xonu - 28-10-2020 at 13:29
Hello! Recently I received 1 kilogram of phthalic annhydride, and i'm wondering if I could do any interesting reactions with it besides fluorescein
and luminol.
So far I don't have that many reagents, but here getting most chemicals here is not that hard, so I'm open to any beginner-level stuff.
ArbuzToWoda - 28-10-2020 at 13:37
Maybe make some phtalimide? You could do something with it then.
Texium - 28-10-2020 at 13:42
Happy first post!
Reaction with phenol in the presence of a Lewis acid catalyst such as anhydrous zinc or aluminum chloride will give you phenophthalein. Thymol reacts
analogously to yield thymolphthalein.
You can also convert to phthalimide with urea, and then use that to make copper phthalocyanine, a lovely dark blue pigment with a cool structure,
using copper chloride and more urea.
Here's my video on the phthalocyanine synthesis: https://www.youtube.com/watch?v=Mnx6PBFBGik
Boric acid can be substituted for the ammonium molybdate if you don't have the latter available, though it may not work quite as well.
Phthalimide can also be converted to anthranilic acid by Hoffman degradation, which can be used to make the grape scented ester methyl anthranilate.
Amos - 28-10-2020 at 13:55
Phthalic anhydride can be used in friedel-crafts reactions with benzene derivatives to form anthroquinones; the most familiar example for me is with
resorcinol and boric acid in sulfuric acid to prepare purpuroxanthin, a bright orange crystalline dye that forms pink and purple salts.
xonu - 28-10-2020 at 15:07
Thanks everyone for the warm welcome and answers! Phenolphthalein was on my idea list, and the dyes suggested do sound pretty interesting and I may
have all the reagents to attempt the purpuroxanthin synth at a later point.
karlos³ - 28-10-2020 at 17:24
I made thalidomide with it, that is something I can recommend.
Its quite simply done, by reacting it with glutamic acid in a first reaction, then followed by the amide forming ring closure, with for example urea
or another suitable nitrogen source and heat, usually in a high boiling solvent.
Alternatively, glutamine is used in the first step, which is then followed by ring closure with any of a number of suitable reagents, for example acid
chlorides, - anhydrides, or ideally some acid activating reagent:
Or you simply mix everything used for the first variation together, except a solvent, and nuke it in the microwave, for a quick although lower
yielding one-pot way.
Thats a very interesting target compound too, even if the preparation is nothing overly special.
Although it is an entertaining process, it will almost always work in the one or other variation and almost all reagents can be substituted with other
ones, with varying results.
Except of course phthalic anhydride, the key reagent.
And when after the usual purification, and finally the one or other recrystallisation the melting point and appearance fit, one has made a
pharmaceutical agent in good purity, isn't that something too?
I am just about to review what I wrote right now in my thread about that, and then possibly update the latest results in case I'm happy with.