- Pentamethylphenyl (Ph*) and Related Derivatives as Useful Acyl Protecting Groups for Organic Synthesis: A Preliminary Study
-
A study of acyl protecting groups derived from the Ph? motif is reported. While initial studies indicated that a variety of functional groups were not compatible with the Br 2-mediated cleavage conditions required to release the Ph? group, strategies involving the use of different reagents or a modification of Ph? itself (Ph*OH) were investigated to solve this problem.
- Cheong, Choon Boon,Frost, James R.,Donohoe, Timothy J.
-
p. 1828 - 1832
(2020/10/06)
-
- Deoxyalkylation of guaiacol using haggite structured V4O6(OH)4
-
When V2O5 is used for the deoxygenation of guaiacol in methanol, it is reduced in situ to haggite structured V4O6(OH)4. Guaiacol prevents further reduction of the haggite phase in methanol and haggite catalyzes the partial deoxygenation of guaiacol. Haggite is a metastable redox catalyst for the deoxygenation of guaiacol, which follows the reverse Mars-van Krevelen mechanism. In addition, haggite is also a Lewis acid catalyst and catalyzes the alkylation of guaiacol with methanol as the alkylation reagent. The main products of the guaiacol deoxyalkylation are 2,6-dimethylphenol, 2-methoxy-6-methylphenol, 2,4,6-trimethylphenol, 2,3,6-trimethylphenol, 2,3,5,6-tetramethylphenol and 6-methyl-2-tert-butylphenol. Oligomerization takes place during the reaction but it is reversible. When the reaction is performed at 300 °C for 6 h, the 83.5% total selectivity for alkylphenols is achieved with a 99.0% conversion.
- Yan, Fei,Wen, Zhe,Wu, Kai,Cui, Kai,Mai, Fuhang,Ma, Zewei,Sang, Yushuai,Bai, Yunfei,Chen, Hong,Li, Yongdan
-
p. 1922 - 1932
(2019/04/29)
-
- Phenolic Oxidation Using H2O2 via in Situ Generated para-Quinone Methides for the Preparation of para-Spiroepoxydienones
-
Phenols are attractive starting materials for the preparation of highly substituted cyclohexane rings via dearomative processes. Herein we report an efficient preparation of dearomatized 1-oxaspiro[2.5]octa-4,7-dien-6-ones (para-spiroepoxydienones) via the nucleophilic epoxidation of in situ generated para-quinone methides from 4-(hydroxymethyl)phenols using aqueous H2O2. The developed protocol bypasses the need for stoichiometric bismuth reagents or diazomethane, which are frequently deployed for p-spiroepoxydienone preparation. The p-spiroepoxydienones are further elaborated in numerous downstream complexity-building transformations.
- McLaughlin, Michael F.,Massolo, Elisabetta,Cope, Thomas A.,Johnson, Jeffrey S.
-
supporting information
p. 6504 - 6507
(2019/09/04)
-
- Synthesis of phenols and aryl silyl ethers via arylation of complementary hydroxide surrogates
-
Two transition-metal-free methods to access substituted phenols via the arylation of silanols or hydrogen peroxide with diaryliodonium salts are presented. The complementary reactivity of the two nucleophiles allows synthesis of a broad range of phenols without competing aryne formation, as illustrated by the synthesis of the anesthetic Propofol. Furthermore, silyl-protected phenols can easily be obtained, which are suitable for further transformations.
- Reitti, Marcus,Gurubrahamam, Ramani,Walther, Melanie,Lindstedt, Erik,Olofsson, Berit
-
p. 1785 - 1788
(2018/04/14)
-
- Experimental Investigation on Upgrading of Lignin-Derived Bio-Oils: Kinetic Analysis of Anisole Conversion on Sulfided CoMo/Al2O3 Catalyst
-
Kinetics of the hydroprocessing of anisole, a compound representative of lignin-derived bio-oils, catalyzed by a commercial sulfided CoMo/Al2O3, was determined at 8–20 bar pressure and 573–673 K with a once-through flow reactor. The catalyst was sulfided in an atmosphere of H2 + H2S prior to the measurement of its performance. Selectivity-conversion data were used as a basis for determining an approximate, partially quantified reaction network showing that hydrodeoxygenation (HDO), hydrogenolysis, and alkylation reactions take place simultaneously. The data indicate that these reactions can be stopped at the point where HDO is virtually completed and hydrogenation reactions (and thus H2 consumption) are minimized. Phenol was the major product of the reactions, with direct deoxygenation of anisole to give benzene being kinetically almost insignificant under our conditions. We infer that the scission of the Cmethyl–O bond is more facile than the scission of the Caromatic–O bond, so that the HDO of anisole likely proceeds substantially through the reactive intermediate phenol to give transalkylation products such as 2-methylphenol. The data determine rates of formation of the major primary products. The data show that if oxygen removal is the main processing goal, higher temperatures and lower pressures are favored.
