cas 56-75-7, Chloramphenicol | Articles data

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Catalytic Syn-Selective Nitroaldol Approach to Amphenicol Antibiotics: Evolution of a Unified Asymmetric Synthesis of (-)-Chloramphenicol, (-)-Azidamphenicol, (+)-Thiamphenicol, and (+)-Florfenicol
A unified strategy for an efficient and high diastereo- and enantioselective synthesis of (-)-chloramphenicol, (-)-azidamphenicol, (+)-thiamphenicol, and (+)-florfenicol based on a key catalytic syn-selective Henry reaction is reported. The stereochemistry of the ligand-enabled copper(II)-catalyzed aryl aldehyde Henry reaction of nitroethanol was first explored to forge a challenging syn-2-amino-1,3-diol structure unit with vicinal stereocenters with excellent stereocontrol. Multistep continuous flow manipulations were carried out to achieve the efficient asymmetric synthesis of this family of amphenicol antibiotics.
Chen, Fener,Cheng, Dang,Huang, Huashan,Jiang, Meifen,Liu, Minjie,Qu, Hongmin,Xia, Yingqi,Xiong, Tong,Zhang, Yan
p. 11557 - 11570
(2021/09/02)

Method for continuously preparing chloramphenicol by using micro-reaction system
The invention belongs to the technical field of pharmaceutical engineering, and particularly relates to a method for continuously preparing chloramphenicol by using a micro-reaction system. The method comprises the following steps: respectively and simultaneously pumping an organic solution of raw materials (1R, 2R)-2-amino-1-(4-aminophenyl) propane-1, 3-diol and an organic solution of methyl dichloroacetate into a micro-reaction system of a first micro-mixer and a first micro-channel reactor which are communicated with each other, and carrying out continuous amidation reaction; adding acetone, water and a buffer solution into the mixed solution flowing out, and then respectively and simultaneously pumping the mixed solution and the aqueous solution of the potassium hydrogen persulfate composite salt into a micro-reaction system of a second micro-mixer and a second micro-channel reactor which are communicated with each other for continuous oxidation reaction; and finally, carrying out quenching, extraction and other processes to obtain a chloramphenicol product. The method is short in reaction time, convenient to operate, continuous, controllable, free of amplification effect and high in technological process efficiency, the yield of the product chloramphenicol is larger than 90%, and the method has good industrial application prospects.
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Paragraph 0030-0044

(2021/08/19)

Unified Strategy to Amphenicol Antibiotics: Asymmetric Synthesis of (-)-Chloramphenicol, (-)-Azidamphenicol, and (+)-Thiamphenicol and Its (+)-3-Floride
The asymmetric synthesis of (-)-chloramphenicol, (-)-azidamphenicol, and (+)-thiamphenicol and its (+)-3-floride, (+)-florfenicol, is reported. This approach toward the amphenicol antibiotic family features two key steps: (1) a cinchona alkaloid derived urea-catalyzed aldol reaction allows highly enantioselective access to oxazolidinone gem-diesters and (2) a continuous flow diastereoselective decarboxylation of thermally stable oxazolidinone gem-diesters to form the desired trans-oxazolidinone monoesters with two adjacent stereocenters that provide the desired privileged scaffolds of syn-vicinal amino alcohols in the amphenicol family.
Liu, Jinxin,Li, Yaling,Ke, Miaolin,Liu, Minjie,Zhan, Pingping,Xiao, You-Cai,Chen, Fener
p. 15360 - 15367
(2020/11/30)

Oxidant controlled regio- and stereodivergent azidohydroxylation of alkenes via I2 catalysis
A novel, I2 catalyzed regio- and stereodivergent vicinal azidohydroxylation of alkenes leading to 1,2-azidoalcohols in high yields (up to 92%) and excellent dr (up to 98%) has been developed. This unprecedented transformation employs NaN3 and DMF as N- and O-nucleophiles respectively. The role of DMF as the O-source in the reaction has been unequivocally proven by 18O labelling studies.
Prasad,Reddi,Sudalai
p. 10276 - 10279
(2015/06/25)

Enantioselective synthesis of (-)-chloramphenicol via silver-catalysed asymmetric isocyanoacetate aldol reaction
The highly enantio- and diastereoselective aldol reaction of isocyanoacetates catalysed by Ag2O and cinchona-derived amino phosphines applied to the synthesis of (-)- and (+)-chloramphenicol is described. The concise synthesis showcases the utility of this catalytic asymmetric methodology for the preparation of bioactive compounds possessing α-amino-β-hydroxy motifs.
Franchino, Allegra,Jakubec, Pavol,Dixon, Darren J.
p. 93 - 96
(2015/12/30)

