Sciencemadness Discussion Board - Easy-to-synthesize odor compounds

Easy-to-synthesize odor compounds

Rando1234 - 7-1-2022 at 16:45

I'm looking for concise and simple syntheses of odor compounds with a pleasant smell. I don't want to make esters. Do you have any suggestions?

-JacobM

Texium - 7-1-2022 at 18:07

Welcome to the forum! Hate to burst your bubble though: esters are about as easy and simple as it gets, so if you aren't equipped to make those, you aren't going to have an easy time accessing anything else.

Edit: though, you can always steam distill some plant material and isolate the aroma compounds. Cloves and anise work really well (yielding anethole and eugenol respectively). All you need for that is clean water and a simple distillation apparatus.

[Edited on 1-8-2022 by Texium]

Rando1234 - 7-1-2022 at 18:16

I see, but I have trouble making concentrated sulfuric acid. I have to distill battery acid, and it never gets above ~80-90%. I do have a jar of polyphosphoric acid, which does work for simpler aliphatic esters, albeit in poor yields (20%).

What's your opinion of cyclopentanone? I've made it before, and I think it smells alright, but it does have a bit of a chemical undertone to the minty smell.

I've done all sorts of other things that polyphosphoric acid and my weakish sulfuric acid will easily catalyze. Esterifications just seem to be difficult for me for some reason.

[Edited on 8-1-2022 by JacobM]

Bedlasky - 7-1-2022 at 20:24

Use directly battery acid. Sulfuric acid is used in very small amount anyways, so 0,5 ml of water doesn't hurt reaction much.

DraconicAcid - 7-1-2022 at 20:54

I've had rotten luck with a lot of esters, but one thing I've learned is that you need primary alcohols. Secondary ones don't work very well (they require very long refluxes, or the use of anhydrides), and tertiary ones don't work at all.

Bedlasky - 7-1-2022 at 21:08

Quote: Originally posted by DraconicAcid

I've had rotten luck with a lot of esters, but one thing I've learned is that you need primary alcohols. Secondary ones don't work very well (they require very long refluxes, or the use of anhydrides), and tertiary ones don't work at all.

Secondary and tertiary alkyl acetates can be made from alcohol and acetic acid using manganese(III) acetate catalyst. Never tried that, but looks interesting.

https://www.sciencedirect.com/science/article/abs/pii/S13811...

DraconicAcid - 7-1-2022 at 21:13

Quote: Originally posted by Bedlasky

Quote: Originally posted by DraconicAcid

Yes- I've seen the article, but haven't tried it yet. I wasn't going to mention it until confirmed.

Rando1234 - 8-1-2022 at 04:58

That looks interesting, but I find that alternative catalysts don't work well for me.
I think the reaction is more water sensitive than you think, Bedlasky. It would probably do for simple esters of primary alcohols, but for aryl esters, no way.
Tertiary alcohols just dehydrate to alkenes. I am aware of that.

Tsjerk - 8-1-2022 at 05:10

80% sulfuric acid is perfect for a Fischer esterification. Maybe not perfect, but fine at least.

Rando1234 - 8-1-2022 at 05:33

Okay. I might have to try it.

To be honest I have had some success with aryl esters. I made methyl benzoate once. It was fine up until I had to distill. I just got a flask of tar and some liquid with a BP 40 degrees too low. I didn't use vacuum distillation because I thought it would be fine and I have a heating mantle good enough.

Edit: Battery acid sold by the autozone a few minutes away from my house is only 30-50%.

[Edited on 8-1-2022 by JacobM]

[Edited on 8-1-2022 by JacobM]

teodor - 8-1-2022 at 05:37

Quote: Originally posted by DraconicAcid

But the secondary alcohols give a better, more gentle smell. I have examples: isopropyl and sec-butyl acetates. Yes, the reflux time is longer, but the yield is good.
If you don't like long-time reactions try to use a Dean-Stark with hexane / benzene / toluene, depending on what you have. This also eliminates the problem with wet starting components - all the water is collected in the Dean-Stark anyway.

But I think to get the pure aroma from alcohols like sec-butanol you have to purify the alcohol by fractional distillation and selecting fraction with the most stable boiling temperature, and it usually has the most nice smell. It should not be pungent like in my commercial sec-butanol sample prior to fractionation.

p-toluenesulfonic acid is a better catalyst than H2SO4 and it is not restricted in EU.
But both don't work for cyclohexanol, HCl is recommended instead. Also, probably, for some secondary alcohols, you have to use HCl.
The best method to saturate the alcohol with HCl is to add some calculated amount of acetyl chloride. Otherwise, gaseous HCl is used. I am curious, can be 36% HCl be used instead in a Dean-Stark rearrangement (I planned to check it but now I am working on menthyl acetate which has the best smell of all esters I saw till this moment).

