Schiff's bases

[JayH]

Err, read what I wrote again and look at my diagrams, and my links. You're correcting something I haven't said. You're also confused on the mechanism.

EDIT: The mechanism for the reaction between a ketone and a secondary amine, I mean. It's not the same as for a primary amine. [And indole does not react as a typical secondary amine.]

[luigi_g]

Err, read what I wrote again and look at my diagrams, and my links. You're correcting something I haven't said. You're also confused on the mechanism.

EDIT: The mechanism for the reaction between a ketone and a secondary amine, I mean. It's not the same as for a primary amine.

my point was the product is NOT a schiff base, it is an enamine, as you did mention,
so perfumers should not call the product a schiff base.

i am not confused with the mechanism, i only explained the attack from a primary amine use
the second deprotonation comes from one of the hydrogen electrons in the adjacent carbon, when using a secondary amine
like indole.

i didnt say your diagram was wrong......

i suppose it might have been much easier to simply say that perfumers
shouldn't call the product in your diagram a schiff base, rather than trying to explain why

that's all ......

[JayH]

I'm terribly sorry, I didn't realize. My apologies for being overly sensitive. I wasn't even sure what I was supposed to have gotten wrong. I get that way sometimes when I'm confused.

You're right, products from indole are not Schiff bases. I'd prefer not to call them that myself (condensation products, maybe?), but it's one of those cases where I'm torn between strict usage and deferring to tradition.

[luigi_g]

JayH,

no need to apologize, it just wrote my reply wrong....

peace

[Kennel No5]

Luigi how do I get Vanillyl isobutyrate (Isobutavan) which is an aldehyde, to react with methyl anthranilate? I've tried heating on a water bath but with no observable reaction, no cloudiness. Is there a catalyst I can use ?

[luigi_g]

Luigi how do I get Vanillyl isobutyrate (Isobutavan) which is an aldehyde, to react with methyl anthranilate? I've tried heating on a water bath but with no observable reaction, no cloudiness. Is there a catalyst I can use ?

Kennel,

that is a good question, looking at the structure is looks more like an ester though?

[Kennel No5]

Luigi
Yes its an ester at one end of the benzene molecule but an aldehyde at the other as is vanillin.
K5

[David Ruskin]

Much as I would love to discuss the minutiae of Organic Chemistry, I don't think that this is the best place to do it; do you? For the per poses of this discussion I do not care abut the mechanism of Schiff's Base formation, nor whether a specific chemical be called a Schifff's Base or not, nor how Schiff's Bases are made commercially. All I'm interested in, here, is trying to help those who would like to make a Schiff's Base by mixing a couple of chemicals together. And I will repeat that some are easier to make than others. It may well be, theoretically possible to make a Schiff's Base from Aldehyde C16; but for the amateur it isn't. Methyl Anthranilate reacts with most Aldehydes (and not all) with ease; it does not react with Esters, Acids, Lactones or Ketones in the same way. Ditto, Indole; very difficult to make Indolene in the amateur workroom.

[Nizan]

I'm pretty discouraged anyway.. It seems that the process is a bit too involved for me right now
(not sure where to get desiccants), and the results don't smell too different, nor last longer..
Would have been nice if there was a blue base, but doesn't seem there is, so I don't really
get the point anymore.. :\

[Kennel No5]

Nizan you really shouldn't be discouraged. I've successfully made many Schiff base products with chemicals such as scentenal, canthoxal, safranal, benzaldehyde and other aldehydes (isobutavan still the exception). Don't be concerned about using desiccants or getting rid of the water produced by the reaction. I make a 10% solution in alcohol of the Schiff base once the reaction is complete and then use it in formulation. Given the small amount of the Schiff base used in an overall formulation the amount of water from the reaction is insignificant. There will be more water in your alcohol.
On your question about making an aldehyde more "long lived" by reacting it with methyl anthranilate, the resulting Schiff base will be well removed in odour from the original aldehyde. For a real base note aldehyde use muguet aldehyde or adoxal.

[David Ruskin]

What is a "blue base"? What has the colour got to do with it? Or do you mean that it is a base that makes you sad?

It is very simple to make several Schiff's Bases; that is what I was trying to point out. The only problem is removing the water that is produced, and there are ways around that. If you can buy several obscure Aromachemicals and Essential Oils I am sure it is not beyond your capability to get hold of some anhydrous Sodium Sulphate.

