- Method for preparing paraben
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The invention discloses a method for preparing paraben. The method comprises the following steps: adding p-hydroxybenzoic acid (Amol), an alcohol (Bmol) and a benzimidazole ionic liquid (Cmol) into adry three-neck flask, slowly heating, carrying out reflux reaction, and carrying out TLC monitoring until reaction is finished; carrying out reduced pressure distillation to remove a solvent, washingresidues with ethyl acetate, carrying out suction filtration, and carrying out spin-drying on an obtained filtrate to obtain paraben. The yield can reach 90% or above; an obtained filter cake is the benzimidazole ionic liquid and can be recycled; the ratio of A to B to C is 1: 5: (0.2-0.5). The method provided by the invention has the advantages that the catalyst can be recycled, green and environment-friendly effects are realized, the cost is reduced, and the method is an efficient method for synthesizing paraben.
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Paragraph 0029-0032
(2020/03/25)
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- Proline ionic liquid and method for catalyzing synthesis of paraben by proline ionic liquid
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The invention discloses proline ionic liquid and a method for catalyzing synthesis of paraben by the proline ionic liquid. The preparation method comprises the following steps: adding N-butylbenzimidazole, a solvent and proline into a dry three-neck flask, carrying out reflux reaction until the reaction is complete (monitored by TLC), evaporating to remove the solvent to obtain a faint yellow oilyliquid, namely the proline ionic liquid, adding p-hydroxybenzoic acid, alcohol and a proline ionic liquid into a dry three-necked bottle, heating to reflux reaction, monitoring by TLC until the reaction is finished, evaporating under reduced pressure to remove the solvent, extracting residues with diethyl ether, evaporating the diethyl ether phase to remove the solvent to obtain the methylparabenwith the yield of 88% or above, wherein the remainder is the ionic liquid, and carrying out washing and drying so that the product can be recycled for many times. The method disclosed by the invention is efficient, environment-friendly and safe, the catalyst can be recycled, the cost is reduced, the requirement on equipment is low, and the method is an efficient method for synthesizing paraben.
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Paragraph 0051-0054
(2020/09/16)
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- Method for preparing parabens
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The invention discloses a method for preparing parabens. The method comprises the following steps: adding an appropriate amount of methanol (A) into a reaction container, sequentially adding a benzothiazole ionic liquid (B) and p-hydroxybenzoic acid (C) while stirring, slowly heating the obtained solution to a reflux temperature, and carrying out TLC monitoring until the reaction ends; and distilling off methanol, washing the obtained reaction product with ethyl acetate, carrying out suction filtration (the filter cake is the benzothiazole ionic liquid), carrying out rotary evaporation on thefiltrate, washing the product with water, carrying out suction filtration, and drying the product to obtain colorless crystals (methylparaben) at a yield of 91% or above. A ratio of A:B:C is 1:4:0.15, and a catalyst has a high activity and a good stability, and can be recycled. Additionally, the method also has a high esterification rate of 87%% or above to other parabens (ethylparaben, propylparaben, isopropylparaben, butylparaben and n-dodecyl 4-hydroxybenzoate), and provides a good method for industrial synthesis of parabens.
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Paragraph 0026; 0030-0032; 0048; 0050-0053
(2019/07/01)
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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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- A process for preparing Nepal jin zhi method (by machine translation)
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The invention discloses a method for preparing Nepal jin zhi method: in a reaction container by adding of formula choline chloride (Amol) and methanesulfonic acid (Bmol), for 80 °C stirring to complete dissolution shall be low altogether [...]; cooling to room temperature, then added to the hydroxy benzoic acid of formula (Cmol) acrylic (Dmol), slow heating, reflux reaction, TLC monitoring until a reaction is finished (1 - 2 h); reaction liquid-cooled to the room temperature, precipitate solid, filtered, cake of a small amount of washing, get [...], a yield of 90% or more; recycling the filtrate to obtain low altogether [...]. Wherein A: B: C: D is 1: (1 - 4): 1: (1.1 - 1.5). The method of the invention short reaction time, efficiency is high, the catalyst can be recycled, environmental protection, and reducing the cost; to reduce the consumption of the stinging; low requirements on equipment, is an efficient method of synthesizing [...]. (by machine translation)
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Paragraph 0042; 0043; 0044; 0045; 0046; 0047; 0048
(2019/10/02)
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- Synthesis of Hydroxybenzoic Acids and Their Esters by Reaction of Phenols with Carbon Tetrachloride and Alcohols in the Presence of Iron Catalysts
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Alkyl esters of hydroxy-, methoxy-, and ethoxybenzoic and cresotic acids have been synthesized by reaction of phenols, anisole, phenetole, and cresols with carbon tetrachloride and alcohols in the presence of iron catalysts.