An unusual peroxo intermediate of the arylamine oxygenase of the chloramphenicol biosynthetic pathway
Streptomyces venezuelae CmlI catalyzes the six-electron oxygenation of the arylamine precursor of chloramphenicol in a nonribosomal peptide synthetase (NRPS)-based pathway to yield the nitroaryl group of the antibiotic. Optical, EPR, and M?ssbauer studies show that the enzyme contains a nonheme dinuclear iron cluster. Addition of O2 to the diferrous state of the cluster results in an exceptionally long-lived intermediate (t1/2 = 3 h at 4 °C) that is assigned as a peroxodiferric species (CmlI-peroxo) based upon the observation of an 18O2-sensitive resonance Raman (rR) vibration. CmlI-peroxo is spectroscopically distinct from the well characterized and commonly observed cis-μ-1,2-peroxo (μ-η1:η1) intermediates of nonheme diiron enzymes. Specifically, it exhibits a blue-shifted broad absorption band around 500 nm and a rR spectrum with a β(O-O) that is at least 60 cm-1 lower in energy. M?ssbauer studies of the peroxo state reveal a diferric cluster having iron sites with small quadrupole splittings and distinct isomer shifts (0.54 and 0.62 mm/s). Taken together, the spectroscopic comparisons clearly indicate that CmlI-peroxo does not have a μ- η1:η1-peroxo ligand; we propose that a μ- η1:η2-peroxo ligand accounts for its distinct spectroscopic properties. CmlI-peroxo reacts with a range of arylamine substrates by an apparent second-order process, indicating that CmlI-peroxo is the reactive species of the catalytic cycle. Efficient production of chloramphenicol from the free arylamine precursor suggests that CmlI catalyzes the ultimate step in the biosynthetic pathway and that the precursor is not bound to the NRPS during this step.
Makris, Thomas M.,Vu, Van V.,Meier, Katlyn K.,Komor, Anna J.,Rivard, Brent S.,Münck, Eckard,Que, Lawrence,Lipscomb, John D.
supporting information
p. 1608 - 1617
(2015/03/05)

Stereocontrolled synthesis of syn-β-hydroxy-α-amino acids by direct aldolization of pseudoephenamine glycinamide
β-Hydroxy-α-amino acids figure prominently as chiral building blocks in chemical synthesis and serve as precursors to numerous important medicines. Reported herein is a method for the synthesis of β-hydroxy- α-amino acid derivatives by aldolization of pseudoephenamine glycinamide, which can be prepared from pseudoephenamine in a one-flask protocol. Enolization of (R,R)- or (S,S)-pseudoephenamine glycinamide with lithium hexamethyldisilazide in the presence of LiCl followed by addition of an aldehyde or ketone substrate affords aldol addition products that are stereochemically homologous with L- or D-threonine, respectively. These products, which are typically solids, can be obtained in stereoisomerically pure form in yields of 55-98 %, and are readily transformed into β-hydroxy-α-amino acids by mild hydrolysis or into 2-amino-1,3-diols by reduction with sodium borohydride. This new chemistry greatly facilitates the construction of novel antibiotics of several different classes. On aldol: Enolization of (R,R)- or (S,S)-pseudoephenamine glycinamide with lithium hexamethyldisilazide (LiHMDS) in the presence of LiCl followed by addition of either an aldehyde or ketone substrate affords aldol addition products which are stereochemically homologous with L- or D-threonine, respectively. These products can be obtained in stereoisomerically pure form in yields of 55-98 %, and are readily transformed into β-hydroxy-α-amino acids by mild hydrolysis or into 2-amino-1,3-diols by reduction.
Seiple, Ian B.,Mercer, Jaron A. M.,Sussman, Robin J.,Zhang, Ziyang,Myers, Andrew G.
supporting information
p. 4642 - 4647
(2014/05/20)

Stereoselective synthesis of (-)-chloramphenicol, (+)-thiamphenicol and (+)-sphinganine via chiral tricyclic iminolactone
The stereoselective syntheses of (-)-chloramphenicol, (+)-thiamphenicol and (+)-sphinganine are described. The two continuous chiral centers within three target molecules were constructed through aldol reaction of chiral tricyclic iminolactone and aldehyde. Concise and efficient syntheses of (-)-chloramphenicol, (+)-thiamphenicol and (+)-sphinganine have been accomplished in practical four or three steps. The synthetic route featured in an aldol reaction between iminolactone 1a and 1b with aldehyde, which introduced the two continuous chiral centers within three target molecules. Copyright
Li, Qiong,Zhang, Hongbo,Li, Chenguang,Xu, Pengfei
p. 149 - 153
(2013/08/24)

