- 2,2':5',2''-Terthiophene-5-carboxylic Acid and 2,2':5',2''-Terthiophene-5,5''-dicarboxylic Acid
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2,2':5',2''-Terthiophene-5-carboxylic acid was obtained in excellent yield by treating 2,2':5',2''-terthiophene with lithium diisopropylamide, followed by carboxylation of the lithium salt with solid carbon dioxide.The 5,5''-dicarboxylic acid was obtained similarly, when 2 equiv of base were used.Attempted syntheses of the monoacid, based on the oxidation of the corresponding aldehyde or the acetyl derivative, were unsuccessful.Both the monoacid and the 5,5'-diacid sensitized the hemolysis of human erythrocytes in the presence of ultraviolet light.
- Kagan, Jacques,Arora, Sudershan K.,Uestuenol, Ayse
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Read Online
- Convenient preparation and use of potassium tetracarbonylferrate, K2[Fe(CO)4], an easy-to-handle analogue of the Collman reagent
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A convenient synthesis of K2[Fe(CO)4] from Fe(CO)5, KOH and tri(n-butyl)phosphine is described. This non-pyrophoric dianionic potassium ferrate displays the same reactivity as Na2[Fe(CO)4], provided that the reactions are conducted in DMAC or THF-DMAC solvent mixtures.
- Baby,Brunet,Kindela,Neibecker
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Read Online
- Pd-Catalyzed Regioselective Branched Hydrocarboxylation of Terminal Olefins with Formic Acid
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A regioselective Pd-catalyzed hydrocarboxylation of terminal olefins with HCOOH is described. A wide variety of branched carboxylic acids can readily be obtained with high regioselectivities under mild reaction conditions. The reaction is operationally simple and requires no handling of toxic CO. The ligand and LiCl are important factors for reaction reactivity and selectivity.
- Chu, Jianxiao,Guo, Jianqiong,Ren, Wenlong,Shi, Yian,Shi, Yuan,Wang, Mingzhou,Zhou, Jintao
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supporting information
p. 886 - 891
(2022/02/07)
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- Ruthenium-catalysed hydroxycarbonylation of olefins
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State-of-the-art catalyst systems for hydroxy- and alkoxycarbonylations of olefins make use of palladium complexes. In this work, we report a complementary ruthenium-catalysed hydroxycarbonylation of olefins applying an inexpensive Ru-precursor (Ru3(CO)12) and PCy3as a ligand. Crucial for the success of this transformation is the use of hexafluoroisopropanol (HFIP) as the solvent in the presence of an acid co-catalyst (PTSA). Overall, moderate to good yields are obtained using aliphatic olefins including the industrially relevant substrate di-isobutene. This atom-efficient catalytic transformation provides straightforward access to various carboxylic acids from unfunctionalized olefins.
- Dühren, Ricarda,Kucmierczyk, Peter,Jackstell, Ralf,Franke, Robert,Beller, Matthias
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p. 2026 - 2030
(2021/04/09)
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- Synthesis of Carboxylic Acids by Palladium-Catalyzed Hydroxycarbonylation
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The synthesis of carboxylic acids is of fundamental importance in the chemical industry and the corresponding products find numerous applications for polymers, cosmetics, pharmaceuticals, agrochemicals, and other manufactured chemicals. Although hydroxycarbonylations of olefins have been known for more than 60 years, currently known catalyst systems for this transformation do not fulfill industrial requirements, for example, stability. Presented herein for the first time is an aqueous-phase protocol that allows conversion of various olefins, including sterically hindered and demanding tetra-, tri-, and 1,1-disubstituted systems, as well as terminal alkenes, into the corresponding carboxylic acids in excellent yields. The outstanding stability of the catalyst system (26 recycling runs in 32 days without measurable loss of activity), is showcased in the preparation of an industrially relevant fatty acid. Key-to-success is the use of a built-in-base ligand under acidic aqueous conditions. This catalytic system is expected to provide a basis for new cost-competitive processes for the industrial production of carboxylic acids.
