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Nicodem
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Am I dumb or there really is nothing on that link. I can't find any paper or literature reference. Your link only leads to a useless blog saying
something is, or will be, published about the Leuckart reaction.
PS: This thread is such crap! Unless someone posts something interesting, I will consider closing it.
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twodogs
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Which is why I said .."I wonder how this works".
The guy has stated
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In this work a fast non-microwave procedure for the Leuckart reaction was developed. The new procedure can be completed in minutes instead of hours.
It minimizes the use of heat and practically eliminates any thermal decomposition of the reaction mixture |
I thought someone might have some more info on it.
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Bluetooth
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Here’s an other one from U.S. Pat. 3,222,395
135g (460mmol) 3,4-di-p-chlorophenyl-2-butanone and 84gr (1.86mol) formamide where heated under reflux at 170C for 14 hours. Formic acid (about 35cc)
is added in smal portions from time to time to keep the vapours above the reaction mixture acidic. After cooling, the mixture is extracted with
benzene. The benzene layer is separated and evaporated. The residu is boiled with 65cc concentrated hydrochloric acid for about 8 hours thus forming
the diastereoisomers of 3,4-di-p-chlorophenyl-2-aminobutane hydrochloride in 70% yield.
I think that the use of BMK instead of the above ketone, will give somewhat higher yields.
[bewerken aan 19-1-2009 door Bluetooth]
[bewerken aan 19-1-2009 door Bluetooth]
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twodogs
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Yes but 14 hours?? The idea is to do the Leuckart in 30 minutes without using a microwave.
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Sauron
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Nicodem, this is what is on that link above:
The "greener" Leuckart reaction.
By: Bobylev, Mikhail M.
Publication: Proceedings of the North Dakota Academy of Science
Date: Tuesday, April 1 2008
You are viewing page 1
The Leuckart reaction is a unique one step method of reductive amination. It is a remarkably simple process that includes only two components: the
carbonyl compound and formamide. The reaction is completed simply by heating the components at 160[degrees]C to 185[degrees]C for 6 to 25 hours. The
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long processing time seems to be the only shortcoming of the reaction. However, it is associated with a number of serious practical problems. First,
the prolonged exposure of the reaction mixture to high temperatures inevitably leads to significant thermal decomposition of the components, and,
consequently, to lower yields of the products and large amounts of waste. Second, maintaining high temperatures for a long period of time means high
consumption of energy and increasing production costs which make the Leuckart reaction unattractive to the chemical industry.
In this work a fast non-microwave procedure for the Leuckart reaction was developed. The new procedure can be completed in minutes instead of hours.
It minimizes the use of heat and practically eliminates any thermal decomposition of the reaction mixture. The specific examples of the reactions will
be presented. The project is supported by NIH grant P20 RR016741 from the NCRR.
Mikhail M. Bobylev
Division of Science--Chemistry, Minot State University, Minot, North Dakota 58707
Sic gorgeamus a los subjectatus nunc.
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Vogelzang
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There's some Leuckart articles here:
http://www.4shared.com/dir/4188850/a5ae1be6/Leuckart_Synthes...
This is from the articles.txt file.
Extensions of the Leuckart Synthesis of Amines
A. W. Ingersoll, J. H. Brown, C. K. Kim, W. D. Beauchamp, Garland Jennings
J. Am. Chem. Soc.; 1936; 58(9); 1808-1811.
http://pubs.acs.org/cgi-bin/searchRedirect.cgi/jacsat/1936/5...
Secondary Amines by the Leuckart Synthesis
Armando Novelli
J. Am. Chem. Soc.; 1939; 61(2); 520-521.
http://pubs.acs.org/cgi-bin/searchRedirect.cgi/jacsat/1939/6...
STUDIES ON THE LEUCKART REACTION
FRANK S. CROSSLEY, MAURICE L. MOORE
J. Org. Chem.; 1944; 9(6); 529-536.
http://pubs.acs.org/cgi-bin/searchRedirect.cgi/joceah/1944/9...
Analgesics. I. N-Alkylated-1,2-diphenylethylamines Prepared by the Leuckart Reaction
L. H. Goodson, C. J. W. Wiegand, Janet S. Splitter
J. Am. Chem. Soc.; 1946; 68(11); 2174-2175.
http://pubs.acs.org/cgi-bin/searchRedirect.cgi/jacsat/1946/6...
Studies on the Mechanism of the Leuckart Reaction
Elliot R. Alexander, Ruth Bowman Wildman
J. Am. Chem. Soc.; 1948; 70(3); 1187-1189.
http://pubs.acs.org/cgi-bin/searchRedirect.cgi/jacsat/1948/7...
The Leuckart Reaction: A Study of the Mechanism
Vincent J. Webers, William F. Bruce
J. Am. Chem. Soc.; 1948; 70(4); 1422-1424.
http://pubs.acs.org/cgi-bin/searchRedirect.cgi/jacsat/1948/7...
Preparation of Tertiary Amines by the Leuckart Reaction
J. F. Bunnett, Jean Lovendahl Marks
J. Am. Chem. Soc.; 1949; 71(5); 1587-1589.
http://pubs.acs.org/cgi-bin/searchRedirect.cgi/jacsat/1949/7...