[Edited on 8-1-2022 by teodor]

[Edited on 8-1-2022 by teodor]

Bedlasky - 8-1-2022 at 05:45

From what I know, H2SO4/H3BO3 mixture is used as catalyst for phenyl esters, not just H2SO4 alone. But I am not an organic chemist,maybe just sulfuric works.

Why do you avoid esters of primary alcohols? And do you really think, that 0,5 ml of water significantely affect reaction? Much more water is formed by reaction itself. If you do esterification, in which water significantely reduce yield, you must remove water with Dean-Stark anyways, so where is problem with 0,5 ml of water from battery acid?

Bedlasky - 8-1-2022 at 05:51

Quote: Originally posted by teodor

You read my mind Teodor with that Dean-Stark trap

. If you like esters with gentle smell, try oxalic acid esters. They have weak and pleasant smell, quite characteristic. I can give you some diethyl oxalate if you want, I have lots of it.

teodor - 8-1-2022 at 06:03

Quote: Originally posted by Bedlasky

Quote: Originally posted by teodor

You read my mind Teodor with that Dean-Stark trap

. If you like esters with gentle smell, try oxalic acid esters. They have weak and pleasant smell, quite characteristic. I can give you some diethyl oxalate if you want, I have lots of it.

Thanks for the recommendation. I will definitely try to do it by myself. I am in a process of vacuum distillation of menthyl acetate, which I already mentioned, and while waiting for some equipment (which I need to complete the process) I am playing with making trioxalato complexes. And when I started to do it I was wondering "how oxalate esters should smell"? I didn't find any info, and now you say they have a gentle smell. So, probably you also are reading my mind

Amos - 8-1-2022 at 06:37

One of my favorite aroma compound syntheses was making methyl cinnamate, which smells like strawberry, from cinnamon powder. You steam distill the oil out of cinnamon, react the oil with chromic acid in a Jones oxidation, get nearly pure cinnamic acid out of that via acid base extraction, and finally esterify that with methanol.

You can try extracting piperine out of pepper and oxidize it to piperonal, which is nice.

teodor - 8-1-2022 at 06:41

From the book "Perfumery, Practice and Principles, Calkin / Jellinek" (you can download it you know where)

"The following is a list of the 162 natural and synthetic materials that it is suggested students should learn to identify within the first six months of their studies. It is intended to cover a wide range of odor types. These materials are mainly used in fine perfumery. (Materials marked with an asterisk form the list of 50 materials to be learned first.) .. "

I will skip the natural ones. The full list is in the book, and I will list here only those marked with asterisks. I am not an expert to fast answer the question which are easy to make and which are not, probably it could be a topic for the discussion:

Aldehyde C11 undecylenic
Aldehyde C12 MNA
Aldehyde C14 (gamma-undecalactone)
Amyl salicylate
Benzyl acetate
Citronellol
Dihydromyrcenol
Ethyl phenylacetate (I believe Fery posted the synthesis here)
Eugenol
Galaxolide
Geranyl acetate
cis-3-Hexenyl acetate
Hexyl cinnamic aldehyde
Hexyl salicylate
Hivertal
Hydroxycitronellal
Indol
Isobornyl acetate
Iso butyl quinoline
Linalool
Linalyl acetate
Methyl anthranilate
Methyl ionone gamma
Phenylacetaldehyde
Phenylethyl alcohol
Rose oxide
Styrallyl acetate
Terpineol
Vanillin
Vertofix

Also, I could recommend the book "Fenaroli's handbook of Flavor ingredients" (which could be downloaded also). It contains the list of probably all known compounds which are used for their smell and for many of them there are notes about synthetic methods used.

Tsjerk - 8-1-2022 at 09:00

Quote: Originally posted by JacobM

Edit: Battery acid sold by the autozone a few minutes away from my house is only 30-50%.

Boil it down until it is produces heavy fumes, be careful because the fumes are very acidic. This should be around 80% sulfuric.

Texium - 8-1-2022 at 09:23

Quote: Originally posted by JacobM

Edit: Battery acid sold by the autozone a few minutes away from my house is only 30-50%.

Since you have AutoZone I’m going to assume you’re in the US, and if that’s the case, you likely also have an Ace Hardware near you (they’re in all 50 states) and I know for a fact that they sell 98% sulfuric acid by the gallon as drain cleaner.

Rando1234 - 8-1-2022 at 09:55

Tsjerk, that's what I did. I guess it was the distillation after all?

