Hi, I have to reduce the NO2 group to NH2 group in the following reaction. Kindly suggest some good catalyst to reduce the NO2 to NH2 group without affecting any other position.
Fe + NH4Cl in methanol or ethanol at 60-80°C could be used for the reduction of nitro to amine by keeping all your groups intact.
Alternatively SnCl2 reduction can be tried.
Fe + NH4Cl in methanol or ethanol at 60-80°C could be used for the reduction of nitro to amine by keeping all your groups intact.
Alternatively SnCl2 reduction can be tried.
Hello Subramaniyan, Just check the article attached herewith and you will find the solution of your problem. In this paper, they have selectively reduced the nitro group to amino group remaining all the other functionalities intact.
Fe powder + Acetic acid in ethyl acetate at 60°C could be used for the reduction of nitro to amine by keeping all your groups intact.
Dear Bala!
You did not mention your scale. For large scale synthesis (up to several moles) the reduction performed with iron is best choice in our labs. For example 170 g of iron powder ("carbonyl iron" grade) suspended in 300 ml of hot water in 2L round vessel under vigorous stirring was treated with 10 ml of concentrated HCl (slowly, foaming!). After 5 min into the hot suspesion a solution of one mole of nitrocompoud in 400-500 ml of ethylacetate was run as a thin stream. At first 15-20 ml was added to ensure that the reaction started (can be seen as intensity of boiling in condeser ad blackening of the reaction mixture). At this point heating was set aside and exothermic reaction was controled by addition of nitrocompound. Reaction is very fast and solution of substrate can be spend within 20-30 min. After addition the reaction mix stirred additionally for 10 min ad treated with slightly more than equivalent quantity of solid bicarbonate to neutralise 10 ml of HCl. Cooled solution was filtered through paper mass and filter cake of Fe3O4 was washed succesively with ethanol and ethylacetate. Organic layer was separated and worked up as usual. In your case it seems that the product can be distilled in high vacuum.
You can do reduction by SnCl2.2H2O in ethanol at reflux, I have done it succesfully
Fe powder + NH4Cl in ethanol could be used for the reduction of nitro to amine. You can see our report ChemistrySelect 2017, 2, 260–264.
"Fe" or "SnCl2" methods is not good because You have NH moiety, that can "catch" heavy metals (when they are in molar or more quantities) to reduce the yield. The best "pure" method to my mind would be the redusing by hydrogen at atmospheris pressure using Ni renay, or Pd on activated carbon. Using Na2S as a redusing agent is possible too but this method would not be so pure. About all the details if You don't know how to make a laboratory equpment to work with H2 on Pd/C ask me please, I have some experience in this field.
After. The simplest case. Take hydrogen-gas in a rubber ball, substance (5g in about 50-70 ml) and the catalyst is dissolved in methanol in a one-neck reactor. Vacuumate the reactor until the methanol boils and input then hydrogen into reactor with vigorous stirring with a magnetic stirrer. The bubbling is not nessesary, make only the H2 atmosphere. The reaction should proceed with a some heating, up to about 30-40 0C
- Hhydrogenation under one atmosphere of H2 at 0 degree Celius catalyzed by Pd/C
- see my paper where I reduce NO2 without affecting Imine groups
- Easy Synthesis of New Chiral Tetradentate N4 Schiff Bases and Their Use as Ligands for Metal Complexes
- April 2003European Journal of Organic Chemistry 2003(7):1271 - 1276
- DOI10.1002/ejoc.200390182
Very good results are obtained with hydrazine and Ranei nickel in ethanol solution. After the reaction simply filtrate the catalyst.
No Hydrazine!!!! Hydrazine may convert esters groups (COOC2H5) into hyrazides groups (CONHNH2)
Palladium catalyzed hydrogenation at atmospheric pressure is the best way I guess. If you use any metal hydrides there is a possibility of defluorination.
You can use iron powder and NH4Cl in methanol for the reduction of nitro group to amino without affect the carbethoxy group.
Fe powder + Acetic acid +Water in ethyl acetate ,toluene EDC or TCE at 60°C could be used for the reduction of nitro to amine by keeping all your groups intact.
