Dhp groups confer new propertiesfunctions to the polymers. The present reaction could be simply conducted by successively adding the metal alkali derivative and substrate to a solution of the hantzsch ester in hexane or thf with stirring at room temperature. The colorimetric estimation of formaldehyde by means of the. Over the last few decades, hantzsch esters have proven to be a useful class of electron donors and proton sources in photoredox catalyzed processes.
It was characterized by sulfuric acid titration overall accuracy 8. Hantzsch reaction under solvent free conditions abolghasem davoodnia1, amir khojastehnezhad department of chemistry, mashhad branch, islamic azad university, mashhad, iran received. The advantages of this protocol are operational simplicity, mild reaction conditions, high yields. An easy method for the synthesis of polyhydroquinoline derivatives via onepot fourcomponent hantzsch condensation of dimedone, aryl aldehydes, ethyl acetoacetate and ammonium acetate in the presence of a catalytic amount of carbonbased solid acid cbsa in solvent free conditions is described. The proposed mechanism for the synthesis of 1, 4 dihydropyridines using tcca.
Recently, we have reported catalyst free synthesis of polyhydroquinolines hantzsch reaction via multicomponent reaction of aldehyde, dimedone, ethylacetoacetate, and ammonium acetate at ambient temperature. Stablereagentsfordeterminationofserumtriglyceridesbya. The hantzsch pyridine synthesis, or wed better say hantzsch dihydropyridine synthesis from the name of the chemist that first discovered it is one of the best approach to get a substituted dihydropyridine and consequently a substituted pyridine. The corresponding pyridine analogues of hantzsch 1,4dihydropyridines could be obtained as a major. Biginelli reaction occurs at 60 c under solvent free conditions, while hantzsch reaction occurs in water at. Hantzsch 1,4dhp synthesis in 1882, hantzsch 1 reported the first synthesis of dialkyl 1,4dihydro2,6dimethylpyridine3,5dicarboxylates from a refluxing mixture of an aldehyde, a.
The reaction proceeds smoothly without any catalyst at room temperature in short reaction time. The initial reaction product is a dihydropyridine which can be oxidized in a subsequent step to a pyridine. Peg800dpilcl could be recovered by simple workup and recycled for at least eight times without obvious activity loss. The main advantages in the use of this reagent are. Excellent reactivity combined with facile catalyst recovery and recyclability. As shown in table 2, the yields of the reaction under solvent free conditions. The methodology provides straightforward access to valuable building blocks for pharmaceutically relevant compounds.
Hantzsch synthesis of polyhydroquinolines a simple. Nash air hygiene laboratory, public health laboratory service, colindale avenue, london, n. Hantzsch reaction, under solvent, catalyst and heat free at room temperature conditions, followed by air oxidation for 72 hours. The irmof3 metalorganic framework mof acts as a suitable green catalyst for the onepot synthesis of dihydropyrimidinone and dihydropyridine derivatives through the biginelli and hantzsch reactions, and the desired products were obtained in high yields with short reaction times under mild solvent free condition. A mild and efficient recyclable catalyst for onepot synthesis of polyhydroquinoline via the hantzsch reaction under solvent free conditions. The mildness of the conversion, experimental simplicity, the mildness of the conversion, experimental simplicity, compatibility with various functional groups, efficient yields, short reaction times, and the easy workup procedure.
Subsequent decarboxylation gives the corresponding pyridines. Hantzsch reaction an overview sciencedirect topics. Faculty of chemistry, buali sina university, hamedan 6517838683, iran b. Hantzsch reaction seems to be one of the earliest procedures for the production of pyridines. Controllable selectivity in biginelli and hantzsch. A clean procedure for the synthesis of 1,4dihydropyridines via. Pdf an efficient hantzsch synthesis of 1,4dihydropyridines using. A novel reagent, acetoacetanilide aaa, was introduced to the determination of formaldehyde based on hantzsch reaction. Eric ej918275 rapid and convenient synthesis of the 1. Since a multitude of reaction intermediates formed by various but convergent reaction paths scheme 2 have been proposed, the hantzsch dhp reaction provides a challenging test for the chargetag approach to esims as. One instrument detected hcho by using the wetchemical hantzsch reaction for efficient gasphase stripping, chemical conversion and fluorescence measurement al4021, aero laser gmbh. The main advantages of the present approach are relatively short reaction.
Runs from 1 to 12 in the table represent the results of reductions of some carbonyl compounds with the hantzsch ester 1. The reaction provides easy access to highly substituted symmetric 1,4dihydropyridines which are readily oxidised to the corresponding pyridines with oxidants such as ceriumiv salts, nitric acid or chlorine. Apr 01, 20 in the presence of nanozno and zno, direction of the mcr reaction in either biginelli or hantzsch way is possible by choice of the reaction conditions. Hantzsch synthesis of 2,6dimethyl3,5dimethoxycarbonyl4o.
