- A New and Efficient Heterogeneous System for the Oxidative Cleavage of 1,2-Diols and the Oxidation of Hydroquinones
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Sodium periodate/wet silica gel in the presence of dichloromethane is an efficient reagent for the oxidative cleavage of 1,2-diols and the oxidation of hydroquinones.This easily prepared reagent provides a good alternative of classical metaperiodate oxidation, especially for the preparation of aldehydes, which easily form hydrates.
- Daumas, M.,Vo-Quang, Y.,Vo-Quang, L.,Goffic, F. Le
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Read Online
- One-pot synthesis of aryloxypropanediols from glycerol: Towards valuable chemicals from renewable sources
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Glycerol offers an easy and green route for the synthesis of aryloxypropanediols of known pharmacological activity. Glycerol is selectively converted to aryloxypropanediols in a one-pot reaction, through in situ formed glycerol carbonate, under benign and solvent-free conditions. Catalyst and unreacted reagent can be recycled.
- Truscello, Ada M.,Gambarotti, Cristian,Lauria, Mirvana,Auricchio, Sergio,Leonardi, Gabriella,Shisodia, Suresh U.,Citterio, Attilio
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Read Online
- Ligand-Free Copper-Catalyzed Ullmann-Type C?O Bond Formation in Non-Innocent Deep Eutectic Solvents under Aerobic Conditions
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An efficient and novel protocol was developed for a Cu-catalyzed Ullmann-type aryl alkyl ether synthesis by reacting various (hetero)aryl halides (Cl, Br, I) with alcohols as active components of environmentally benign choline chloride-based eutectic mixtures. Under optimized conditions, the reaction proceeded under mild conditions (80 °C) in air, in the absence of additional ligands, with a catalyst [CuI or CuII species] loading up to 5 mol% and K2CO3 as the base, providing the desired aryloxy derivatives in up to 98 % yield. The potential application of the methodology was demonstrated in the valorization of cheap, easily available, and naturally occurring polyols (e. g., glycerol) for the synthesis of some pharmacologically active aryloxypropanediols (Guaiphenesin, Mephenesin, and Chlorphenesin) on a 2 g scale in 70–96 % yield. Catalyst, base, and deep eutectic solvent could easily and successfully be recycled up to seven times with an E-factor as low as 5.76.
- Capriati, Vito,García-álvarez, Joaquín,Marinò, Manuela,Perna, Filippo M.,Quivelli, Andrea Francesca,Vitale, Paola
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- Method for green, efficient and selective synthesis of chlorphenesin
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The invention discloses a method for green, efficient and selective synthesis of chlorphenesin. Glycerol and 4-chlorophenol directly serve as raw materials, diethyl carbonate serves as a selective synthesis agent, separate synthesis can be performed in situ, orientation reaction is ensured, other by-products are omitted, separation and purification are simple, yield is 95% under proper conditions,and purity is 99.5% or more. The yield of the chlorphenesin is greatly improved, high-toxic and expensive 3-chlorine-1, 2-propanediol is abandoned by the aid of low-cost and non-toxic glycerin, reaction conditions are mild, and industrial production is facilitated.
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Paragraph 0028-0043
(2018/09/13)
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- Exploration of the expeditious potential of Pseudomonas fluorescens lipase in the kinetic resolution of racemic intermediates and its validation through molecular docking
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A profoundly time-efficient chemoenzymatic method for the synthesis of (S)-3-(4-chlorophenoxy)propan-1,2-diol and (S)-1-chloro-3-(2,5-dichlorophenoxy)propan-2-ol, two important pharmaceutical intermediates, was successfully developed using Pseudomonas fluorescens lipase (PFL). Kinetic resolution was successfully achieved using vinyl acetate as acylating agent, toluene/hexane as solvent, and reaction temperature of 30°C giving high enantioselectivity and conversion. Under optimized condition, PFL demonstrated 50.2% conversion, enantiomeric excess of 95.0%, enantioselectivity (E?=?153) in an optimum time of 1?hour and 50.3% conversion, enantiomeric excess of 95.2%, enantioselectivity (E?=?161) in an optimum time of 3?hours, for the two racemic alcohols, respectively. Docking of the R- and S-enantiomers of the intermediates demonstrated stronger H-bond interaction between the hydroxyl group of the R-enantiomer and the key binding residues of the catalytic site of the lipase, while the S-enantiomer demonstrated lesser interaction. Thus, docking study complemented the experimental outcome that PFL preferentially acylated the R form of the intermediates. The present study demonstrates a cost-effective and expeditious biocatalytic process that can be applied in the enantiopure synthesis of pharmaceutical intermediates and drugs.
