Total synthesis of neokotalanol, a potent α-glucosidase inhibitor isolated from Salacia reticulata / 中国天然药物

Neokotalanol, a potent α-glucosidase inhibitor isolated from Salacia reticulata, was synthesized through a key coupling reaction between a perbenzylated thiosugar and an appropriately protected perseitol triflate derived from D-mannose. This key step was found to be quite temperature dependent, and a simultaneous cyclization of the triflate leading to a characteristic 2,4,7-trioxabicyclo[4.2.1]nonane system was detected.

Synthesis and β-adrenergic blocking activity of oxime ether hybrids derived from a natural isochroman-4-one / 中国天然药物

AIM@#In a search for new cardiovascular drug candidates, a series of novel oxime ethers derived from a natural isochroman-4-one were synthesized.@*METHOD@#Compounds 3 and 6, derived from the natural antihypertensive compound 7, 8-dihydroxy-3-methyl-isochroman-4-one (XJP), were designed and synthesized. Subsequently, a series of novel isochroman-4-one oxime ether hybrids were prepared by hybridizing various N-substituted isopropanolamine functionalities to isochroman-4-one oxime. Furthermore, β1-adrenergic blocking activities of the synthesized compounds were assayed using the isolated rat left atria.@*RESULTS@#Twenty target compounds were obtained, and the preliminary structure-activity relationships were deduced. The most promising compound Ic exhibited β1-adrenoceptor blocking activity (inhibition: 52.2%) at 10(-7) mol·L(-1), which was superior to that of propranolol (inhibition: 49.7%).@*CONCLUSION@#The results suggested that natural product XJP/isopropanolamine moiety hybrids may provide a promising approach for the discovery of novel cardiovascular drug candidates.