14210-97-0

Two new phenol-based ester derivatives, namely C13H9ClO2 (I) and C20H14O4 (II) have been synthesized and characterized by NMR spectroscopy, single crystal X-ray diffraction and density functional theory (DFT) geometry optimization and molecular orbital calculations. Compound I crystallizes in the orthorhombic space group Pca2(1),with a = 7.6297 (5) ?, b = 5.5875 (3) ?, c = 26.1624 (12) ?, α = β = γ = 90°, V = 1115.33(11) ?3 and Z = 4. Compound II crystallizes in the triclinic space group P $βar 1$$ 1 ˉ, with a = 5.7970 (4) ?, b = 8.1366 (8) ?, c = 8.8057 (9) ?, α = 83.246 (8)°, β = 72.138 (8)°, γ = 76.696 (8)°, V = 384.22 (6) ?3 and Z = 1. Geometry optimization calculations for each compound is consistent with these observations. A comparison of the dihedral angles between mean planes of the benzene rings in the crystal with the DFT theoretical calculations and weak intermolecular hydrogen bond interactions has been included for each molecule. Electronic transitions have been predicted by DFT Molecular Orbital calculations and compared with experimental absorption spectra.

The amide C-N cleavage has drawn a broad interest in synthetic chemistry, biological process and pharmaceutical industry. Transition-metal, luxury ligand or excess base were always vital to the transformation. Here, we developed a transition-metal-free hydrogen-bond-assisted esterification of amides with only catalytic amount of base. The proposed crucial role of hydrogen bonding for assisting esterification was supported by control experiments, density functional theory (DFT) calculations and kinetic studies. Besides broad substrate scopes and excellent functional groups tolerance, this base-catalyzed protocol complements the conventional transition-metal-catalyzed esterification of amides and provides a new pathway to catalytic cleavage of amide C-N bonds for organic synthesis and pharmaceutical industry. [Figure not available: see fulltext.]

An efficient solid-phase benzoylation of phenols and alcohols was developed under microwave irradiation. A stoichiometric amount of benzoyl chloride was sufficient to carry out the reaction. This benzoylation features short reaction time, good yields, and easy workup procedures. Furthermore, the scope of the reaction was extended to prepare 3,5-dinitrobenzoyl derivatives of alcohols.

The present report outlines our efforts toward a simple yet elegant protocol for O-acylation of a wide variety of phenols. This highly enabling and solventless method relies on vinyl acetate as an innocuous acyl donor and DABCO as an organocatalyst. Operational simplicity, excellent yields, higher and faster conversion rates without excess reagents, a simple workup and essentially no need of columns are some of the salient features of the reported protocol.

Hierarchical ZSM-5 and Beta zeolites were investigated in the synthesis of wide range of industrially important aromatic/heterocyclic ketones by Friedel-Crafts acylation and benzoylation reactions. For comparative study, conventional ZSM-5 and Beta, and amorphous mesoporous Al-MCM-41 were investigated. Hierarchical zeolites were prepared by multi-ammonium structure directing agents whereas conventional zeolites were prepared by mono-ammonium structure directing agents. Among the catalysts investigated in this study, hierarchical Beta exhibited the highest reactant conversion in the acylation and benzoylation reactions. In this study, the systematic assessment of the catalytic activity of acid catalysts for wide range of aromatic and heterocyclic compounds is shown under one umbrella. To the best of our knowledge, these reactions over hierarchical zeolites (ZSM-5 and Beta) are reported here for the first time. Structure activity relationship is explained based on the physico-chemical properties, molecular size, reactivity of reactants, and reaction mechanism. Catalysts can be easily recovered and reused with negligible loss in the catalytic activity.

Monoacylation and trifluoromethanesulfonylation of phenolic diols were achieved by the aid of HF-pyridine, whereas diacylation occurred with pyridine alone. Furthermore, HF-pyridine was found to promote the direct conversion of t-butyldimethylsilyl ethers to the corresponding acetates.

Mo(CO)mediates the alkoxycarbonylation of aryl halides in their reaction with alcohols to afford arenecarboxylic acid esters. The molybdenum carbonyl complexes act as the catalyst and the source with carbon monoxide. The alkoxycarbonylation proceeds with a small excess of carbon monoxide in the form of Mo(CO)and the procedure is simple compared to the conventional method, which uses palladium catalyst under gaseous carbon monoxide. Using this procedure, a variety of carboxylic acid esters were prepared. Georg Thieme Verlag Stuttgart ? New York.

