Sciencemadness Discussion Board

Organic Goal

DFliyerz - 17-12-2015 at 09:15

Lately I've been feeling a lack of motivation to do chemistry, I think in part because all of the things I made aren't part of a larger goal. Does anyone have any ideas for good "goal compounds?"

karlos³ - 17-12-2015 at 12:06

Make luminol, that is an interesting compound, a multiple step synthesis for which each intermediate requires purification, and the final product is really appreciable even by chemophobic persons if you do a show experiment.
If you do not much have access to chemicals, it can even be made totally "OTC".

DFliyerz - 17-12-2015 at 14:01

Quote: Originally posted by karlos³  
Make luminol, that is an interesting compound, a multiple step synthesis for which each intermediate requires purification, and the final product is really appreciable even by chemophobic persons if you do a show experiment.
If you do not much have access to chemicals, it can even be made totally "OTC".

That sounds pretty good, I already have a decent quantity of nice phthalic acid crystals. Any other ideas like this are greatly appreciated.

aga - 17-12-2015 at 14:12

Phenolpthalein, seeing as you got pthalic acid.

See what yield you can get.


[Edited on 17-12-2015 by aga]

Volanschemia - 17-12-2015 at 14:31

2-Aminobenzoic Acid (Anthranilic Acid) from phthalates?
You could then esterify it to Methyl 2-Aminobenzoate, which smells like grapes.

User123 - 17-12-2015 at 15:32

Rather than just making 'something', why not prepare some useful reagents, or solvents? I don't know what your interests are, but reagents such as methyl iodide, ethyl bromide and so on are useful to have to hand, so perhaps you could spend your time constructively to increase the range of reagents that you have available, then you can put them to use when you have a more well thought out project to do.
Personally I don't understand the mentality of just doing a synthesis for no reason, as a lot of people seem to be doing, or suggesting.
Maybe you could prepare some pure ethanol by fractionally distilling methylated spirits, then prepare some sodium ethoxide as a useful base. Use the opportunity to add to your range of available chemicals, rather than just following a procedure for no reason. Perhaps you might even spend your time pursuing something other than chemistry? Read a history book!

j_sum1 - 17-12-2015 at 15:47

You could enter a competition.

DFliyerz - 17-12-2015 at 17:36

Quote: Originally posted by User123  
Rather than just making 'something', why not prepare some useful reagents, or solvents? I don't know what your interests are, but reagents such as methyl iodide, ethyl bromide and so on are useful to have to hand, so perhaps you could spend your time constructively to increase the range of reagents that you have available, then you can put them to use when you have a more well thought out project to do.
Personally I don't understand the mentality of just doing a synthesis for no reason, as a lot of people seem to be doing, or suggesting.
Maybe you could prepare some pure ethanol by fractionally distilling methylated spirits, then prepare some sodium ethoxide as a useful base. Use the opportunity to add to your range of available chemicals, rather than just following a procedure for no reason. Perhaps you might even spend your time pursuing something other than chemistry? Read a history book!


This is what I've mainly been doing this whole time, but a part of the problem is that there are too many things to make!

numos - 17-12-2015 at 17:38

Rubrene!

Complex enough to make you feel accomplished afterwards, plus it's a high priced chemical and it glows!!

Synthesis is not the easiest but doable, I've been at it for the last two months (only do this on weekends) and I'm nearly there!

-numos

DFliyerz - 17-12-2015 at 17:40

Quote: Originally posted by aga  
Phenolpthalein, seeing as you got pthalic acid.

See what yield you can get.


[Edited on 17-12-2015 by aga]

I did this a while ago and didn't calculate the yield although I think it was pretty bad. My separatory funnel's stopcock would turn purple for a while after doing that prep!

Texium - 17-12-2015 at 17:49

I'm currently working on a total synthesis of indigo starting from toluene. I'm stuck at figuring out a way to get from 2-nitrotoluene to 2-nitrobenzaldehyde. Once I get past that it should be a breeze from there. Then I plan to also make indigo carmine and tyrian purple.

I'll make a writeup in Prepublication once I'm finished.

