Then dry the DCM+oil with some DRY MgSO4 and decant in 2L erlenmeier.
Wash this MgSO4 with some fresh, DRY DCM and add the DCM washings to the now dry DCM+oil. Total volume DCM+oil =1000 ml, colour is honey/red.
Start now bubbling this 1000 ml with HCl-gas, while 2L erlenmeier stands in icebath on magn.mixer and mix strongly.
Check pH frequently, proceed until pH 6.
Pour the now acidified 1000 ml in a 2 L evap.flask and put on Rotavap machine. Speed= 100 rpm , temp= 80 C, mode=p/auto, little vacuum=800 mbar, to hold the flask.
After distillating off nearly all the DCM, suddenly the contents of the flask turns from dark honey colour to
creamy milk color and it dries out to a round cake on the bottom.
Remove the 1 L DCM, now in the collector flask, and hang that empty flask on again.
Now put full vacuum on to remove the last traces of water.
Cleaning by 3 x recrystalization: Put MINIMUM quantity of hot (40 C) DRY DCM (or dry 98+% Ethanol) in the flask until the last remains of the dry stuff dissolves, and add 4 x this DCM-quantity in the form of DRY acetone. Close with stopper and put 1 hr in freezer.
A solid dirty-white crystal mass is formed with a layer of dark red fluid on top of it.
Decant the fluid and repeat this step another 2 x and 2 Hrs. You have, the last time, snow white crystals.
Dry Weight = 141,5 gram, close to quantitative yield.
You can eventually melt this crystal mass in a alu flatbottom pot on a heaterplate at 170-175 C. Then let this
melt, VERY SLOWLY, and do not go higher then necessary to melt it, or its starts smoking ( you have your first quick-test then: enjoy!). Cool down to 150 C again, really slowly, 1 degree C per 30 min. (regulate with your temp controller!), and you got d,l-ICE, after you let it very slowly again cool down to roomtemperature (with a closed lid on it!, its hygroscopic ! ).
Advantage: you removed ALL the water in this process!!!
You can better make the sulfate salt following Logicals method :
Let 10% H2SO4/Ethanol mix acidifying a 1:4 mix of freebase Meth/Ethanol. This is not so hygroscopic. Filter and dry the crystals.
So now you know at last how to make ICE cream……. Ravers LOVE it!!!! LT/
——————
EMOTIONSwill always beFREE!
——————————————————————————–
LaBTop ………. posted 06-23-99 01:19 PM
Member
Yohoo, forgot to tell:
Use d-Tartraric acid to get d-Meth !!!!!!!!
2 Flies in one hit….
Ask your beloved moderator, the unforgettable Mr. Spit_tartrar_Ball, he knows how to do that, he recently
posted the method, but needs a little explaining for most of you, I’m afraid. But thou should NOT be afraid, its
easy! (See for a blatent error the Chirality thread in the Serious Chemistry forum).
Then you have d-Meth (the softer part) AND l-Meth (which is speedy only). Life becomes easier and easier……? LT/
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Sunlight’s method of preparing 10% Methylamine solution in Methanol, from aqueous 40% Methylamine .
This is a convenient adaptation of the NaBH4 One Pot procedures using aqueous Methylamine instead of the gaseous form.
He liberated the MeNH2 as a gas with dry NaOH pellets :
sunlight
(Hive Researcher)
07-10-00 02:15
If you should try to use directly a 40% aq. MeNH2 solution you will get a 60 % yield based on the pure ketone.
The procedure to dehydrate ( get rid of the water-part) the aq. methylamine is, for example:
Put in a 2-neck flask 700 grams of commercial dry NaOH, and using a compensating pressure separatory funel attached to one of the necks, add slowly over one hour 350 cc of aq. methylamine to the NaOH. In the other neck attach a rubber stopper with a teflon tube and to it a glass tube with a gas diffusor ( a tiny glasfunnel with a glasfilter glued in it with 6 seconds glue or two component glue or just melt it tight with a torch ), and bubble the MA-gas in 1000 cc of methanol in a flask in a methanol- or water/ice bath.
Reaction is endothermic, finally you can heat a bit the NaOH containing flask to force the liberation of the last gas, but it’s not really necessary, just shake it to see a homogeneus paste.
The compensation of pressure can be done using a regular separatory funel if you attach a 1-hole rubber stopper with a teflon tube connecting to the NaOH flask, if you use a 3-neck flask you can use the other neck, and if you use a two neck flask, you can use in one of the necks a 2-hole rubber stopper, 1 hole connecting to the stopper in the neck of the separatory funel and one to the … dripping hole of it (sorry, it’s my english…)
You can refill your sep. funnel with aq. methylamine if it’s not enough big to complete the whole liberation of all the gas, close the valve and close the other tube, open it and put the aq. solution in, then stop it and free the other tube.
The absortion of methylamine in methanol at 0-5 C is perfect, you don’t even need to redirect possible fumes from the methanol, there aren’t, but stop the flask with some papertissue to prevent the entry of humidity.
