Von Gunten, Urs
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p. 5177 - 5186
(2008/01/27)
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- Spirodiclofen and spiromesifen - Novel acaricidal and insecticidal tetronic acid derivatives with a new mode of action
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The broad spectrum acaricides spirodiclofen (BAJ2740, trade name: Envidor) and spiromesifen (BSN2060, trade name: Oberon) with an additional excellent activity against whiteflies, both belong to the new chemical class of tetronic acid derivatives discovered at Bayer CropScience during the 1990s. The discovery process starting from herbicidal PPO (protoporphyrinogen oxidase) chemistry, the synthetic routes leading to the products, and some insight into process development of central intermediates is given. Spirodiclofen and spiromesifen have a new mode of action (interference with lipid biosynthesis), show no cross-resistance to any resistant mite or whitefly field population and are therefore valuable tools for resistance management.
- Bretschneider, Thomas,Benet-Buchholz, Jordi,Fischer, Reiner,Nauen, Ralf
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p. 697 - 701
(2007/10/03)
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- Behavior of biradicals generated from a Norrish type-I reaction of 2,2- diphenylcycloalkanones. Chain-length dependence and magnetic field effects
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The reaction course of acyl-diphenylmethyl biradicals (α-oxo-ω, ω- diphenyl-α,ω-alkanediyl biradicals), O=C↑(CH2)η-2-C↑Ph2 (3BR-η), generated from the Norrish type-I reaction of 2,2-diphenylcycloalkanones (CK- η) with various ring sizes in methanol, is switched from intramolecular disproportionation (n = 6, 7), giving a diphenylalkenal, to acylphenyl recombination (n ≥ 9), affording a cyclophane derivative. The behavior of 3BR-9 derived from CK-9 was studied in detail; the photolysis of CK-9 afforded an open-chain and a cyclic decarbonylation product together with an unsaturated aldehyde and a 4-methylene-2,5-cyclohexadienyl ketone (a pre- cyclophane). The photolysis of this ketone gave the same products that arose from the photolysis of CK-9, presenting the possibility that the decarbonylation products and a part of the aldehyde are formed as secondary products during irradiation. The magnetic field dependence of the lifetimes of 3BR-η (η = 12 and 13) generated from CK-12 and 13, respectively, was measured in methanol by means of a pulsed-laser excitation technique. The rate constants for intersystem crossing showed a maximum at a relatively low field strength, which decreased with increasing the field strength to level off to an asymptotic value at > 1.5 kG. The results show that the role of hyperfine coupling in intersystem crossing is less important in these systems, presumably because of the presence of a carbonyl oxygen and the absence of a hydrogen atom at the radical center.
- Suzuki, Itsuko,Tanaka, Ryoko,Yamaguchi, Akinori,Maki, Shin-Ichiro,Misawa, Hiroaki,Tokumaru, Katsumi,Nakagaki, Ryoichi,Sakuragi, Hirochika
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p. 103 - 113
(2007/10/03)
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- A convenient one-pot synthesis of quaternary α-methoxy- and α- hydroxycarboxylic acids
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Several α-methoxy- and α-hydroxycarboxylic acids have been synthesized by a new one-pot synthesis using ketones, tribromomethane, and potassium hydroxide in methanol and water, respectively, in good yields.
- Yabuuchi, Tetsuya,Kusumi, Takenori
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p. 684 - 686
(2007/10/03)
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- Oxidative decarboxylation of cyclohexane monocarboxylic acid as a degenerate branching chain reaction II. Mechanism
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Based on the experimental results obtained studying the oxidative decarboxylation of cyclohexane monocarboxylic acid and published earlier, a mechanism is suggested, according to which in the thermal oxidation two main chain carrier radicals exist: tertiary and secondary peroxy radicals yielding cyclohexanone as well as hydroxy and keto acids in parallel reaction sequences. Carbon dioxide is formed in both pathways independently. The corresponding hydroperoxide molecules, formed during oxidation, decompose partly into radicals and partly into molecules resulting in degenerate branching and chemiluminescence phenomena, respectively. The rate determining termination is the cross combination process between secondary and tertiary peroxy radicals. The combinatorial generation of the mechanism of the thermal process and its reduction enabled the construction of the sequence network of the formation of products indicating that the primary attack of the hydrogen abstraction (secondary or tertiary) determines the product distribution.
- Heberger,Keszler,Vidoczy,Gal,Cotarca,Delogu
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p. 1303 - 1307
(2007/10/02)
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- Heterocyclic compounds
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Compounds of formula I wherein nis 1 to 6; mis 0 to 2n+2; X is oxygen, sulphur, sulphinyl or sulphonyl; R1, R2 and R3 are each, independently, hydrogen, halogen, formyl, cyano, carboxy, azido or optionally substituted alkyl, alkenyl, alkynyl, alkoxy, alke
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- Cyclic Ether Formation in Superacid Media
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The formation of ethers in superacids by interaction of a primary hydroxy group with a carbocation centre has been investigated by a study of cyclisation of suitable substrates, mainly 1-(2-hydroxyethyl)cyclohexanols to give hydrobenzofurans.Cyclisation traps thermodynamically stable ionic species, with rates of reaction dependent upon the size of the ether ring formed.Three- and four-membered ether rings were not formed, five-membered ether rings formed readily, the reaction being comparable in rate with a 1,2-methyl shift.Six-membered rings formed a little less readily and seven-membered rings less readily still, though a yield of 34 percent from a suitable substrate has been recorded.An unexpected feature of the reactions was their stereospecificity; in one case, this is believed to result from a methyl shift concerted with attack of the primary hydroxy group, the reaction proceeding through hindered transition state, in which methyl loss, probably as CH3+, competes with a 1,2-methyl shift.
- Carr, Graham,Whittaker, David
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p. 359 - 366
(2007/10/02)
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- Lactone Formation in Superacidic Media
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The reaction of substituted 1-hydroxycyclohexanecarboxylic acids in fluorosulphuric acid has been studied.Cyclisation takes place around 0 deg C, accompanied by rearrangement in appropriate cases, yielding the thermodynamically stable lactone or mixture of lactones.An unexpected feature of these reactions is that the carboxy-substituted cyclohexyl carbocation does not undergo ring contraction, unlike the unsubstituted cyclohexyl carbocation, although the cycloheptyl system contracts to cyclohexyl.We suggest that the cyclohexyl carbocation is strongly stabilised by carboxyl substitution, as a result of through-space interaction between the carboxyl oxygen atom and the carbocation centre.
- Carr, Graham,Whittaker, David
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p. 1877 - 1880
(2007/10/02)
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- 2-Amino-5-spiro substituted oxazoline-4-one compounds
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A novel series of 2-amino-5-spiro substituted oxazolin-4-ones and intermediates for making said compounds. These compounds are prepared by first converting the appropriately substituted cycloketone to the corresponding cyclocyanohydrin; converting this co
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