AvBaeyer - 17-12-2015 at 19:30

zts16,

The conversion of o-nitrotoluene to o-nitrobenzaldehyde is not as straightforward as one might think. However, if you do not have to do everything "otc", you should look at the following:

Organic SYntheses Coll Vol 3, p641 [ Note "Methods of Preparation" Section for more references]
Organic Syntheses Coll Vol 5, p825

You can get these two refernces online.

AvB

Texium - 17-12-2015 at 20:01

Thanks AvB, unfortunately both of those methods are out of my reach currently as far as the reagents go.

I had found a couple mentions of using manganese dioxide and sulfuric acid, but they were vague, with no explanation of the conditions or time required, other than that above 40ºC benzoic acid would form instead. I performed a couple shots in the dark with the method using unsubstituted toluene, unsuccessfully. Another option that I'm considering is using chromyl chloride, though I'm rather nervous about handling it. However, a chlorochromate salt may work instead, and would be much safer to use. It may be worth a try.

aga - 18-12-2015 at 09:31

Quote: Originally posted by DFliyerz  
My separatory funnel's stopcock would turn purple for a while after doing that prep!

EVERYTHING turns purple after that prep !

It took at least two washes of all the glassware, plus some NaOH sloshed about to find the remains, before it was all gone.

HeYBrO - 18-12-2015 at 13:30

Quote: Originally posted by zts16  
I'm currently working on a total synthesis of indigo starting from toluene. I'm stuck at figuring out a way to get from 2-nitrotoluene to 2-nitrobenzaldehyde. Once I get past that it should be a breeze from there. Then I plan to also make indigo carmine and tyrian purple.

I'll make a writeup in Prepublication once I'm finished.


awesome, i have actually been looking to do a total synthesis on that as well for a while now. I have found a prep on oxidising on o-nitrotoluene to o-nitrobenzaldehyde w/ otc products. Hope it is useful.




Attachment: Synthesis of 2-Nitrobenzaldehyde from 2-Nitrotoluene Alexander Popkov.pdf (203kB)
This file has been downloaded 564 times

[Edited on 18-12-2015 by HeYBrO]

[Edited on 18-12-2015 by HeYBrO]

[Edited on 18-12-2015 by HeYBrO]

Texium - 18-12-2015 at 14:55

Thanks HeYBrO, that looks like a promising prep, although I'm not sure how sodium methoxide qualifies as OTC if you don't have a good source of sodium metal. I'll keep it in mind though in case I obtain some.

aga - 18-12-2015 at 15:01

For us noobs to all this OC craziness, does Everything with 'Nitro' in the name explode ?

Just that "2-nitrotoluene to 2-nitrobenzaldehyde" sounds scary, cos it has 'nitro' in the name.

Texium - 18-12-2015 at 15:09

Nope, neither of them are explosive. Flammable, yes, but not explosive. Compounds containing only one nitro group are usually pretty safe.
Compare any of the mononitrotoluenes to trinitrotoluene. There's a huge difference.

HeYBrO - 18-12-2015 at 15:33

Quote: Originally posted by zts16  
Thanks HeYBrO, that looks like a promising prep, although I'm not sure how sodium methoxide qualifies as OTC if you don't have a good source of sodium metal. I'll keep it in mind though in case I obtain some.


sodium can be easily had from gallium source or eBay (not otc). Additionally, sodium may be produced by the electrolysis of molten NaOH (see caster cell thread in prepub). there is also a thread about making sodium ethoxide from NaOH, acetone and ethanol. I kind of skimmed it at the time, but perhaps such a process could be implemented with methanol ( just look at the pKa's of each component)

hence, sodium methoxide can be made from OTC components

http://www.sciencemadness.org/talk/viewthread.php?tid=2656&a...
this thread also had some interesting tid bits; perhaps another metal cation could be employed?

http://www.sciencemadness.org/talk/viewthread.php?tid=1630&a...

