Author Topic: The reason to use a PTC is to have the anion...  (Read 1386 times)

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Lilienthal

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The reason to use a PTC is to have the anion...
« on: July 11, 2004, 04:06:00 PM »
The reason to use a PTC is to have the anion in the organic phase aided by the PTC. Therefore is doesn't make sense to add the base dropwise.

Biphasic reactions have to be heavily stirred, otherwise the reaction rate will drop dramatically.

descent

  • Guest
I know very well what is PTC, but I am sure...
« Reply #1 on: July 11, 2004, 07:47:00 PM »
I know very well what is PTC, but I am sure that TEBA will easily extract the MONO-anion, but not so easily the DI-anion of hydroquinone. My idea is to start with 1 eq NaOH which is enough for the reaction to begin, and then gradually add more base for the second hydroxyl.
And I know that such reaction are usually - but not always - stirred, and I still hope to know: Did hest used mixing? Because my magnetic stirrer is far from being perfect.

hest

  • Guest
Mixing/stirring
« Reply #2 on: July 11, 2004, 10:16:00 PM »
Yes I used a MagStirr with a big magnet. Mixin is werye important.
Why tune a 80% reaction _ the starting materials is free. Use your pover on the grignard step.

descent

  • Guest
thanks
« Reply #3 on: July 12, 2004, 10:06:00 PM »
Thanks! I will use my biggest magnet. I have the intention to mix a 1.5 l mixture, to prepare a suffisant amount of you know what, and use all my power on the cyclization step. I plan to try cyclization in a planetary ball mill with Mg, Zn, Li, Na ... It sounds crazy but "crazy experiments lead to Nobel or to nothing" (Erasmus Darwin).

hest

  • Guest
:-)
« Reply #4 on: July 13, 2004, 08:28:00 AM »

I plan to try cyclization in a planetary ball mill with Mg, Zn, Li, Na



Sodium in a ball mill, I would love to see that. Might add some permanganate ;)
Have fun


azole

  • Guest
Friedel-Crafts rxn with CF3CONHCH(R)COCl
« Reply #5 on: August 03, 2004, 06:52:00 PM »
Friedel-Crafts Acylation with N-(Trifluoroacetyl)-?-amino Acid Chlorides. Application to the Preparation of ?-Arylalkylamines and 3-Substituted 1,2,3,4-Tetrahydroisoquinolines
J. E. Nordlander, M. J. Payne, F. G. Njoroge, M. A. Balk, G. D. Laikos, and V. M. Vishwanath
J. Org. Chem.
, 49(22), 4107-4111.


(Ref. #13 from

https://www.thevespiary.org/rhodium/Rhodium/pdf/nichols/nichols-dragonfly-2.pdf

.)


Abstract

   Several N-(trifluoroacetyl)-?-amino acid chlorides have been reacted with PhH, MeOPh, and 1,2-(MeO)2PhH in the presence of AlCl3 or SnCl4 to produce ArCOCH(NHCOCF3)R in fair to high yields. The (trifluoroacetyl)amino group of the products can be N-methylated with MeI/K2CO3 in boiling Me2CO. Reduction of the ketones with H2 - Pd/C in EtOH under neutral conditions resulted in alcohols. Hydrogenation in the presence of HCl led to complete deoxygenation. Reductions with Et3SiH in refluxing CF3COOH or in BF3·Et2O at rt gave alcohols (Ar = Ph) or deoxygenated products (Ar = 4-MeOPh or 3,4-(MeO)2Ph). The products of reduction can be readily detrifluoroacetylated by mild basic hydrolysis and thence converted to the corresponding 3-substituted 1,2,3,4-tetrahydroisoquinolines by condensation with CH2O.


N-(Trifluoroacetyl)-?-amino Acid Chlorides as Chiral Reagents for Friedel-Crafts Synthesis
J. E. Nordlander, F. G. Njoroge, M. J. Payne, and D. Warman
J. Org. Chem.
, 50, 3481-3484 (1985).



Abstract

   Chiral N-(trifluoroacetyl)-?-amino acid chlorides undergo Friedel-Crafts reaction with PhH and 1,2-(MeO)2PhH under mild conditions commonly with complete (>99%) preservation of configurational identity. The resultant (trifluoroacetyl)amino ketones may be deoxygenated with Et3SiH or H2/Pd-C in acidic media to the corresponding N-(trifluoroacetyl)-?-arylalkylamines likewise without loss of configurational purity.


A Short Enantiospecific synthesis of 2-Amino-6,7-dihydroxy-1,2,3,4-tetrahydronaphthalene (ADTN)
J. E. Nordlander, M. J. Payne,  F. G. Njoroge, V. M. Vishwanath, Gi Rin Han, G. D. Laikos, and M. A. Balk
J. Org. Chem.
, 50, 3619-3622 (1985).






A Short Synthesis of (S)-(+)-Tylophorine
J. E. Nordlander and F. G. Njoroge
J. Org. Chem.
, 52, 1627-1630 (1987).



Abstract

   Friedel-Crafts acylation of 2,3,6,7-tetramethoxyphenanthrene with (S)-N-(trifluoroacetyl)prolyl chloride (1.2 eq.) followed by deoxygenation of the resultant ketone with Et3SiH in BF3·Et2O at rt, removal of the trifluoroacetyl group (NH3 - MeOH), and Pictet-Spengler cyclomethylenation with CH2O in ethanolic HCl resulted in  (S)-(+)-Tylophorine.


Facile Approach to Enantiomerically Pure ?-Amino Ketones by Friedel-Crafts Aminoacylation and Their Conversion into Peptidyl Ketones
Maria Luisa Di Gioia, Antonella Leggio, Angelo Liguori, Anna Napoli, Carlo Siciliano, and Giovanni Sindona
J. Org. Chem.
, 66(21), 7002-7007 (2001).
DOI:

10.1021/jo010414q







   See also

Post 475692

(Rhodium: "A two-step method for chiral cathinones", Novel Discourse)
.

Organikum

  • Guest
The link in scarmanis post Post 514666 to the...
« Reply #6 on: August 25, 2004, 11:05:00 PM »
The link in scarmanis post

Post 514666 (missing)

(scarmani: "Et3SiH / TFA Reduction - Improvements?", Serious Chemistry)
to the uploaded article is broken. Not the DOI which leads to a download for registered users only but the link to the uploaded file here on the board.

regards
ORG


java

  • Guest
The wrong thread......
« Reply #7 on: August 25, 2004, 11:29:00 PM »
OrganikumI think you meant to post on the serious chemistry Phenylalanine to
amphetamine.... I have the article , do you want me to upload it ....java

Edit: I uploaded it on the Phenylalanine to a
amphetamine thread......java