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Topic: Halogenation of Amino Alcohols  (Read 5914 times)

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Offline java

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Halogenation of Amino Alcohols
« on: January 03, 2006, 05:49:20 PM »
In the halogenation of primary non benzylic alcohols such as Phenylalaninol require more than the requirements for the secondary and tertiary alcohols.  There may be some merits to the Lucas Test in the halogenation of tertiary , secondary and possible primary with some heating of the solution .

The Lucas test  involves using ZnCl + HCl  for the chlorination of alcohols however there must be other ways to halogenate the alcohols save the use of thionyl chloride and the Phosphorous acids .

I'm looking for suggestions on a method with some references as primary alcohols are very stubborn to halogenation save using big guns which are not readily available.

Ref:  

http://jchemed.chem.wisc.edu/JCESoft/CCA/CCA5/MAIN/1ORGANIC/ORG11/TRAM11/C/0362502/MOVIE.HTM
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Offline HP

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Re:Halogenation of Amino Alcohols
« Reply #1 on: January 04, 2006, 01:58:08 PM »
I am thinking about possible halogenation of colamine with H2SO4conc/NaCl by this sheme:
NH2(CH2)2OH + H2SO4conc.-->HSO3-NH3+(CH2)2-
OSO3H (N,O-hydrogene sulfate). This reaction should be done with cooling to prevent dehydration of the O-hydrogensulfate. If next you add some NaCl to generate nascent HCl and may be heat then O-hydrogensulfate as leaving group should react with HCl to obtain the hydrogensulfate amonium salt of 2-Cl ethylamine. After that NaOH to obtain the free 2-chlorethylamine. May be the N,O-hydrogenesulfate intermediate will react and with conc. HCl in heating and so the yeld product could be better. Just try i dont know :)
xpp

Offline java

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Re:Halogenation of Amino Alcohols
« Reply #2 on: January 04, 2006, 05:03:48 PM »
Preparative synthesis of primary and secondary alkyl chlorides from alcohols
N. P. Volynskii1, L. I. Perepelitchenko1 and L. A. Zegel''man1
Russian Chemical Bulletin (Historical Archive),(1987), Volume 36, Number 11, pg.2326 - 2328
ISSN: 1066-5285 (Paper) 1573-9171 (Online)
DOI: 10.1007/BF00957308

Conclusions We have developed a preparative single-stage tosylate method for obtaining chlorides from secondary and primary alcohols which isomerize when chlorinated by other methods.
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2506–2508,
November, 1987
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Offline java

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Re:Halogenation of Amino Alcohols
« Reply #3 on: January 12, 2006, 10:23:47 AM »
(Chloro-phenylthio-methylene)dimethylammonium chloride
(CPMA) an e?cient reagent for selective chlorination and
bromination of primary alcohols

Laurent Gomez,a FrancË oise Gellibert,b Alain Wagnera,* and Charles Mioskowskia,*
 
Abstract
(Chloro-phenylthio-methylene)dimethylammonium chloride reacts smoothly with a variety of alcohols, to a?ord the corresponding alkyl chloride in good yields. In the presence of tetrabuthylammonium bromide the corresponding bromide is obtained. Selective halogenation of primary hydroxyl groups in the presence of an unprotected secondary one is described. The mild reaction conditions involved are compatible with the major alcohol protecting groups as well as with acid sensitive functions like epoxides.
« Last Edit: January 12, 2006, 10:24:26 AM by java »
It's better to die on your feet, than live on your knees.Emiliano Zapata..."Prefiero morir de pie que vivir siempre arrodillado."

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