If you think that the Schiff's Base smells like the two original chemicals used, then it means you have not made the Base properly. A Schiff's Base lasts much longer, and is a Base note supreme. It is also a fixative. Schiff's Bases are try useful, and are worth exploring.

[Renegade]

The Indolene I bought doesn't seem that strong to me or long lasting. Is that typical of Indolene or is it perhaps a bad sample of it? From what I've observed, I don't consider either Indole or Hydroxycitronellal as true base notes (more like mid-base notes), but am I wrong in expecting that Indolene should last longer than both do individually?

[JEBeasley]

What is a "blue base"? What has the colour got to do with it? Or do you mean that it is a base that makes you sad?

It is very simple to make several Schiff's Bases; that is what I was trying to point out. The only problem is removing the water that is produced, and there are ways around that. If you can buy several obscure Aromachemicals and Essential Oils I am sure it is not beyond your capability to get hold of some anhydrous Sodium Sulphate.

If you think that the Schiff's Base smells like the two original chemicals used, then it means you have not made the Base properly. A Schiff's Base lasts much longer, and is a Base note supreme. It is also a fixative. Schiff's Bases are try useful, and are worth exploring.

David speaks the truth, I got my desiccant from an online vendor of
biodiesel supplies: http://www.dudadiesel.com/search.php...ium+sulfate%22

They are easy to find once you know what to look for: http://en.wikipedia.org/wiki/List_of_desiccants

I also have some Calcium Chloride I have not tried yet.

It would be great to know how to make some of these other bases as in what type of catalysts are needed, temps, etc

[David Ruskin]

The Indolene I bought doesn't seem that strong to me or long lasting. Is that typical of Indolene or is it perhaps a bad sample of it? From what I've observed, I don't consider either Indole or Hydroxycitronellal as true base notes (more like mid-base notes), but am I wrong in expecting that Indolene should last longer than both do individually?

Smell is so subjective. I find Indole and Indolene very strong indeed (INdolene is softer and more floral; the rough edges have been rounded off) whilst Hydorxycitronellal fairly strong. I do remember the first time I smelled Hydroxycitronellal I could barely detect it, and I think it was because I couldn't describe it to myself, and had never smelled anything like it before. Once I had learned its smell, I found it unmistakeable, and an obvious presence. Indole solution on a smelling strip will last for days, so I have always classed it as a Middle/Base note material. I would class Indolene, in the same way. As it is a larger molecule you would expect Indolene to last longer than Indole.

[Nizan]

Thanks David and Kennel! I guess I misunderstood David's initial reply.
Now I need to get me some MA.. I guess I could do a few drops of each
of the components, as I don't have enough of the aldehydes I want to
play with (for some reason neither PA nor Hermitage sell phenyacetaldehyde)..

What is a "blue base"? What has the colour got to do with it? Or do you mean that it is a base that makes you sad?

You made me seriously laugh! I meant a blue color.. It would be nice to have
blue (colored) components in the mix.. Or even purple!

I guess I can initially leave the water in the mix, if I work in high dilutions..
And later, I could dissolve in alcohol and add desiccants.. (Can't I freeze the
water out somehow?).

[JayH]

Much as I would love to discuss the minutiae of Organic Chemistry, I don't think that this is the best place to do it; do you?

We're discussing synthesis, so yes, it absolutely is. Understanding the reactions helps a lot when exploring new possibilities and allows for less common aromachemicals to be produced from readily available ones. You may not be interested in certain details; that's fine just as I'm not really interested in others. Hearing about someone else's experience with a reaction is always helpful. But this sort of theoretical discussion as well is quite useful.

[JayH]

I guess I can initially leave the water in the mix, if I work in high dilutions..
And later, I could dissolve in alcohol and add desiccants.. (Can't I freeze the
water out somehow?).

You can heat the water out. Perfumer's World has phenylacetaldehyde.

[JEBeasley]

You can heat the water out. Perfumer's World has phenylacetaldehyde.

That was what I noticed when I was intentionally trying to oxidize the C11 base by heating/boiling, I don't think it did much in the way of oxidizing it but it definitely boiled the water off. Actually, regardless of whether or not it oxidized I think the resulting base smelled pretty good and it definitely didn't hurt it. So, just for the record, you can cook the heel out of a C11 base and it won't hurt it as long as it doesn't solidify, lol. I think I kept it somewhere in the range of 50-70C as I never set my hot plate over that temp.