- Sang, Rui,Kucmierczyk, Peter,Dühren, Ricarda,Razzaq, Rauf,Dong, Kaiwu,Liu, Jie,Franke, Robert,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 14365 - 14373
(2019/09/06)
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- Pd-Catalyzed Highly Chemo- And Regioselective Hydrocarboxylation of Terminal Alkyl Olefins with Formic Acid
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An efficient Pd-catalyzed hydrocarboxylation of alkenes with HCOOH is described. A wide variety of linear carboxylic acids bearing various functional groups can be obtained with excellent chemo- and regioselectivities under mild reaction conditions. The reaction process is operationally simple and requires no handling of toxic CO.
- Ren, Wenlong,Chu, Jianxiao,Sun, Fei,Shi, Yian
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supporting information
p. 5967 - 5970
(2019/08/26)
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- Synthetic method of terminal carboxylic acid
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The invention discloses a synthetic method of a terminal carboxylic acid. The synthetic method is characterized by comprising the steps of adding an olefin represented by a formula (3) shown in the description, formic acid, acetic anhydride, Pd(OAc)2 and a monophosphorus ligand TFPP into an organic solvent in a proportion, carrying out hydrogen carbonylation reaction on the olefin represented by the formula (3) shown in the description, formic acid and acetic anhydride at 80-90 DEG C for 48h-72h under the catalysis of the metal palladium salt Pd(OAc)2 and the monophosphorus ligand TFPP so as to obtain the terminal carboxylic acid represented by a formula shown in the description, and separating a target product, namely the terminal carboxylic acid after the reaction is finished, wherein olefin represented by the formula (3) is selected from cycloolefins, or linear olefins of which the R1 is electron donating groups. By virtue of the method disclosed by the invention, corresponding terminal carboxylic acid and a derivative thereof can be prepared through the reaction under mild conditions of low temperature and no high pressure; and the steps of the synthetic method are simple and convenient, the operation is convenient, the yield is high, the energy source can be greatly saved, and the synthetic efficiency can be greatly improved.
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Paragraph 0043-0046
(2019/11/21)
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- Synthetic organic raw materials synthesis method of thirteen acid (by machine translation)
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Abstract Raw materials of organic synthesis tridecanoic acid synthesis method, comprises the following steps: 2 mol 2-bromotetradecanol, 4-6 mol dioctyl phthalate solution 5 were added to the reaction vessel, controlled the stirring speed at 150-180 rpm for 70-90 min and controlled solution temperature to 2-5 "C, added 3-4 mol titanium aluminium chloride, continued to react 130-160 min, added 700 ml sodium bromide solution, standing for 20-40 min, separated the oil layer, washed with m-chlorophenol solution, washed with formamide solution, recrystallizated in the methyl sulfide 10 solution, dehydrated with dehydration, got the finished product tridecanoic acid.
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Paragraph 0006; 0009-0014
(2018/07/30)
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- α-Oxidative decarboxylation of fatty acids catalysed by cytochrome P450 peroxygenases yielding shorter-alkyl-chain fatty acids
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Cytochrome P450 peroxygenases belonging to the CYP152 family catalyse the oxidation of fatty acids using H2O2. CYP152N1 isolated from Exiguobacterium sp. AT1b exclusively catalyses the α-selective hydroxylation of myristic acid at physiological H2O2 concentration. However, a series of shorter-alkyl-chain fatty acids such as tridecanoic acid were produced from myristic acid by increasing the concentration of H2O2 (1-10 mM). The yield of tridecanoic acid from myristic acid reached 17%. An 18O-labeled oxidant study suggested that CYP152N1 catalysed the overoxidation of α-hydroxymyristic acid to form α-ketomyristic acid, which in turn was spontaneously decomposed by H2O2 to yield tridecanoic acid. Crystal structure analysis of CYP152N1 revealed its high similarity to other CYP152 family enzymes, such as CYP152A1 and CYP152B1. MD simulations of α-hydroxymyristic acid accommodated in CYP152N1 proposed a possible pre-oxidation conformation of α-hydroxymyristic acid for the decarboxylation reaction.
- Onoda, Hiroki,Shoji, Osami,Suzuki, Kazuto,Sugimoto, Hiroshi,Shiro, Yoshitsugu,Watanabe, Yoshihito
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p. 434 - 442
(2018/02/07)
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- Carboxylation of Aromatic and Aliphatic Bromides and Triflates with CO2 by Dual Visible-Light–Nickel Catalysis
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We report the efficient carboxylation of bromides and triflates with K2CO3 as the source of CO2 in the presence of an organic photocatalyst in combination with a nickel complex under visible light irradiation at room temperature. The reaction is compatible with a variety of functional groups and has been successfully applied to the synthesis and derivatization of biologically active molecules. In particular, the carboxylation of unactivated cyclic alkyl bromides proceeded well with our protocol, thus extending the scope of this transformation. Spectroscopic and spectroelectrochemical investigations indicated the generation of a Ni0 species as a catalytic reactive intermediate.
