- Non-Cryogenic, Ammonia-Free Reduction of Aryl Compounds
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A method of reducing an aromatic ring or a cyclic, allylic ether in a compound includes preparing a reaction mixture including a compound including an aromatic moiety or a cyclic, allylic ether moiety, an alkali metal, and either ethylenediamine, diethylenetriamine, triethylenetetramine, or a combination thereof, in an ether solvent; and reacting the reaction mixture at from ?20° C. to 30° C. for a time sufficient to reduce a double bond in the aromatic moiety to a single bond or to reduce the cyclic, allylic ether moiety.
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- Preparation method of cis, cis-3, 5-dimethyl-1-cyclohexanol
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The invention belongs to the field of chemistry, and discloses a synthesis method of a cis, cis-3, 5-dimethyl-1-cyclohexanol compound shown as a formula (I). Acetaldehyde and ethyl acetoacetate are used as raw materials, and cis, cis-3, 5-dimethyl-1-cyclohexanol is synthesized by a series of reactions such as knoevenagel condensation, hydrolysis, decarboxylation, hydrogenation reduction, reduction, acylating chlorination, hydrolysis and the like. The raw materials and auxiliary materials of the route are simple and easily available, the reaction conditions are mild, the operation is simple andconvenient, the synthesis cost is low, and the obtained product has high chiral purity (the product/isomer ratio is 30: 1-100: 1) and is suitable for large-scale production.
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Paragraph 0079-0081; 0082-0083
(2020/08/18)
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- Access to Functionalized Quaternary Stereocenters via the Copper-Catalyzed Conjugate Addition of Monoorganozinc Bromide Reagents Enabled by N, N-Dimethylacetamide
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Monoorganozinc reagents, readily obtained from alkyl bromides, display excellent reactivity with β,β-disubstituted enones and TMSCl in the presence of Cu(I) and Cu(II) salts to synthesize a variety of cyclic functionalized β-quaternary ketones in 38-99% yields and 9:1-20:1 diastereoselectivities. The conjugate addition features a pronounced improvement in DMA using monoorganozinc bromide reagents. A simple one-pot protocol that harnesses in situ generated monoorganozinc reagents delivers comparable product yields.
- Fulton, Tyler J.,Alley, Phebe L.,Rensch, Heather R.,Ackerman, Adriana M.,Berlin, Cameron B.,Krout, Michael R.
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p. 14723 - 14732
(2018/11/23)
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- Metal-Free I2-Catalyzed Highly Selective Dehydrogenative Coupling of Alcohols and Cyclohexenones
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The I2 catalyzed highly selective oxidative condensation of cyclohexenones and alcohols for the synthesis of aryl alkyl ethers has been described. DMSO is employed as the mild terminal oxidant. This novel methodology offers a metal-free reaction condition, operational simplicity and broad substrate scope to afford valuable products from inexpensive reagents. Various meta-substituted aromatic ethers which are hardly synthesized from the reported methods requiring meta-substituted phenols, are efficiently prepared by the present protocol.
- Liang, Yu-Feng,Yuan, Yizhi,Shen, Tao,Song, Song,Jiao, Ning
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p. 233 - 240
(2018/02/19)
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- Synthesis of α,β-unsaturated carbonyl compounds via a visible-light-promoted organocatalytic aerobic oxidation
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α,β-Unsaturated ketones and aldehydes have been synthesized from their corresponding silyl enol ethers in a straightforward protocol involving a visible-light promoted organocatalytic, aerobic oxidation reaction. A cheap organic dye was used catalytically in these reactions as the photosensitizer.
- Zhang, Junlin,Wang, Leming,Liu, Qi,Yang, Zhen,Huang, Yong
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supporting information
p. 11662 - 11664
(2013/12/04)
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- The scent of bacteria: Headspace analysis for the discovery of natural products
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Volatile compounds released by 50 bacterial strains, 45 of them actinobacteria in addition to three chloroflexi and two myxobacteria, have been collected by use of a closed-loop stripping apparatus, and the obtained headspace extracts have been analyzed by GC-MS. Excluding terpenes that have recently been published elsewhere, 254 compounds from all kinds of compound classes have been identified. For unambiguous compound identification several reference compounds have been synthesized. Among the detected volatiles 12 new natural products have been found, in addition to mellein, which was released by Saccharopolyspora erythraea. The iterative PKS for this compound has recently been identified by in vitro experiments, but mellein production in S. erythraea has never been reported before. These examples demonstrate that headspace analysis is an important tool for the discovery of natural products that may be overlooked using conventional techniques. The method is also useful for feeding experiments with isotopically labeled precursors and was applied to investigate the biosynthesis of the unusual nitrogen compound 1-nitro-2-methylpropane, which arises from valine. Furthermore, several streptomycetes emitted compounds that were previously recognized as insect pheromones, thus questioning if bacterial symbionts are involved in insect communication.