- Rahimpour, Hamid Reza,Saidi, Majid,Rostami, Parisa,Gates, Bruce C.,Rahimpour, Mohammad Reza
-
p. 702 - 713
(2016/09/28)
-
- A protocol to generate phthaloyl peroxide in flow for the hydroxylation of arenes
-
A flow protocol for the generation of phthaloyl peroxide has been developed. This process directly yields phthaloyl peroxide in high purity (>95%) and can be used to bypass the need to isolate and recrystallize phthaloyl peroxide, improving upon earlier batch procedures. The flow protocol for the formation of phthaloyl peroxide can be combined with arene hydroxylation reactions and provides a method for the consumption of peroxide as it is generated to minimize the accumulation of large quantities of peroxide.
- Eliasen, Anders M.,Thedford, Randal P.,Claussen, Karin R.,Yuan, Changxia,Siegel, Dionicio
-
supporting information
p. 3628 - 3631
(2014/08/05)
-
- CYCLIC PEROXIDE OXIDATION OF AROMATIC COMPOUND PRODUCTION AND USE THEREOF
-
The present invention provides a method for converting an aromatic hydrocarbon to a phenol by providing an aromatic hydrocarbon comprising one or more aromatic C-H bonds and one or more activated C-H bonds in a solvent; adding a phthaloyl peroxide to the solvent; converting the phthaloyl peroxide to a di-radical; contacting the di-radical with the one or more aromatic C-H bonds; oxidizing selectively one of the one or more aromatic C-H bonds in preference to the one or more activated C-H bonds; adding a hydroxyl group to the one of the one or more aromatic C-H bonds to form one or more phenols; and purifying the one or more phenols.
- -
-
Page/Page column 9; 10
(2014/10/15)
-
- Metal-free oxidation of aromatic carbon-hydrogen bonds through a reverse-rebound mechanism
-
Methods for carbon-hydrogen (C-H) bond oxidation have a fundamental role in synthetic organic chemistry, providing functionality that is required in the final target molecule or facilitating subsequent chemical transformations. Several approaches to oxidizing aliphatic C-H bonds have been described, drastically simplifying the synthesis of complex molecules. However, the selective oxidation of aromatic C-H bonds under mild conditions, especially in the context of substituted arenes with diverse functional groups, remains a challenge. The direct hydroxylation of arenes was initially achieved through the use of strong Bronsted or Lewis acids to mediate electrophilic aromatic substitution reactions with super-stoichiometric equivalents of oxidants, significantly limiting the scope of the reaction. Because the products of these reactions are more reactive than the starting materials, over-oxidation is frequently a competitive process. Transition-metal-catalysed C-H oxidation of arenes with or without directing groups has been developed, improving on the acid-mediated process; however, precious metals are required. Here we demonstrate that phthaloyl peroxide functions as a selective oxidant for the transformation of arenes to phenols under mild conditions. Although the reaction proceeds through a radical mechanism, aromatic C-H bonds are selectively oxidized in preference to activated-H bonds. Notably, a wide array of functional groups are compatible with this reaction, and this method is therefore well suited for late-stage transformations of advanced synthetic intermediates. Quantum mechanical calculations indicate that this transformation proceeds through a novel addition-abstraction mechanism, a kind of 'reverse-rebound' mechanism as distinct from the common oxygen-rebound mechanism observed for metal-oxo oxidants. These calculations also identify the origins of the experimentally observed aryl selectivity.
- Yuan, Changxia,Liang, Yong,Hernandez, Taylor,Berriochoa, Adrian,Houk, Kendall N.,Siegel, Dionicio
-
p. 192 - 196
(2013/08/23)
-
- Optimization of (2,3-dihydro-1-benzofuran-3-yl)acetic acids: Discovery of a non-free fatty acid-like, highly bioavailable G protein-coupled receptor 40/free fatty acid receptor 1 agonist as a glucose-dependent insulinotropic agent
-
G protein-coupled receptor 40 (GPR40)/free fatty acid receptor 1 (FFA1) is a free fatty acid (FFA) receptor that mediates FFA-amplified glucose-stimulated insulin secretion in pancreatic β-cells. We previously identified (2,3-dihydro-1-benzofuran-3-yl)acetic acid derivative 2 as a candidate, but it had relatively high lipophilicity. Adding a polar functional group on 2 yielded several compounds with lower lipophilicity and little effect on caspase-3/7 activity at 30 μM (a marker of toxicity in human HepG2 hepatocytes). Three optimized compounds showed promising pharmacokinetic profiles with good in vivo effects. Of these, compound 16 had the lowest lipophilicity. Metabolic analysis of 16 showed a long-acting PK profile due to high resistance to β-oxidation. Oral administration of 16 significantly reduced plasma glucose excursion and increased insulin secretion during an OGTT in type 2 diabetic rats. Compound 16 (TAK-875) is being evaluated in human clinical trials for the treatment of type 2 diabetes.
