The epoxidation reactions proceeded smoothly to afford the desired products in good yields with good enantioselectivities. As part of a senior capstone project, a onepot synthesis for chalcone epoxides has been developed. Catalytic test of pll s and pll cthe manner in which pll is prepared turned out to be of crucial importance for all of the developed juliacolonna protocols 25. The reaction products had enantiomeric purities of up to 55%. The reaction takes place in presence of methanol not so green, water and dimethyl sulfoxide. The epoxidation of ethylene involves its reaction of oxygen according to the following stoichiometry.
Chalcone was chosen as a test compound substrate in order to draw compar isons with the results published in the literature for the asymmetric epoxidation process. Chapter 64 solutions a small scale approach to organic. Oxidation of substituted chalcones by quinaldinium. We investigated the asymmetric epoxidation reaction of chalcone 1a using an aqueous hydrogen peroxide solution aq. These compounds are also known as benzalacetophenone or benzylidene acetophenone. Pdf efficient epoxidation of chalcones with ureahydrogen. Popa the chemical modification of lignin through hydroxymethylation and epoxidation is a way to develop new application fields and improvement of lignin performances.
Htmc was found to shown g1 phase cellcycle arrest in a549 lung. The reaction was reported by sebastian julia at the chemical institute of sarria in 1980, with further elaboration by both julia and stefano colonna istituto di chimica industriale delluniversita, milan, italy. Asymmetric epoxidation reactions of chalcone derivatives catalyzed by chiral calcium complexes using. Chalcones and its derivatives are used in organic synthesis and they are used in evaluating new product that possesses different biological activities.
Study of enantioselective epoxidation, asymmetric reduction. An efficient epoxidation of chalcones with ureahydrogen peroxide uhp. The chalcone is the starting unit of all the classes of flavonoids. Particular attention in such work has been devoted to the asymmetric epoxidation of. Abstract chalcones and chalcone epoxides are important synthetic intermediates in organic and medicinal chemistry. An excellent example is the reaction of chalcone with h 2 o 2 naoh in. As a chiral calcium catalyst, we employed a chiral calciumpybox complex prepared from calcium triflate caotf 2 and indapybox l1, which is a calcium complex that is tolerant toward water. Asymmetric epoxidation of chalcones in the presence of sugarbased crown ethersthe epoxidation of chalcones 5 with tertbutylhydroperoxide tbhp, 2 equiv was carried out in a liquidliquid twophase system in toluene, employing 20% aq naoh 3. Oxidation of substituted chalcones by quinaldinium fluorochromate.
Primary, secondary, and tertiary amino alcohols are able to promote the reaction with variable activity and level of asymmetric induction. The initial epoxidation protocol is limited to electron. Epoxidation of electrophilic olefine with alkaline hydrogen peroxide. Quaternary salts and nonionic surfactants based on 6amino6 deoxy glucose were explored as chiral phase transfer catalysts for the asymmetric. Chalcones organocatalyzed by amino alcohols russo, alessio. Stereochemically inert and positively charged chiral complexes of coiii were shown to catalyze the asymmetric epoxidation of chalcones with h 2 o 2 under phase transfer conditions. The reactants in this experiment were our chalcone, hydrogen peroxide, and sodium hydroxide. Epoxy chalcone is a heterocyclic molecule and an important precursor for the synthesis of biologically active compounds. Using a process of elimination, we can conclude that the rate limiting step for chalcone mechanism via aldol condensation is the elimination step in the dehydration process. This prompted us to investigate the oxidation of chalcones by quinaldinium fluorochromate in aqueous acetic acid medium. Chalcone are aromatic ketone that forms the central. Quaternary salts and nonionic surfactants based on 6amino6 deoxyglucose were explored as chiral phase transfer catalysts for the asymmetric. A low concentration of hydrogen peroxide can be used as the epoxidizing agent.
Various chalcone epoxides can be synthesized from substituted benzaldehydes and acetophenones by onepot consecutive reactions of aldol condensation and epoxidation. H 2 o 2 as an oxidant in the presence of insoluble polyamino acid. Chalcones as versatile synthons for the synthesis of 5 and. Chiral calciumcatalyzed asymmetric epoxidation reactions using.