- Citron, Christian A.,Rabe, Patrick,Dickschat, Jeroen S.
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p. 1765 - 1776
(2013/01/15)
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- The use of Hagemann's Esters to prepare highly functionalized phenols and benzenes
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Hagemann's esters can be converted into highly functionalized phenols or arenes. The systematic functionalization of Hagemann's ester derivatives permits the preparation of tri-and tetraalkyl-substituted phenols or tetra-, penta-, and hexaalkyl-substituted benzenes. Kotnis's aromatization procedure was found to be solvent dependent, and Suzuki couplings were found to be sensitive to steric hindrance. Wittig olefination and ortho-Claisen reactions were reliable means to introduce alkyl substituents at C-4 and/or C-5 positions, respectively. The acid-promoted dehydration of tertiary alcohol 46 to produce enone 47, followed by its selective alkylation (cf. 48) is new. ARKAT USA, Inc.
- Majetich, George,Allen, Scott
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p. 104 - 124
(2012/11/07)
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- 2-iodoxybenzenesulfonic acid as an extremely active catalyst for the selective oxidation of alcohols to aldehydes, ketones, carboxylic acids, and enones with oxone
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Electron-donating group-substituted 2-iodoxybenzoic acids (IBXs) such as5-Me-IBX (1g), 5-MeO-IBX (1h), and 4,5-Me2-IBX were superior to IBX 1a as catalysts for the oxidation of alcohols with Oxone (a trad emark of DuPont) under nonaqueous conditions, although Oxone was almost insoluble in most organic solvents. The catalytic oxidation proceeded more rapidly and cleanly in nitromethane. Furthermore, 2-iodoxybenzenesulfonic acid (IBS, 6a) was much more active than modified IBXs. Thus, we established a highly efficient and selective method for the oxidation of primary and secondary alcohols to carbonyl compounds such as aldehydes, carboxylic acids, and ketones with Oxone in nonaqueous nitromethane, acetonitrile, or ethyl acetate in the presence of 0.05-5molpercentof 6a, which was generated in situ from 2-iodobenzenesulfonic acid (7a) or its sodium salt. Cycloalkanones could be further oxidized to α,β- cycloalkenones or lactones by controlling the amounts of Oxone under the same conditions as above. When Oxone was used under nonaqueous conditions, Oxone wastes could be removed by simple filtration. Based on theoretical calculations, we considered that the relatively ionic character of the intramolecular hypervalent iodine-OSO2 bond of IBS might lower the twisting barrier of the alkoxyperiodinane intermediate 16.
- Uyanik, Muhammet,Akakura, Matsujiro,Ishihara, Kazuaki
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supporting information; experimental part
p. 251 - 262
(2009/06/28)
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- METHOD FOR PRODUCING CARBONYL COMPOUND AN PRO-OXIDANT USED FOR PRODUCTION OF CARBONYL COMPOUND
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The invention provides a process for the preparation of a carbonyl compound in high efficiency by oxidizing an alcohol. The process for the preparation of a carbonyl compound of the present invention includes a step of oxidizing an alcohol in the presence of a compound of the formula (I) or a derivative or a salt thereof, and an oxidant, wherein R1 and R2 independently represent hydrogen, a halogen, a nitro or acidic group, or an alkyl or alkoxy group, each of which optionally has a substituent, or R1 and R2 combine the two carbon atoms to which they are boned to form an aromatic ring.
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Page/Page column 15-16
(2009/08/16)
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- An efficient synthesis of some 5-substituted-3-methyl-2-cyclohexen-1-ones using microwaves
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3-Methyl-2-cyclohexenone and its 5-substituted-derivatives are prepared in high yields and short duration of time, using the microwave irradiation technique by the condensation of ethyl acetoacetate with eight different aldehydes and piperazine.
- Jyothi, Divya,Hari Prasad
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p. 630 - 632
(2008/09/19)
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- Recyclization of 1,4-dihydropyridine derivatives in acidic medium
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The recyclization of 1,4-dihydropyridines in aqueous-alcoholic hydrochloric acid medium proceeds with cleavage of a C-N bond and pyridine ring opening. Cyclohexenone derivatives are formed as a result of the subsequent intramolecular crotonic condensation of the acyclic intermediate. The leaving carbonyl substituents depart simultaneously with recyclization, depending on the acidity of the reaction medium.