The gas diffusor can be done with a regular glass tube, try to enlarge a bit one of the ends, and then try to weld inside it a piece of fine filterglass for the gas bubbles feed, it will act as a diffusor, not very good, but enough, and it won’t heighten the pressure too much (one stopper could jump and you would have a toxic ambient atmosphere of methylamine in your viginity).
Probably using a pipette will work, absortion is very good.
You can weight finally the 10% methanolic solution of methylamine to know the exact weight of gas you have in it (you weighted it before).
You will have a bit of water, but don’t worry, mix it with the ketone (350 grams), add silica gel (160 gr) and shake and let stand , shake and so on … during an hour, filter and wash the silica with 200 – 300 cc of methanol, add the NaBH4 at +7 C ( an ice/salt bath works fine) to get from 75 – 87 % of the desired product depending on the purity of your ketone.
You can dehydrate the methylamine gas by passing it through a flask with NaOH, but it’s not necessary due to the addition of silica gel.
Beaker
(Hive Researcher)
07-10-00 10:11
From *http://rhodium.lycaeum.org/chemistry/meam-pdc.txt*; :
” KrZ (Hive Researcher) : The mix {MeNH2 + 2H2O (The product of catalytic hydrogenation of methylamine) in methanol with Na2SO4} was split in half and each half sat with 1500g of Na2SO4 for an hour, with occasional stirring. The Na2SO4 ( sodiumsulfate) was filtered off for a long time, until it was quite dry in appearance, the mix halves were combined and washed 2x with 1L of CH3OH (methanol), which was filtered off and added back to the solution.”
sunlight
(Hive Researcher)
07-11-00 00:39
We did something similar with MgSO4, trying to dry a mixture of 40% MeNH2 and methanol, and the end product was titrated and it was about 3 % instead of 10 % w/w (weight/weight), the MgSO4 had a strong smell of methylamine, so we thought most of the gas was ended in the water and in the magnesiumsulfate, and we tried the above procedure, that works fine.
WISDOMwillWIN
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
IVa.— 2,5-DIMETHOXYBENZALDEHYDE—* 2CH—* 2CB
Posted by :
Beaker
(Hive Researcher)
07-09-00 00:48
2CB for the LAH impaired.
The following is a synthesis of 2CB from 2,5-dimethoxybenzaldehyde that does not require the use of the
slightly hazardous and/or difficult to obtain reagents normally associated with its synthesis, notably LAH,
pressurized H2, and Br2. No doubt some clandestine chemists have been discouraged from attempting the synthesis of what is, IMHO, a pretty cool substance by the nature of these reagents and the lack of a clearly written procedure for an alternate route that does not use them. However, alternate routes do exist, and one of them is detailed below. Note that this route does require one additional step to acheive the nitrostrene reduction than with the use of H2 or LAH, but that the yield is actually substantially higher than what others have reported with those reducing systems. Also, the bromination procedure is somewhat unrefined at present and does not result in the greatest of yields or the easiest of workups, so feel free to use the classical
procedure if you want to make or buy your own bromine. As a final note, although this route will happily accomodate batch sizes of ~50g in 2L glassware, it does not scale anywhere near as well as catalytic hydrogenation, so if you’re trying to go huge, it’s probably not for you.
Scaleup should not be a problem, but due to the rather low product loading that you can obtain with the method as written, it is rather impractical at *50g scale. Bigger than that and I would suggest that one look into catalytic hydrogenation a la KrZ’s mescaline writeup or finding a way to cut the amount of solvent back quite a bit. For most people, ~80g of 2CB out of 100g, or $60 worth of 2,5-dimethoxybenzaldehyde is more than enough.
Step 1
Condensation of 2,5-dimethoxybenzaldehyde with nitromethane
In a 500mL RBF equipped with a reflux condensor and a stir bar, place 100g 2,5-dimethoxybenzaldehyde, 15g ammonium acetate, and 250mL of nitromethane. Heat to a gentle reflux while magnetically stirring. Maintain reflux for ~45min, by which time the color of the solution should progress from clear/yellow to a deep reddish-black. Remove heat and carefully pour the hot rxn mixture into 1L of ice-cold 70% IPA. Allow the IPA/rxn mixture to stand for a while. You should now have a flask full of orange solids floating in red/black mother liquor. Vacuum-filter the solids and wash them with additional portions of ice-cold 70% IPA until the
filtrate is no longer reddish(It will become very slightly orange in color with small amounts of dissolved nitrostyrene. Thoroughly dry the collected orange solids by pulling air through the filter for a while and then dry under vaccum. It is very important that the nitrostyrene be completely dry before proceding to the next step.
