Study On The Synthesis Of Super High-potency Aspartame Derivative

The development of high potency sweetener changes rapidly from day to day, sweetener with safety, low cost, high degree of sweetness and top properties is the major goal of food industry. The sweetness of aspartyl derivatives is about from several hundred to several thousand times as suerose. The most important trait is their excellent stability with non-calorie. Based on the sweetness theory and Neotame synthesis principle, 3-hydroxy-4-methoxybenzylaldehyde which substitude 3,3-dimethylbutanal and Aspartame can get the new derivative of Aspartame, whose sweetness is 23,000 times of sucrose, and stability is also greatly improved.This research uses 3-hydroxy-4-methoxybenzylaldehyde, acetaldehyde and Aspartame as three main material, Pd/C as catalyst for selective hydrogenation, successfully producing the target product, N-[N-[3-(3-hydroxy-4methoxyphenyl)propyl]-L-.alpha.-aspartyl]-L-phenylala-ninel-methy ester, synthesis technology has been optimized and the best experimental solution has been confirmed, crude product has been refined. Then I determine some physical and chemical properties to insure that is what we need with Infrared and Ultraviolet Analysis.During the preparation of 3-hydroxy-4-methoxycinnamaldehyde (HMC) in three ways, the effects of raw material ration, duration, duration of aldehyde addition, concentration of katalyst, solvent and temperature on the yield of HMC have been studied. Results of orthogonal test show that the optimum reaction conditions are, the molar ratio of 3-hydroxy-4-methoxyphenylformaldehyde and aldehyde is 1.7:1, temperature 25℃, duration of aldehyde addition 30min and concentration of KOH 5%. The optimum yield is 85.4%. In the preparation of N-[N-[3-(3-hydroxy-4methoxyphenyl)propyl]-L-.alpha.-aspartyl]-L-phenylala-ninel-methy ester, the effects of the mole ratio of 3-hydroxy-4-methoxycinnamaldehyde and Aspartame, duration, pH, the addition of Pd/C catalyst and the pressure of hydrogen on the yield of the target have been studied. Results of orthogonal test show that the optimum reaction conditions are, temperature 35℃, the pressure of hydrogen 1Mpa, pH 5.5, duration 18h, Pd/C catalyst (dry weight) for the reaction of the total reactants 10%, the mole ration of 3-hydroxy-4-methoxycinnamaldehyde and Aspartame 1:1. The optimum yield is 85.4%.In the experiment of purifying of crude products, the influences of the category, volume ratio and concentration of solevent and pH on the purify of outcome are been studied. Results show the optimum recrystallizing condition, the optimized solvent are blending methanol and water with volume ratio 150ml:50ml, pH5.0.The experiment also do some researches on the chemicophysical properties of the target product, sweetness mechanism. The target is little dissolve in water at 60℃with 15.8g/L, but easy in ethanol at room temperature with 947.2g/L, the pH value of them in water solution is sourish, have little influence on the solution pH, the absorbency and concentration have a good linear relationship. Hydrolysis of the target product make microscopic methanol which is safty for people. The stability gradually descends when temprature ascends. At pH 5.5, the target can be deposited for a long time. The product have high-intensity sweetness, 23,000 times of sucrose, which has a good many advantageous properties such as good taste, low calorie, non-nutritious and high sweetness, can widely used in the food industry.