- Meng, Qing-Yuan,Wang, Shun,K?nig, Burkhard
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supporting information
p. 13426 - 13430
(2017/10/07)
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- New lipoxygenase and cholinesterase inhibitory sphingolipids from Carthamus oxyacantha
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Two new sphingolipids: oxyacanthin A [(2S,3S,4R)-2-{[(2R,5E)-2-hydroxyoctadec-5-enoyl]amino}hexaeicosane-1,3,4-triol; 1] and B [(2S,3S,4R)-2-{[(2R,5E)-2-hydroxyoctadec-5-enoyl]amino}hexaeicosane-1,3,4-triol-1-O-β-D-glucopyranoside; 2], together with 1-octacosanol, β-sitosterol, β-sitosterol 3-O-β-D-glucopyranoside and luteolin 7-O-β-glucopyranoside were isolated from the methanolic extract of the whole plant of Carthamus oxyacantha. Their structures were elucidated using1H and13C NMR spectra and 2D NMR analyses (HMQC, HMBC and COSY) in combination with mass spectrometry (EI-MS, HR-EI-MS, FAB-MS and HR-FAB-MS) experiments and in comparison with the literature data of the related compounds. Both the compounds 1 and 2 showed inhibitory potential against lipoxygenase (LOX) in a concentration-dependent manner with IC50values 83.3?±?1.3 and 245.7?±?1.1?μM, whereas compound 2 showed inhibition against enzymes acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with IC50values 65.3?±?0.1 and 93.6?±?0.1?μM, respectively.
- Dilshad, Muhammad,Riaz, Naheed,Saleem, Muhammad,Shafiq, Nusrat,Ashraf, Muhammad,Ismail, Tayaba,Rafiq, Hafiza Mehwish,Jabbar, Abdul
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p. 1787 - 1795
(2016/08/16)
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- Determination of Key Hydrocarbon Autoxidation Products by Fluorescence
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Hydroperoxides and carboxylic acids are key primary products that arise in the autoxidation of hydrocarbons. We have developed a simple approach to rapidly and simultaneously determine both types of products using hydroperoxide- and acid-sensitive moieties conjugated to nonpolar coumarin- and BODIPY-based fluorophores. The coumarin- and BODIPY-conjugated amine probes described here undergo 38- and 8-fold enhancement, respectively, upon protonation in a solvent system compatible with heavy hydrocarbons. The latter can be used directly with our previously described hydroperoxide-sensitive coumarin-conjugated phosphine probe to enable rapid quantification of both carboxylic acids and hydroperoxides in hydrocarbon samples. The utility of the approach is illustrated by the ready determination of the differing relative rates of hydroperoxide and acid formation with changes in hydrocarbon structure (e.g., n-hexadecane vs 1-hexadecene vs a lubricant base stock). The method offers significant versatility and automation compared with common but laborious titration approaches, and greatly improves screening efficiency and accuracy for the identification of novel radical-trapping antioxidants for high temperature applications. This application was demonstrated by the automated analysis of hydroperoxides and carboxylic acids (by microplate reader) in samples from 24 inhibited autoxidations of a lubricating oil, which were carried out on a parallel synthesizer at 160 °C in triplicate in a single day.
- Shah, Ron,Pratt, Derek A.
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p. 6649 - 6656
(2016/08/16)
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- Photodegradation of Hydrophobic Pyridineketoximes in Toluene and Heptane
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The goal of the research was to study the reactivity of the hydrophobic 2- and 3-pyridineketoximes under exposure to UV-VIS light. The photodegradation was conducted in both toluene and heptane for 10 h under atmosphere of argon. Ten-hour irradiation experiments demonstrated that the pyridineketoximes underwent the facile E-Z photoisomerization, photo-Beckmann rearrangement, and to a lesser extent, the photosubstitution to the pyridine ring. From LC-MS and NMR analysis of the irradiated solutions, it was found that the photosubstitution proceeded to give the corresponding 6-substituted 2- or 3-pyridylketoxime via the replacement of the ring hydrogen by the benzyl or heptyl group. The photo-Beckmann rearrangement led to the formation of the corresponding amides, but also other products formed in the photo-decomposition reaction.