Yield – 106.1g (84%) of 2,5-dimethoxynitrostyrene
Purity – Single spot by TLC, NMR is clean
Step 2
Sodium borohydride reduction of 2,5-dimethoxynitrostyrene
Into a dry 2L RBF flask equipped with a stir bar was added 400mL of anhydrous ethanol(If you can’t get anhydrous ethanol, use anhydrous IPA. DO NOT USE METHANOL!!!). The rxn was cooled to 0C in an ice/water bath and 36.2g of sodium borohydride was added(slight H2 evolution). A pressure-equalized addition funnel was charged with a pre-made saturated solution of 50g 2,5-dimethoxynitrostyrene in THF(about 600mL) and attached to the flask. A piece of tubing was attached to the top of the addition funnel and run outside to vent the hydrogen that will evolve during the course of the reaction. While maintaining the ice/water bath, all of the bright yellow nitrostyrene solution(refill the addition funnel if necessary) was slowly(reaction is
exothermic, so watch it) added to the sodium borohydride solution over the course of ~90 min (Note: gas will evolve over the course of the addition. It is H2. Be careful). After the addition is complete, the rxn was allowed to stir for an additional 10 min and then poured into a 4L erlenmeyer containing 1L of H2O and a 3″ stir bar (H2 evolution). While stirring, 250mL GAA (Heavy H2 evolution) was carefully added (one could use 400 mL 31.45% HCl). The quenched reaction mixture was divided into three portions. In a 2L sep funnel, each portion was combined with 500mL Et2O(or toluene) and 500mL brine. The funnel was shaken and the aqueous (bottom) layer was discarded. The organics were washed with 3 additional 500mL portions of brine. This was
repeated with the other two portions. The organics were combined, dried over MgSO4, filtered and the solvent
evaporated to give a clear yellow oil.
Yield – 47.0g of crude 2,5-dimethoxynitroethane
Purity – Two spots by TLC. NMR analysis indicates a 50:1 molar ratio of the desired product to dimeric impurity (this is the only impurity present). Adjusted yield of 2,5-dimethoxynitroethane is 45.2g (89.5%).
Step 3
Catalytic Transfer Hydrogenation of Crude 2,5-dimethoxynitroethane
The crude product of the previous step was dissolved in 400mL MeOH and placed in a 1L RBF equipped with a stir bar. In a separate beaker away from all combustible materials, 1 g of 10% Pd/C was carefully wetted down with MeOH and the resulting slurry transferred to the rxn flask. To the rxn flask was added 62g ammonium formate. The flask was equipped with a reflux condensor, a piece of tubing was attached to the top of the condensor, and the end of the tubing was submenged in a container of water (this works to exclude O2 from the rxn while allowing the evolving CO2 to escape). The rxn was gently refluxed for 24 hr.(CO2 evolution), cooled, filtered through celite to remove the Pd/C, and the solvent evaporated. The residue was taken up in 150 mL of Et2O (or toluene) and 300 mL of H2O and the pH adjusted to *12 with 20% NaOH. The mixture was transfered to a sep funnel, shaken, and separated. The aqueous layer was extracted with 2 x 100 mL portions of Et2O (or toluene). The combined organics were dried over MgSO4, filtered, and gassed with HCl (2CH x HCl is partially soluble in DCM, so don’t gas in that solvent). The resulting white crystalline solids were filtered, washed with Et2O, and allowed to air dry to give 2CH Hydrochloride.
Yield – 43.8g (94%) of 2CH Hydrochloride.
Purity – Single spot by TLC. NMR is clean.
Step 4
Bromination of 2CH Freebase.
The 2CH x HCl was dissolved in a 300 mL H20. The pH was adjusted to *12 with 20% NaOH and the aqueous layer was extracted with 4 x 100 mL DCM. The DCM was evaporated to give 2CH freebase, which was dissolved in 500 mL of 3:1 AcOH/H2O. The rxn was cooled to 0C in an ice/water bath. 37.3g of 48% aq. HBr was added, followed immediately by 23.8g of 30% H2O2. The rxn was stirred for 6 hr, allowing the ice bath to melt. The majority of the AcOH was removed under vacuum and the nasty reddish-black rxn mixture was
partitioned between 1L H20 and 500 mL EtOAc(EtOAc was found to be much better for dissolving the impurities in this rxn than Et2O or toluene. This is messy at first, but everything should go into solution after much agitation). The layers were separated and the aqueous extracted with an additional 500 mL EtOAc.
The aqueous was basified to pH *12 with 20% NaOH and extracted with 3 x 200 mL portions of Et2O.
The combined organics were washed with 400 mL brine, dried over MgSO4, filtered and gassed with HCl.
The resulting tan crystalline solids were filtered and recrystalized from boiling 1:1 IPA/Toluene to give pure 2CB x HCl as a white crystaline solid.
Yield – 34.0g (57%) of 2CB Hydrochloride.
Purity – Single spot by TLC. NMR is clean.
I have references for the two reduction steps and the bromination, but can’t seem to find them. If someone asks really nicely I might be persuaded to find and post them.
Also, before some jackass reads this procedure and asks me why 4 eq.of sodium borohydride is used for the reduction, here is a interesting little table for your reading pleasure.
(Eq. NaBH4) -* Molar ratio of 2,5-dimethoxynitroethane to dimer :
(2.5) -* 6.25 : 1
(3.5) -* 44 : 1
(4.0) -* 50 : 1
Rhodium
(Chief Bee)
07-09-00 05:55
Beaker – this was certainly one of the single best posts to the Hive after the software change! Great!
*http://rhodium.lycaeum.org*
~~~~~~~~~