Sciencemadness Discussion Board - The Short Questions Thread (4)

The Short Questions Thread (4)

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solo - 8-2-2022 at 14:31

Thank you for the time you've taken to reply, yes i appreciate your insight and would welcome the references you mentioned. Both of my inquiries you've taken time to assist me, your contribution is very positive and well received........solo

AvBaeyer - 8-2-2022 at 19:54

Solo,

Pleased to know you appreciate my comments. I must confess, however, that I was enjoying my after-dinner glass of port when I wrote my comments. I mentioned the nitration of 1-phenylethanol as a possible starting point which could be nitrated. I do not think that alcohol would survive nitration even if protected. I think starting from acetophenone would be a much better starting point. So much for that.

As for references, here is what I have and with one exception they are all patents.

Non-patent reference: J. Keck et al., Arzneim-Forsch., (1972), v22, 861 and 869 (two articles, synthesis and pharmacology)

For Synthesis 1 (per my previous post):
DOS 1,793,419 (Thomae)
BE 704,213 (Thomae)
US 3,536,712 (Boehringer Ing)

For Synthesis 2:
DOS 2,157,040 (Thomae)
DE 1,543,928 (Thomae)

Additional Patents:
DAS 2,354,959 (Thomae) - alternative synthesis
US 3.536,712 (synthesis)

DOS and DAS are German patents, that is all I can tell you.

My information comes from:
Dictionary of Pharmacological Agents
A. Kleeman, et al., "Pharmaceutical Substances, Syntheses and Patents," 4th ed, 2001 (Georg Thieme Verlag)
Merck Index

Happy reading! Now to my evening port.

AvB

solo - 2-3-2022 at 15:07

It came to mind that if i can manage to oxidice ethy acetate via some alkane intermediate , i can synthesise acetic anhydride.....any tips on how can i go about accomlishing this.......solo

ethyl acetate

acetic anhydride

Note: however i did read this "Alkanes usually resist oxidation with oxidising agents such as KMnO4, K2Cr2O7 etc. However, alkanes containing tertiary hydrogen can be oxidised to corresponding alcohols."

Note 2:how abot a transterification with totsyl chloride hecemaking it an acidic transterification adding sodium acstate to replace the totsyl chloride all sone in toluene.....just a thought

[Edited on 2-3-2022 by solo]

[Edited on 3-3-2022 by solo]

clearly_not_atara - 8-3-2022 at 20:48

If you have tosyl chloride, you can just make acetic anhydride from that by reacting with sodium acetate. Boom.

The problem with oxidizing ethyl acetate is that it will tend to oxidize at the acetyl carbon rather than the carbon you want to oxidize, giving instead ethyl glycolate or ethyl glyoxylate. Maybe if you tried to do a radical halogenation of benzyl acetate, instead, you could get acetic anhydride or acetyl chloride upon rearrangement. In fact, that might even be a good idea.

Attachment: he2011.pdf (866kB)
This file has been downloaded 79 times

mayko - 15-3-2022 at 05:53

I tried to grow some rochelle's salt crystals... it seemed pretty foolproof: neutralize potassium hydrogen tartrate with sodium carbonate until effervescence ceases, then let it slowly evaporate. Mine has become a thick syrup that refuses to solidify... has anyone encountered this?

solo - 15-3-2022 at 06:49

Quote: Originally posted by clearly_not_atara

If you have tosyl chloride, you can just make acetic anhydride from that by reacting with sodium acetate. Boom.

The problem with oxidizing ethyl acetate is that it will tend to oxidize at the acetyl carbon rather than the carbon you want to oxidize, giving instead ethyl glycolate or ethyl glyoxylate. Maybe if you tried to do a radical halogenation of benzyl acetate, instead, you could get acetic anhydride or acetyl chloride upon rearrangement. In fact, that might even be a good idea.

thaks for that, however a bit puzzled by this.....