- Bayguzina,Tarisova,Khusnutdinov
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p. 208 - 215
(2018/03/26)
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- Palladium-Catalyzed Aerobic Oxidative Carbonylation of C–H Bonds in Phenols for the Synthesis of p-Hydroxybenzoates
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This work reports the synthesis of p-hydroxybenzoates directly from phenols by oxidative carbonylation of phenolic C–H bonds, proceding through oxidative iodination. The developed methodology is efficient and economically attractive because phenols are cheap and easily available starting materials. This one-pot strategy was expediently applied to the synthesis of a variety of p-hydroxybenzoates by utilizing simple primary and secondary alcohols with different phenols under mild reaction conditions. Advantageously, the procedure has no need for co-catalysts, co-solvents or external ligands. The utilization of molecular oxygen as a terminal oxidant for C–H bond oxidation represents an additional benefit.
- Gaikwad, Vinayak V.,Bhanage, Bhalchandra M.
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p. 2877 - 2881
(2018/06/21)
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- A method for the preparation method of the hydroxybenzoic acid propyl ester (by machine translation)
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This invention discloses a method for the preparation method of the hydroxybenzoic acid propyl ester, comprising the following steps: in the bottle to join the ports of the three-hydroxy benzoic acid, n-propanol and NKC - 9 type macroporous resin, mix, then put into the electromagnetic solder, in microwave oven, stir, reaction, and released timely separated in the water separator; the reaction 2 - 3h off after, pouring the reaction liquid clean three mouth bottle and the excess of steam distillation is propanol, distillation of the residual liquid in the beaker of putting into the clean, cooling crystallization, for 10% of the sodium carbonate solution to the pH value of the washing is 7.0 - 8.0, filtered, the filter cake wash with distilled water, drying, refining to obtain white solid of the product to the hydroxy benzoic acid propyl ester. The invention to NKC - 9 type macroporous resin as catalyst, to hydroxy benzoic acid and propanol as raw materials, the microwave method is adopted for the preparation of hydroxy benzoic acid propyl, excess of the tetrabutylorthotitanate can be reclaimed and reused, to corrode the apparatus, environmental pollution is small, high yield, purity is good, the preparation method is simple, and is suitable for industrial production. (by machine translation)
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Paragraph 0015; 0016; 0017; 0018; 0019; 0020; 0021-0026
(2017/02/28)
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- Trifluoromethanesulfonic acid immobilized on zirconium oxide obtained by the sol-gel method as catalyst in paraben synthesis
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The parabens, alkylic esters of p-hydroxybenzoic acid, were synthesized using trifluoromethanesulfonic acid immobilized on zirconium oxide (zirconia) as catalyst. The oxide was obtained by the sol-gel method, using urea as a pore-forming agent. After removing urea by extraction with water, the solid was dried and then calcined at 100, 205, 310 and 425 °C for 24 h. Afterward, it was impregnated with trifluoromethanesulfonic acid in toluene at reflux and leached to remove the weakly adsorbed acid. Mesoporous materials were obtained, whose mean pore diameter increased with the temperature of the thermal treatment of the support, while the specific surface area and the amount of acid bonded to the support decreased. The samples are crystalline from 400 °C and are thermally stable up to 250 °C. The catalysts have strong acidity and the number of acid sites decreased with the acid content in the support. The catalytic activity in the synthesis of propyl paraben, expressed as moles of ester formed at 5 h/mol acid in the catalyst, decreased when samples obtained from supports thermally treated at higher temperature were used. The activity also slightly diminished for the synthesis of different parabens in the order propyl > ethyl > methyl ester.
- Gorsd, Marina,Pizzio, Luis,Blanco, Mirta
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scheme or table
p. 91 - 98
(2012/02/02)
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- HPLC analysis of a syrup containing nimesulide and its hydrolytic degradation product
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The present paper deals with the evaluation of nimesulide, 2-phenoxy-4-nitroaniline, the main hydrolytic degradation product of nimesulide, of methylparaben and propylparaben, and eventually of 4-hydroxybenzoic acid by HPLC with UV detection at 254 nm in syrup as a pharmaceutical formulation. HPLC analysis was employed on the reversed phase C18 with methanol and 0. 01 M dibasic ammonium phosphate (ρr = 60: 40, pH 4. 0). Validation was performed using standards and a pharmaceutical preparation containing the compounds described above.