Thanks for all of the suggestions, I think that I'll either make a simple ester (butyl acetate seems niceish) or 1-phenylethanol (it will take some
effort to obtain acetophenone). I have done the dry distillation of calcium acetate and benzoate, and I got a terrible smelling liquid. It had the BP of acetophenone though....are there any methods to make acetophenone?

I'm interested in making acetophenone for the purpose of exploring its chemistry even though I can buy it. Borohydride is available to me with difficulty. I really want to avoid carcinogens like benzene, and because I'm in the US, acetyl chloride is a controlled substance and difficult to acquire, not to mention the HCl it fumes.

Edit: What are your favorite esters? I might make an ester instead.

[Edited on 8-1-2022 by JacobM]

Texium - 8-1-2022 at 11:53

Quote: Originally posted by JacobM

because I'm in the US, acetyl chloride is a controlled substance

Um, no. Acetyl chloride is most definitely not a "controlled substance." It isn't even a listed chemical. It isn't the easiest thing to acquire, that's true, nor is it the most pleasant thing to work with, but I want to nip that misinformation in the bud because there isn't anything illegal about owning acetyl chloride in the US.

Also, to repeat myself now that you've confirmed you're in the US: I can almost guarantee that you can find concentrated sulfuric acid OTC near you and you don't need to waste your time and money on battery acid. You can also order it from Duda Diesel for a really good price.

Rando1234 - 8-1-2022 at 12:28

Texium,

Well shows how much I know about US drug law. I thought it would be controlled because it can be used to make heroin but apparently not.
I can buy sulfuric acid at the Ace Hardware near me. I'll use that when I do make an ester sometime soon.

Rando1234 - 8-1-2022 at 14:46

Terpineol is also an option, however I haven't had the best luck with it. I've purchased 1/2 litre of alpha-pinene and attempted the reaction of some of it with acetic acid and polyphosphoric acid. After 2 hours reflux and a simple basic workup, I just got a yellow oil that smelled horrid in an indescribable way. If that was terpinyl acetate, I wouldn't know of it.

myr - 8-1-2022 at 17:49

http://libgen.rs/book/index.php?md5=34B65FF56EE3EFE564EB5423...

Really out of date but it's a good range of many fragrance and flavor chemicals in industry c 1965.

Rando1234 - 8-1-2022 at 18:08

Thanks, that might help.

Texium - 8-1-2022 at 18:16

Quote: Originally posted by JacobM

Texium,

Well shows how much I know about US drug law. I thought it would be controlled because it can be used to make heroin but apparently not.
I can buy sulfuric acid at the Ace Hardware near me. I'll use that when I do make an ester sometime soon.

Yeah, it is honestly kind of weird that acetic anhydride is listed while acetyl chloride is not, even though they can accomplish the same things. Just goes to show how arbitrary some of these laws are. To be clear though, List I and List II chemicals are not controlled substances. They are not illegal to own, and the legal requirements fall on companies that import, manufacture, or distribute them, not on individuals who purchase them. Take a look here: https://en.m.wikipedia.org/wiki/DEA_list_of_chemicals You can see here that for List II chemicals (which includes acetic anhydride along with such OTC staples as acetone, toluene, and sulfuric acid) the only requirement that could potentially affect an end user is that “unusual” purchases be reported to the DEA. For List I chemicals, sellers have to report mail-order purchases (I suppose online purchases count?) as well if they are to non-registered buyers like us. But even then, unless you order large amounts of red phosphorus and iodine and recently purchased a lot of Sudafed, I don’t think you have to worry about the DEA coming knocking over a List I chemical… and once again, owning them is not illegal unless you secretly imported them from another country.

While you’re at Ace, look for toluene if you don’t already have some. I never see it at the larger hardware stores, but I’ve seen it there before.

Rando1234 - 8-1-2022 at 18:54

Yeah, I'll get that.

One more thing: can dilute (50-80%) H2SO4 be used to form butyl bromide from butanol?

I'm actually still only pretty young, but I have lots of chemicals and safety gear at my disposal. I also am on good terms with a university professor who I can contact for things like this. Trouble is, they take a long time to reply which doesn't surprise me and their replies usually focus on chemistry from papers that's probably small potatoes to them, but is like moving mountains for me.
I honestly have no intention of making massive amounts of (or any amount of) explosives or toxic gases or anything else that could be considered kewlism and I do take safety as seriously as possible with my conditions. I have a flammable cabinet. I only want to focus on reactions for their educational or novelty value.
For some reason, my mom doesn't want me using toluene or storing lots of concentrated sulfuric acid in bulk. Sulfuric acid is reasonable, but toluene? I don't think toluene is that bad. The cartridges in my respirator are BTX proof.

dawt - 9-1-2022 at 02:04

Just want to add this to the list of reading material: Panten, Johannes; Surburg, Horst (Ed.): Common Fragrance and Flavor Materials. Preparation, Properties and Uses. 6th Ed. Weinheim: Wiley-VCH, 2016. Quite up to date and contains a shit ton of references for synthetic pathways.

teodor - 9-1-2022 at 02:56

Yes, dawt, I also think this book is a good one because there is a good systematic approach. For example, it lists some alcohols having an interesting smell. Like 3-octanol. And now I am thinking about exploring esters of 3-octanol.