Direct synthesis of β-hydroxy-α-amino acids via diastereoselective decarboxylative aldol reaction
A straightforward metal-free synthesis of anti-β-hydroxy-α-amino acids is described. The organic base-mediated decarboxylative aldol reaction of cheap, readily available α-amidohemimalonates with various aldehydes afforded under very mild conditions anti-β-hydroxy-α-amido esters in high yields and complete diastereoselectivity. Simple one-pot subsequent transformations enabled the corresponding anti-β-hydroxy-α-amino acids or in a few examples their syn diastereomers to be obtained directly using epimerization conditions.
Singjunla, Yuttapong,Baudoux, Jeroime,Rouden, Jacques
p. 5770 - 5773
(2013/12/04)

CmlI is an N-oxygenase in the biosynthesis of chloramphenicol
The N-oxygenation of an amine group is one of the steps in the biosynthesis of the antibiotic chloramphenicol. The non-heme di-iron enzyme CmlI was identified as the enzyme catalyzing this reaction through bioinformatics studies and reconstitution of enzymatic activity. In vitro reconstitution was achieved using phenazine methosulfate and NADH as electron mediators, while in vivo activity was demonstrated in Escherichia coli using two substrates. Kinetic analysis showed a biphasic behavior of the enzyme. Oxidized hydroxylamine and nitroso compounds in the reaction were detected both in vitro and in vivo based on LC-MS. The active site metal was confirmed to be iron based on a ferrozine assay. These findings provide new insights into the biosynthesis of chloramphenicol and could lead to further development of CmlI as a useful biocatalyst.
Lu, Haige,Chanco, Emmanuel,Zhao, Huimin
p. 7651 - 7654
(2012/09/08)

Enzymatic regioselective production of chloramphenicol esters
An enzymatic study has been performed in the search for synthetic routes to produce chloramphenicol derivatives through regioselective processes using lipases. Complementary transesterification and hydrolytic reactions have been carried to synthesize chloramphenicol regioisomers. Reaction parameters, such as biocatalyst, solvent, acyl donor, and temperature have been optimised in order to obtain chloramphenicol esters with high yields through acylation processes. Scale-up of the enzymatic reactions (1 g-scale at 0.25 M) and catalyst recycling (up to 10 cycles) have been successfully achieved. Furthermore, monoacylated derivatives at the more hindered secondary position could also be obtained employing hydrolysis processes.
Bizerra, Ayla M.C.,Montenegro, Tasso G.C.,Lemos, Telma L.G.,De Oliveira, Maria C.F.,De Mattos, Marcos C.,Lavandera, Iván,Gotor-Fernández, Vicente,De Gonzalo, Gonzalo,Gotor, Vicente
scheme or table
p. 2858 - 2862
(2011/05/12)

Synthesis of dendrimer-type chiral stationary phases based on the selector of (1S,2R)-(+)-2-amino-1,2-diphenylethanol derivate and their enantioseparation evaluation by HPLC
In our recent work, a series of dendritic chiral stationary phases (CSPs) were synthesized, in which the chiral selector was L-2-(p-toluenesulfonamido)-3- phenylpropionyl chloride (selector I), and the CSP derived from three-generation dendrimer showed the best separation ability. To further investigate the influence of the structures of dendrimer and chiral selector on enantioseparation ability, in this work, another series CSPs (CSPs 1-4) were prepared by immobilizing (1S,2R)-1,2-diphenyl-2-(3-phenylureido)ethyl 4-isocyanatophenylcarbamate (selector II) on one- to four-generation dendrimers that were prepared in previous work. CSPs 1 and 4 demonstrated the equivalent enantioseparation ability. CSPs 2 and 3 showed the best and poorest enantioseparation ability respectively. Basically, these two series of CSPs exhibited the equivalent enantioseparation ability although the chiral selectors were different. Considering the enantioseparation ability of the CSP derived from aminated silica gel and selector II is much better than that of the one derived from aminated silica gel and selector I, it is believed that the dendrimer conformation essentially impacts enantioseparation.
He, Bao-Jiang,Yin, Chuan-Qi,Li, Shi-Rong,Bai, Zheng-Wu
experimental part
p. 69 - 76
(2010/09/09)

