Sandmeyer
National Hazard
Posts: 784
Registered: 9-1-2005
Location: Internet
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Amines by reduction of nitriles and reductive amination of ketones with ammonia
A generic approach for the catalytic reduction of nitriles
S. Caddick, D. B. Judd, A. K. de K. Lewis, M. T. Reich, M. R. V. Williams, Tetrahedron, 2003, 59, 5417-5423.
Abstract: The scope of nickel boride mediated reduction of nitriles has been extended further to allow the preparation of Boc
protected amines via a mild catalytic process. The toxicity of this procedure is greatly reduced due to the catalytic use of nickel(II) chloride in
combination with excess sodium borohydride. This protocol is practical and tolerates air and moisture. Although the yield is sometimes moderate, the
cleanliness of the method is exceptional. No further purification is necessary after work-up.
http://rapidshare.de/files/10137030/A_generic_approach_for_t...
Chemoselective reductive alkylation of ammonia with carbonyl compounds: synthesis of primary and symmetrical secondary amines
B. Miriyala, S. Bhattacharyya, J. S. Williamson, Tetrahedron, 2004, 60, 1463-1471
Abstract: An efficient, general procedure for highly chemoselective reductive mono-alkylation of ammonia with ketones is reported.
Treatment of ketones with ammonia in ethanol and titanium(IV) isopropoxide, followed by in situ reduction with sodium borohydride, and a simple workup
afforded primary amines in good to excellent yields. Reductive alkylation of ammonia with aldehydes, on the other hand, afforded the corresponding
symmetrical secondary amines selectively.
http://rapidshare.de/files/10137037/Chemoselective_reductive...
General procedure for the synthesis of primary
amines from ketones
A mixture of the ketone (10 mmol), titanium(IV) isopropoxide (6.0 mL, 20 mmol) and ammonia in ethyl alcohol (2 M, 25 mL, 50 mmol) was stirred under
argon in a capped flask a ambient temperature for 6 h. Sodium borohydride (0.6 g, 15 mmol) was then added and the resulting mixture was stirred at
room temperature for an additional 3 h. The reaction was then quenched by pouring into ammonium hydroxide (2 M, 25 mL), the resulting inorganic
precipitate was filtered off, and washed with ethyl acetate (25 mL x 2). The organic layer was separated and the remaining aqueous layer was extracted
with ethyl acetate (25 mL x 2).
The combined organic solution was next extracted with hydrochloric acid (1 M, 30 mL) to separate the neutral materials. The acidic aqueous extracts
were washed with ethyl acetate (50 mL), then treated with aqueous sodium hydroxide (2 M) to pH 10–12, and extracted with ethyl acetate (50 mL x 3).
The combined organic extracts were washed with brine (50 mL), dried (Na2SO4), and concentrated in vacuo to afford the corresponding primary amine.
Yield/Purity
4-fluoroamphetamine 78/99
2,4-DMA 87/97
For further examples see the paper...
[Edited on 31-12-2005 by Sandmeyer]
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Organikum
resurrected
Posts: 2329
Registered: 12-10-2002
Location: Europe
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Mood: busy and in love
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Link dead, paper here attached
Attached is the second paper, pure gold...
Attachment: phptgQAFc (288kB)
This file has been downloaded 160 times
And as it comes I have some more on the topic....
N-alkylation of ammonia and amines with alcohols catalyzed by Ni-loaded CaSiO3
Attachment: phpTj9gRo (1.4MB)
This file has been downloaded 137 times
Intrinsic mechanism of active metal dependent primary amine
selectivity in the reductive amination of carbonyl compounds
Attachment: phpldWS8p (2MB)
This file has been downloaded 137 times
[Edited on 27-12-2022 by Organikum]
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