- Mokry, Milan,Klimes, Jir,Pechova, Jana
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body text
p. 405 - 408
(2011/10/09)
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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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- Allantoin-containing preparations for administration as gels and aerosols
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Allantoin-containing preparations are prepared in a form suitable for administration as gels and aerosols. In one embodiment of the aerosol formulation, an allantoin-containing composition comprises: (1) water; (2) allantoin in a therapeutically effective quantity; (3) an anionic ethoxylated surfactant; (4) lanolin oil; and (5) cod liver oil. The composition has a viscosity and surface tension in a range that allows the composition to be administered to the skin of a user as an aerosol by a mechanical spray pump. In another aspect of this invention, the allantoin-containing preparations are prepared in a form suitable for administration as gels. The compositions can be substantially anhydrous or can contain water. In one embodiment of the gel formation, an allantoin-containing composition comprises: (1) allantoin in a therapeutically effective quantity; (2) a complex comprising mineral oil and at least one hydrogenated alkylene copolymer; (3) lanolin oil; and (4) cod liver oil. The compositions can comprise other ingredients. Compositions according to the present invention are suitable for the treatment of a number of skin conditions or diseases characterized by ulceration, inflammation, or blistering of the skin, such as epidermolysis bullosa.
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- Regioselective Carboxylation of Phenols with Carbon Dioxide
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A few novel methods were developed for the regioselective preparation of p-hydroxybenzoic acid (pHBA) and its amino derivative by means of the Kolbe-Schmitt reaction. Thus, the carboxylation of tetraalkylammonium phenoxide at 125°C under the CO2 pressure of 5.0 MPa in the presence of K2CO3 gave pHBA in a maximum yield of 56% with the regioselectivity of 97-100%. The carboxylation of potassium phenoxide (PhOK) at 230°C under the CO2 pressure of 0.5 MPa also gave pHBA regioselectively in a 39% yield, together with unaltered phenol (61%) Under such conditions, the potassium salt of salicylic acid (SA) once formed was transformed into pHBA. Heat treatment of the dipotassium salt of 13C labeled SA indicated that the transformation occurs via two pathways, i.e., the intramolecular rearrangement of the salicylate (66%) and the decarboxylation of the salicylate followed by the recarboxylation of the resulting PhOK (34%). Furthermore, the carboxylation of cesium m-aminophenoxide and 5-amino-1-naphthoxide with CO2 gave regioselectively 4-hydroxyanthranilic and 8-amino-4-hydroxy-1-naphthoic acids, respectively, in good yields. This is a simple one-pot reaction giving these industrially useful acids with good yields.
- Rahim, Mohammad Abdur,Matsui, Yoshihisa,Matsuyama, Takanori,Kosugi, Yoshio
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p. 2191 - 2195
(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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- Emollient
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The present invention is a compound containing a cactus extract, which moistens the skin when the skin is exposed to radiation, such as during radiation treatment, sunburn or other types of burns.
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- Diphenyl disulfide and sodium in NMP as an efficient protocol for in situ generation of thiophenolate anion: Selective deprotection of aryl alkyl ethers and alkyl/aryl esters under nonhydrolytic conditions
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Aryl methyl ethers, methyl esters, aryl esters, and aryl sulfonates are chemoselectively deprotected under nonhydrolytic conditions by treatment with Ph2S2 (0.6 equiv) and Na (1.6 equiv) in NMP under reflux or at 90°C. Quantitative utilization of the 'PhS' moiety as the effective nucleophilic species represents conservation of atom economy. Other solvents such as HMPA, DMPU, DMEU, and DMF afforded comparable results. Chloro, nitro, aldehyde, α,α-diketone, and α,β-unsaturated ketone functionalities remain unaffected. The deprotection was found to take place in the order aryl ester > alkyl ester > aryl alkyl ether. Substrates bearing strong electron-withdrawing groups react at a faster rate than those not having such substitution. The differences in rate of reaction has been exploited for selective deprotection for intramolecular competition. An aryl acetate/benzoate is deprotected selectively in preference to a methyl ester or aryl methyl ether. Selective deprotection of a methyl ester is observed in the presence of an aryl alkyl ether.
- Chakraborti, Asit K.,Nayak, Mrinal K.,Sharma, Lalima
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p. 1776 - 1780
(2007/10/03)
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- Influence of hydrogen bonding in the activation of nucleophiles: PhSH- (catalytic) KF in N-methyl-2-pyrrolidone as an efficient protocol for selective cleavage of alkyl/aryl esters and aryl alkyl ethers under nonhydrolytic and neutral conditions
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The nucleophilicity of arenethiols can be augmented via hydrogen bonding with 'naked' halide anion. The activity of the halide anions follow the order F- ?Cl- ～ Br- ～ I- and is dependent on the countercation (Bu4N ～ Cs ～ K > Na ?Li). The solvent plays an important role in nucleophilic activation as well as regeneration of the effective nucleophile (e.g. ArS-) and those with high dielectric constant, high molecular polarizability, high donor number (DN), and low acceptor number (AN) are the most effective. Selective deprotection of alkyl/aryl esters and aryl alkyl ethers can be achieved under nonhydrolytic and neutral conditions by the treatment with thiophenol in 1-methyl-2-pyrrolidone (NMP) in the presence of a catalytic amount of KF. Aryl esters are selectively deprotected in the presence of alkyl esters and alkyl methyl ethers during intramolecular competitions.