- Wieszczycka, Karolina,Zembrzuska, Joanna
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p. 786 - 796
(2015/07/07)
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- Nickel-butadiene catalytic system for the cross-coupling of bromoalkanoic acids with alkyl grignard reagents: A practical and versatile method for preparing fatty acids
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The knights who say Ni: A practical and convenient synthetic route to fatty acids involves the Ni-catalyzed alkyl-alkyl cross-coupling of bromoalkanoic acids and alkyl Grignard reagents in the presence of 1,3-butadiene as an additive (see scheme). Copyright
- Iwasaki, Takanori,Higashikawa, Kiyokazu,Reddy, Vutukuri P.,Ho, Willbe W. S.,Fujimoto, Yukari,Fukase, Koichi,Terao, Jun,Kuniyasu, Hitoshi,Kambe, Nobuaki
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supporting information
p. 2956 - 2960
(2013/03/28)
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- Solvent-free oxidation of aldehydes to acids by TBHP using environmental-friendly MnO-14-exchanged Mg-Al hydrotalcite catalyst
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A number of hydrotalcite (Mg-Al, Mn-Al, Co-Al, Ni-Al, Mg-Fe, Mg-Cr and Cu-Al) catalysts, with or without MnO-14-exchange, were evaluated for their performance in the solvent-free oxidation of benzaldehyde to benzoic acid by tert-butyl hydroperoxide under reflux in the absence of any solvent. The MnO-14 - exchanged Mg-Al-hydrotalcite (Mg/Al = 10) showed high activity in the oxidation of different aromatic and aliphatic aldehydes to their corresponding acids and also showed excellent reusability in the oxidation process which is environmental-friendly. Indian Academy of Sciences.
- Choudhary, Vasant R.,Dumbre, Deepa K.,Narkhede, Vijay S.
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p. 835 - 839
(2012/11/13)
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- Aerobic photooxidative cleavage of vicinal diols to carboxylic acids using 2-chloroanthraquinone
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We developed the aerobic photooxidative cleavage of vicinal diols to carboxylic acids using 2-chloroanthraquinone in the presence of photoirradiation with a high-pressure mercury lamp. This is the first metal-free reaction using molecular oxygen as the terminal oxidant. Georg Thieme Verlag Stuttgart New York.
- Matsusaki, Yoko,Yamaguchi, Tomoaki,Tada, Norihiro,Miura, Tsuyoshi,Itoh, Akichika
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p. 2059 - 2062
(2012/11/07)
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- Oxidation reactions using air as oxidant thanks to silica nanoreactors containing GOx/peroxidases bienzymatic systems
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A new kind of enzymes encapsulation method is presented. It combines the sol-gel method with a templating process using bilayers of phospholipids to provide an organized network of phospholipids inside the silica and in the same time protect the embedded
- Laveille,Phuoc, L. Truong,Drone,Fajula,Renard,Galarneau
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scheme or table
p. 94 - 100
(2011/01/04)
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- Manufacture of C13 higher fatty acids from their esters by carbonylation of dodecene-1 in ionic liquid medium
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The effect of catalyst nature, temperature, acidity, promoters, and feedstock composition on dodecene-1 carbonylation in the presence of Pd compounds in an ionic liquid medium yielding higher fatty acid and their esters was studied. Palladium salts without phosphine ligands show high activity in tetrabutylammonium bromide. In systems of this kind, the catalyst is suspended in the reaction mass in the form of Pd particles with a size of 4-10 nm. It was shown that the catalytic system can be repeatedly used without loss of activity. It is acceptable to use synthesis gas instead of bare carbon monoxide with the selectivity for tride-canoic acid increasing.
- Lapidus,Eliseev,Bondarenko,Chau
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experimental part
p. 442 - 449
(2011/10/03)
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- Reductive carboxylation of alkyl halides with CO2by use of photoinduced SmI2/Sm reduction system
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Upon visible-light irradiation, reductive carboxylation of alkyl halides takes place by using a Sml2/Sm mixed system under atmospheric CO 2 to afford the corresponding carboxylic acids in good to excellent yields.