[Edited on 9-1-2022 by teodor]

Fery - 9-1-2022 at 13:30

Amos - I bought methyl cinnamate from es-drei.de and the scent was very weak. Is there a way to make it stronger? I just sniffed directly from the bottle. Maybe grounding to very fine powder? Or heat it slightly? (Zimtsäuremethylester (min. 98%) 500g but it is now unavailable from their eshop).
teodor - I made allyl phenoxyacetate and allyl phenylacetate. First one is pineapple-flowers and second one honey. I was lazy to synthesize methyl and ethyl phenylacetates as I was able to buy them, both are honey scents. But too heavy and strong for me, I like the allyl phenylacetate much more. Maybe I should dilute methyl and ethyl phenylacetates. You already sniffed the compound Amos suggested (oxidizing piperine to piperonal) - that tiny vial with ground glass joint with a label Heliotropin, I told you that it is similar to Violet flowers (Viola odorata).
JacobM - acetophenone has very pleasant scent. Also good esters not yet mentioned are methyl anthranilate (grapes) and diethyl malonate (apples) - I tested both. You can also make apple scent fructone from ethyl acetoacetate with ethylene glycol.
Orange oil is very pleasant (D-limonene) and alfa pinene too (monoterpenes).
JacobM - you should react triflouroacetic acid or at least trichloroacetic acid with alfa pinene or d-limonene and then hydrolyze to alfa terpineol.
https://sci-hub.ee/http://dx.doi.org/10.1590/S0100-404220090...

DraconicAcid - 9-1-2022 at 13:36

Methyl cinnamate doesn't have much scent as a solid- I find that sprinkling a bit on top of some warm water releases the scent. i think it's strawberry with artificial undertones, but most of my students couldn't actually identify it.

Rando1234 - 9-1-2022 at 14:56

I've read the same reference - but who has CF3CO2H? I don't, and I really don't want to work with it either.
I had a good idea- a first for this forum, and an easy one too. I'm not telling what it is, but look forward to it in the coming weeks.

Edit: I UTFSE'd to verify my claims.

[Edited on 9-1-2022 by JacobM]

Fery - 10-1-2022 at 04:08

DraconicAcid - exactly, I almost did not feel any scent of methyl cinnamate.
JacobM the link I posted uses trichloroacetic acid. Also coumarin is very pleasant, but the reagents are not easy to obtain (salicylaldehyde + acetic anhydride + anhydrous Na acetate). In case of interest use the search engine here on forum to find it.

teodor - 10-1-2022 at 05:50

Quote: Originally posted by Fery

I was lazy to synthesize methyl and ethyl phenylacetates as I was able to buy them, both are honey scents. But too heavy and strong for me, I like the allyl phenylacetate much more. Maybe I should dilute methyl and ethyl phenylacetates. You already sniffed the compound Amos suggested (oxidizing piperine to piperonal) - that tiny vial with ground glass joint with a label Heliotropin, I told you that it is similar to Violet flowers (Viola odorata).

Even the allyl phenylacetate was too intrusive for me. Piperonal is great, it is one of my most valuable vials now.

I've got some success with the ester of menthol - menthyl acetate. It is a very great scent, also one of the main components of natural peppermint oil. But I used acetyl chloride. I think I will make write-up for the first version of the preparation soon - I didn't manage the vacuum distillation yet, so the preparation is not completed. There is a big difference in the density of vapors during the process compared to distillation under atmospheric pressure, I need to acquire some new skills to finish the process. But the crude ester has already a very delicious scent.
Generally I think terpene alcohols is an interesting field of exploration to an ester-maker.

[Edited on 10-1-2022 by teodor]

clearly_not_atara - 10-1-2022 at 08:33

Quote: Originally posted by JacobM

One more thing: can dilute (50-80%) H2SO4 be used to form butyl bromide from butanol?

No form of sulfuric acid is a good way to make alkyl bromides because H2SO4 can oxidize HBr, and even a small amount of Br2 byproduct can make your life very unpleasant.

Keep in mind that volatile alkyl bromides are carcinogenic, and recommended exposure is less than 15 micrograms per day. They might not seem harmful, but if you haven't got appropriate safety equipment (at least one of fume hood/respirator and preferably both), you might want to target other things.