- Stupnikova,Petushkova,Muceniece,Lūsis
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- The Roles of 2- and 3-Axial Methoxy Groups in Determining the Stereochemistry of the Complex Metal Hydride Reduction of Cyclohexanones: Examination of the Cieplak Model
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The 2- and 3-axially substituted methoxy groups in cyclohexanones exhibit steric hindrance similar to that of the methyl group in LiAlH4 and NaBH4 reductions. The chelate complex formation between the zinc ion and the two oxygens in the molecule was suggested in the zinc borohydride reduction. The relative reactivities of cyclohexanones in which the 2-axial position is substituted by the methyl or the methoxy group in the LiAlH4 reduction strongly support Cieplak's proposal, which focuses on the importance of the stabilization of the transition state by anti-periplanar allylic bonds.
- Senda, Yasuhisa,Sakurai, Hiroshi,Nakano, Shigeru,Itoh, Hiroki
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p. 3297 - 3303
(2007/10/03)
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- Dienediolates of Unsaturated Carboxylic Acids in Synthesis. Synthesis of Cyclohexenones and Polycyclic Ketones by Tandem Michael-Dieckmann Decarboxylative Annulation of Unsaturated Carboxylic Acids.
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Substituted 2-cyclohexenones 4 to 7 and hexahydronaphthalenones and hexahydroindenones 13 to 18 are prepared by tandem Michael-Dieckmann addition of lithium dienediolates of acyclic and alicyclic unsaturated carboxylic acids to the lithium salts of the same or other unsaturated carboxylic acids.
- Aurell, Maria J.,Gavina, Pablo,Mestres, Ramon
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p. 2571 - 2582
(2007/10/02)
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- A New Annulation Reagent, 2-Oxo-3-alkenylphosphonates. Reactions with Carbonyl-Stabilized Carboanions or Silyl Enol Ethers Leading to Cyclohexanones
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The reactions of 2-oxo-3-alkenylphosphonates with carbonyl-stabilized carbanions directly lead to 2-cyclohexen-1-ones through a sequence of Michael reaction and intramolecular Horner-Emmons olefination.On the other hand, the Lewis acid-mediated reactions with silyl enol ethers produce 1,5-diketones as Michael adducts, which then undergo cyclization on treatment with sodium hydride or triethylamine/zinc (II) bromide to afford 2-cyclohexen-1-ones or 2-phosphinyl-2-cyclohexen-1-ones, respectively.
- Wada, Eiji,Funakoshi, Junji,Kanemasa, Shuji
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p. 2456 - 2464
(2007/10/02)
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- Dienediolates of unsaturated carboxylic acids in synthesis. Tandem Michael-Dieckmann synthesis of substituted 2-cyclohexenones
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3,5-Disubstituted 2-Cyclohexenones are prepared by tandem Michael-Diekcmann addition of lithium dienediolates of dimethylacrylic and β-methylcinnamic acids to lithium carboxylates of unsaturated carboxylic acids.
- Aurell,Gavina,Gil,Parra,Tortajada,Mestres
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p. 1825 - 1831
(2007/10/02)
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- PHOTOCLEAVAGE OF CARBON-TIN BOND ACTIVATED BY NEIGHBORING
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β-Stannyl ketones underwent various types of reaction upon UV-irradiation, depending upon the substitution pattern of the substrate, and upon the solvent used.
- Sato, Tadashi,Takezoe, Kohji
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p. 4003 - 4006
(2007/10/02)
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- ETHYLENIC ACYL CYANIDES IV : INTRAMOLECULAR ENE CYCLISATION OF 5-METHYL-5-HEXENOYL CYANIDES TO 3-METHYL-2-CYCLOHEXENONES
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Condensation of methallyltrimethylsilanes with α,β-ethylenic acyl cyanides leads to 5-methyl-5-hexenoyl cyanides which after thermal cyclisation give 3-methyl-2-cyclohexenones and hydrogen cyanide.
- El-Abed, Douniazad,Jellal, Abdelkebir,Santelli, Maurice
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p. 1463 - 1466
(2007/10/02)
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- ALKALI METAL-HEXAMETHYLPHOSPHORAMIDE REDUCTION. PART V. REDUCTION OF SOME MONO- AND DIALKYLANISOLES BY LITHIUM IN HMPA
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o-, m- and p-Alkylanisoles have been reduced.To extend our observations some dialkylanisoles have been reduced, too.In most cases results comparable with those in Birch reduction have been obtained.
- Kotlarek, Wojciech
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p. 809 - 815
(2007/10/02)
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