SWIM experience hydrogenating mostly chloroephedrine to meth, using methanol as the solvent and Pd. 10%/C. SWIM found that many times the catalyst gets poisoned , although it will hydrogenate but slow , so it’s best to change your catalyst 2-3 times until it kicks and you see it taking hydrogens at a good rate so you can be done in less than and hour. At a good rate the hydrogen gets consumed so fast that at the end your bottle is very hot from the reaction ........java
Edit :see also Patent US3458576 originally provided by polysam, then Roger2003 , and recently reviewed by Aurelius
Post 439559 (https://www.thevespiary.org/talk/index.php?topic=9650.msg43955900#msg43955900)
(Aurelius: "US Patent 3458576 reduction of phenylnitropropene", Methods Discourse)
Nice Hest! :)
I have two questions:
- What is your setup to contain 6 bar of pressure? Is there any way to do it for a kitchen chemist, without Parr Apparatus?
- For EveryknowledgableBee:
This is the hydrogenation of a mandelonitrile intermediate to the PEA, at RPT condition, is there any reason that it could not work on a normal phenylacetonitrile, or is this only applicable to O-Ethoxycarbonyl mandelonitriles? Otherwise it would bee a very convenient way to PEA from acetonitrile derivates.
Synthesis of meta-Methoxyphenethylamine via O-(Ethoxycarbonyl)-3-Methoxy-Mandelonitrile
J. Org. Chem. 47, 2638-2643 (1982) (https://www.thevespiary.org/rhodium/Rhodium/pdf/mandelonitrile.carbamate2pea.pdf)
(https://www.thevespiary.org/rhodium/Rhodium/pdf/mandelonitrile.carbamate2pea.pdf)
This is the original reference for the KrZ way to 2C-H (https://www.thevespiary.org/rhodium/Rhodium/chemistry/2cb.mandelonitrile.html)
(https://www.thevespiary.org/rhodium/Rhodium/chemistry/2cb.mandelonitrile.html)
Attempted preparation of 2-(m-methoxyphenyl)ethylamine (4) by reduction of nitrostyrene 6 with lithium aluminum hydride1 gave a product containing a persistent impurity which could be eliminated only if nitrostyrene 6 was rigorously purified. Catalytic hydrogenation2 of 6 gave variable results as the scale was increased. However, an efficient and convenient synthesis of phenylethylamine 4, independent of scale, proceeded in high yield from m-anisaldehyde (5) by first treatment with potassium cyanide and ethyl chloroformate to form O-(ethoxycarbonyl)-3-methoxymandelonitrile (7). Hydrogenation3,4 of 7 over palladium on charcoal in ethanol at atmospheric pressure gave 4 reproducibly in 92% yield.
O-(Ethoxycarbonyl)-3-methoxymandelonitrile (7)
To a stirred solution of 13.6 g (0.1 mol) of m-anisaldehyde (5) and 11.9 g (0.11 mol, 10.8 mL) of ethyl chloroformate in 20 mL of THF, cooled in an ice-water bath, was added in one portion 7.2 g (0.11 mol) of KCN dissolved in 25 mL of water. The reaction mixture was stirred for 4 h at 5°C and then slowly warmed to room temperature overnight. Water (100 mL) was added, the aqueous solution was extracted with 3x40 mL of ether, the combined extracts were dried and evaporated, and the residue was distilled to afford 21.4 g (0.92 mol, 92%) of the cyanohydrin carbamate 7: bp 110-115°C/0.3mmHg [lit. bp 132°C/0.4 mmHg].
2-(m-Methoxyphenyl)ethylamine (4)
A solution of 23.5 g (0.1 mol) of 7 in 300 mL of absolute ethanol was added dropwise (0.5 drop/s) to a mechanically stirred solution of 300 mL of absolute ethanol containing 1.5 g of 10% Pd/C catalyst and 12.9g (0.13 mol, 7 mL) of concentrated sulfuric acid as hydrogen was bubbled through the solution. After the addition, stirring and bubbling were continued for 8 h, the reaction mixture was filtered, the filtrate was evaporated, water (100 mL) was added, and the cooled aqueous solution was made alkaline with 4 M sodium hydroxide. The solution was extracted with 4x50 mL of ether, the combined extracts were dried and evaporated, and the residue was distilled to afford 13.9 g (0.09 mol, 92%) of phenylethylamine 4: bp 93-95°C/0.1mmHg [lit. bp 122-123°C/1.0mmHg].
References
[1] J. Chem. Soc. C, 2632 (1971)
[2] Synth. Commun. 1, 47 (1971) and references cited therein. Post 472313 (missing)
(Rhodium: "Catalytic Hydrogenation of Nitrostyrenes", Serious Chemistry)
[3] J. Am. Chem. Soc. 55, 2593 (1933) Post 471993 (missing)
(Rhodium: "Catalytic Reduction of Mandelonitriles", Serious Chemistry)
[4] Justus Liebig's Ann. Chem. 564, 49 (1949) Post 485823 (https://www.thevespiary.org/talk/index.php?topic=12468.msg48582300#msg48582300)
(Rhodium: "Kindler: Phenylacetonitriles to Phenethylamines", Serious Chemistry)
This is reference #5 from Post 471993 (missing)
(Rhodium: "Catalytic Reduction of Mandelonitriles", Serious Chemistry):
Studien über den Mechanismus chemischer Reaktionen. II.
Ûber den Mechanismus der Synthese von sekundären und tertiären Aminen durch Reduktion
Karl Kindler
Ann. Chem. 485, 113-126 (1931) (https://www.thevespiary.org/rhodium/Rhodium/pdf/nitrile.kindler.pdf)
(https://www.thevespiary.org/rhodium/Rhodium/pdf/nitrile.kindler.pdf)
____ ___ __ _
This is reference #4 from Post 448639 (https://www.thevespiary.org/talk/index.php?topic=12468.msg44863900#msg44863900)
(Chimimanie: "Phenethylamines via Mandelonitrile Carbamates", Serious Chemistry):
Studien über den Mechanismus chemischer Reaktionen. XI.
Ûber die Lenkung der Katalytischen Hydrierung bei Estern des Mandelonitrils
Karl Kindler und Karl Schrader
Ann. Chem. 564, 49-54 (1949) (https://www.thevespiary.org/rhodium/Rhodium/pdf/mandelonitrile.ester2pea.pdf)
(https://www.thevespiary.org/rhodium/Rhodium/pdf/mandelonitrile.ester2pea.pdf)