[MCResonance]

Hi everyone,

I previously posted a question about attaching methylene blue to an oxygen plasma treated surface, and I figured out a chemical reaction that may work. I just needed to know: Is there a way to synthesize methylene blue, so that rather than the dimethyl amine substituent, there is an amine substituent?

What chemical reactions can change remove methyl groups to convert dimethyl amine to amine?

Thanks for any input.

[rolnor]

You can cleave a aliphatic amine-carbon bond with bromine but I dont think it works on aromatic amines. I think it could be complicated to make a completely new route to methyleneblue to get the amine free, might need protectiongroups etc. Also it might be that you get a completely new molecule that is less strong dye than methyleneblue alltogether. I sound very negative, sorry for that but this project does not seem so easy I am afraid.

[kriggy]

Methylene blue is made by reaction of dimethyl-4-phenylenediamine  with H₂S and FeCl₃. Im pretty sure that if you used differently substitued amino group - like dibenzyl or maybe diacetyl then you would get the derivative of methylene blue which can then be deprotected to yield the free amino groups

[AWK]

https://wiki2.org/en/Thionine+Newton

[MCResonance]

Thank you for the responses so far, and I always welcome more input. I will definitely look into all of your suggestions and post back any new information I find.

[MCResonance]

I believe that thionine may be the best route for my experiment to go. I will take my plasma treated surface with its carboxylates, and react it with N-hydroxysuccinimide then thionine. I'll have to find a procedure for this, but I believe the thionine will be covalently attached to the treated surface without losing any photo-properties.