Nahata college of pharmacy, mandsaur university, mhow neemuch. Polyalanine, leucine and isoleucine are among the most efficient catalysts for the juliacolonna epoxidation with a preference for longer polymer chain in terms of reacti on rates and enantiomeric excess. In this table, chalcones exhibit cytotoxicity against a number of cell lines from a wide range of tumors, mainly including leukemia, hepatoma, breast cancer, colorectal cancer, stomach cancer, prostate cancer, and epidermoid carcinoma. In literature this epoxidation is referred as green epoxidation of chalcones and it is used in performing the reactions given in this experiment. Butenolides have been recognized as an important structural framework in a number of natural products and medicinally important agents. The infrared spectra of chalcones show usually a band near 16251650 cm1, characteristic of an. Attempts have been made to correlate rate and structure in such a reaction. Experiment 62 in pavia 5th edition, prelab include the usual prelab components, chemical equation, and a detailed reagent table. Chalcone can be synthesized by several methods using aldehydes and ketones as starting material. The effect of chiral ptcs 38 on the enantioselectivity in epoxidation of chalcone 1 entry catalyst yield of 2, % ee, %a a 3 no reaction b 4 no reaction c 5 no reaction d 6 78 9. It was found that chalcones and induced an increase of proapoptotic proteins bax, bid, and bak only chalcone.
Chalcones are the important building blocks in the synthesis of variety of such heterocyclic compounds68. In this work we describe a new metalfree sequential strategy for the asymmetric synthesis of substituted. O, which indicates that deprotonation 2 is not the ratelimiting step. Pdf asymmetric epoxidation of chalcone catalyzed by. The formation of chalcone or substituted chalcone was observed to be faster in d. Pdf phasetransfer catalyzed asymmetric epoxidation of. This chapter focuses on onepot synthesis of chalcone epoxides via claisen schmidt condensation and epoxidation as a green organic chemistry laboratory. Except for the poor ee, this protocol demonstrated the preferential formation of. Epoxidation of chromones and flavonoids in ionic liquids. May 14, 2008 cyclic and acyclic amino alcohols were examined as organocatalysts in the epoxidation of trans. Savizky department of chemistry, the cooper union for the advancement of science and art, 41 cooper square, new york, new york 3, united states the kinetics of chalcone epoxidation in a biphasic waterheptane medium system consisting of chalcone as. Chalcones are naturally occurring compounds found in various plant species like angelica, glycyrrhiza, humulus and scutellaria, which are widely used as traditional folk remedies. The work continued by synthesizing various substituted chalcones, which were used in epoxide formation investigations.
Ketoaldehydes derived from chalcone epoxides by lewis acidcatalyzed rearrangement underwent smooth deformylation when refluxed in tetrahydrofuran. Comparison of the inhibitory potential towards carbonic anhydrase. So in this case we will be using hydrogen peroxide in aqueous sodium hydroxide. Chalcones are of major interest to medicinal chemistry1 and materials chemistry. Organocatalyzed synthesis of epoxides from chalcones utilizing. Chalcone omethyltransferase chomt methylates the 2. The term chalcones was coined by kostanecki and tambor. An excellent example is the reaction of chalcone with h 2 o 2 naoh in the three. Chalcones,and induced apoptosis via an activated caspasesdependent pathway. Journal of chemical and pharmaceutical research, 2018, 10. The various classes of flavonoids are chalcones, flavones, flavanols, flavanone, flavanonols, flavans, catechins, flavandiols, and anthocyandins etc. Highly stereoselective epoxidation of chalcone in a triphasic toluene.
Epoxidation of chalcones is a most efficient method for epoxidation of. Aldol condensation and simple epoxidation introduction. Yelyzaveta bessonova, yessica martinez date of experiment. Efficient epoxidation of chalcones with ureahydrogen peroxide. University of groningen dnabased asymmetric catalysis as a. The epoxidation of trans chalcones proceeds under mild conditions at room temperature in alkaline solution to afford the corresponding epoxides in excellent yields using trans3,5dihydroperoxy3,5dimethyl1,2dioxolane as an efficient oxygen source. February 22, 2018 abstract last thursday we worked on the experiment in the lab which looked at the epoxidation of a chalcone. Kinetic analysis of chalcone epoxidation in a biphasic system. Naturally occurring chalcones enhuizhang, 1 rufengwang, 1 shuzhenguo, 2 andbinliu 1 school of chinese medicine, beijing university of chinese medicine, beijing, china. The optimized epoxidation reaction involves chalcone as a substrate, with water as a solvent and proline as a catalyst.