[Edited on 10-1-2022 by clearly_not_atara]

Fery - 10-1-2022 at 08:50

teodor the menthol I gave you is natural, levomenthol, from India, from Mentha arvensis. Maybe also the acetyl ester you prepared is optically pure and the reaction itself or HCl or whatever did not cause racemization?
heliotropin I do not know whether natural or synthetical but it should not have optical isomers so it should not matter
optical isomers are sometimes very important in scents, e.g. I prepared L-carvone from D-limonene with nice minty scent, but its isomer D-carvone has a scent like cumin or caraway

teodor - 10-1-2022 at 11:53

Fery, I didn't know it is natural & optical pure, thank you. I had a plan to collect 3 fractions and compare the smell, I also thought in the case of different optical isomers should be a difference, but I didn't expect much, so it is good to know that it could be a big difference.
My main concern was the presence of unreacted menthol in the ester because they have the same boiling point, so I planned to perform a saponification test.
But just by smell, there is not much menthol, the smell is completely changed but the ester still has the "coldness" effect of the menthol.

[Edited on 10-1-2022 by teodor]

Also, I created a separate thread for menthyl acetate, so I think we can discuss the rest there.

[Edited on 10-1-2022 by teodor]

Boffis - 10-1-2022 at 11:54

@ clearly_not_atara your claim above that sulphuric acid shouldn't be used to prepare alkyl bromides is dis-information, little more than urban myth!! I have used sulphuric acid in almost every alkyl bromide preparation I have ever run, I have posted very detailed procedures for bromination of such compounds as 1,4-butanediol to 1,4-dibromobutane on this site and referred to others. It clearly does work and my only caveat is that the total concentration of sulphuric acid in the aqueous phase should not exceed about 85%; this seems to be about the point where sulphuric starts to act as an oxidizing agent towards bromide ions/ hydrogen bromide. Iodide is another matter!

Lionel Spanner - 11-1-2022 at 11:45

If you like nutty coffee-type smells, give the Gutknecht pyrazine synthesis a go. It involves self-condensation of α-amino acetaldehyde, which you may have to prepare in situ.

A fun experiment I did in the second year of university involved isolating eugenol by steam-distilling oil of cloves, then isomerising it to isoeugenol, and oxidising it to vanillin with KMnO4.

ed: just realised that pyrazine precursor is the aldehyde form of glycine, so yes, you will definitely have to prepare it in situ.

[Edited on 11-1-2022 by Lionel Spanner]

[Edited on 11-1-2022 by Lionel Spanner]

Rando1234 - 14-1-2022 at 04:46

Fery: Piperonal has been on my list for a while...ozonolysis of piperine.

clearly_not_atara: That makes no sense. I've seen preps of alkyl bromides using sulfuric acid before.
Yes. I am aware of the hazards of 1-bromobutane, and have a respirator as well as a ventilated work area.

Lionel Spanner: Pyrazines have been on my radar before, specifically 2,5-dimethylpyrazine. The issues are that I don't have ether (not OTC in the US anymore) and that it takes a butt ton of stannous chloride (and ammonium persulfate) for the prep I found.

Edit: Terpene chem is definitely an interesting field, but one I haven't had much luck in. Terpin hydrate, terpineol and its esters, and pinene controlled aromatization have all just given me terrible smelling bullcrap.

I might make methyl salicylate. Nice smell, works OK with polyphosphoric acid, and other uses I'll demonstrate later.

[Edited on 14-1-2022 by JacobM]

draculic acid69 - 30-1-2022 at 00:39

Quote: Originally posted by Fery

Amos - I bought methyl cinnamate from es-drei.de and the scent was very weak. Is there a way to make it stronger? I just sniffed directly from the bottle. Maybe grounding to very fine powder? Or heat it slightly? (Zimtsäuremethylester (min. 98%) 500g but it is now unavailable from their eshop).
teodor - I made allyl phenoxyacetate and allyl phenylacetate. First one is pineapple-flowers and second one honey. I was lazy to synthesize methyl and ethyl phenylacetates as I was able to buy them, both are honey scents. But too heavy and strong for me, I like the allyl phenylacetate much more. Maybe I should dilute methyl and ethyl phenylacetates. You already sniffed the compound Amos suggested (oxidizing piperine to piperonal) - that tiny vial with ground glass joint with a label Heliotropin, I told you that it is similar to Violet flowers (Viola odorata).
JacobM - acetophenone has very pleasant scent. Also good esters not yet mentioned are methyl anthranilate (grapes) and diethyl malonate (apples) - I tested both. You can also make apple scent fructone from ethyl acetoacetate with ethylene glycol.
Orange oil is very pleasant (D-limonene) and alfa pinene too (monoterpenes).
JacobM - you should react triflouroacetic acid or at least trichloroacetic acid with alfa pinene or d-limonene and then hydrolyze to alfa terpineol.
https://sci-hub.ee/http://dx.doi.org/10.1590/S0100-404220090...