- Nomoto, Akihiro,Kojo, Yusuke,Shiino, Go,Tomisaka, Yuri,Mitani, Ikuko,Tatsumi, Masahiko,Ogawa, Akiya
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scheme or table
p. 6580 - 6583
(2011/02/24)
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- Development of a one-pot method for the homologation of aldehydes to carboxylic acids
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A highly efficient method is described for the one-carbon homologation of aldehydes to carboxylic acid derivatives employing the reaction of a 1,1-bis-dimethylphosphonate derivative with the aldehyde and controlled acid hydrolysis of the derived α-phosphonoenamine intermediate.
- McNulty, James,Das, Priyabrata
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experimental part
p. 7794 - 7800
(2009/12/26)
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- Facile and chemoselective cleavage of allyl carboxylic ester utilizing NaBH4 in DMSO
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A new method for deprotection of allyl carboxylic ester has been observed by using the inexpensive reagent sodium borohydride in dimethyl sulfoxide (DMSO). Aliphatic and aromatic allyl carboxylic ester undergo deprotection smoothly. The allyl ester group can selectively deprotect better than phenol.
- Pawar, Bharati V.,Lokhande, Pradeep D.
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experimental part
p. 2445 - 2453
(2009/12/06)
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- PROCESS FOR ALKALINE HYDROLYSIS OF CARBOXYLIC ACID DERIVATIVES TO CARBOXYLIC ACIDS
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The invention relates to a process for alkaline hydrolysis of carboxylic acid derivatives, especially carboxylic esters, to carboxylic acids, wherein, for the alkaline hydrolysis of the carboxylic acid derivatives, red mud which is produced by the Bayer process used for aluminum production is used as a reaction-promoting component, especially as a hydroxide ion source.
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Page/Page column 5
(2009/10/31)
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- Hydrocarboxylation of terminal alkenes in supercritical carbon dioxide
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The catalytic hydrocarboxylation of linear alkenes to carboxylic acids using supercritical carbon dioxide as a solvent was studied. High selectivities in acids have been obtained. The best results were achieved when adding a perfluorinated surfactant to the reaction mixture (93% conversions and ca. 80% selectivity). Comparative multinuclear high-pressure NMR spectroscopic studies in [D8]THF and in supercritical CO2 show the formation of Pd0 species. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Estorach, Clara Tortosa,Orejon, Arantxa,Ruiz, Nuria,Masdeu-Bulto, Anna M.,Laurenczy, Gabor
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experimental part
p. 3524 - 3531
(2009/02/07)
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- Wolff rearrangement of α-diazoketones using in situ generated silver nanoclusters as electron mediators
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We report Wolff rearrangement of α-diazoketones by in situ generated silver nanoclusters (Agn, 2-4 nm) from silver(I) oxide (Ag 2O) involving a nonclassical electron-transfer process. Our results show that Agn+/Agn0 redox couple allows the initial removal of an electron from α-diazoketone and its back-donation after chemical reaction(s). Controlled potential coulometry (CPC) of various α-diazoketones results in the realization of Wolff-rearranged carboxylic acids in excellent yields.
- Sudrik, Surendra G.,Sharma, Jadab,Chavan, Vilas B.,Chaki, Nirmalya K.,Sonawane, Harikisan R.,Vijayamohanan, Kunjukrishna P.
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p. 1089 - 1092
(2007/10/03)
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- Silver nanocluster redox-couple-promoted nonclassical electron transfer: An efficient electrochemical wolff rearrangement of α-diazoketones
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In this work we report the unique electrocatalytic role of benzoic acid protected silver nanoclusters (Agn, mean core diameter 2.5 nm) in the Wolff rearrangement (Scheme 1) of α-diazoketones. More specifically, the presence of a Agn0/Agn+ redox couple facilitates a nonclassical electron-transfer process, involving chemical reaction(s) interposed between two electron-transfer steps occurring in opposite directions. Consequently, the net electron transfer between the electron mediator (Agn) and α-diazoketone is zero. In-situ UV-visible studies using pyridine as a nucleophilic probe indicate the participation of α-ketocarbene/ketene as important reaction intermediates. Controlled potential coulometry of α-diazoketones using Agn as the anode results in the formation of Wolff rearranged carboxylic acids in excellent yield, without sacrificing the electrocatalyst.
