Merrifield resin LL (100-200 mesh)

Merrifield resin was the standard support for the synthesis of peptide acids by Boc SPPS ^[1,2]. In peptide chemistry, it is now really only used in the synthesis of small to medium sized peptides, as the benzylic ester resin linkage is not completely stable towards repetitive treatment with TFA. Attachment of the C-terminal residue is generally achieved by heating the resin in DMF with the appropriate amino acid cesium salt in the presence of KI ^[3]; although,Me₄N salts ^[4], sodium salts^[5] in THF with Bu₄NF catalysis ^[6] and zinc salts in EtOH have also been used ^[7]. Cleavage is normally effected by treatment of resin with HF or TFMSA, or by hydrogenolysis ^[8]. Alcohols can be released using reducing agents such as DIBAL ^[6] or LiBH₄ ^[9]. Methyl esters can be produced by transesterification with methoxide ^[10].

Associated Protocols and Technical Articles
Protocols for Loading of Peptide Synthesis Resins

Replaces: 01-64-0008

Color (visual): white to yellow to beige
Appearance of substance (visual): beads
Loading (determined by elemental analysis for sulfur after derivatization with KSAc): 0.40 - 1.00 mmol/g
Swelling Volume (in CH₂Cl₂): lot specific result
The polymer matrix is copoly (styrene-1 % DVB), 100 -200 mesh (75 - 150 µm)

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