Zn dust + Ammonium chloride in Ethyl acetate for reduction of nitro to amine without effect of other function groups.
Dear Bala,
Fe+NH4Cl in ethanol works good even at room temperature sometimes.
A mixture of 1 g compound+ 2.2 g Fe powder + 1mL con HCl + 20 mL EtOH/ 5mL water was refluxed for 5 hours.The reaction output is up to 90% .
Dear Bala!
I recommend you to use sodium dithionite (Na2S2O4) for this purpose. It is necessary to use 3.5 moles of Na2S2O4 for 1 mole of substrate and boil for 1-1.5 hours in a mixture of ethanol-water (4:1). And then acidify with conc. HCl and boil for additional 5-10 minutes.
The best method for reduction of NO2 to NH2 is to use H2 /Pt in acetic acid. This gives the clean reaction product.Fe in aq.HCl is cheaper but the quality of the product is not so good.
Bala,
FeCl3. 6H20 with hydrazine monohydrate and charcoal worked well for me. Another option would be using Raney-Ni (becareful when use Ra-Ni!!). If these cheaper options do not work, then go for Pd/C. Should work.
Thanks
Sodium dithionite in ammonia solution could be helpful. See synthesis of luminol. Also treatment with indium powder in aqueous ethanolic ammonium chloride is more selective than catalytic hydrogenation.
Indium is toxic,
the simplest and greener method is the Hydrogenation (1 atm of H2) using Pd/C at 0-10°C.
Dear Bala
Click on the following link to see several examples: http://www.organic-chemistry.org/synthesis/N1H/reductionsnitrocompounds.shtm
Very good at addressing the scientific subject that deals with converting NO2 to NH2. I therefore request references in this field, especially in heterogeneous compounds containing pyridine nucleus. Excuse
Nitration:
Nitration makes it possible to introduce an NO2 group on an aromatic ring. It was one of the first chemical processes used to functionalize an aromatic derivative. It makes it possible to obtain nitroaromatic compounds, which may be of interest, but they are essentially intermediate compounds.
It is an electrophilic substitution reaction. It is conducted in a strong acid medium to generate the nitronium ion, an active and electrophilic species of nitration [15,16]. [15] - G. Cheng, X. Duan, X. Qi, C. Lu., Nitration of aromatic compounds with NO2 / air catalyzed by sulfonic acid-functionalized ionic liquids., Catalysis Communications. Flight. 10. 2008, pp. 201-204, 2008.
[16] - I.J. Lochert, H. E. Dorsett., Nucleophilic nitration of selected aza-aromatics: Experiments and Modeling., Aeronautical and Maritime Research Laboratory, Australia, 2001.
so many ways for nitro to amino reductions.go with raney nickel/H2 in meoh.
i guess remaining groups doesnt effect
there is also another method i believe to use a mercury salt and aluminium foil coils, along with EtOAc i cant remember the exact ratios but i know its out there, often high yielding
Zinc dust + ammonium chloride in Ethyl acetate solventa t 70-75°C for 2-3hrs.a
HI ramakoti, it is actually a reaction i have tried this week and is very un-efficient for me
try this reaction with raney nickel in presence of hydrogen in ethanol.dont use methanol it may exchange your ethyl ester
This reduction would be straightforward except for the enamine double bond which is easily reduced also. I think that a catalytic transfer hydrogenation using 3% Royer Pd polymer complex with ammonium formate in EtOH may be selective enough. The catalyst is nonpyrophoric and can be removed by hot filtration then washed with hot EtOH. Metal reductions (e. g . Fe or Zn in AcOH) work well except that removing the metal salts during workup can be difficult especially if your product is sensitive to base. Also it looks like your compound is set up for cyclization to a 4-quinolinone. Good luck.
i strongly recommend Nadia Sadiq Majeed answer. Because i used Fe with NH4Cl in ethanol with controlled heat condition. I got my expected result.
I think Zn/NH4Cl soln alone cannot reduce -NO2 to -NH2, instead it may requires additional agents. For eg., find the below articles.
S. M. Kelly, B. H. Lipshutz, Org. Lett., 2014, 16, 98-101 and
G. Sheng, X. Wu, X. Cai, W. Zhang, Synthesis, 2015, 47, 949-954
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