This is a solid synthesis used remarkably for the peptides synthesis.
Principle : Merrifield resin is a solid matrix where we bond by a chemical way molecules we want make react using notably covalent bond.
The matrix has to stay solid during the synthesis that which simplify the purification (washing then filtration of the matrix).
The matrix is a resin composed of polymers which have to be insoluble in all the solvents used for the synthesis.
Merrifield resin is a polystyrene resin based on a copolymer of styrene and chloromethylstyrene:
The first step is called “the grafting”:
Only one extremity of the molecule is bonded to the site reaction of the resin, the other one is free and only it will reacts. This free extremity has some functions which will not used so they need to be protected during the reaction. The reaction chain will grows up by steps chained.
The second step: Retrieve the molecule
When all the synthesis steps has been realized, the molecule is retrieved. When it is detached of the resin we call the step as a “cleavage” . The bond between the solid matrix and the molecule is broken is broken then the molecule is retrieved by washing and filtration of the resin.