- Sudrik, Surendra G.,Chaki, Nirmalya K.,Chavan, Vilas B.,Chavan, Sambhaji P.,Chavan, Subhash P.,Sonawane, Harikisan R.,Vijayamohanan
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p. 859 - 864
(2007/10/03)
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- INHIBITORS OF YEAST FILAMENTOUS GROWTH AND METHOD OF THEIR MANUFACTURE
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The invention broadly relates to the use of α, β-unsaturated fatty acids to inhibit the filamentous growth of fungi and yeasts and to a method for producing same. In particular the invention relates to the use of optionally substituted C8 to C15 α, β-unsaturated fatty acids or salts, esters or amides thereof for inhibiting or retarding the yeast-to-mycelium transition of organisms having a dimorphic life cycle.
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Page/Page column 12-14
(2008/06/13)
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- TEMPO-mediated environmentally benign oxidation of primary alcohols to carboxylic acids with poly[4-(diacetoxyiodo)styrene]
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An operationally simple and environmentally benign oxidation of primary alcohols to the corresponding carboxylic acids with a TEMPO-mediated poly[4-(diacetoxyiodo)styrene] system in acetone and water was carried out.
- Tashino, Yousuke,Togo, Hideo
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p. 2010 - 2012
(2007/10/03)
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- A novel ZrO2-SO42- supported palladium catalyst for syntheses of disubstituted ureas from amines by oxidative carbonylation
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The syntheses of disubstituted ureas by carbonylation of a series of amines in the presence of a sulfate modified zirconia supported palladium catalyst was investigated at an initial total pressure of 4.0 MPa and 135°C. High conversions and yields were achieved for the synthesis of symmetric dialkylureas. This supported catalyst could also be easily separated and recovered after reaction.
- Shi, Feng,Deng, Youquan,SiMa, Tianlong,Yang, Hongzhou
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p. 2161 - 2163
(2007/10/03)
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- Novel palladium(II) complex containing a chelating anionic N-O ligand: Efficient carbonylation catalyst
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(matrix presented) A novel palladium(II) complex containing chelating anionic pyridine-2-carboxylato and labile tosylato ligands is a highly efficient catalyst for the carbonylation of organic alcohols and olefins to carboxylic acids/esters. Carbonylation of primary, secondary, and tertiary alcohols as well as linear and functionalized terminal olefins was studied. In all cases remarkable activity and selectivity were observed. The catalyst is stable under reaction conditions even in the absence of excess phosphine ligands.
- Jayasree,Seayad,Chaudhari
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p. 203 - 206
(2007/10/03)
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- Ion-induced specificity change in polymer-catalyzed solvolyses of p-nitrophenyl alkanoates
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Spheres, rods, or vesicles are formed by the polymer 1, depending on the added salt (tris(hydroxymethyl)methylammonium chloride (TrisCl) or NaCl) and its concentration. Consequently, ion-induced substrate specificity occurs in the 1-catalyzed solvolysis o
- Wang,Fife
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p. 1543 - 1545
(2007/10/03)
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- Two-phase hydroformylation of higher molecular olefins by ethoxylated tris(p-hydroxyphenyl)-phosphine as complex ligand for the rhodiumcarbonyl catalyst
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Water-soluble rhodiumcarbonyl complexes with new nonionic complex ligands prepared by ethoxylation of tris(p-hydroxyphenyl)phosphine were successfully used in the two-phase hydroformylation of higher-molecular olefins. Their efficiency depends likely on a temperature controlled circulation of the catalyst complex between the organic and the water phase: At the temperature of the hydroformylation (100-130°C) the ethoxylated tri-(p-hydroxyphenyl)phosphine becomes water-insoluble (appearance of a miscibility gap) and is now available for the catalysis in the organic phase. After cooling to room temperature the catalyst system is dissolved again in the water phase and can be recovered by a simple phase separation. Johann Ambrosius Barth 1996.
