- Selectivity engineering of solid base catalyzed O-methylation of 2-naphthol with dimethyl carbonate to 2-methoxynaphthalene
-
2-Methoxynaphthalene is an important intermediate used in the production of naproxen which is widely used as a non-steroidal, anti-inflammatory, analgesic and antipyretic drug. In the current work, catalytic methylation of 2-naphthol was studied by using dimethyl carbonate as a greener agent vis-à-vis methyl halides and dimethyl sulfate. Catalysts based on calcined-hydrotalcite (CHT) supported on hexagonal mesoporous silica (HMS) were synthesized. Effect of CHT loading on HMS was systematically studied including full characterization. The activity and selectivity of CHT/HMS was examined by studying the effects of different operating parameters to deduce mechanism and kinetics. Conversion of 2-naphthol at 463 K and autogenous pressure was 92% with 90% selectivity toward 2-methoxynaphthalene on 20% (w/w) CHT/HMS. The catalyst was easily recovered and reused without any significant loss in activity. A kinetic model was developed. It follows zero order kinetics based on Langmuir-Hinshelwood-Hougen-Watson mechanism with strong adsorption of reactants. The apparent activation energy is 32.3 kcal/mol.
- Yadav, Ganapati D.,Salunke, Jeetendra Y.
-
-
Read Online
- Lewis Acid-Mediated Cyanation of Phenols Using N-Cyano-N-phenyl-p-toluenesulfonamide
-
Lewis acid-mediated cyanation of phenol derivatives with N-cyano-N-phenyl-p-toluenesulfonamide (NCTS) has been developed. The reaction proceeded efficiently with high regioselectivity to produce aromatic nitriles in moderate to excellent yields, which provides a direct and practical access to valuable products. (Figure presented.).
- Zhang, Wu,Li, Tao,Wang, Qingli,Zhao, Wanxiang
-
p. 4914 - 4918
(2019/11/03)
-
- Palladium(I) Dimer Enabled Extremely Rapid and Chemoselective Alkylation of Aryl Bromides over Triflates and Chlorides in Air
-
Disclosed herein is the first general chemo- and site-selective alkylation of C?Br bonds in the presence of COTf, C?Cl and other potentially reactive functional groups, using the air-, moisture-, and thermally stable dinuclear PdI catalyst, [Pd(μ-I)PtBu3]2. The bromo-selectivity is independent of the substrate and the relative positioning of the competing reaction sites, and as such fully predictable. Primary and secondary alkyl chains were introduced with extremely high speed (5 min reaction time) at room temperature and under open-flask reaction conditions.
- Kalvet, Indrek,Sperger, Theresa,Scattolin, Thomas,Magnin, Guillaume,Schoenebeck, Franziska
-
supporting information
p. 7078 - 7082
(2017/06/13)
-
- TRICYCLIC PIPERIDINE COMPOUNDS
-
The present invention relates to compounds of the formula (I) wherein R1a, R1b, R2, R3, (R4)n and ring (A) are as described in the description, to their preparation, to pharmaceutically acc
- -
-
Page/Page column 92
(2016/11/21)
-
- Lewis Acid Assisted Nickel-Catalyzed Cross-Coupling of Aryl Methyl Ethers by C-O Bond-Cleaving Alkylation: Prevention of Undesired β-Hydride Elimination
-
In the presence of trialkylaluminum reagents, diverse aryl methyl ethers can be transformed into valuable products by C-O bond-cleaving alkylation, for the first time without the limiting β-hydride elimination. This new nickel-catalyzed dealkoxylative alkylation method enables powerful orthogonal synthetic strategies for the transformation of a variety of naturally occurring and easily accessible anisole derivatives. The directing and/or activating properties of aromatic methoxy groups are utilized first, before they are replaced by alkyl chains in a subsequent coupling process.
- Liu, Xiangqian,Hsiao, Chien-Chi,Kalvet, Indrek,Leiendecker, Matthias,Guo, Lin,Schoenebeck, Franziska,Rueping, Magnus
-
p. 6093 - 6098
(2016/05/19)
-
- Cross-coupling reaction with lithium methyltriolborate
-
We newly developed lithium methyltriolborate as an air-stable white solid that is convenient to handle. The good performance of this triolborate for metal-catalyzed bond-forming reactions was demonstrated in palladium-catalyzed cross-coupling reactions wi
- Yamamoto, Yasunori,Ikizakura, Kazuya,Ito, Hajime,Miyaura, Norio
-
p. 430 - 439
(2013/03/13)
-
- Tandem reduction + cyclization of ortho-substituted cinnamic esters
-
Conjugate reduction of ortho-substituted cinnamic esters by Stryker's reagent to form copper enolates, followed by intramolecular aldol-type cyclization, successfully generated indane and tetralin rings in one pot efficiently. This tandem reaction is generally diastereoselective and provides good yields.