Magnesium bistrifluoromethanesulfonimide catalyzed the acetylation of phenols, alcohols, and thiols under solvent-free conditions at room temperature and in short times. Electron-deficient and sterically hindered phenols provided excellent yields. The catalyst was found to be general for acylation with other anhydrides, such as propionic, isobutyric, pivalic, chloroacetic, and benzoic anhydrides. The rate of acylation was influenced by the electronic and steric factors associated with the anhydride. The reaction with less electrophilic anhydrides (e.g., chloroacetic and benzoic anhydrides) required higher temperature (～80 °C). Chemoselective acetylation, pivalation, and benzoylation took place with acid-sensitive alcohols without any competitive dehydration/rearrangement.

A simple and efficient method for the transprotection of aryl methyl ether to easily cleavable arylbenzoate mediated by microwave activation has been developed. One important feature of this method is its high tolerance towards sensitive functionalities and to some extent to bulky environment.

A newly synthesized 3,6-dibenzoxyl-1,2-pyridazine 3 has been investigated for its potential to transfer the benzoyl group to various organic substrates carrying -NH2, -OH and -SH groups. The benzoyl transfer is fairly general in scope, occurs under convenient conditions and provides good to excellent yields of benzoylated products. Moreover, by choosing proper conditions, it is possible to achieve chemoselective benzoylation in bi-functional molecules. For instance, N-benzoylation of aromatic amines can be selectively accomplished over that of aliphatic amines and vice versa by manipulating reaction conditions. Selective N- or O-benzoylation in aminophenols is also possible. Although, not studied in detail, we final that dibenzoate 3 can also be used to effect C-benzoylation of reactive phenols and ketones, as exemplified by the C-benzoylation of resorcinol and acetophenone, respectively. Dibenzoate 3, besides being a crystalline, easy to handle, solid possesses twice the potential as an acyl carrier compared to the other known acyl carriers. These features make 3 as an attractive choice for many applications pertaining to benzoyl transfer reactions.

Alkali and alkaline earth metal perchlorates exhibit electrostatic catalysis in the activation of anhydrides for the acylation reaction. Perchlorates with higher values of the charge-size function of the metal ion exhibit better catalytic activity following the order Mg(ClO4) 2>Ba(ClO4)2>LiClO4. Acylation of structurally diverse phenols, thiols, alcohols, and amines have been carried out with stoichiometric amounts of anhydride at room temperature under solvent free conditions in the presence of catalytic amount of Mg(ClO4) 2. Sterically hindered and electron deficient phenols are efficiently acylated. Acylation with sterically hindered anhydrides such as iso-butyric, pivalic, and benzoic anhydrides are carried out with phenols and alcohols in excellent yields. Acid-sensitive alcohols are acylated in excellent yields without any competitive side reactions.

Carbon-centered radicals generated from the corresponding organotellurium compounds react with a variety of quinones under photo-thermal conditions to give the monoaddition product in moderate to excellent yield. The reaction can be used for the synthesis of polyprenyl quinoid natural products and C-glycosides.

Efficient acetylation and benzoylation of alcohols and phenols with acetic and benzoic anhydrides have been carried out under catalysis of bismuth(III) salts including BiCl3, Bi(TFA)3 and Bi(OTf)3. Selective acetylation and benzoylation of alcohols in the presence of phenols is an additional advantage of this procedure.

Trimethylsilyl trifluoromethanesulfonate is an excellent catalyst for the acylation of alcohols with acid anhydrides. Highly functionalized primary, secondary, tertiary, and allylic alcohols, and phenols, were acylated cleanly and efficiently and in a fraction of the time used under the standard DMAP conditions.

Scandium trifluoromethanesulfonate (triflate), which is commercially available, is a practical and useful Lewis acid catalyst for acylation of alcohols with acid anhydrides or the esterification of alcohols by carboxylic acids in the presence of p-nitrobenzoic anhydrides. The remarkably high catalytic activity of scandium triflate can be used for assisting the acylation by acid anhydrides of not only primary alcohols but also sterically-hindered secondary or tertiary alcohols. The method presented is especially effective for selective macrolactonization of ω-hydroxy carboxylic acids.

The invention relates to a method for preparing an ester composition in which at least one activated phenolic ether group of a molecule is reacted with at least one haloformyl group of another molecule.

Fourteen aromatic ester oligomers have been synthesised, the majority of which have not been described previously.They can be considered as model compounds for liquid crystalline polyesters, and as such give useful information regarding the relationship between chemical structure and thermal properties.Such oligomers are also potentially important as precursors to liquid crystalline monomers.