[Edited on 18-12-2015 by HeYBrO]

[Edited on 18-12-2015 by HeYBrO]

[Edited on 18-12-2015 by HeYBrO]

UC235 - 18-12-2015 at 16:27

Quote: Originally posted by zts16  
I'm currently working on a total synthesis of indigo starting from toluene. I'm stuck at figuring out a way to get from 2-nitrotoluene to 2-nitrobenzaldehyde. Once I get past that it should be a breeze from there. Then I plan to also make indigo carmine and tyrian purple.

I'll make a writeup in Prepublication once I'm finished.


Tyrian purple is not a straightforward prep and cannot be made from regular indigo. You need to make the 4-bromo-2-nitrobenzaldehyde if you're using the Baeyer-Drewson Approach (or other appropriate precursor).

I would look into free-radical benzylic bromination followed by a mild oxidation (Kornblum, Sommelet, etc.)

A mixture of AcOH, Ac2O, and CrO3 will generate the benzylidene diacetate which hydrolyzes readily to the aldehyde. Yield is somewhat lacking for the unpleasantness of the reagents, though.

http://www.orgsyn.org/demo.aspx?prep=CV4P0713

Texium - 18-12-2015 at 16:43

Quote: Originally posted by UC235  
Tyrian purple is not a straightforward prep and cannot be made from regular indigo. You need to make the 4-bromo-2-nitrobenzaldehyde if you're using the Baeyer-Drewson Approach (or other appropriate precursor).

I would look into free-radical benzylic bromination followed by a mild oxidation (Kornblum, Sommelet, etc.)
Yeah, I'm aware of that. I know I made it sound like I wanted to make it from indigo, but I was just mentioning it because it happens to be another thing that I'd like to make. I was thinking of making it using the first method that you mentioned, though I haven't looked into the practicality of synthesizing 4-bromo-2-nitrobenzaldehyde since I am still working on the plain 2-nitrobenzaldehyde synthesis.

UC235 - 18-12-2015 at 17:14

Quote: Originally posted by zts16  
Quote: Originally posted by UC235  
Tyrian purple is not a straightforward prep and cannot be made from regular indigo. You need to make the 4-bromo-2-nitrobenzaldehyde if you're using the Baeyer-Drewson Approach (or other appropriate precursor).

I would look into free-radical benzylic bromination followed by a mild oxidation (Kornblum, Sommelet, etc.)
Yeah, I'm aware of that. I know I made it sound like I wanted to make it from indigo, but I was just mentioning it because it happens to be another thing that I'd like to make. I was thinking of making it using the first method that you mentioned, though I haven't looked into the practicality of synthesizing 4-bromo-2-nitrobenzaldehyde since I am still working on the plain 2-nitrobenzaldehyde synthesis.


I have made tyrian purple via Baeyer-Drewson. I have about 2g. I used the aforementioned AcOH/Ac2O/CrO3 oxidation. p-toluidene is an ideal start point if you can manage to mononitrate it ortho to the methyl group. In sulfuric acid, this is the major product as the aniline nitrogen remains protonated and thus a meta-director. About 20% of the wrong isomer forms but can largely be ignored since it won't participate in the final reaction. The m.p.s will be low and broad, though.

A Sandmeyer to 4-bromo-2-nitrotoluene is probably the highest-yielding I've encountered and was nearly quantitative using the procedure from http://www.orgsyn.org/demo.aspx?prep=CV4P0160.

The oxidation, as I mentioned, should be reworked.

My overall yield was 6% from p-toluidene (obviously non-optimized)

blogfast25 - 18-12-2015 at 18:02

Quote: Originally posted by UC235  


My overall yield was 6% from p-toluidene (obviously non-optimized)


Is there a reason why you haven't responded to 2 of my U2Us, with a mere request for information re. a paper you co-authored?

Best regs.

UC235 - 18-12-2015 at 18:15

Quote: Originally posted by blogfast25  
Quote: Originally posted by UC235  


My overall yield was 6% from p-toluidene (obviously non-optimized)


Is there a reason why you haven't responded to 2 of my U2Us, with a mere request for information re. a paper you co-authored?

Best regs.


Co-authored? No. I was just providing some literature.