"As swim said,I mean Dry distillation.(i did this method many times with Tosyl chloride and even Benzene sulfonyl chloride)

Try 2:1 and 3:1 ratio of sodium acetate : Aryl Sulfonyl chloride"

[Edited on 11-3-2022 by Waffles SS]

,,,,source Acetic Anhydride preparation thread

[Edited on 15-3-2022 by solo]

[Edited on 15-3-2022 by solo]

solo - 20-3-2022 at 19:28

.......well after doing the reaction with the ratios 3:1 , sodium acetate: toluene sulfonyl choride...using 30 grams sodium acetate : 10 grams of toluenesulfonyl chloride , i got 15 ml of a liquid, still not analysed or redistilled ther was no bang!!!, however i did place my reaction vessel in a metal cage ....just in case.....solo

solo - 22-3-2022 at 16:45

…… result, not promising…. I will do the reaction again and will do the reaction on a sand medium keeping temp at 80C …. Keeping reactants from carbonizing …..solo

note : Waffles can you give any other details on your procedure as i seem i didn't have any success....thanks

B4ABBE0F-2715-4160-9B95-F7EEC3B6330C.jpeg - 96kB

[Edited on 23-3-2022 by solo]

artemov - 31-3-2022 at 21:57

Can isobutyl nitrite be used in place of n-butyl nitrite for azide and dimethylglyoxime synthesis (I only have isobutanol)?

I keep reading about n-butyl nitrite in various synthesis, rarely other butyl nitrites ...

mackolol - 22-4-2022 at 06:56

Will plain lithium metal be able to react with phenylacetylene to form lithium phenylacetylide?
I know that one would generally use some sort of a strong base like lithium hydride or amide etc...

But what about the metal? Will it be strong enough to replace the hydrogen? If not, then why?

solo - 10-5-2022 at 03:26

goal is to make 4-amino acetophenone

theory....use ethyl p-aminobenzoate (benzocaine) and ethylacetate in a cleisen condensation in ethanol with Naoetoh , because its a base driven reaction the amine group on the benzene ring won't be affected....however the reaction requires Hcl in order to keep the reaction to the right, now since i want to decarboxylate the alpha-beta ketone that requires an acid and heat.

now all this acid use concerns me since the amine on the benzene ring can be affected , any thoughts of an alterantive or is my premise wrong and i could just heat the solution right after the alpha beta ketone is formed and avoid the use of an acid( whichi doubt) ....solo

solo - 11-5-2022 at 18:15

.....actually there was no need to be concerned with the addition of acid, and the possible reaction with the benzyl amine, after the claisen condensation reaction in order for the reaction to remain to the right.....solo

[Edited on 12-5-2022 by solo]

Texium - 11-5-2022 at 22:25

Quote: Originally posted by mackolol

Will plain lithium metal be able to react with phenylacetylene to form lithium phenylacetylide?
I know that one would generally use some sort of a strong base like lithium hydride or amide etc...

But what about the metal? Will it be strong enough to replace the hydrogen? If not, then why?

I don’t think it would work. Normally using a base like lithium amide or an alkyl lithium, it’s essentially just a simple acid-base reaction. You have a strongly basic anion that deprotonates the alkyne. Li+ as a spectator. With lithium metal, now there’s a redox reaction that needs to occur. Li needs to get oxidized from 0 to +1. Normally this is done by reacting the metal with alkyl halides. Good electrophiles. The metal reduces both the carbon and the halide so 2 Li + RX -> RLi + LiX. In your case, you don’t have a good electrophilic, you’re asking it to form lithium hydride as a byproduct instead. Doesn’t sound so promising. My recommendation, use NBS to convert the phenylacetylene to (bromoethynyl)benzene (I’ve done this reaction before- be warned, the product smells awful) and react that with lithium metal to get your lithium phenylacetalide plus LiBr.

