Author Topic: 4-Methyl-2,5-dimethoxybenzyl chloride (French)  (Read 2559 times)

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Rhodium

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4-Methyl-2,5-dimethoxybenzyl chloride (French)
« on: December 07, 2001, 12:52:00 PM »

Osmium

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Re: French translation please
« Reply #1 on: December 07, 2001, 03:26:00 PM »
2,5-dimethoxy-4-methyl-benzyl chloride:
A 3 neck round bottomed flask equipped with a mechanical stirrer and a reflux condenser is charged with 31.5g 2,5-dimethoxytoluene, 120ml conc. HCl and 53ml 38% formadehyde solution. Stirring is started and dry HCl is rapidly bubbled through the reaction. The mixture heats up, and after one hour, when the temperature begins to drop, external heating with a 95-100°C oil bath is employed for another hour. After cooling the mixture is extracted three times with ether, which causes a colourless solid to precipitate (5-6g) which is removed by (?) wringing out/centrifugation (?), washed with ether and recrystallized from two parts of benzene. F. 144-146°C

Edit by Rhodium: Apparently this precipitate is the diphenylmethane dimer. The rest of the procedure reads as follows:

The pooled etheral layers are washed with water and dried over Na2SO4. After evaporation of the solvent, the residue is fractionately distilled to give 17.3g of the benzyl chloride (bp 150-158°C/17mmHg), which crystallizes upon cooling. It is recrystallized from a small amount of benzene/petroleum ether 1:1 to give crystals melting at 62-63°C.

Rhodium

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Re: French translation please
« Reply #2 on: December 07, 2001, 03:59:00 PM »
Oh, that yield sucked bigtime. Thanks anyway. As it turns out, I was lucky and found a much better yielding method in JOC 25, 1453 (1960):

4-Methyl-2,5-dimethoxybenzyl chloride

Gaseous hydrogen chloride was bubbled into a well-stirred mixture of 200 ml. of 35% formaldehyde, 100 ml. of conc. hydrochloric acid, and 400 ml. of dioxane for 15 min. at such a rate that the temperature of the mixture remained between 55-60°C with no external heating. To this mixture 152g (1.0 mole) of 2,5-dimethoxytoluene was added, dropwise, over a period of 20 min., while the temperature was maintained between 55-60°C. When the addition was completed, the passage of hydrogen chloride was stopped. The mixture was cooled and poured into 2 1. of ice water and 300 ml. of ethyl ether. The aqueous layer was extracted twice more, with 250-ml. portions of ether. The combined ether extracts were washed with cold water until the washings were neutral to litmus, then dried with anhydrous magnesium sulfate, and evaporated under reduced pressure. The residue was distilled through a 4-in. Vigreux column to give 110-130g (55-65%) of colorless liquid, b.p. 144-153°C/14-16mmHg, which solidified on cooling. Recrystallization from acetonitrile gave white crystals, mp 61.5-62.5%.

Rhodium

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Re: French translation please
« Reply #3 on: December 09, 2001, 07:55:00 PM »
This is also french, could I have that translated too?

https://www.thevespiary.org/rhodium/Rhodium/archive/french.jpg


hypo

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Re: French translation please
« Reply #4 on: December 10, 2001, 06:36:00 AM »
does that make sense?

2,5-dimethoxy-4-methyl-phenylacetonitrile (XIX). 13.2g of the molten mixture (XVIII) are introduced in a mixture of 40g NaCN, 65ml H20 and 70ml alcohol. After boiling at reflux for 20 min the alcohol is removed by distilation, the residue diluted with 1 volume water and extracted with ether. The residue is dryed over Na2CO3, the ether evaporated and the residue fractionated under vacuum (23 mm Hg); One gets two fractions with bp 163-166° (8.4 g) and 179-180° (3.0 g) respectively. The latter fraction solidifies on cooling (mp 55-64°) and can be recristalysed in 1-2 parts of alcohol. One gets 1.30 g of mp 66°. With further recrystalisation the mp climbs to 67-68°.

The first fraction solidifies partly after cooling to 0°. The solid (3.8 g) is fractionated with destillation under vacuum (21-22 mm Hg). One thus obtains 3.0 g with bp 155-156° and 0.54 g with bp 165°. The second fraction still provides 0.20 g of the nitrile. The bulk of the first fraction solidifies and gives crystals of mp 28-29° which, after their composition in percent [huh??] and their alcoxyl group content, consist of a mixture of 90% 2,5-dimethoxy-4-ethoxymethyl-toluene [wtf??] and 10% of 2,5-dimethoxy-4-methyl-benzylalcohol. With HCl gas treatment in ether one recovers the derivative XVIII of benzyl chloride.

2,5-dimethoxy-4-methyl-phenylaceticacid (XX).. 1.15 g of the derivate XVII of benzyl chloride is treated with NaCN like before. The residue of the ethereal solution is not fractionated, but directly saponified with alkali. One adds 6 ml alcohol and a solution of 1.5 g KOH in 3.8 ml water and refluxes for 10 hours. After addition of 5 ml H2O, the neutral productsare eliminated by extraction with ether. After acidifying the aqueous solution with conc HCl, 700 mg of crystals with mp 124-126° appear. After recrystalisation in 60 parts water, the mp climbs to 131-132°.

The same product was obtained by methylation of 2-hydroxy-5-methoxy-4-methyl-phenylaceticacid (XIII) with DMS in presence of NaOH in the usual conditions.

Rhodium

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Re: French translation please
« Reply #5 on: December 10, 2001, 07:00:00 AM »
It sounds really strange. XVII is the benzyl chloride, made as in the first post in this thread, which is supposed to be turned into the phenylacetonitrile with NaCN. But I can not understand which of the fractions which really is the phenylacetonitrile, and what the yield of it was. If 2,5-dimethoxy-4-ethoxymethyl-toluene is a misspelling for the nitrile, then the yield is quite okay with 90%, but I still don't understand shit.

Are you a native french speaker, hypo? Perhaps someone really french guy like Masquerade could help us understand the details?

The reference is Helvetica Chimica Acta 34(6), 1564-1579 (1956) is someone is interested.

hypo

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Re: French translation please
« Reply #6 on: December 10, 2001, 07:13:00 AM »
but the yield is not 90%. they start with 13,2g XVIII and end up with 3g crystals of which 90% are the supposed nitrile and 10% the benzyl alcohol. (after 2 distillations and multiple crystalisations). let's see what masquerade thinks.

Rhodium

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Re: French translation please
« Reply #7 on: December 10, 2001, 07:16:00 AM »
They MUST get a better yield than 25%, even if they are using lab technique from the 1950's...

hypo

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Re: French translation please
« Reply #8 on: December 10, 2001, 07:29:00 AM »
probably, but look what they are doing: they fractionate the reaction residue and get one fraction with 8.4 g (the good one). they cool this fraction to 0°C and only take the the part that solidifies (3.8 g). i bet the rest is full with good stuff. these solids are again fractionated and remains only 3.0 g!