- Novel Benzothiazole Ionic Liquids as Catalysts for the Synthesis of Parabens
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Abstract: A simple and green approach to the esterification of p-hydroxybenzoic acid and aliphatic alcohols to obtain parabens was developed. First, two novel benzothiazole ionic liquids [HBth]H2PW12O40 (IL1) and [HBth]H4PMo12O41 (IL2) were synthesized with benzothiazole and heteropolyacids as starting materials. The synthesized ionic liquids were characterized by FTIR spectroscopy, TGA, PXRD analysis, and SEM. The application of IL1 and IL2 as catalysts for the synthesis of parabens was explored. The results showed that the ILs had a high catalytic activity in the synthesis of parabens, and, at the same time, they could be easily recovered and reused five times without loss of activity.
- Liu, B.,Liu, Y.,Sun, J.,Yin, D.
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p. 1476 - 1483
(2020/10/02)
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- Single-Step Dual Functionalization: One-Pot Bromination-Cross-Dehydrogenative Esterification of Hydroxy Benzaldehydes with CCl 3 Br - A Comparison with Selectfluor
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Bromination of phenolic compounds without directly using molecular bromine possesses much importance. In this article an Ir III /CCl 3 Br-assisted single-step double functionalization of hydroxy benzaldehydes is reported. It involves simultaneous esterification of the aldehyde group and bromination of the aryl ring of phenolic aldehydes in one-pot. The reaction proceeds under mild conditions in the presence of 445 nm blue LED light to obtain highly functionalized bromo hydroxy benzoates in moderate to good yields. In comparison, Selectfluor as an oxidant gives only non-bromo phenolic esters.
- Talukdar, Ranadeep
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supporting information
p. 1713 - 1718
(2019/08/28)
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- Zirconocene-catalyzed direct (trans)esterification of acyl acids (esters) and alcohols in a strict 1:1 ratio under solvent-free conditions
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A highly efficient way for the direct (trans)esterification of acyl acids (esters) and alcohols in a strict 1:1 ratio using a zirconocene complex (1, 1 mol%), a strong Lewis acid of good water tolerance, as a catalyst under solvent-free conditions has been developed. A wide range of acid and alcohol (esters) substrates undergo (trans)esterification to produce carboxylic ester motifs in moderate to good or excellent yields with good functional tolerance, such as that towards C-Br as well as CC and CC bonds. And complex 1 can be recycled six times without showing a significant decline in catalytic efficiency. It was demonstrated that cyclandelate, which is used to treat high blood pressure as well as heart and blood-vessel diseases, can be directly synthesized on a gram scale with 81% yield (6.70 g) using complex 1.
- Tang, Zhi,Jiang, Qiutao,Peng, Lifen,Xu, Xinhua,Li, Jie,Qiu, Renhua,Au, Chak-Tong
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supporting information
p. 5396 - 5402
(2017/11/22)
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- Dipole architecture of molecules and mesomorphic behavior of liquid crystals with rigid T-shaped mesogenic fragment
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A number of liquid crystalline polyesters having a rigid T-shaped mesogenic fragment and differing in dipole architecture were synthesized and examined by polarizing optical microscopy, differential scanning calorimetry, and IR and 1H NMR spectroscopy. The thermal stability of the mesophase in the given series of compounds was shown to increase with extension of arms in the T-shaped mesogenic fragment, as well as on replacement of the terminal ester groups (COOAlk) therein by ether moieties (OAlk). Such replacement also enhances smectogenic properties.
- Zuev
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experimental part
p. 1559 - 1564
(2009/06/28)
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- Inhibition of estrone sulfatase (ES) by alkyl and cycloalkyl ester derivatives of 4-[(aminosulfonyl)oxy] benzoic acid
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In our search for potent inhibitors of the enzyme estrone sulfatase (ES), we have undertaken the synthesis and biochemical evaluation of a range of esters of 4-[(aminosulfonyl)oxy] benzoic acid. The results of the study show that the synthesised compounds possess potent inhibitory activity, indeed the cyclooctyl derivative was found to be more potent than 667-COUMATE, which is currently undergoing clinical trials.