Catalyst for solvent free hantzsch reaction at room temperature. A variety of polyhydroquinolines have been synthesized under ecobenign conditions. The reaction was performed under solvent free condition in a short time and the products were obtained in high yield and purity. An efficient onepot fourcomponent hantzsch reaction to. The colorimetric estimation of formaldehyde by means of the hantzsch reaction t. Controllable selectivity in biginelli and hantzsch reactions. Amtd comparison of formaldehyde measurements by hantzsch. Jul 26, 2011 a facile and efficient protocol is described for the synthesis of 4aryl1,4,7,8tetrahydro3,5 dimethyldipyrazolo3,4b.
Generalized reaction under mechanochemical conditions a generalization of the hantzsch pyrrole synthesis was developed by estevez, et al. Hantzsch reaction starting directly from alcohols through a. Hantzsch synthesis of 2,6dimethyl3,5dimethoxycarbonyl4. Synthesis of 1,4dihydropyridines under solventfree.
Pyrroles are found in a variety of natural products with biological activity, so the synthesis of substituted pyrroles has important applications in medicinal chemistry. Hantzsch synthesis of 2,6dimethyl3,5dimethoxycarbonyl4 mdpi. Hantzsch reaction starting directly from alcohols through. Development of novel reagent for hantzsch reaction for the. Transitionmetal free and visiblelightmediated desulfonylation and dehalogenation reactions. Various modifications have been applied for this reaction and prepare unsymmetrical 1,4. Recently, this reaction has been introduced into polymer chemistry in order to develop polymers having 1,4. Thestable reagent method method acompared withtheoxfordalumina adsorption procedure 1methodb,seefigure 1hasacoefficient ofcorrelation rof 0. This reaction allows the preparation of dihydropyridine derivatives by. This catalyst promotes the reaction under solvent free condition in.
Complex 1 was used as a catalyst towards the hantzsch reaction for the synthesis of 1,4. A short, semimicroscale synthesis of two 1,4dihydropyridine drug analogues via a hantzsch reaction is described, which is appropriate for a secondyear undergraduate organic laboratory. Moreover, under photoredox catalytic conditions, alkyl1, synthetic methodology in obc. Hantzsch condensation methods fortriglyceride determination. Hantzsch dihydropyridine synthesis major reference. Green approach for synthesis of bioactive hantzsch 1,4. The hantzsch synthesis is a fourcomponent reaction between an aldehyde, two equivalents of a. Notwithstanding the reaction mechanism is particularly complex and were just proposing the more. However, the classic hantzsch reaction generates one equivalent eq of hydrogen halide, which can cause significant loss of optical purity with substrates prone to epimerization under original hantzsch conditions refluxing ethanol. The colorimetric estimation of formaldehyde by means of the hantzsch reaction by t. A simple and highly sensitive fluorometric method was achieved by using aaa. Excellent reactivity combined with facile catalyst recovery and recyclability nadiya koukabi,a eskandar kolvari,b ardeshir khazaei,a mohammad ali zolfigol,a behzad shirmardishagasemic and hamid reza khavasid a. Besides this, this reaction has been adapted to occur under microwave irradiation. An internal permeation hcho source allows for daily calibrations.
A facile protocol for the synthesis of 4aryl1,4,7,8. However, the classic hantzsch reaction produces one equivalent eq. The corresponding pyridine analogues of hantzsch 1,4dihydropyridines could. The methodology initially involved the formation of 1,2dihydropyridine intermediates via reaction of a variety of aromatic aldehydes with ethyl methyl acetoacetate and ammonium acetate, which were the same starting materials as the hantzsch reaction, under solvent, catalyst and heat free at room temperature conditions, followed by air. Later on, hantzsch 1,4dihydropyridines, which mimic nadh reduction process in vitro, have shown.
High isolated yields, operational simplicity, clean reaction conditions and minimum pollution of the environment. A kie comparison of nd and cd,d hantzsch derivatives gave values 5. Hantzsch reaction which involves the condensation of alde hydes, bketoester and. H catalyzed hantzsch threecomponent reaction of an aromatic aldehyde, ethyl acetoacetate, and ammonium acetate is developed. Click the structures and reaction arrows in sequence to view the 3d models and animations respectively. Pdf hantzsch reaction seems to be one of the earliest procedures for. Synthesis of 1, 4dihydropyridines dhp scientia iranica. Cdpu was proved to be an efficient heterogeneous catalyst that could be easily handled and removed from the reaction mix. As an innovation, the present study makes use of green and solvent free conditions for this reaction. The hantzsch pyrrole synthesis, named for arthur rudolf hantzsch, is the chemical reaction of. A piperidinefunctionalized poly ethylene glycol bridged dicationic ionic liquid peg800dpilcl was synthesized and applied to catalyze the fourcomponent hantzsch reaction under solvent free conditions and afford hydroquinolines with high to excellent yields. The reaction was performed under mild conditions with good to excellent yields in the absence of any byproduct. A hantzsch condensation reaction dihydropyridine cascade synthesis on zeolite substrate 191 bmimclo 4 16, aluminium dodecyl sulfate trihydrate alds 3.
