[Qfbale]

Good evening,
I'm working with natural products, trying to modify their chemical structure ... The site has a reactive carboxylic acid, the carboxylic acid is esterified and then reduced to a primary alcohol. Subsequently, the step-aldehyde with PCC. I need to bring this aldehyde to amine. It says there are items where using amines in acidic and basic to prepare. But I wonder if anyone has experience with this reaction for the preparation of amines from an aldehyde, with the intent to see if anyone has simple and easy to prepare amines or imines from aldehydes.

I will appreciate it.

[discodermolide]

Well you don't say which amine you will use. However, you can go from the methyl or ethyl ester directly to the amide. Depending upon the amine you are using.

[wildfyr]

Making an amine is a whole different ballgame than an imine. Amines will add directly to aldehydes to form imines in one of the simplest chemical reactions I can think of. Amines directly from aldehydes sounds like a trip down the scifinder hole

[wildfyr]

Also, there are ways to go from alcohol to amine. You could convert the alcohol to a halide then use gabriel reaction to go directly to primary amine. Another method from the halide is to make the azide then reduce it with PPh3, can often be done in situ, no need to work up azide.

[discodermolide]

Sorry, for some reason I read amide. Need new specs.

[TheUnassuming]

Depends on the amine you want to make, but generally reductive amination is a good one-pot that can get you from the aldehyde to an amine with good yields. 

[Qfbale]

Well you don't say which amine you will use. However, you can go from the methyl or ethyl ester directly to the amide. Depending upon the amine you are using.

It happens that in the laboratory initially tried to prepare amides using DCC and EDC ( carbodiimide ) , but did not succeed . In Mexico the sale of thionyl chloride is prohibited to make an acid chloride .
So we decided to change the carboxylic acid to ester, then  reduce the ester to alcohol, then oxidize the alcohol to aldehyde, and the aldehyde would react with primary amines to form imines, these imines would be reduced to form primary amines.
In theory , it is easy to prepare amines by reaction with aldehyde in basic or acidic medium , and then make a reductive amination .
I found some methods in the literature , but I have few milligrams of sample so I would like to know if anyone has experience in this type of reactions.

[Qfbale]

Depends on the amine you want to make, but generally reductive amination is a good one-pot that can get you from the aldehyde to an amine with good yields.

I have propylamine , triethylamine , benzylamine , ammonia , aniline , dimethylamine.

[TheUnassuming]

Reductive amination will be your go to I think for all but your triethylamine since it doesn't work to form quaternary amines.  Look through the literature (scifinder/reaxsys will be your best friend) to find the methods used by the closest analogue you can find to your substrate and follow it directly.  There are a number of different specific conditions used so its best to find the conditions that will match best to your exact substrate.   

[Qfbale]

Reductive amination will be your go to I think for all but your triethylamine since it doesn't work to form quaternary amines.  Look through the literature (scifinder/reaxsys will be your best friend) to find the methods used by the closest analogue you can find to your substrate and follow it directly.  There are a number of different specific conditions used so its best to find the conditions that will match best to your exact substrate.

Reaxys program is free??

[TheUnassuming]

Now that I don't know.  I know I can use it but that might just be with my institutional email, never tried with a gmail account.

[wildfyr]

Can you use Oxalyl chloride, PCl3 or PBr3? All are great halogenating agents. Oxalyl chloride is known for being especially mild

[Dan]

No, Reaxys isn't free, like SciFinder you need a license for this database (which your institution may or may not have).

Reductive amination of aldehydes is a very well studied and widely used reaction. Common methods are:

aldehyde + amine + H₂ + Pd/C
aldehyde + amine + H₃BCN

But many other catalysts and hydride reducing agents can be used. A textbook like March's Advanced Organic Chemistry is a good investment.

[wildfyr]

I've always wondered, how effective is transfer hydrogenation from cyclohexene compared to using H2? We don't have a pressure setup for using H2, and I've always been tempted to try the typical sophmore organic approach of using cyclohexene with Pd/C for hydrogenation, then just rotovap off the benzene.

[Dan]

I've always wondered, how effective is transfer hydrogenation from cyclohexene compared to using H2? We don't have a pressure setup for using H2, and I've always been tempted to try the typical sophmore organic approach of using cyclohexene with Pd/C for hydrogenation, then just rotovap off the benzene.

For a lot of basic Pd-catalysed hydrogenation/hydrogenolysis reactions you don't need high pressure, a balloon of H₂ overnight is fine. I used to do reductive amination, azide reduction and benzyl deprotection this way routinely.

I've used ammonium formate for transfer hydrogenation of aromatic nitros before, but only because the process for getting H₂ gas was inconvenient at the institution I was working in at the time. It works but often requires heating.