- Negoro, Nobuyuki,Sasaki, Shinobu,Mikami, Satoshi,Ito, Masahiro,Tsujihata, Yoshiyuki,Ito, Ryo,Suzuki, Masami,Takeuchi, Koji,Suzuki, Nobuhiro,Miyazaki, Junichi,Santou, Takashi,Odani, Tomoyuki,Kanzaki, Naoyuki,Funami, Miyuki,Morohashi, Akio,Nonaka, Masami,Matsunaga, Shinichiro,Yasuma, Tsuneo,Momose, Yu
-
experimental part
p. 3960 - 3974
(2012/07/28)
-
- Complexation of dichlorocarbene by methylanisoles
-
Dichlorocarbene generated by laser flash photolysis of dichlorodiazirine readily forms UV-vis active π- and O-ylidic complexes with methylanisole derivatives.
- Moss, Robert A.,Wang, Lei,Odorisio, Christina M.,Krogh-Jespersen, Karsten
-
body text
p. 1467 - 1470
(2010/05/18)
-
- FUSED CYCLIC COMPOUNDS
-
The present invention provides a compound represented by the formula (I): wherein each symbol is as defined in the description, or a salt thereof. The compound or a salt thereof or a prodrug thereof has a GPR40 receptor function modulating action and is useful as an insulin secretagogue or an agent for the prophylaxis or treatment of diabetes and the like.
- -
-
Page/Page column 77
(2008/06/13)
-
- Syntheses of sterically hindered pyridinium phenoxides as model compounds in nonlinear optics
-
Noncentrosymmetric molecules with a π-conjugated system and, among them, push-pull molecules such as pyridinium phenoxide, are a promising new class of materials for applications in optoelectronics due to their nonlinear optical (NLO) properties. Modelling studies have indicated that an increase in the twist angle between the two aromatic rings leads to an enhancement of the NLO properties. In order to confirm this feature experimentally, it was necessary to prepare a series of new hindered pyridinium phenoxides. Their efficient syntheses by Suzuki cross-coupling reactions are described herein. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Diemer, Vincent,Chaumeil, Helene,Defoin, Albert,Fort, Alain,Boeglin, Alex,Carre, Christiane
-
p. 2727 - 2738
(2007/10/03)
-
- Ortho-alkylation of phenol with methanol using Pb-Cr promoted magnesium oxide catalysts
-
In this study, Pb-Cr promoted magnesium oxide catalysts were used to catalyze the ortho-alkylation of phenol in the presence of excess methanol. The Cr/MgO catalyst exhibited a high conversion of phenol and a relatively high selectivity for the ortho-alkylation of phenol. The catalytic activity and the stability of Cr/MgO were improved by the addition of a fairly small amount of Pb. The Pb-Cr/MgO catalyst showed specificity for the ortho-alkylation of phenol, which was proved by a series of phenol derivative reactions with methanol.
- Ke, Jyh-Harng,Zena, Jyh-Myng,Wang, Fey-Long
-
p. 1407 - 1410
(2007/10/03)
-
- Amino-, Aminophenoxy- and Aminobenzoyl Derivatives of Durene
-
Various durene derivatives have been prepared including 4-hydroxy-, 4-aryloxy- and 4-aroyl- derivatives of 2,3,5,6-tetramethylaniline and bis(4-aminophenoxy)- and bis-(4-aminobenzoyl)durene.
- Barclay, George G.,Candlin, Jack P.,Lawne, William,Pauson, Peter L.
-
p. 2169 - 2187
(2007/10/02)
-
- ORTHO-METHYLATION OF PHENOLS WITH ETHYL(IODOMETHYL)ZINC
-
The regioselective ortho-methylation of phenols by in situ generated ethyl(iodomethyl)zinc via an internal alkylation process is described.
- Lehnert, Erich K.,Sawyer, J. Scott,Macdonald, Timothy L.
-
p. 5215 - 5218
(2007/10/02)
-
- The Baeyer-Villiger Oxidation of Aromatic Aldehydes and Ketones with Hydrogen Peroxide Catalyzed by Selenium Compounds
-
A series of organoselenium compounds was investigated as activators of hydrogen peroxide in the Baeyer-Villiger oxidation.As a result, a convenient and cheap method for transformation of aromatic aldehydes, having polycondensed ring systems or electron-donating substituents, and polymethoxy derivatives of acetophenone, into phenols was elaborated.This method utilizes hydrogen peroxide activated by areneseleninic acids, as oxidizing agent.