On the subject of scents and oranges I grabbed a few leaves off an orange tree recently and it was the exact smell of a box of froot loops.

SWIM - 30-1-2022 at 23:50

Quote: Originally posted by clearly_not_atara

Quote: Originally posted by JacobM

One more thing: can dilute (50-80%) H2SO4 be used to form butyl bromide from butanol?

H2SO4 was used for years in 1st year organic labs for this purpose.
(the more volatile ethyl bromide, no less)
Works fine as long as you don't dump it all in at once. A thiosulfate wash deals with any bromine traces before the final distillation.

Many schools had students doing this without fume hoods or respirators.

Feiser and Feiser's lab manual had them doing it with an old fashioned open drip tip on the condenser instead of one that spigots into the collection flask, which may be going a bit far when you've got a roomful of undergrads all doing it at once.

You probably use a fume hood and respirator when you peroxide your curly locks

DraconicAcid - 31-1-2022 at 00:12

I made 2-naphthyl acetate, but haven't purified it from the starting naphthol enough to tell what it smells like.

Fery - 31-1-2022 at 23:11

DraconicAcid - interesting, please let us know the scent of 2-naphthyl acetate. How did you prepare it? Fischer esterification?
So far I found only these good scenting compounds but they are different from your ester, alfa and beta acetonaphtones
http://www.thegoodscentscompany.com/data/rw1008371.html
http://www.thegoodscentscompany.com/data/rw1033571.html
Does anyone have an idea how to prepare them? I have acetylchloride, AlCl3, naphthalene at hand. Maybe alfa formed at low temperature and beta at high similarly as when sulfonating naphthalene? Of course acetylation in home lab at elevated temp is a nonsense. At very cold temperature preferably the alfa formed during acetylation?
Any idea how to prepare the beta isomer then?
Also 2-methoxynaphthalene and 2-ethoxynaphthalene have good scents but I did not have time to prepare them (from beta naphthol and methyl iodide / ethyl bromide)
http://www.thegoodscentscompany.com/data/rw1012112.html
http://www.thegoodscentscompany.com/data/rw1001632.html

edit:
I found how to prepare pure isomers by acetylation of naphthalene here:
https://patents.google.com/patent/US2487777A/en

also preparation of 2-methoxynaphthalene here, they used 2-naphthol+methanol+NaHSO4:
https://patents.google.com/patent/CN102285871A/en

Attachment: US2487777A.pdf (281kB)
This file has been downloaded 203 times

[Edited on 1-2-2022 by Fery]

DraconicAcid - 1-2-2022 at 11:20

I haven't looked into acylations much (I don't have anhydrous aluminum chloride, nor do I have any acid halides or thionyl chloride)- I thought I'd read that acid anhydrides could be used, but haven't found many preps involving them.

The reaction of naphthoxide with ethyl bromide works pretty well, as long as the KOH dissolves in the alcohol to start with. For some reason, that step decided it just didn't want to go last time the class did the lab, and yields were low (but I recovered a LOT of unreacted naphthol from the waste). Extrapolating this to ethylating vanillin or salicaldehyde has been utterly fruitless so far.

Reaction of 2-naphthol with 1-bromobutane gave a hard-to-purify compound (low melting point), and apparently, it smelled like raspberries, but I was the only one who couldn't smell it.

[Edited on 1-2-2022 by DraconicAcid]

Fery - 1-2-2022 at 22:56

DraconicAcid - interesting idea, you are right, it should be raspberry:
http://www.thegoodscentscompany.com/data/rw1413311.html
Also isobutyl seems to be promising:
http://www.thegoodscentscompany.com/data/rw1020171.html
I did not find info about n-propyl, n-amyl and isoamyl ethers of 2-naphthol, I wonder what are they scents like.

DraconicAcid - 5-2-2022 at 10:36

I've purified the 2-naphthyl acetate, and I can't smell a damned thing from it.

SWIM - 5-2-2022 at 13:38

How about Draconic Acid?

Although he's far too modest to mention it, he is reputed to have a sweet floral odor.

Lionel Spanner - 14-2-2022 at 06:21

I've found a good one - you can synthesise corylone (sweet/spicy coffee-like smell) from diethyl adipate in three steps, namely:

1. Dieckmann condensation, with additional methyl iodide to methylate the enolate;
2. α-chlorination of the ketone with chlorine or NCS;
3. Dilute hydrochloric + acetic acid, to remove the remaining ester.

