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Starch Derivatives of High Degree of Functionalization. 4. Homogeneous Tritylation of Starch and Subsequent Carboxymethylation
Author(s) -
Heinze Thomas,
Heinze Ute,
Grote Carsten,
Kötz Joachim,
Lazik Waldemar
Publication year - 2001
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/1521-379x(200106)53:6<261::aid-star261>3.0.co;2-z
Subject(s) - chemistry , surface modification , reagent , chemical modification , starch , ether , organic chemistry , polymer chemistry , chloride , fourier transform infrared spectroscopy , nuclear magnetic resonance spectroscopy , quantum mechanics , physics
The synthesis of monomethoxytriphenylmethyl (MMtrityl) starch and the subsequent carboxymethylation of the 6‐ O ‐functionalized products were investigated. The trityIation both in N,N ‐dimethylacetamide (DMA)/LiCl and in dimethyl sulfoxide (DMSO) occurred homogeneously. The highest degree of substitution of trityl groups (DS TrityI ) obtained after a single conversion step was 0.77 in both solvents. A complete functionalization of primary OH‐groups was achieved only with unsubstituted triphenylmethyl chloride in these reaction media. In case of monomethoxytriphenylmethyl chloride (MMTMC) as reagent an additional conversion step is necessary to synthesize products with a DS TrityI = 1. The structure of the products was analyzed by FTIR‐ and 13 C‐NMR spectroscopy. Subsequent carboxymethylation of the MMtrityl starch samples leads to products with a preferred functionalization of the unprotected secondary OH‐groups. After removal of the trityl moieties, the DS CM and the distribution of carboxymethyl groups within the anhydroglucose unit was investigated by means of HPLC and 1 H‐NMR spectroscopy. The carboxymethylation was more effective at O‐2 than at O‐3. In case of ether products with DS Trityl < 1 a partial substitution of the primary OH group took place as well.