Preparation of Tertiary Amines by the Leuckart Reaction
Peter A. S. Smith, A. John Macdonald
J. Am. Chem. Soc.; 1950; 72(2); 1037-1038.
http://pubs.acs.org/cgi-bin/searchRedirect.cgi/jacsat/1950/7...
The Behavior of Aliphatic Aldehydes in the Leuckart-Wallach Reaction
Peter L. deBenneville, Jane H. Macartney
J. Am. Chem. Soc.; 1950; 72(7); 3073-3075.
http://pubs.acs.org/cgi-bin/searchRedirect.cgi/jacsat/1950/7...
THE MECHANISM OF THE LEUCKART REACTION
C. B. POLLARD, DAVID C. YOUNG
J. Org. Chem.; 1951; 16(5); 661-672.
http://pubs.acs.org/cgi-bin/searchRedirect.cgi/joceah/1951/1...
Preparation of tertiary N, N-dimethylamines by the Leuckart reaction
Robert D. Bach
J. Org. Chem.; 1968; 33(4); 1647-1649.
http://pubs.acs.org/cgi-bin/searchRedirect.cgi/joceah/1968/3...
Catalytic Leuckart-Wallach-Type Reductive Amination of Ketones
Kitamura, M.; Lee, D.; Hayashi, S.; Tanaka, S.; Yoshimura, M.
J. Org. Chem.; (Note); 2002; 67(24); 8685-8687. DOI: 10.1021/jo0203701
http://pubs.acs.org/cgi-bin/searchRedirect.cgi/joceah/2002/6...
THE PREPARATION OF SECONDARY AMINES THROUGH THE WALLACH REACTION1
RICHARD BALTZLY, OTTO KAUDER
J. Org. Chem.; 1951; 16(2); 173-177.
http://pubs.acs.org/cgi-bin/searchRedirect.cgi/joceah/1951/1...
[Edited on 27-1-2009 by Vogelzang]
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DNA
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Vogelzang, haven't you got any recent literature....the newest article you posted is from 1951, not immediately claiming that old literature is bad
but fresh literature is in my opinion somewhat more reliable
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Sauron
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Youmight just consider getting fresh lit. yourself.
Google
ACS Pubs search engine
RSC search engine
Org Reactions
Chemical Reviews
just for starters.
Sic gorgeamus a los subjectatus nunc.
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twodogs
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Here's some info on the accelerated Leuckart
http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sec...
[Edited on 4-7-2009 by twodogs]
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jon
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where is that reference that promises 95% yeilds by means of microwave irridatiation???
read it somewhere just glancd over it looked interesting though.
i'll find it again.
what of pyrimidine by-products aren't they a pain to to separate??
[Edited on 8-7-2009 by jon]
[Edited on 8-7-2009 by jon]
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greenimp
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TD- On your accelerated Leuckart. I wanted to gauge the feeling here if it was only the concentration of the ketone/aldehyde that was critical or if
the product concentration would limit the reaction.
I feel mass action is not the only reason in use such high ratios of amine:ketone/aldehyde.
An idea has been floated that perhaps running the reaction in cycles, adding a small amount of ketone each time in order to keep the concentration
low, might be possible. The goal being to effectively increase the amount of ketone that could be processed per reaction, the real down side of this
procedure being the large volume of amine needed to process a given amount of ketone. Cycling would keep the thermal decomposition and mixing issues
to a minimum.
[Edited on 17-7-2009 by greenimp]
Green Imp
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europa
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United States Patent 5504253:-
1. N- ((3-Methoxyphenyl)methyl)-α-methyl!formamide
A mixture of 281 g (1.87 moles) of 3-methoxyacetophenone and 352 g (5.558 moles) of ammonium formate was stirred at 180° C. After 24 hours, TLC
analysis (1:1 Hex/EtOAc) indicated that the reaction was complete. The solution was poured into water and extracted with methylene chloride. The
organic layer was washed once with H 2 O and dried with MgSO 4. The solution was concentrated to afford 292 g (87%) of a dark oil.
2. 3-methoxy-α-methylbenzylamine
A solution of 287 g (1.60 moles) of N- ((3-Methoxyphenyl)methyl)-α-methyl!formamide and 1400 mL of concentrated HCl was stirred at reflux. After
1.5 hours, TLC analysis (85:10:5 EtOAc/MeOH/isopropylamine) indicated the reaction was complete. The solution was concentrated to dryness and the
resulting green residue was recrystallized from acetonitrile to afford a white solid. The solid was dissolved in water and the pH was raised to 12
with 50% NaOH. The product was extracted with ethyl ether. The organic layer was washed with saturated NaCl solution and dried with K 3 CO 3 . The
solution was concentrated to afford 188.2 g (78%) of a dark oil. Distillation of 174 g of the dark oil at 760 mm Hg afforded 140 g of a clear liquid,
bp 180° C.
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rannyfash
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Sorry to revive a dead thread, however I feel that the leuckart reaction would be sped up if drying agents were used to remove water, removing water
from the imine formation equilibrium would push more imine to be produced, maybe the hydrolysis of an imine competes against the reduction step? And
if so then the removal of water would push the reaction to completion, it's just a hunch tell me where I'm wrong
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Vogelzang
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http://www.sciencemadness.org/talk/viewthread.php?tid=3613#p...
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