- Patel, Chirag K.,Owen, Caroline P.,Ahmed, Sabbir
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p. 605 - 609
(2007/10/03)
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- Synthesis and biochemical evaluation of some novel benzoic acid based esters as potential inhibitors of oestrone sulphatase
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Oestrone sulphatase is an important target in the fight against hormone-dependent breast cancer. In an effort to investigate the reported definitive pharmacophore for oestrone sulphatase and continue our search for potent inhibitors of this enzyme, we have undertaken extensive synthesis, biochemical evaluation and physicochemical property determination of a range of benzoic acid based esters. Here, we report the initial results of our study into a series of straight chain alkyl esters of 4-sulphonylbenzoic acid. Using these compounds, we have investigated the involvement of two physicochemical properties, namely logP and pKa. The results of this study show that there was a strong correlation between the inhibitory activity and the logP of the parent compound. Within the series of compounds studied, hydrophobicity appears to be a more important factor than pKa in determining the overall inhibitory activity. In a previous report, we showed that pKa plays an important role in stabilizing the phenoxide ion resulting from the hydrolysis of the sulphamate group. Here, we propose that although pKa is an important factor in determining the overall inhibitory activity when a wide range of compounds are considered, both hydrophobicity and pKa need to be considered in the design of potential inhibitors of oestrone sulphatase.
- Owen, Caroline,James, Karen,Sampson, Luther,Ahmed, Sabbir
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- Liquid crystal compounds, mixtures and devices
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An electroclinic device having two spaced cell walls each bearing electrode structures and treated on at least one facing surface with an alignment layer, a layer of a smectic liquid crystal material enclosed between the cell walls, where the liquid crystal material contains one or more of the compounds described by formula I as defined in the specification.
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Page column 12
(2008/06/13)
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- Inhibition of estrone sulfatase (ES) by derivatives of 4-[(aminosulfonyl)oxy] benzoic acid
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In our search for potent inhibitors of the enzyme estrone sulfatase (ES), we have undertaken the synthesis and biochemical evaluation of a range of straight chain alkyl esters of 4-[(aminosulfonyl)oxy] benzoic acid. The results of the study show that the synthesised compounds possess greater inhibitory activity when compared to COUMATE, although they were all found to possess lower inhibitory activity with respect to EMATE. Furthermore, the data suggest a strong correlation between logP and IC50 and therefore adds further support to our previous report where we suggested a link between inhibitory activity and hydrophobicity.
- Ahmed, Sabbir,James, Karen,Owen, Caroline P
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p. 2391 - 2394
(2007/10/03)
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- Liquid crystal compounds, mixtures and devices
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An electoclinic device having two spaced cell walls each bearing electrode structures and treated on at least one facing surface with an alignment layer, a layer of a smectic liquid crystal material enclosed between the cell walls, where the liquid crystal material contains one or more of the compounds described by formula I as defined in the specification.
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- New Liquid Crystal Compounds: (+)-4-Alkoxycarbonylphenyl-4-benzoate
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New Liquid Crystal Compounds: (+)-4-Alkoxycarbonylphenyl-4-benzoates (5) were synthesized.The mesomorphic behavior of these compounds is compared with that of (+)-4-(2-methylbutyloxycarbonyl)phenyl 4-(5-alkyl-1,3-dioxan-2-yl)benzoates (6).Compounds 5 exhibited cholesteric and smectic A phases and their transition temperatures to the isotropic state were lower than those of corresponding compounds 6.These properties are supposed to originate in the greater molecular widths of the formers caused by 2-methylbutyl group at the 5 position of the 1,3-dioxane ring.Though compounds 6 exhibit the ferroelectric behavior, compounds 5 don't.This might mean that a short distance between the carbonyl and chiral group is one factor for the appearance of the SmC* phase.
- Haramoto, Y.,Kamogawa, H.
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p. 161 - 166
(2007/10/02)
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- TRANSITIONS AND RELAXATIONS IN MESOPHASE POLYMERS: THERMOTROPIC LIQUID CRYSTALLINE POLYESTERS WITH MESOGENIC GROUPS IN THE MAIN CHAIN.
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The thermal and dynamic viscoelastic behavior of some thermotropic liquid crystalline polyesters based on alpha , omega -bis(4-hydroxybenzoyloxy)alkanes and terephthalic acid is reported.
- Frosini,De Petris,Chiellini,Galli,Lenz
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p. 223 - 242
(2007/10/02)
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