Synthesis And Characterization Of A Novel Neotame Derivatives

Neotame derivatives are novel sweetener with high sweetness strength,the sweetness potency of sweeteners could reach about hundreds or thousands higher than that of sugar.The high sweetness strength about artificial sweetener is clean taste,low calorie,excellent safety and reliability.It is the trend of the development of industrialization of ultra-high intensity sweeteners in the future,and is also a manifestation of the national industrial strength of sweeteners.Firstly,in order to synthesis of the novel dipeptide sweetener,using methanol and 3,3-dimethylanrylic acid as starting materials,concentrated sulfuric acid as a catalyst,then through Fischer-Speier esterification to synthesis 3,3-dimethylacrylate,then 2,5-dimethylphenol was treated with 3,3-dimethylacrylate in the presence of methanesulfonic acid to give 4,4,5,8-tetramethyl-3,3-dihydroguccin through Friedel-Crafts acylation.A solution of previous compound added to lithium aluminium hydride to give 3-?2-hydroxy-3,6-dimethylphenyl?-3-methylbutanol,after two steps to protected the alcoholic hydroxyl and phenolic hydroxyl,then acetic acid eliminated the tertButyldimethylsilyl that could obtain the alcohol which protected by acetyl.The alcohol was oxidation by Dess-Martin periodinane and give the intermediate about neotame derivatives is 3-?2-acetyl-3,6-dimethylphenyl?-3-methylu tyraldehyde.Finally,the intermediate combined with aspartame though Borch reduction by sodium borohydride,the final product N-[N-[3-?2-acetyl-3,6-dimethylph enyl?-3-methylbutyl]-L-?-asparttyl]-L-phenylalaniel-methyl ester was obtained,using Infrared spectroscopy?IR?,ESI mass spectrometry?MS?and nuclear magnetic reson-ance spectroscopy?NMR?for structure identification and characterization.Secondly,the final product is colorless and its aqueous solution is slightly acidic,and its melting point is 98.6?⁹9.3?and optical rotation is[?]_D²⁰=-23.3?c=0.1,CH₃OH?,under the 25?,its solubility is 8.7 g/L in water.When the sweetener is in neutral or slightly acidic external environment,it's very stable,but if the environment becomes high temperature or strong acid or strong alkali,it easy takes place hydrolysis reaction.Finally,the sweetness of the final high-intensity sweetener was measured,and the sweetness was evaluated by sensory evaluation and data analysis,and the sweetener was appropriately diluted.The sweetness was compared with the sucrose solution of considerable sweetness under the same conditions.The product is 70000 times sweeter than sucrose.