- Jin, Zilin,Yan, Yuanyoung,Zuo, Huanpie,Fell, Bernhard
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p. 124 - 128
(2007/10/02)
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- An efficient and expeditious synthesis of funcionalized trifluoromethyl ketones through lithium-iodine exchange reaction
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A straightforward and very efficient synthesis of unsaturated long-chain trifluoromethyl ketones is achieved by metallation of the corresponding iodides in the presence of an equimolecular amount of tert-butyllithium, followed by reaction with a fluoroacylating agent.Metallation occurs quantitatively at -78 deg C and, in contrast to what has been generally recommended, there is no need to add the second equivalent of base, since its presence may be detrimental if other electrophilic functions are present in the molecule.
- Villuendas, Isabel,Parrilla, Alfredo,Guerrero, Angel
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p. 12673 - 12684
(2007/10/02)
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- Hair growth composition containing citric acid esters
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Triesters of citric acid are used for inducing, maintaining or increasing hair growth. Compositions for topical application to mammalian hair or scalp comprise an effective amount of from 1% to 99% by weight of an ester of citric acid having the structure (1): where, R1, R2 and R3 each independently represent a branched or unbranched alkyl, alkenyl, aryl, alkylaryl or arylalkyl group, each said group having from 1 to 18 carbon atoms, R4 represents -H, or a branched or unbranched saturated or unsaturated acyl, alkyl, aryl, alkylaryl or aylalkyl group having from 1 to 18 carbon atoms, in the presence of a cosmetically acceptable vehicle for the citric acid ester and in the absence of solid absorbent for the ester;, said effective amount of said ester being sufficient to increase hair growth in the rat, when said composition is applied topically thereto over a period of no more than three months, by at least 10% more than that obtainable using a control composition from which the said ester has been omitted, in accordance with the Rat Hair Growth Test.
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- Carbonylation of alkyl sulfonates catalyzed by cobalt complexes
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Alkyl sulfonates (R1-OSO2R2) react with carbon monoxide and alcohol (R3-OH) in the presence of catalytic amounts of Co complex and Nal to afford the corresponding esters (R1-COOR3) in moderate to good yields.
- Urata, Hisao,Goto, Daisuke,Fuchikami, Takamasa
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p. 3091 - 3094
(2007/10/02)
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- Synthesis of ω-Unsaturated Acids
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A short, high-yield method for the synthesis of ω-unsaturated acids have been developed that precludes any double-bond migration or hydrogenation.Key is the coupling reaction between Grignards of ω-unsaturated alkyl halides and the bromomagnesium salt of ω-bromo fatty acids.The reaction has been successfully extended to ω-bromo nitriles.The use of ω-chloro acids or α-bromo acids gives lower yields of heterocoupling products and substantial homocoupling.A catalyst study shows Li2CuCl4 to yield the most heterocoupling of several catalysts tried for the chloro acids, and Ni(II) or Cu(I) are best for the α-bromo acids.
- Mirviss, Stanley B.
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p. 1948 - 1951
(2007/10/02)
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- SELECTIVE MIXED COUPLING OF CARBOXYLIC ACIDS (II). -PHOTOLYSIS OF UNSYMMETRICAL DIACYLPEROXIDES WITH ALKENYL-, HALO-, KETO-, CARBOXYL-GROUPS AND A CHIRAL α-CARBON. COMPARISON WITH THE MIXED KOLBE ELECTROLYSIS.
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- Alkenoyl and functionalized alkanoyl dodecanoyl peroxides are prepared in 70 to 97 percent yield and photolyzed at -78 deg C.Thereby 4- to 10-alkenoyl and 4-alkynoyl peroxides afford good yields (56 - 68 percent) of unsymmetrical coupling products.Similarly α- to δ-haloalkanoyl, cholanoyl or 3- and 4-carboxyalkanoyl peroxides can be coupled (40 - 70 percent).The α-chiral diacyl peroxide 1s undergoes the photochemical coupling reaction with 80 percent retention of its configuration.The photolysis of diacyl peroxides at -78 deg C proves to be a favorable supplement of the Kolbe-electrolysis in cases, where the electrolysis fails or produces low yields.
- Feldhues, Michael,Schaefer, Hans J.
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p. 4213 - 4236
(2007/10/02)
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- Preparation of carboxylic acids from salts of nitroketones
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A method of preparing carboxylic acids is provided by contacting an ammonium, Group IA or Group IIA metal salt of a nitroketone in an aqueous medium. The method is preferably undertaken in the presence of an acidic mineral acid salt.
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