- Soni, Surbhi,Dwivedee, Bharat P.,Sharma, Vishnu K.,Patel, Gopal,Banerjee, Uttam C.
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- A synthesis method of chlorphenesin
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The invention relates to a synthetic method of chlorobenzene glyceryl ether. 3-chloro-1,2-propanediol and parachlorophenol are directly used as raw materials, high-corrosion chemical solvents are not introduced, a reaction is simple, the yield is high, and the yield can reach 95 percent or more under the optimal reaction condition. By adding a few phase transfer catalysts, the reaction can be promoted to be conducted quickly and effectively, and the reaction time can be shortened by at least two hours.
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Paragraph 0082; 0083
(2017/09/01)
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- Synergistic dual activation catalysis by palladium nanoparticles for epoxide ring opening with phenols
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Synergistic dual activation catalysis has been devised for epoxide phenolysis wherein palladium nanoparticles induce electrophilic activation via coordination with the epoxide oxygen followed by nucleophilic activation through anion-π interaction with the aromatic ring of the phenol, and water (reaction medium) also renders assistance through 'epoxide-phenol' dual activation.
- Seth, Kapileswar,Roy, Sudipta Raha,Pipaliya, Bhavin V.,Chakraborti, Asit K.
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supporting information
p. 5886 - 5888
(2013/07/25)
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- Chiral epoxides via borane reduction of 2-haloketones catalyzed by spiroborate ester: Application to the synthesis of optically pure 1,2-hydroxy ethers and 1,2-azido alcohols
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An enantioselective borane-mediated reduction of a variety of 2-haloketones with 10% spiroaminoborate ester 1 as catalyst is described. By a simple basic workup of 2-halohydrins, optically active epoxides are obtained in high yield and with excellent enantiopurity (up to 99% ee). Ring-opening of oxiranes with phenoxides or sodium azide is investigated under different reaction conditions affording nonracemic 1,2-hydroxy ethers and 1,2-azido alcohols with excellent enantioselectivity (99% ee) and in good to high chemical yield. 2011 American Chemical Society.
- Huang, Kun,Wang, Haiyang,Stepanenko, Viatcheslav,De Jesus, Melvin,Torruellas, Carilyn,Correa, Wildeliz,Ortiz-Marciales, Margarita
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supporting information; scheme or table
p. 1883 - 1886
(2011/06/20)
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- An unusual (R)-selective epoxide hydrolase with high activity for facile preparation of enantiopure glycidyl ethers
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A novel epoxide hydrolase (BMEH) with unusual (R)-enantioselectivity and very high activity was cloned from Bacillus megaterium ECU1001. Highest enantioselectivities (E>200) were achieved in the bioresolution of ortho-substituted phenyl glycidyl ethers and para-nitrostyrene oxide. Worthy of note is that the substrate structure remarkably affected the enantioselectivities of the enzyme, as a reversed (S)-enantiopreference was unexpectedly observed for the ortho-nitrophenyl glycidyl ether. As a proof-of-concept, five enantiopure epoxides (>99% ee) were obtained in high yields, and a gram-scale preparation of (S)-ortho-methylphenyl glycidyl ether was then successfully performed within a few hours, indicating that BMEH is an attractive biocatalyst for the efficient preparation of optically active epoxides. Copyright
- Zhao, Jing,Chu, Yan-Yan,Li, Ai-Tao,Ju, Xin,Kong, Xu-Dong,Pan, Jiang,Tang, Yun,Xu, Jian-He
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experimental part
p. 1510 - 1518
(2011/08/03)
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- Highly regioselective ring opening of epoxides with polymer supported phenoxide and naphthoxide anions
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Amberlite IRA-400 supported phenoxide and naphthoxide anions are easily prepared. These polymer supported reagents that are highly air stable are used for the regioselective ring opening reactions of different epoxides to give aryl ether alcohols in high yields under mild reaction conditions.