solo - 13-5-2022 at 15:38

I want to chlorinate 4-amino acetophenone not sure if i have to use a metal as a catalyst FeCl3 with a chlorinaing agent.....i saw a reaction where they used TCCA in MeCN at RT for chlorination ....confused .....any suggestions as to chlorinating agent and solvent with or without a metal catalyst.....solo

AvBaeyer - 13-5-2022 at 16:09

Solo,

Solo:

4-Aminoacetophenone has been iodinated with KI/hydrogen peroxide.
Reddy et al., Synth. Commun. 38, 3894 (2008)

2-Aminoacetophenone has been brominated with KBr/sodium perborate i acetic acid
Roche et al., Tetrahedron Letters 41, 2083 (2000)

o- and p-aminobenzoate esters have also been halogenated similarly to the above but I cannot find the exact reference.

You should be able to accomplish chlorination of your compound with KCl/Oxone in water-methanol or water-acetonitrile.
do a Google Scholar search on papers by N.Narender using the terms "oxyiodination", "oxybromination" and "oxychlorination"to get leading references.

AvB

solo - 13-5-2022 at 19:21

.....thank you for your support and advice, slowly i'm working myself to the complete synthesis of clenbuterol......solo

AvBaeyer - 13-5-2022 at 20:00

Solo,

Here is the bromination of p-aminoacetophenone with NaBr/Oxone in aqueous acetonitrile. I expect that chlorination should also work with NaCl or KCl.

Lee, et al., Bull. Korean Chem. Soc. 23, 773 (2002).

AvB

[Edited on 14-5-2022 by AvBaeyer]

solo - 27-5-2022 at 18:56

Does a Claisen cross condensation need to be an anhydrous reaction? I seem to be getting my ester hydrolysed and no beta keto ethyl ester.....I've run the reaction 5 times with the same results even though i changed the addition of reagents in different order ....Hence a friend suggested i use anhydrous ethanol dry my esters....k.

AvBaeyer - 27-5-2022 at 19:08

Dry, very dry.

AvB

solo - 30-5-2022 at 09:38

......after distilling all of my solvents since i didn't have and anhydrous, the cleisen cross condensation finally worked for me after 7 attempts .....therefore 4-amino acetophenone with a MP of 105-106˚C was acquired with broken glass clear crystals ....thanks for the assistance......as the chlorination is next.......solo

solo - 12-6-2022 at 19:36

....i have terbutyl alcohol and need to make terbutyl amine, thought of first making terbutyl chloride with HCl then treating it with aqueous ammonia......any thoughts would be appreciated.....solo

DraconicAcid - 13-6-2022 at 14:05

Quote: Originally posted by solo

....i have terbutyl alcohol and need to make terbutyl amine, thought of first making terbutyl chloride with HCl then treating it with aqueous ammonia......any thoughts would be appreciated.....solo

That will probably work, although the presence of water might muck it up. It's an Sn1 reaction- the carbocation will form, and then react with whatever is closest. You might want to dissolve the ammonia in a non-nucleophilic solvent and then add the t-butyl chloride.

AvBaeyer - 20-6-2022 at 19:46

The reaction of t-butyl chloride with ammonia is destined for failure. t-Butyl chloride is a tertiary halide and will undergo elimination to isobutylene in the presence of ammonia more rapidly than any other reaction.

You can react your t-butanol with acetonitrile in a Ritter reaction to get N-t-butylacetamide. However, I would not bet on an easy hydrolysis of this compound to get t-butylamine. You will need to look up the hydrolysis conditions for such highly hindered amides.

AvB

clearly_not_atara - 20-6-2022 at 20:09

Might consider a Reformatsky reaction of chloroacetate ester and acetone, which eliminates to a 3,3-dimethylacrylate that can, as I understand it, attack ammonia as an electrophile "properly".

