(Stranger)
11-16-02 13:51
No 380306
(Rated as: excellent)
This is a translation of a french article Bull. Soc. Chim. Fr. (1973), (4)(Pt. 2), 1424-6. It was wanted by Rhodium and I had it, so I post the experimental details of it....
Abstract
The Mannich reaction of ClCH2CHO with indoles in the presence of NHR32 gave gramines I (R = H, Me; NR32 = NMe2 morpholino; R3 = H, MeO) which were reduced by NaBH4 to the corresponding tryptamines II. Hydrolysis of I gave the amino alcs. which also rearranged to the a-hydroxytryptamines; dimerization during hydrolysis was also obsd. Treating II with addnl. ClCH2CHO gave tetrahydrocarbolines III (Q = CHCH2X, X = Cl, OH, H, SO2C6H4Me-p) by a Pictet-Spengler condensation. Redn. with NaBH4 gave the azepinoindole III (Q = CH2CH2).
Introduction:
The condensation of indole with chloroacetaldehyde and dimethylamine provided the alpha-chloro-methyl-gramine 1a isolated in the form of its chlorhydrate. The base of Mannich 1e of the methoxy-5-indole with chloroacetaldehyde and dimethylamine also has been prepared. The yields vary from 30 to 45%.
An interesting and simple reaction of those chloromethyl-gramines was the reduction in ionizing medium (6, 7). The reduction of the alpha-chloromethyl-gramine 1a by sodium tetrahydroborate in diglyme provided the dimethyl tryptamine (DMT) (yield 37 %).
The methyl-1 and methoxy-5 dimethyl tryptamines 2b and 2e have also been prepared.
(...)
Experimental:
alpha-chloro-methyl-gramine 1a, method A
Stir at RT, till dissolution, 2,75g of anhydrous sodium carbonate in a slurry of 50 mL of GAA and 25 mL of propionic acid. Add to this solution 11.7 g of indole (0.1 mol) and 8.8g (0.11mol) of dimethylamine-HCl in 5 mL of diglyme. Cool between -5°C and 0°C and add 11g of chloroacetaldehyde hydrate (containing 75% of the chloroacetaldehyde, 0.1 mol). Stir for 1 hour and keep the temp below 0°C then keep it for 5 days in the freezer at +5°C. Pour the reaction on some piece of ice. A white, snow-like precipitate form. This precipitate (the product of the indolic condensation) is essored. The acid filtrate is extracted with cold ether. The aqueous layer is then energically cooled and ether is added. With stiring this solution is neutralised with some aqueous NaOH. The following operations are then effectued rapidly: decant the ether layer, dry it on Na2SO4, and then with stirring and at low temperature add some hydrochloric ether.
The alpha-chloromethyl-gramine HCl (1a) fall as a viscous oil. The ether is decanted, and the oil is recrystallised with a little absolute EtOH. Add if necessary anhydrous Et2O. The product may have a pink coloration.
Crude yield: 11.7 g (45%), mp=131°C. Recrystallise 3 times in Et2O-EtOH or acetonitrile, final yield: 8.2g (32%), mp=138°C.
N,N-dimethyl tryptamine 2a
1 g of alpha-chloromethyl-gramine HCl is added to a suspension of 2,5 g of NaBH4 in 75 mL of diglyme at 55°C with stirring. The slurry is warmed to 85-90°C and is kept at that temperature for 48h. The yellow coloration has disappeared. After 24h the mixture is cooled and poured on some ice. This is extracted with ethyl acetate and then the solvent is removed. The remaining oil has got a scatole stench and the TLC show two spot with Rf equal respectively to authentic sample of scatole and of DMT. These two products are separated by column chromatography (silice-celite 1/1). The scatole is eluted first with benzene and is identified by its mp and its picrate salt. The DMT is eluted with methanol (270 mg, 37%). After one recrystalisation with hexane, the product melt at 45°C, this mp is inchanged when authentic sample is mixed with it. The DMT is confirmed by its picrate salt, mp 166°C, and by its UV and IR spectra.
5-methoxy-N,N-dimethyl tryptamine
Same procedure. With 1g of the chloromethyl-amino-indole HCl we obtain an oil with only one spot on TLC. The picrate of this indolic base has got a correct analyse on C,H and N. It melt at 176°C. The freebase crystallise and its mp is 69°C. Yield: 28%, the HCl salt has a mp of 146°C.
(Hive Bee)
11-16-02 19:46
No 380402
good job :)
"Turn on, Tune in and Drop Out"
(Hive Bee)
11-17-02 03:20
No 380452
Pr(+)tium
(Hive Bee)
12-06-02 10:31
No 386909
Decant the ether layer, dry it on Na2SO4, and then with stirring and at low temperature add some hydrochloric ether.
What is hydrochloric ether? Is that a mixture of HCl and diethyl ether? I have already UTFSE, but didn't found anything useful.
And also, what is chloroacetaldehyde hydrate?
I'm dreaming of the white crystals.
(Moderator)
12-06-02 13:15
No 386968
It should probably read: '...add some hydrochloric acid.'
A hydrate is the condensation product of aldehydes with water: -CHO + H2O __> -CH(OH)2. The free aldehyden (if available) should work as well.
(Stranger)
12-07-02 08:20
No 387154
They mean some ether (dry) that has been gased (satured) with some DRY gaseous HCL, because you have got the chlorydrate in water, then you basify with aq NaOH, the freebase go in the ether, you decant that ether, dry it, and then add some dry ether with some HCL dissolved in it (but you can gas it directly with dry HCL) the insoluble chlorydrate formed fall out of the ether, then you decant that ether and add some alcool to crystallise the oil. I dont know the solubility of HCl in ether though.