That multicomponent reaction often affords the target compounds in. This catalyst promotes the reaction under solvent free condition in excellent. A simple, green and onepot fourcomponent synthesis of 1. In this paper, we also systematically reinvestigated the classic hantzsch reaction under different reaction conditions, analyzed the main products as well. Efficient synthesis of polyhydroquinolines via the. Research note silica boron sulfonic acid as heterogeneous and. Synthesis and aromatization of hantzsch 1,4dihydropyridines. Basic isoreticular nanoporous metalorganic framework for. Synthesis of 1,4dihydropyridines under solvent free. Compared with the classical hantzsch reaction, this new method has the advantages of good yield, short reaction time and methodological simplicity. Research note silica boron sulfonic acid as heterogeneous. The hantzsch reaction discovered in 1889 is still one of the most reliable routes to thiazoles. Hantzsch ester anion as electron and hydrogen atom donor september 2020 the journal of organic. Free energy changes of electron transfer were 167178 kjmol vs hydride 7590.
Development of novel reagent for hantzsch reaction for the determination of formaldehyde by spectrophotometry and fluorometry. Efficient synthesis of hantzsch esters and polyhydroquinoline derivatives in aqueous micelles a. The colorimetric estimation of formaldehyde by means of. Hantzsch dihydropyridine synthesis major reference works. The hantzsch reaction discovered in 1889 remains one of the most reliable routes to thiazoles. The purpose of this research is the synthesis of meso structured silica or santa barbara amorphous sba15 as a green nano catalyst witch, is used in the hantzsh synthesis synthesis of 1,4dihydropyridine derivatives.
In the first step, for the optimization of the reaction conditions, the various effects such as amount of catalyst and reaction temperatures were investigated on the reaction of benzaldehyde 1 mmol with acetyl acetone 2 mmol scheme 1. Polyaniline salt containing 1hydroxyethane1,1diphosphonic acid with nanosphere morphology in semicrystalline powder form was successfully synthesized by interfacial polymerization pathway and demonstrated as polymer based acid catalyzed in the synthesis of 1,4dihydropyridines and polyhydroquinoline derivatives. A hantzsch condensation reaction dihydropyridine cascade. A hantzsch condensation reaction dihydropyridine cascade synthesis on zeolite substrate 193 2. Efficient synthesis of polyhydroquinolines via the hantzsch. Allspecimens werechosenwithout conscious bias andallresults aresingleanalyses bytherespective methods. Hantzsch esters were often previously used as reductants in thermal catalytic hydrogenation reactions. Products are specifically chosen to highlight the biological relevance of this compound type while introducing the notion of a privileged structure. Pdf the colorimetric estimation of formaldehyde by means of. Journal of heterocyclic chemistry 2012, 49 1, 232236. A conjugate addition between the two fragments, followed by proton transfers and finally intramolecular enamine formation gives the dihydropyridine.
Recent advances in hantzsch 1,4dihydropyridines anil saini, sanjay kumar and jagir s sandhu department of chemistry, punjabi university, patiala 147 002 received 20 august 2007. The product of preparation 2c has also a number of uses in agriculture as a carotene stabiliser in grass. The reaction mechanism of the hantzsch reaction was first explained by nash. Sep 15, 2010 the hantzsch ester, as a calcium antagonist, has important applications in drug design.
The classical hantzsch synthesis is a onepot cyclocondensation between an aldehyde. Mechanism of the hantzsch dihydropyridine synthesis. The present work utilizing alcohols instead of aldehyde in hantzsch reaction is a valid and green. Hantzsch reaction with esims monitoring using a strategy involving alternate reactions with chargetagged reagents scheme 4. Nash 1 air hygiene laboratory, public health laboratory service, colindale avenue, london, n. The hantzsch pyridine synthesis or hantzsch dihydropyridine synthesis is a multicomponent organic reaction between an aldehyde such as formaldehyde, 2 equivalents of a. Onepot and solvent free synthesis of 1,4dihydropyridines and 3,4dihydropyrimidine2ones using new synthetic recyclable catalyst via biginelli and hantzsch reactions. Hantzsch, polyhydroquinolines, catalyst free, solvent free condition, room temperature 1,4dihydro pyridyl compounds are important class of. Structure, mechanism and reactivity of hantzsch esters.
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