Molecular Design of New Oligohydroxyethylaminoethylurethane Dendrimers
摘要
This paper presents the synthesis of first- to fourth-generation (G1–G4) oligohydroxyethylaminoethylurethane dendrimers using a two-stage divergent method. The dendrimers were obtained by the reaction of triethanolamine with dimethyl carbonate and diethanolamine in strictly stoichiometric ratios, which ensured high product yields (97.4% for G1, 98.2% for G2, 98.4% for G3, 98.8% for G4). The resulting compounds are resinous substances with a colour range from reddish-brown (G1) to rich amber (G2) to dark brown (G3, G4), with a characteristic sweetish odour. Dendrimers (G1-G4) are soluble in water, dimethyl sulfoxide, dichloromethane, acetone, dioxane, dimethylformamide and alcohols, but are insoluble in chloroform, tetrachloromethane, aromatic and aliphatic hydrocarbons. The structure of dendrimers has been proven by 1H, 13C NMR, IR, titrimetry, and elemental analysis. An increase in molecular weight (498, 1152, 2504, and 5164 g/mol) and the number of hydroxyl groups (6, 12, 24, and 48) has been established with the increase in generation from 1 to 4, as well as the transformation of 1 (G1), 3 (G2), 5 (G3), and 11 (G4) urethane groups into amino groups due to the elimination of carbon dioxide. The thermal stability of dendrimers is in the range of 104–106°C. Prospects for further research are related to the study of the use of these dendrimers as effective platforms for catalysts, which opens up new opportunities in the field of chemical synthesis.