hypo (Hive Bee)
12-30-01 15:24
No 251334
      gassing tryptamine out of DCM?  Bookmark   

suppose you have a mixture of tryptophan, tryptamine and indole in DCM.

1) would it be possible to gas with HCl and filter the tryptophan and tryptamine off as HCl salts? or in other words: is tryptamine.HCl soluble in DCM?

2) am i right, when i believe that indole does not easily form a HCl salt and thus would stay in the DCM? (because the nitrogen in the indole ring is not basic)
 
 
 
 
    hypo
(Hive Bee)
01-05-02 11:50
No 252903
      Please Help!  Bookmark   

okay, okay, okay. the question was stupid. had i looked in the merck index, i would have known that tryptamine is not soluble in chloroform and thus propbably neither in DCM.

but that leads me to new questions that puzzle me:

1) in Post 211603 (Rhodium: "Another tryptophan decarboxylation", Tryptamine Chemistry):

A suspension of the L-Tryptophan copper chelate in DMSO was heated at 170-175C for 10 minutes (until the evolution of carbon dioxide had ceased). After cooling, the resultant solution was filtered and to the filtrate was added a suitable amount of water. The reaction mixture was made basic with 30% sodium hydroxide solution and extracted with chloroform. After distillation of the solvent, the product was purified through column chromatography on silica gel, yield 40%. The tryptamine was identified as its hydrochloride salt, mp 246-248C.


why are they extracting with chloroform?? tryptamine is not soluble in chloroform i thought! and it is not soluble in water either, so i would expect it to crash out of the solution when adding water. what's happening here??

2) in ../rhodium/chemistry /tryptophan.html:
 
A good way to purify tryptamine without having to resort to distillation under strong vacuum is to dissolve the crude tryptamine hydrochloride in water, adjust the pH to between 7.6 and 8.2 and extract the solution with chloroform. The pH is then adjusted to 14 with NaOH and the pure tryptamine is filtered off with suction and air dried.

what is the purpose of this? is tryptamine at pH 7.6 - 8.2 still mainly the HCl salt? why extract with chloroform? tryptophan is only slightly sol in chloroform, isn't it?

in short: i dont get it. any help appreciated.
 
 
 
 
    Lilienthal
(Moderator)
01-05-02 12:29
No 252910
      Re: Please Help!  Bookmark   

Tryptophan should me more or less insoluble in DCM due to it's zwitterionic nature and the same is true for (most) tryptamine salts.But tryptamine base is soluble in DCM (but it may take a while + heating to dissolve it). Indole is also soluble in DCM and doesn't form salts (under normal circumstances, it's somehow similar to an amide-NH).
 
 
 
 
    terbium
(Old P2P Cook)
01-05-02 20:47
No 252966
      Re: Please Help!  Bookmark   

Yes, the Merck Index says that it is pratically insoluble in water, chloroform, ether and benzene.

  Monograph number: 9927
  Title: Tryptamine. 
  CAS Registry number: [61-54-1]
  CA name(s): 1H-Indole-3-ethanamine; 3-(2-aminoethyl)indole;
  Additional name(s): 2-(3-indolyl)ethylamine. 
  Molecular formula: C10H12N2
  Molecular weight: 160.22
  Composition: C 74.97%, H 7.55%, N 17.48%. 
  Literature references: Occurs in plants.  Synthesis starting with nitroethylene and indole:  Noland, Hartman, J. Am. Chem. Soc. 76, 3227 (1954).  Alternate routes:  Thesing, Schulde, Ber. 85, 324 (1952); Jackson, Smith, J. Chem. Soc. 1965, 3498; Tacconi, Farmaco Ed. Sci. 20, 902 (1965); S. Takano et al., Heterocycles 6, 1167 (1977); I. Fleming, M. Woolias, J. Chem. Soc. Perkin Trans. I 1979, 829.  X-ray structure determn:  Wakahara et al., Tetrahedron Letters 1970, 4999.  Review of tryptamine syntheses:  J. E. Saxton in R. H. F. Manske, The Alkaloids, vol. VIII (1965) pp 8-10.
  Properties: Needles from petr ether, mp 118 deg.  uv max (ethanol):  222, 282, 290 nm (log .epsilon. 4.56, 3.78, 3.71).  Sol in ethanol, acetone.  Practically insol in water, ether, benzene, chloroform.
  Melting point: 118
  UV Maxima: 222; 282; 290

  Derivative: Hydrochloride
  Molecular formula: C10H12N2.HCl
  Properties: needles from ethanol + ethyl acetate, mp 248 deg.  uv max (95% ethanol):  221, 275, 281, 290 nm (log .epsilon. 4.52, 3.73, 3.75, 3.69).
  Melting point: 248
  UV Maxima: 221; 275; 281; 290