I'm not sure about the mechanism for the last step, but all three steps are relatively simple.

Lionel Spanner - 18-2-2022 at 15:01

Another good one is making coumarin from malic acid and phenol in a Pechmann condensation. When mixed with conc. sulphuric acid and heated to 100 °C, malic acid decarboxylates and oxidises to form formylacetic acid, which reacts with phenol to form coumarin. Aluminium chloride may or may not be required.

Fery - 19-2-2022 at 09:26

Hi Lionel Spanner, coumarin has very nice scent. I prepared it from salicylaldehyde + acetic anhydride + anhydrous Na acetate:
https://www.sciencemadness.org/whisper/viewthread.php?tid=15...

DocX - 17-3-2022 at 14:03

How about just making benzaldehyde from bensyl alcohol? Sure has a nice smell of Amaretto liquor

Fantasma4500 - 17-4-2022 at 10:50

combining HCl or NaOH with acetone and letting it sit for a while (maybe some sunlight for good luck)
forms an oily compound, phorone or something like it, i remember long ago i had wiped some of this off on a piece of paper towel and on a hot summer day it was drying near a window and as i woke back up again it was the most beautiful aroma ive ever come across

personally i really like the smell of resorcinol, but i believe its mostly made by extraction from exotic wood barks

Lionel Spanner - 18-4-2022 at 02:52

Quote: Originally posted by Antiswat

combining HCl or NaOH with acetone and letting it sit for a while (maybe some sunlight for good luck)
forms an oily compound, phorone or something like it, i remember long ago i had wiped some of this off on a piece of paper towel and on a hot summer day it was drying near a window and as i woke back up again it was the most beautiful aroma ive ever come across

Sounds like a mixture of phorone and mesityl oxide, both products of acetone self-condensation. The former has a floral smell, the latter is more sweet.

DraconicAcid - 26-3-2023 at 14:49

SO I made 2-hydroxynaphthaldehyde by the reaction of chloroform with basic naphthol. Pain in the neck to purify without vacuum distillation, and mostly full of purple impurities, but it smells nice.

I'd like to convert some of it to the ethyl or methyl ether (either with ethyl bromide/KOH, as for ethoxynaphthalene, or with methanol/KHSO4, as for methoxynaphthalene). Will the aldehyde group stand up to and/or prevent these reactions? I ask because I've never managed to alkylate salicaldehyde.....

Fery - 26-3-2023 at 22:03

Interesting, what's its smell? Similar to vanillin? I made only methyl, ethyl, allyl ethers of 2-naphthol where methyl and ethyl are solids and have scents similar to orange but different than limonene (they resemble me soaps of my childhood of Na palmitate type, but not the soap scent itself, just the additives added to soaps). Allyl is liquid and odorless.

DraconicAcid - 26-3-2023 at 22:09

No, it was very fruity- more like methyl anthranilate. Definitely grape, although it might have tricked my brain into thinking of grapes by the aforementioned purple impurities.

Fery - 27-3-2023 at 08:51

Are the purple impurities oxidation products of naphthol? Complex with Fe3+ ? My naphthol was pale yellow/brown as solid and quite dark after dissolving, but the ether product was easy to purify by steam distillation. The steam distillation was not true steam distillation, it was just a lazy hydrodistillation - one distillation round bottomed flask with water as well the product and dropping funnel to add water which distilled out. I reused condensed water to refill dropping funnel as the product was slightly soluble in water and I distilled significant volumes of water.

DraconicAcid - 27-3-2023 at 14:06

No idea. I'll probably try steam distillation next time I try it. Also extraction with dichloromethane, as naphthol itself isn't very soluble in DCM (and the aldehyde is).

I'm thinking it would be good to make ethers of, as well as salen-type ligands.

Raid - 3-4-2023 at 06:24

I'm not sure if it has been said yet, but you could make chloroacetone if you're looking for something easy.
It's as simple as bubbling dry Chlorine gas through acetone.
It makes something that has a very strong vapor and was used as a tear gas in WW1.
It's quite potent so be careful when making or handling it.

you could also make a dispersal method for it if you're looking to get gassed. just try not to breathe much in at one time

Raid - 3-4-2023 at 06:25

One more idea, You could make wintergreen it's simple and does not take a whole lot of time, it also smells very good.

Texium - 3-4-2023 at 11:06

Quote: Originally posted by Raid

I'm not sure if it has been said yet, but you could make chloroacetone if you're looking for something easy.
It's as simple as bubbling dry Chlorine gas through acetone.
It makes something that has a very strong vapor and was used as a tear gas in WW1.
It's quite potent so be careful when making or handling it.

you could also make a dispersal method for it if you're looking to get gassed. just try not to breathe much in at one time

What the hell. Is this some kind of joke? How could chloroacetone be considered a pleasant-smelling compound? Clearly you didn't understand the premise of the thread before you posted (emphasis added by me):

Quote: Originally posted by JacobM

I'm looking for concise and simple syntheses of odor compounds with a pleasant smell. I don't want to make esters. Do you have any suggestions?