[Nizan]

You can heat the water out. Perfumer's World has phenylacetaldehyde.

That's where I got mine.. But they were kind of weird - they sent it a month after I layed them and they don't respond to inquiries (such as - why was half of the benzaldehyde solid white..).. Would have been nice to have better options.

[David Ruskin]

We're discussing synthesis, so yes, it absolutely is. Understanding the reactions helps a lot when exploring new possibilities and allows for less common aromachemicals to be produced from readily available ones. You may not be interested in certain details; that's fine just as I'm not really interested in others. Hearing about someone else's experience with a reaction is always helpful. But this sort of theoretical discussion as well is quite useful.

As this is a DIY forum to discuss Perfumery, I do not think that you comparing the size of your retort stands with each other is of much use. This Forum is not about Organic Chemistry or Chemical Synthesis, it is about Perfumery.

[David Ruskin]

That's where I got mine.. But they were kind of weird - they sent it a month after I layed them and they don't respond to inquiries (such as - why was half of the benzaldehyde solid white..).. Would have been nice to have better options.

If half of the Benzaldehyde was solid white, it was half Benzoic Acid.

[lpp]

We're discussing synthesis, so yes, it absolutely is. Understanding the reactions helps a lot when exploring new possibilities and allows for less common aromachemicals to be produced from readily available ones. You may not be interested in certain details; that's fine just as I'm not really interested in others. Hearing about someone else's experience with a reaction is always helpful. But this sort of theoretical discussion as well is quite useful.

There's always the private messaging facility for continuing discussions that have become off topic to the thread.

[lpp]

We don't argue with moderation decisions.

http://www.basenotes.net/content/92-...ct-for-Members

[lpp]

As this is a DIY forum to discuss Perfumery, I do not think that you comparing the size of your retort stands with each other is of much use. This Forum is not about Organic Chemistry or Chemical Synthesis, it is about Perfumery.

Posts arguing with moderation requests are deleted and are inclined to lead to suspension.

Please feel free to discuss any subject by private message or even start a new thread or Group for discussing chemistry issues.

[Nizan]

Hmm.. So much drama..

Anyhow, I think I'll try benzaldehyde and indole today.. How warm do you usually make things
to get a reaction in a reasonable time? I thought just of putting the vial in a bath at around 40-50
Celsius. I'm going to make a small amount (I guess around 20 mg) - should I also dilute it before
the reaction?

Thanks

Update - done! It's red and smells like benzaldehyde (although much weaker) and indole/indolene..

[pkiler]

Hmm.. So much drama..

Anyhow, I think I'll try benzaldehyde and indole today.. How warm do you usually make things
to get a reaction in a reasonable time? I thought just of putting the vial in a bath at around 40-50
Celsius. I'm going to make a small amount (I guess around 20 mg) - should I also dilute it before
the reaction?

Thanks

Update - done! It's red and smells like benzaldehyde (although much weaker) and indole/indolene..

Did it undergo a change? Exhibit heat or color change?

[Nizan]

I warmed it, so I don't know if it heated.. It became thick and very deep raspberry red..
Doesn't seem like it's long lived on a strip - even though the strip is red, I can't really
smell it anymore (though my nose could be fried, and I checked it in 10% dilution).
I also did the same with phenylacetaldehyde..

[pkiler]

That particular red color change seems to be Indole related, if I remember right, but can't remember if the color change is because of a Schiff base forming, or because of the indole doing something odd all by itself...

[Nizan]

Hmm.. could be - as the almond smell evaporates pretty quickly..
On the other hand, the phenyacetaldehyde didn't turn red - it turned amber..
And I like the effect in the latter much better - it gave it some herbal depth.
How can I tell if a new molecule was formed? I thought the stickiness would
be a good indication, but it seems the longevity didn't improve..

[julian35]

Have I posted my Schiff's Base Compendium here?

Paul, absolutely brilliant Schiff's Base Compendium. Thank you for putting such a great document together and for making it available. I am enjoying working through the different combinations and seeing and smelling the effects. I have yet to actually figure out how one gets the mixture to clear. Once they return to cool they go cloudy, which I understand is the H2O. Just not clear HOW to use the desiccant to remove the H20.

(p.s. - Also wanted to mention I recently purchased a fantastic pair of Koure frames, I know you are someone that would appreciate that from a post I read somewhere.