- Tamami,Iranpoor,Rezaei
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p. 2789 - 2795
(2007/10/03)
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- Naphthyloxy acetic acid derivatives and a pharmaceutical composition comprising them as an active ingredient
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The naphthyloxyacetic acid derivatives of the formula (I) wherein A is H, -(alkylene)COOR1, -(alkylene)CONR2R3, -(alkylene)OH, -(alkylene)tetrazole, -(alkylene)CN; E is single bond or alkylene; G is —S—, —SO—, —SO2—, —O— or —NR4—; L is alkylene, —(CH2)m—CH═CH—(CH2)n— or —(CH2)x—CH(OH)—(CH2)y—; M is phenyl, phenyl(thio, oxy, amino), diphenylmethyl, diphenylmethyl(thio, oxy, amino), and pharmaceutical composition comprising them as an active ingradient. The compounds of the formula (I) can combine PGE2receptor and exhibit the activity to antagonize or agonize for PGE2receptor. Therefore, they are useful as anti-hyperlipemia, for the prevention of abortion, for analgesics, as antidiarrheals, sleep inducer, diuretic, anti-diabetes, abortient, cathartics, antiulcer, anti-gastritis or antihypertensive etc.
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Referential example 6
(2010/11/29)
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- Ring opening of epoxides with carboxylates and phenoxides in micellar media catalyzed with Ce(OTf)4
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Efficient ring opening reaction of epoxides with carboxylates and phenoxide anions catalyzed with ceric triflate is performed in micellar media. This new method is a useful procedure for the preparation of β-carboxy and phenoxy alcohols from epoxides under mild reaction conditions.
- Iranpoor,Firouzabadi,Safavi,Shekarriz
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p. 2287 - 2293
(2007/10/03)
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- Baker's yeast mediated stereoselective biotransformation of 1-acetoxy-3-aryloxypropan-2-ones
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A series of 1-acetoxy-3-aryloxypropan-2-ones 1a-m were synthesized and subjected to biotransformation by baker's yeast yielding optically active monoacetates 5 or ent-5 and/or diols 4 of moderate to excellent enantiomeric purity. The dependence of the reduction/hydrolysis ratio and stereoselectivity on the size and substitution pattern of the aromatic moiety in the substrate is also discussed.
- Egri, Gabriella,Kolbert, Attila,Balint, Jozsef,Fogassy, Elemer,Novak, Lajos,Poppe, Laszlo
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p. 271 - 283
(2007/10/03)
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- Sulfamates as antiglaucoma agents
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Sulfamate esters of the formula where A is aryloxyalkyl, p is the number of unreacted hydroxy groups present on the alkyl moiety and may be zero, z is the number of --OS(O)2 NR1 R2 groups attached to carbons of the alkyl moiety and is always at least one; R1 and R2 are selected from hydrogen, loweralkyl, carboxy, and the like are useful in treating glaucoma.
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- Compounds having one or more aminosulfaonyloxy radicals useful as pharmaceuticals
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Methods of treating chronic arthritis and osteoporosis which utilize both known and novel compounds which would fall under the general formula:(HO)p--A--[--OS(O) 2 NR 1 R 2 ] zwherein A encompasses a wide range of values including but not limited to aryl, loweralkyl, cycloalkyl, and carbohydrates including sucrose and fructose; p is equal to the number of unreacted hydroxy groups contained on the molecule and may be zero; z is the number of --OS(O) 2 NR 1 R 2 groups and is always at least one; R 1 and R 2 are selected from hydrogen, loweralkyl, carboxy and the like; a novel process for preparing the compounds is provided wherein an appropriate sulfamic acid aryl ester is reacted with a hydroxy substituted A radical which may or may not contain thereon protected carboxyl, amino or hydroxy substituents, in an aprotic solvent containing a tertiary amine base. Pharmaceutical compositions for the treatment of chronic arthritis and osteoporosis are also provided.
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- New non-proteogenic aminoacids bearing an enol aryl-ether moiety
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Aminoacids bearing an enol aryl-ether moiety have been synthesized by a new method allowing a great versatility in the introduction of N-protective groups and enol ether functions. This method involves a Wittig-Horner condensation affording alpha, beta-dehydrohomoserine ether derivatives, followed by a regio and stereoselective isomerization into the desired E enol ether. Clean deprotection was achieved providing new 2-amino-4-aryloxybut-3(E)-enoic acids 3.
- Daumas,Vo-Quang,Le Goffic
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p. 2373 - 2384
(2007/10/02)
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- Formation of Optically Active Aryloxyacetaldehyde Cyanohydrin Acetates with the Aid of a Microorganism
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Microorganisms that hydrolyze the one enantiomer of dl-phenoxyacetaldehyde cyanohydrin acetate were screened, and Bacillus coagulans isolated from soil was found to be the best.This bacterium was applied to the asymmetric hydrolysis of other aryloxyacetaldehyde derivatives to give satisfactory results.The effect of adding dimethyl sulfoxide to the medium is also described.
- Ohta, Hiromichi,Miyamae, Yoshitaka,Tsuchihashi, Gen-ichi
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p. 215 - 222
(2007/10/02)
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