- Sass, Daiane Cristina,De Lucca Jr., Emílio Carlos,Da Silva Barbosa, Jader,De Oliveira, Kleber Thiago,Constantino, Mauricio Gomes
-
scheme or table
p. 5371 - 5374
(2011/10/31)
-
- A new protocol for O-methylation of phenolic compounds with trimethyl phosphite or trimethyl phosphate under solvent-free condition and microwave irradiation
-
A simple method for the preparation of industrially important alkyl aryl ethers is reported. Several phenolic compounds such as phenols, naphthols, and hydroxy coumarins were O-methylated with trimethyl phosphite or trimethyl phosphate under microwave irradiation and solvent-free condition in almost quantitative yields. Reaction of 2-naphthol with trimethyl phosphate gave mixture of 2-methoxynaphthalene and 1-methyl-2-methoxynaphthalene while the reaction with trimethyl phosphite gave mostly 2-methoxynaphthalene. This method is highly efficient for the methylating of phenolic compounds with very easy experimental procedure and environmental friendly conditions.
- Saidi, Mohammad R.,Rajabi, Fatemeh
-
p. 2343 - 2348
(2007/10/03)
-
- Oxovanadium(V)-Induced Cross-Coupling Reaction between Two Ligands of Organozinc Compounds
-
Oxovanadium(V) compounds such as VO(OEt)Cl2 serve as useful oxidants for organozinc compounds, providing the corresponding cross-coupling products derived from two ligands of organozinc compounds. In particular, triorganozincates undergo selective cross-coupling smoothly by the action of oxovanadium(V).
- Hirao, Toshikazu,Takada, Takashi,Ogawa, Akiya
-
p. 1511 - 1515
(2007/10/03)
-
- Oxidation of 2-substituted cycloalkanones with cerium(IV) sulfate tetrahydrate in alcohols and acetic acid
-
The reaction of 2-substituted cycloalkanones with cerium(IV) sulfate tetrahydrate (CS) in alcohols and acetic acid gave the corresponding alkyl esters of oxo acids (80-96%) and oxo acids (78-96%), respectively, by oxidative cleavage of the C(R).C=O bond. In the case of 2-iodocycloalkanones in methanol, the dimethyl ester was obtained in good yield. A treatment of 5α-cholestan-3-one with CS in methanol produced 2-acetal 3-ester of 2,3-seco derivative in good yield. The effects of cerium(IV) and copper(II) salts are also discussed.
- He, Liangyou,Horiuchi, C. Akira
-
p. 2515 - 2521
(2007/10/03)
-
- Regioselective alkylation in ionic liquids
-
The room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate, [bmim][PF6], is used as a 'green' recyclable alternative to dipolar aprotic solvents for the regioselective alkylation at the heteroatom of indole and 2-naphthol.
- Earle, Martyn J.,McCormac, Paul B.,Seddon, Kenneth R.
-
p. 2245 - 2246
(2007/10/03)
-
- Preparation of 2-Alkyl-1-naphthols and 1-Alkyl-2-naphthols
-
C-Alkylation of 1-naphthol and 2-naphthol with n-butyllithium and dialkyl sulphate easily afford 2-alkyl-1-naphthols and 1-alkyl-2-naphthols respectively in relatively good yields.
- Saidi, Mohammad R.
-
-
- Regioselectivity of the Alkylation of Ambident Anionic Species on Alumina or in the Presence of 'Solid Hexamethylphosphoric Triamide'
-
C-Alkylation of the acetoacetate anions and of sodium naphthoxide is highly favoured on alumina, while O-alkylation of the acetoacetate anion predominates in tetrahydrofuran in the presence of solid hexamethylphosphoric triamide.
- Bram, Georges,Geraghty, Niall,Nee, Gerard,Seyden-Penne, Jacqueline
-
p. 325 - 326
(2007/10/02)
-