Starch derivatives of high degree of functionalization. Part 2. Determination of the functionalization pattern of p-toluenesulfonyl starch by peracylation and NMR spectroscopy

In the solvent system N,N-dimethyl acetamide/LiCl homogeneously synthesized ptoluenesulfonyl starch samples were subsequently peracetylated and perpropionylated in order to evaluate their molecular structure by means of NMR spectroscopy. The total degree of substitution of tosyl groups (DSTos) was determined using the signals of the methyl protons of the tosyl, acetyl or propionyl moieties. The distribution of the functional groups were accessible as well. By means of two-dimensional methods an unambiguous assignment of the signals was possible. Tosyl starch of DSTos values of up to one shows a predominate functionalization at position 2. At higher DSTos the primary position is increasingly functionalized, i.e. the tosyl starch samples with a new functionalization pattern were accessible.