Of course, this route is totally different.

solo - 21-6-2022 at 19:17

......I saw this,....solo

Thermodynamic study of direct amination of isobutylene to tert-butylamine
Shangyao Gao
Chinese Journal of Catalysis
38 (2017) 106–114

Abstract
On basis of thermodynamic empirical equations, the thermodynamic parameters for the direct
amination of isobutylene to tert‐butylamine, an atomically economic and green chemical reaction,
were calculated. In particular, the equilibrium conversion of isobutylene under various reaction
conditions close to those used in industry was calculated and discussed. Isobutylene amination is a
temperature sensitive reaction due to its exothermic nature and isobutylene equilibrium conversion
decreases with temperature. However, kinetically, the amination reaction will be faster at a
higher temperature. Thus, there must be an optimum temperature for the reaction. A high pressure
and n(NH3)/n(i‐C4H8) molar ratio promote the transformation of isobutylene to tert‐butylamine.
Developing a highly efficient catalyst under mild reaction conditions is preferred for the amination
process. The reaction was investigated over a series of acidic zeolites. ZSM‐11 zeolite exhibited the
best performance with 14.2% isobutylene conversion (52.2% of the equilibrium conversion) and >
99.0% tert‐butylamine selectivity. The effect of reaction conditions on the performance of the
ZSM‐11 catalyst agreed with the thermodynamic results, which provides guidance for further catalyst
development and reaction condition optimization.

Attachment: Thermodynamic study of direct amination of isobutylene to tert-butylamine.pdf (568kB)
This file has been downloaded 33 times

Sulaiman - 21-6-2022 at 22:03

Quote: Originally posted by mayko

I tried to grow some rochelle's salt crystals.

The salt is deliquescent so I GUESS that some sort of dessicator is required.

Edit : just checked.. <30% RH to dessicate.

Also, decomposes above 55C

[Edited on 22-6-2022 by Sulaiman]

solo - 6-7-2022 at 08:16

Quote: Originally posted by AvBaeyer

Dry, very dry.

AvB

thank you , but tell me this in many of the articles read and videos viewed , the topic of the reaction being anhydrous only shows up when using NaH as a base but otherewise nothing in the use of the bases methoxide or ethoxide....why is that? Is it something one should know from the start .....I had my sample of 4-amina acetophenone analysed , and it turns out to be benzocaine and benzoic acid.....is it that the amine reacted with the enol or the base....quite confused ....I'm currently on test #13 and the same results even though i introduce the ethyl ethoxide last slowly with an excess of benzocaine ....but the results are the same once i add the HCl to keep the reaction to the right.....then heated to decarboxylate.......any hints , and yes i've run the reaction with anhydrous reagents, but the results seems to be the same.......solo

mayko - 6-7-2022 at 20:30

Quote: Originally posted by Sulaiman

Quote: Originally posted by mayko

I tried to grow some rochelle's salt crystals.

The salt is deliquescent so I GUESS that some sort of dessicator is required.

Edit : just checked.. <30% RH to dessicate.

Also, decomposes above 55C

[Edited on 22-6-2022 by Sulaiman]

Where are you getting this? I've never heard of any special drying apparatus being necessary. Wikipedia gives a melting point of 75C, a dehydration point of 130C, and a decomposition point of 220C so I don't feel too bad about heating the aqueous solutions.

I poked and prodded the syrup, dripped ethanol and acetone on the surface, smeared a thin layer on the side of the beaker, left a toothpick in... nothing. I would have thrown it out except I got lazy cleaning and then after many weeks of sitting I thought I saw mold in it... no, the syrup was crystallizing in a couple points! Within a day or so it was solid throughout. I saved a bit, redissolved the crystallized mass, and then used the residue as a seed. I now have a jumble of fat needles, not really the blocks I expect but I'm going to use them to reseed another round and see how that goes.

clearly_not_atara - 7-7-2022 at 07:46

It's on Wikipedia.