Also they constitute an important class of bioactive natural products911. Chalcone is an aromatic ketone and an enone that forms the central core for a variety of. Chemically, they consist of open chain flavonoids in which the two aromatic rings are joined by a three carbon unsaturated carbonyl system. The direct reaction of oxygen with alkenes is useful only for this epoxide. Studies in asymmetric epoxidation of chalcone 1296 table 1. The term chalcone is a generic term used to describe compounds with the 1,3diphenylprop2en1one framework figure 1. General procedure for synthesis of chalcone 7k 7m8. This is the epoxidation of chalcones under phasetransfer conditions. Firstly, in the presence of the chiral calcium complex, the epoxidation. The basic skeletons of the flavonoid classes are shown in figure 1. Chalcones are chemical compounds or natural molecules have a broad spectrum of bioactivities, which are of great. The optimized epoxidation reaction involves chalcone as a substrate, with.
Application of new organocatalysts on asymmetric epoxidation. Efficient synthesis of deoxybenzoins from chalcones. The enantioselective epoxidation of a,bunsaturated ketones employing chiral catalysts has received considerable attention in recent years. The probable structure of quinaldinium fluorochromate as shown, 2.
Chiral octahedral complexes of coiii as catalysts for. A onepot synthesis is a simple, yet efficient green method which allows compounds to be prepared without having to isolate and purify the intermediates thereby reducing waste and increasing reaction efficiency. Chalcones organocatalyzed by amino alcohols asymmetric epoxidation of trans. Chalcone is a member of the class of chalcones that is acetophenone in which one of the methyl hydrogens has been replaced by a benzylidene group. Kinetic analysis of chalcone epoxidation in a biphasic system wai wing leung and ruben m. Unlimited viewing of the articlechapter pdf and any associated supplements and figures. Be sure to calculate the theoretical yield of the product. Highly stereoselective epoxidation of chalcone in a.
Chiral calciumcatalyzed asymmetric epoxidation reactions. It was established that, under slow stirring conditions 100 rpm, the results. Abstract the synthesis of epoxides 3a r is achieved in excellent yields by reaction of the. However, successful examples of highly enantioselective synthesis of epoxyketones still remain few in number. Chalcones are 1,3diphenyl2propene1one, in which two aromatic rings are linked by a three carbon. It was found that reactions with substituents on the r. The work continued by synthesizing various substituted chalcones, which were used in. Stereochemically inert and positively charged chiral complexes of coiii were shown to catalyze the asymmetric epoxidation of chalcones with h2o2 under phase transfer conditions. Studies in asymmetric epoxidation of chalcone using. Nov 20, 20 chalcones are also known as benzyl acetophenone or benzylidene acetophenone. The use of sonochemistry in the asymmetric epoxidation of substituted chalcones with sodium perborate tetrahydrate. The latter compound in alfalfa medicago sativa of fabaceae acts as the transcriptional activator of nod genes of sinorhizobium meliloti. In chalcones, two aromatic rings are linked by an aliphatic three carbon chain.
Jan 19, 2004 chalcone and isoflavone epoxides are useful building blocks in flavonoid chemistry. It is a member of styrenes and a member of chalcones. Dibromochalcone epoxides in solution and solid state mdpi. The common epoxidation reagent mcpba could not be used in this experiment because it does not work well on electronpoor conjugated ketones, such as chalcones. The onepot cycloaddition reaction of hydrazine hydrate with chalcone epoxides followed by dehydration is an efficient and con venient. Synthesis of e chalcones e1,3diarylprop2en1ones supplementary material in this work, which is planned for 1 session or 2 sessions 3 hours each, students individually or in groups of two will synthesize e chalcone derivatives by the reaction of acetophenones with benzaldehydes. The formation of an epoxide from a chalcone can be represented as. Modified heterogeneous silver catalysts are typically employed. Asymmetric epoxidation reactions of chalcone derivatives catalyzed by chiral calcium complexes using hydrogen peroxide were developed. Onepot synthesis of chalcone epoxidesa green chemistry strategy. Journal of chemical and pharmaceutical research, 2018, 104. Once the epoxide is formed the product is analyzed using and spectroscopy.
The juliacolonna epoxidation is an asymmetric polyleucine catalyzed nucleophilic epoxidation of electron deficient olefins in a triphasic system. This fact could explain the different activity observed during the first run of the epoxidation of chalcone using the ipl2 603w as catalyst due to the necessity of a preactivation in the first run as also observed geller. One pot and two pot synthetic strategies and biological. The following changes are expected to be observed in the and spectra of the epoxide product relative to the chalcone starting material in spectroscopy, the starting chalcone will show vinyl bonds left to the absorption band.
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