The Total Syntheses Of β-carboline Alkalids Dichotomines G-H And Oldhamines A-B

β-carboline alkaloids widely existed in natural resources. Every year lots of novel β-carboline alkaloids have been separated, and many of them were proved to be in good bioactivities, which are essential to medical research.Oldhamiaines A and B were separated from’Gypsophila oldhamiana Miq’, which exhibits good resistance to human cancer cells. Dichotomines G and H were separated out from the’Stellaria dichotoma’, which were proved to be in excellent antiallergic activities.Pictet-Spengler reaction is the critical step in the synthesis of parent nucleus of β-carboline alkaloids. We deeply studied their reaction mechanism, and optimized their reaction conditions. Based on the aboved two points, we carried out the total synthesis of β-carboline alkaloids:Oldhamiaines A and B, Dichotomines G and H.Total syntheses of Oldhamiaines A and B starting from L-tryptophan acid and L-aspartic acid were achieved, with respective total yields of 49% and 55% by 6-7 steps; total syntheses of Dichotomines G and H starting from L-tryptophan acid and L-glutamic acid were achieved, with respective total yields of 48% and 51% by 7 steps.