Organocatalytic aziridine synthesis using F+ salts
This paper describes a unique application of the fluoronium cation (F +) as an organocatalyst for mediating the reaction between N-substituted imines and ethyl diazoacetate affording excellent yields of N-substituted aziridines.
Bew, Sean P.,Fairhurst, Shirley A.,Hughes, David L.,Legentil, Laurent,Liddle, John,Pesce, Paolo,Nigudkar, Sanket,Wilson, Martin A.
supporting information; experimental part
p. 4552 - 4555
(2009/12/05)

A short enantioselective synthesis of (-)-chloramphenicol and (+)-thiamphenicol using tethered aminohydroxylation
An efficient enantioselective synthesis of (-)-chloramphenicol (1) and (+)-thiamphenicol (2) is described. These antibiotics have been synthesized from commercially available 4-nitrobenzaldehyde and 4-(methylthio)benzaldehyde, respectively, using tethered aminohydroxylation and Sharpless asymmetric epoxidation as the chirality inducing steps.
George, Shyla,Narina, Srinivasarao V.,Sudalai, Arumugam
p. 10202 - 10207
(2007/10/03)

Stereoselective syntheses of (-)-chloramphenicol and (+)-thiamphenicol
Chloramphenicol and thiamphenicol have been enantioselectively synthesized using an asymmetric halohydrin reaction as a key step. In particular, halomethoxylation reaction was used, where O-methyl functions as a hydroxyl protecting group and eliminates an additional protection step.
Hajra, Saumen,Karmakar, Ananta,Maji, Tapan,Medda, Amiya Kumar
p. 8959 - 8965
(2007/10/03)

A short asymmetric total synthesis of chloramphenicol using a selectively protected 1,2-diol
A general route for the synthesis of chloramphenicol, thiamphenicol and fluoramphenicol is described. Chloramphenicol has been synthesized in 45% overall yield.
Boruwa, Joshodeep,Borah, Jagat C.,Gogoi, Siddhartha,Barua, Nabin C.
p. 1743 - 1746
(2007/10/03)

Amphiphile cyclodextrins, preparation and use thereof for solubilizing organized systems and incorporating hydrophobic molecules
The invention provides cyclodextrin derivatives that may be used to transport hydrophobic molecules for pharmaceutical or cosmetic applications, by forming organised systems in an aqueous medium, alone or with phospholipids. The cyclodextrin derivatives of the present invention have the formula: in which, R1 represents a steroid, R2 represents an alkyl or aryl group, substituted if applicable, R3 represents H or R2, all the R4 represent OR2, or one of the R4 represents —NHCO(CH2)mCONHR1, m is an integer ranging from 1 to 8, and n is equal to 5, 6 or 7.
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(2008/06/13)

A short stereoselective synthesis of (-)-chloramphenicol and (+)-thiamphenicol
A common strategy for the synthesis of (-)-chloramphenicol and (+)-thiamphenicol is described. These antibiotics have been synthesized from commercially available 4-nitrobenzaldehyde and 4-(methylthio)benzaldehyde in three and four steps, respectively.
Bhaskar,Satish Kumar,Venkateswara Rao
p. 1279 - 1283
(2007/10/03)

LIQUID PHARMACEUTICAL FOR ORAL DELIVERY
A liquid pharmaceutical for oral delivery wherein at the time of use, a solid unit dosage form is added to the liquid wherein the unit dosage form is comprised of a substrate soluble in the liquid and a particulate pharmaceutically active material in a pharmaceutically effective amount. At the time of use, the unit dosage form is added to the liquid, without requiring measurement of the liquid, and the entire liquid is consumed to provide for oral delivery of the pharmaceutically effective amount of material.
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(2008/06/13)

An efficient synthesis of (-)-chloramphenicol via asymmetric catalytic aziridination: a comparison of catalysts prepared from triphenylborate and various linear and vaulted biaryls.
[reaction--see text] The antibiotic (-)-choramphenicol has been synthesized in only four steps from p-nitro-benzaldehyde in optically pure form from an asymmetric catalytic aziridination reaction with a chiral catalyst prepared from triphenylborate and the (R)-VAPOL ligand. Catalysts generated from the VAPOL and VANOL ligands give much higher asymmetric induction than do catalysts prepared from 6,6'-diphenylVAPOL, BINOL, and BANOL ligands.
Loncaric,Wulff
p. 3675 - 3678
(2007/10/03)