- Syper, Ludwik
-
p. 167 - 172
(2007/10/02)
-
- Thermal isomerizations of protonated bicyclohexenones
-
The thermal isomerizations of a wide range of protonated methyl substituted bicyclohex-3-en-2-ones to protonated phenols has been examined using triflic acid as a strong acid solvent.The rate constants and activation energies of these isomerization has been determined.The barriers to the isomerizations were shown to be dependent on the number and position of the methyl substituents.The results show that three different mechanisms are needed to account for these isomerizations, two of which involve a preliminary circumambulatory rearrangement prior to ring opening and the other process involving a direct ring opening of the initial protonated bicyclohexenone to give an intermediate meta-protonated phenol.
- Childs, Ronald F.,George, Baha E.
-
p. 1350 - 1354
(2007/10/02)
-
- A quantitative examination of the photoisomerization of some protonated phenols
-
The photoisomerization of a series of protonated, methyl substituted phenols to protonated bicyclohexenones has been examined.These reactions, which were carried out in CF3SO3H as a strong acid solvent at ambient temperatures, provide a convenient route to a variety of bicyclohexenones.The quantum yields for these photoisomerizations vary from 0.018 for protonated 3,5-dimethylphenol to 0.65 for protonated 2,6-dimethylphenol.This variation in efficiency can be understood in terms of a competition between ring opening, to regenerate the starting phenol, or cyclopropyl migration, to give product, of aninitially formed intermediate.
- Childs, Ronald F.,George, Baha E.
-
p. 1343 - 1349
(2007/10/02)
-
- Regioselective Side-Chain Nitration of Polymethylbenzenes Directed by an Acyl Function and Its Application to the Synthesis of Polysubstituted Phthalic Acid Derivatives
-
Nitration of three types of tetramethylacetophenones and pentamethylacetophenone with fuming nitric acid in acetic anhydride was carried out.The product distributions were compared with those estimated from substituent effects.A variety of acylpentamethylbenzenes including pentamethylbenzoic acid were reacted with the nitrating system to give regioselectively 2-(nitromethyl)-3,4,5,6-tetramethylacylbenzenes.The selective nitrations of some benzoic acid derivatives followed by an alkaline treatment have been found to provide the N-hydroxyphthalimide derivatives, which a re readily converted to the phthalic anhydrides and the phthalazines.
- Keumi, Takashi,Morita, Toshio,Teramoto, Koichi,Takahashi, Hisakazu,Yamamoto, Hiroshi,et al.
-
p. 3439 - 3446
(2007/10/02)
-
- PERTURBATION OF THE FUCHSONE CHROMOPHORE BY 3,5-METHYL SUBSTITUTION. STERICALLY CROWDED EXOCYCLIC DOUBLE BOND
-
Several 3,5-methyl substituted fuchsones have been synthesized and characterized by means of UV and NMR spectroscopy as well as dipole moment measurements.Two basic types of behaviour of the longest wavelength band have been found for these derivatives in comparison to 2,6-substituted analogues i.e. hypochromic effect and bathochromic shift.These effects can be attributed to a steric crowding of the C(4)-C(7) double bonds.The role of the steric interactions in the ground state and in the excited state is discussed.
- Koutek, Bohumir,Musil, Lubomir,Velek, Jiri,Lycka, Antonin,Snobl, Dobroslav,et al.
-
p. 2540 - 2556
(2007/10/02)
-
- Substituted spirocyclic derivatives
-
The present invention relates to substituted spirocyclic derivatives having the general formula: STR1 wherein the dotted line represents a carbon-carbon double bond or a carbon-carbon single bond, wherein R1, R2, R3, R4, R5, and R6 are each the same or different, hydrogen or lower alkyl, wherein Z is one of the following: STR2 wherein R7 is either hydrogen or lower alkyl, wherein R8 and R9 are each lower alkyl; their methods of preparation and their use as odor-modifying ingredients in perfumes and perfumed products, and as flavor-modifying ingredients in the flavoring of foodstuffs and tobacco products.
- -
-
-
- Process for the production of spirodienones and spirocyclic ketones
-
This invention concerns processes for preparing compounds having the structure STR1 wherein each of R1, R2, R3, R4, R5 and R6 is the same or different and represents hydrogen or a lower alkyl group and wherein each dashed line represents a carbon-carbon single bond or a carbon-carbon double bond. Those compounds in which all three dashed lines represent carbon-carbon double bonds are prepared by reacting phenols and 2-alkylidene-1,4-disubstituted butanes. Selective reduction of these compounds yields those in which at least one dashed line represents a carbon-carbon single bond. Most of the compounds so prepared are new compounds. All are useful as fragrance materials either directly and/or in compositions and/or have useful fixative properties in fragrance compositions.
- -
-
-