[gypsum]

hello guys, im new to this site...anyway, i just would like to solicit your golden ideas on my problem...wew..im presently synthesizing macrocyclic diamide from salicylic acid and bis-(4-aminophenyl)-methane using one-pot procedure. Anyone here can provide me a new and convienient method for the synthesis of this macrocyclic diamide?my problem was the purification of the product. i got the desired intermediate but after cyclization, i won't be able to get the product..instead the undesired product...anyone can offer his/her brilliant ideas to me?thanx a lot guys..God Bless and More Power!..thanx

[HP]

Well, Doctor Wallace Hume Carothers who is one of the fathers of the polymer science and one of the brightest chemists in history had similar task given him by Du Pont at first - to synthesize large cyclic amides which are suitable for pharmacy and parfume industry...actually he succeeded in this task but his name is best known with invention of Nylon 6,6. Starting from one syntetic route - condensation reaction of aminocarboxylic acid (aminocapronic) his team succeeded in obtaining high molecular polyamide resins and also.. (not commonly known) - of oligocyclic amides! For the last they used such reaction conditions (proper solvent, reaction temp and most important proper low reagent concentration) when cyclization (di-, tri- tetramerization) of the monomers occurs... Really bright example for combination of chemical reactivity and reaction conditions!! Think about it

[gypsum]

thanx a lot for sharing your ideas with me...anyway, I am looking forward to see a specific website of these noble people doing this kind of research so I can check their publications/papers, that might be helpful in my study as well...if you can suggest one, that's better....thatnx a lot...God Bless...

[HP]

Sorry i can't help you with web information about your problem.. As i understand your synthesis task it consist of synthesis of cyclic diamide with one of  the starting reagents being salicilyc acid. Salicylic acid is a bifunctional reagent having COOH and OH functionality as OH is ortho position to carb group. So the first step of your synthesis should be amidation reaction of 2 moles salicylic acid with 1 moles  bis-(4-aminophenyl)-methane. Then you may obtaining bis substituated (4-aminophenyl)-methane aduct with salicylic acid ...May be standard carbodiimide activation of salycilyc acid will work fine with some doubts about possible side esterification reaction of sal acid itself and if it so then you should think about some protection of the OH..The bis salicyl amide aduct of this condesation will be a bifunctional reagent itslelf having 2 free OH groups in ortho position. If you wont to obtain a ciclyc amide it by my opinion will be half amide half ester molecule and you must think about the proper second bifunctional reagent which to do condenzation reaction-ciclyzation of the bis amide salicylate...Anyway it could be a sofisticated procedure to avoid the polycondesation esterification reaction working in solution and may be very dilute solution can help in this case too. Think about it