Quote: Originally posted by JacobM

I honestly have no intention of making massive amounts of (or any amount of) explosives or toxic gases or anything else that could be considered kewlism and I do take safety as seriously as possible with my conditions.

It seems we've been experiencing an epidemic of poor reading comprehension lately... If you're not going to take the time to read and think beforehand, you shouldn't post.

teodor - 12-1-2024 at 02:44

So, I have ordered most of the compounds I mentioned in that post from hekserij.nl . (I post already one negative feedback this week about laboratoriumdiscounter.nl company, so I will compensate that with my positive feedback about hekserij.nl - great assortment, fast delivery, also they work with private individuals).

Quote: Originally posted by teodor

From the book "Perfumery, Practice and Principles, Calkin / Jellinek" (you can download it you know where)

"The following is a list of the 162 natural and synthetic materials that it is suggested students should learn to identify within the first six months of their studies. It is intended to cover a wide range of odor types. These materials are mainly used in fine perfumery. (Materials marked with an asterisk form the list of 50 materials to be learned first.) .. "

I will skip the natural ones. The full list is in the book, and I will list here only those marked with asterisks. I am not an expert to fast answer the question which are easy to make and which are not, probably it could be a topic for the discussion:

Aldehyde C11 undecylenic
Aldehyde C12 MNA
Aldehyde C14 (gamma-undecalactone)
Amyl salicylate
Benzyl acetate
Citronellol
Dihydromyrcenol
Ethyl phenylacetate (I believe Fery posted the synthesis here)
Eugenol
Galaxolide
Geranyl acetate
cis-3-Hexenyl acetate
Hexyl cinnamic aldehyde
Hexyl salicylate
Hivertal
Hydroxycitronellal
Indol
Isobornyl acetate
Iso butyl quinoline
Linalool
Linalyl acetate
Methyl anthranilate
Methyl ionone gamma
Phenylacetaldehyde
Phenylethyl alcohol
Rose oxide
Styrallyl acetate
Terpineol
Vanillin
Vertofix

I can use this set as an inspiration for new syntheses (trying formula variations etc). Also this gives me a reference of what to expect and check if my synthetic product is of a good grade.

I briefly checked all of them yesterday.

Aldehydes C11-C14 are those smells which are often used in toilet deodorants. I mostly dislike C14.
Amyl salicylate - I have a separate thread here about attempts of synthesis. Now I have a reference. I will write some follow up probably in that thread about the comparison. Also about cis-3-Hexenylsalicylate.
Benzylacetate is almost the same smell as n-butyl acetate.
Eugenol has just the strong smell of cloves.

I did several experiment with quinoline and I know that it can give a good smell on formula variations. So the smell of isobutyl quinoline is interesting as well. This type of smell is quite good in low concentrations.

My favorite of yesterday was methyl anthranilate.

The smell of Hexylcinnamicaldehyde is also very good (but surprisingly have nothing in common with cinnamon).

[Edited on 12-1-2024 by teodor]

Fery - 12-1-2024 at 06:12

Hi teodor, I can supply you with Phenylethyl alcohol, I should have 20 L barrel of it somewhere. Also 3 esters of phenylacetic acid (methyl, ethyl, allyl, the last one is my favorite, all of them have honey scent). Also some of methyl anthranilate, IIRC from es-drei.de
Hexylcinnamaledehyde - I'm dreaming of these syntheses for few years. Heptanal or octanal + benzaldehyde cross aldol condensation. The problem is that also heptanal and octanal undergo aldol with themselves producing rancid sideproducts with similar b.p. than the desired cross aldol product. They should have jasmin scent.
Good scent and lazy synthesis is also benzyl methyl ether from benzylchloride + methanol + anh. K2CO3.

teodor - 12-1-2024 at 06:37

Hexylcinnamaledehyde - yes, you are right, the scent is close to jasmin.
The scent of phenylethylphenylacetate which I also have is much better than phenylethyl alcohol and also it is neither honey nor nasty as the phenylacetic acid smell is.
Phenyl Acetaldehyde Dimethyl Acetal in a pure form is not interesting and is typical that "phenylacetic". I would describe it as a "Rose Chinesis" smell. But probably it is better in some combinations/higher dilutions.
Also I have isobutylphenylacetate. It is of that class also.

[Edited on 12-1-2024 by teodor]