- Chakraborti, Asit K.,Sharma, Lalima,Nayak, Mrinal K.
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p. 2541 - 2547
(2007/10/03)
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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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- A mild and chemoselective method for deprotection of aryl acetates and benzoates under non-hydrolytic condition
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Chemoselective deprotection of aryl acetates and benzoates can be achieved under non-hydrolytic condition by treatment with K2CO3 in N-methyl-2-pyrrolidone (NMP) at 100°C. Selective cleavage of aryl acetates and benzoates take place in the presence of alkyl carboxylates during intramolecular competitions.
- Chakraborti, Asit K,Sharma, Lalima,Sharma, Upasana
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p. 9343 - 9346
(2007/10/03)
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- One billionhertz microwave athermal action on the synthesis of aromatic esters at normal pressure
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Benzoic acid or p-hydroxybenzoic acid undergoes rapid reaction with alcohol using H2SO4 as catalyst at normal pressure, under irradiating continuously of the 1 GHz and 50 mW microwave for 22-60 minutes to afford aromatic esters in 76-90% yields.
- Zhang,Zhou,Zhang,Wu,Chen
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p. 2435 - 2439
(2007/10/03)
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- Water-containing external preparations
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Water-containing external preparations are disclosed, which contain, as essential ingredients, (a) 0.05-1 wt. % of deprodone propionate and (b) 1-20 wt. % of a polyhdric alcohol.
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- Healing composition employing an enzyme-modified casein
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A topical use pharmaceutical composition and a process for its preparation, comprising an improved enzyme-modified casein sol. Prior to being enzyme-modified, the casein is solubilized and neutralized by an alkali solution containing a molar weight percent ratio in the range of from 90:10 to 100:0, potassium hydroxide to sodium hydroxide. Said neutralization occurring for a time in the range of 5 to 35 minutes to allow for complete neutralization of the casein. The neutralized casein is then hydrolyzed or modified by enzymatic digestion by a proteolytic enzyme for a time sufficient to achieve a weight ratio of protein nitrogen to amino nitrogen in the range from 7:1 to 9:1. The improved enzyme-modified casein sol may then be mixed with stabilizing and pressuring agents, such as carrageenan, polyvinyl pyrrolidone, methyl paraben or propyl paraben. Topical uses for the improved enzyme-modified casein composition include healing and relieving infections, wounds, burns, dermatitis, skin eruptions, dandruff, hemorrhoids and bruises.
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- Aqueous liquid preparation
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In the aqueous liquid preparation of this invention, which comprises a compound of the formula; STR1 wherein R is an alkyl having 1-6 carbon atoms, and at least one species of the solubilizers selected from the group consisting of polyvinylpyrrolidone, cyclodextrin and caffeine, the solubility of the compound in water can be heightened and the aqueous liquid prepared thereby can afford a desired stability and mitigate eye-irritation or nose-irritation.
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- Macrocyclic lactones
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New and exceptionally potent antineoplastic agents designated bryostatin 1, bryostatin 2 and bryostatin 3 have been isolated from the marine animal Bugula neritina L. (Bryozoan phylum). An x-ray crystallographic analysis led to the assignment of novel structures shown in Charts I, II and III.
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- Method of treating navicular disease in horses
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A method of treating navicular disease in horses comprising the administration of Isoxsuprine over an extended period and an injectable paste composition including isoxsuprine hydrochloride and pharmaceutically acceptable carriers and flavorants for use in said method.
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- Esters of 2-thenoylmercaptopropionylglycine with substituted hydroxybenzenes, process for their preparation and pharmaceutical compositions containing same
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Esters of 2-thenoylmercaptopropionylglycine with substituted hydroxybenzenes, having general formula STR1 wherein R is p-acetamidophenyl, p-propyloxy carbophenyl or o-alkyloxycarbophenyl wherein the oxyalkyl radical contains 1-4 carbon atoms, are prepared by reacting 2-thenoylmercaptopropionylglycine with an alkylchloroformate thus obtaining a mixed anhydride which is reacted with the proper substituted hydroxybenzene selected among p-hydroxybenzeneacetamide, propyl p-hydroxybenzoate and alkyl o-hydroxybenzoate. These esters are useful therapeutical agents as mucolytic and antiinflammatory agents.
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