Quote:

Rochelle salt crystals will begin to dehydrate when the relative humidity drops to about 30 per cent and will begin to dissolve at relative humidities above 84 per cent.

mayko - 7-7-2022 at 11:04

"dehydrate" in that passage refers to the loss of water of crystallization, not crystallization from solution.

karlos³ - 8-7-2022 at 19:09

The benzylic bromination of 2-methylnaphthalene, using NBS, is ideally done in presence of a radical initiator, benzoyl peroxide is usually used for that purpose.
With such a radical initiator, I could use a number of solvents, as the benzylic bromination will in that case be the main- and not side reaction.

Tried it once without, solventless, 20h in a melt, and the yield was(side reaction aromatic bromination) just a third of the theoretical yield.

So, here is the question: can I use the 2,4-dichlorobenzoylperoxide(50% under some silicon oil, because explosive

) as alternative radical initiator?
I expect the answer to be "of course", but I figured it won't hurt to ask.

Tsjerk - 9-7-2022 at 09:56

I'm making 5-formyl vanillyl and after reacting vanillyl and hexamine, and adding HCl I dumped the reaction on ice. The reaction contains 55 grams water, 55 grams acetic acid, 50 ml 30% HCl, and about 50 grams organics. I dumped this hot mixture on 400 grams of ice of approximately 0 degrees.

Now what I didn't expect was this mixture to go below 0 degrees, but it went all the way down to -7 degrees. Why is that? What endothermic process is going on here?

DraconicAcid - 9-7-2022 at 10:20

Quote: Originally posted by Tsjerk

I'm making 5-formyl vanillyl and after reacting vanillyl and hexamine, and adding HCl I dumped the reaction on ice. The reaction contains 55 grams water, 55 grams acetic acid, 50 ml 30% HCl, and about 50 grams organics. I dumped this hot mixture on 400 grams of ice of approximately 0 degrees.

Now what I didn't expect was this mixture to go below 0 degrees, but it went all the way down to -7 degrees. Why is that? What endothermic process is going on here?

Ice melting is endothermic. Because you've got a lot of acid, that lowers the melting point just like salt would.

mayko - 28-7-2022 at 20:06

when nitrosyl chloride reacts with limonene, why does it add only to the cyclohexene double bond, and not to the 2-propene side chain?

Fery - 28-7-2022 at 22:55

Quote: Originally posted by Tsjerk

... adding HCl I dumped the reaction on ice... what I didn't expect was this mixture to go below 0 degrees, but it went all the way down to -7 degrees. Why is that? What endothermic process is going on here?

IIRC the mixture of ice and concentrated HCl solution produces quite low temperatures, you diluted HCl in other reagents but anyway you still observed the endothermic process

Fery - 28-7-2022 at 23:01

Quote: Originally posted by mayko

when nitrosyl chloride reacts with limonene, why does it add only to the cyclohexene double bond, and not to the 2-propene side chain?

Mayko that's true, but I do not know why. I'm not too much skilled in theory, I like practical chemistry more. Anyway it is nice experiment https://www.sciencemadness.org/whisper/viewthread.php?tid=15...

mayko - 29-7-2022 at 05:46

Yep, I've been wanting to try the limonene to carvone conversion for a while, finally getting set up and want to understand more about the mechanisms

solo - 18-8-2022 at 05:39

i want to nitrate this compound....being that the group is large and its an o,p directional i will get the p position.....my concern is if there will be any reaction with my side chain exposed to the sulfuric and nitric acid used to place the nitro group....i.e esterification of the alcohol function ...and it might affect the direction of the nitro placement...?........solo

Tsjerk - 18-8-2022 at 09:14

I guess you will eliminate water forming an alkene before forming an ester. I wouldn't worry about forming an ester as it would probably not effect direction of the nitration too much and it would be reversible.

[Edited on 18-8-2022 by Tsjerk]

solo - 18-8-2022 at 10:14

......thanks i though of making the nitronium ion first with sulfuric acid and nitric acid then add to my compound with some cooling...solo

artemov - 19-8-2022 at 00:36

Can BiCl3(aq) be made easily from Bi2O3? Do I need concentrated HCl or will dilute HCl do? I supposed I need an excess of the acid to prevent the hydrolysis of the BiCl3 in solution.

