Joseph Pitha has found that by controlling basicity of the reaction,it is possible to alkylate preferentially the secondary hydroxyls of cyclodextrins [1].These hydroxyls surround the principal,wide entry into the cyclodextrin cavity and,thus,their substitution by suitably chosen substituents (e.g.methyl groups) can improve the formation of inclusion complexes.The product (CRYSMEB) in which the methyl groups are bonded mostly to 0-2 has been produced and marketed by Roquette [2].It is a mixture of methyl pCDs,which contains one to seven methyl groups in a molecule.The average degree of substitution is 4 methyl groups per native CD molecule,i.e.a typical MS (molar degree of substitution) is 0.57.CRYSMEB,similarly to other industrial CD derivatives,is polydisperse composite material.
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