Synthetic applications of the cyclic iminocarbonate rearrangement Enantioselective syntheses of chloramphenicol and 4-epi-cytoxazone
Chloramphenicol and 4-epi-cytoxazone have been enantioselectively synthesized using the asymmetric dihydroxylation and the cyclic iminocarbonate rearrangement as key steps. (C) 2000 Elsevier Science Ltd.
Park, Jung Nam,Ko, Soo Y.,Koh, Hun Y.
p. 5553 - 5556
(2007/10/03)

Efficient enantioselective syntheses of chloramphenicol and (D)-threo- and (D)-erythro-sphingosine
The chiral diazaborolidine 1 has been applied to the enantioselective syntheses of chloramphenicol (2) and (D)-threo-N-acetylsphingosine (3), a synthetic precursor of the diastereomeric (D)-sphingosines. (C) 2000 Elsevier Science Ltd.
Corey,Choi, Soongyu
p. 2765 - 2768
(2007/10/03)

Stereoselective synthesis of chloramphenicol from D-serine
An efficient synthesis of the widely used antibiotic chloramphenicol (1) is described. The key step in the synthesis involves chelation-controlled addition of phenylmagnesium bromide to a suitably protected D-serinal derivative, affording the pivotal D-threo 1,2-amino alcohol intermediate 3 in a highly stereoselective manner.
Veeresa,Datta, Apurba
p. 8503 - 8004
(2007/10/03)

Enzymatic hydrolysis of chloramphenicol palmitate in the presence of β-cyclodextrin
The aim of this study was to investigate whether β-cyclodextrin (β-CD) can influence the hydrolysis of chloramphenicol palmitate (CAP) polymorphs by lipase. Polymorph II of CAP is hydrolyzed 37 times faster by pancreatic lipase than polymorph I, The physical mixture of β-CD and CAP II in the molar ratio 1:1 shows a slightly higher hydrolysis rate, but not the physical mixture of β-CD with CAP I. However, the solid β-CD/CAP inclusion compound shows an increased hydrolysis rate independently on the polymorph used for its preparation. This could be of therapeutic significance. An excess of the hydrolysis products chloramphenicol and palmitic acid, respectively, does not influence the enzymatic hydrolysis of die inclusion compound. The enzymatic hydrolysis rate of CAP II in the physical mixture with P-CD is increased in the presence of palmitic acid compared to the reactions without β-CD. β-CD has no catalytic effect on the nonenzymatic hydrolysis of solid or dissolved CAP.
Berkel,Mehnert,Froemming
p. 323 - 326
(2007/10/03)

Synthesis of chloramphenicol via a new intermediate 4-para-nitrophenyl- 5-formamido-1,3-dioxane
4-Phenyl-5-amino-1,3-dioxane 4, obtained from β-bromo styrene 2 was protected as formamido derivative 5. Nitration of 5 followed by regioselective acylative cleavage of the nitro product 12 gave N-formyl-N- acetyl hemiacetal diacetate 16, which on sequential base and acid hydrolysis followed by dichloroacetylation gave chloramphenicol 1.
Hazra, Braja G.,Pore, Vandana S.,Maybhate, Shailaja P.
p. 1857 - 1864
(2007/10/03)

Water dispersion containing ultrafine particles of organic compounds
A water-dispersible condensate of water-insoluble ultrafine particles of medicine or hormones having a particle size of at largest 4 μm prepared by the steps of heating the medicine or hormone in a vacuum vessel at a temperature of 30° C. higher than the boiling point and at a pressure between 0.01 Torr and 10 Torr to evaporate the medicine or hormone and condensing the medicine or hormone on a recovery plate to obtain the condensate.
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(2008/06/13)

Asymmetric synthesis of chloramphenicol
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Rao,Rao,Bhanu
p. 859 - 860
(2007/10/02)

REGIOSELECTIVE ACYLATIVE CLEAVAGE OF CYCLIC FORMAL OF CHLORAMPHENICOL
The amide 6 has been synthesised by reacting the amine 3 with dichloroketene in situ.This amide 6 on nitration gave formal 7, which when reacted with acetic anhydride and p-toluene sulfonic acid underwent regioselective cleavage of the dioxane ring to furnish the hemiacetal 11.This on treatment with methanol-water-ammonia yielded chloramphenicol 2.
Hazra, B. G.,Pore, V. S.,Maybhate, S. P.,Natekar, M. V.,Rao, A. S.
p. 1763 - 1770
(2007/10/02)