Bi2O3(s) + 6HCl(aq) = 2BiCl3(aq) + 3H2O

BiCl3 is difficult/expensive to get here, but Bi2O3 is cheap and easily available.

Thanks.

BromicAcid - 19-8-2022 at 03:53

I have never done said reaction but I know bismuth has a tendency to form oxychlorides. A cursory looks seems to indicate it's not as bad as zinc where the isolation of the anhydrous chloride itself is next to impossible but seems it might be difficult to do without that showing up as a contaminant.

artemov - 19-8-2022 at 23:31

Quote: Originally posted by BromicAcid

I have never done said reaction but I know bismuth has a tendency to form oxychlorides. A cursory looks seems to indicate it's not as bad as zinc where the isolation of the anhydrous chloride itself is next to impossible but seems it might be difficult to do without that showing up as a contaminant.

From what I read, the hydrolysis to form oxychlorides can be reversed/prevented by using an excess of acid.

Bedlasky - 27-8-2022 at 13:24

Quote: Originally posted by artemov

Quote: Originally posted by BromicAcid

From what I read, the hydrolysis to form oxychlorides can be reversed/prevented by using an excess of acid.

Yeah, that's correct. Dissolving in 1+1 acid is okay. Maybe even 1+2 would be good.

[Edited on 27-8-2022 by Bedlasky]

Bezaleel - 27-8-2022 at 14:51

The Bismuth question is related to its iodo-complexes discussed here.
I'm also interested in these complexes, but I only have Bi metal. I tried to dissolve it in ~16% HCl, but it did not dissolve at all, neither when boiled.
I then tried to dissolve the same piece in 53% nitric acid and it did dissolve, giving off NO as orange-brown fumes. The solution was neutralised with ammonia solution until pH paper showed the pH was > 9. A fine, slightly off-white precipitate was formed (would do a good job as a warm white pigment).
The precipitate was suction filtered on a piece of Whatman white band filter paper put on a coarse fritte. Approx. 10% of the precipitate ran through during the first filtration, but virtually all was filtered when the filtrate was run through the same filter paper again. The residue was rinsed by pouring water on it after the initial solution has run though (still under suction).

The residue was dissolved in the earlier used 16% HCl solution. Another 0.5ml 36% had to be added in order to dissolve all of the residue. Heating was needed.
Around 10% was spilled and when the spilled drops combined with drops of water in the sink, a milky liquid immediately formed. It is evident that in order to keep Bi in solution, an excess of strong acid is required.

[Edited on 27-8-2022 by Bezaleel]

artemov - 27-8-2022 at 23:19

Quote: Originally posted by Bezaleel

The residue was dissolved in the earlier used 16% HCl solution. Another 0.5ml 36% had to be added in order to dissolve all of the residue. Heating was needed.
Around 10% was spilled and when the spilled drops combined with drops of water in the sink, a milky liquid immediately formed. It is evident that in order to keep Bi in solution, an excess of strong acid is required.

[Edited on 27-8-2022 by Bezaleel]

Thanks Bedlasky.

Bezaleel:
Yes I am trying to make the red salt cesium pentaiodobismuthate.
This is the only color missing from my rainbow salt series. Hope it really turns out red! lol

Would just adding more 16% HCl dissolve all of the ppt, or is a strong acid (>30% HCL?) absolutely necessary?
I have some <20% HCl, but not >30%. Guess I might need to make a small amount.

I bought some cesium salt (expensive!) and Bi2O3. Waiting patiently for their delivery

Oh, I managed to make nickel chloride and lead acetate from nickel coins and lead shots using hydrogen peroxide and the respective acid (dilute HCl/freeze distilled vinegar). Not sure if it will work with bismuth. I dun have nitric acid and dun really want to deal with NO2.

[Edited on 28-8-2022 by artemov]

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