Synthesis And Biological Activity Of Natural Products AB5046A/B And Their Derivatives And Cedarmycins A/B

Owing to the advantages of natural products as lead compounds, in this thesis, the natural triketones AB5046A, B and natural antibiotics cedarmycins A, B were designed and synthesized for the first time, then 96 target compounds were designed and synthesized based on them. All compounds have been characterized by 1H NMR and HRMS, and 98 of them have been identified by 13C NMR. Preliminary bioassay shows that all of them possess some extent biological activity, and there exist structure-activity relationships between them. It is proved that they are worth to be studied more deeply.Firstly, in order to find new herbicide, novel chlorosis-inducing substances, triketones AB5046A and B were firstly prepared from commercially available phloroglucinol in five steps with an overall yield of 36% and 28% respectively. This method was a powerful tool for synthesis of 2-acyl-3,5-dihydroxy-cyclohex-2-ene-l-one derivatives. Then 72 target compounds were designed and synthesized based on the triketones. The in vitro bioassay results demonstrat that some derivates have high herbicidal activity (82.9%), at the dosage of 100μg·mL1 especially their structure were similar with the natural product AB5046A and B. It is important that these triketones herbicides have excellent herbicidal activities, and can be further investigated as lead compounds.Secondly, in order to find new agricultural fungicide, plant growth regulators, medical fungicide and so on, natural antibiotics cedarmycins A and B were firstly synthesized from commercially available y-butyrolactone in seven steps with an overall yield of 20% and 19% respectively. Then 24 analogues and 2 novel by-products were designed and synthesized based on the antibiotics. The in vitro bioassay results demonstrat that cedarmycins A and B have the certain agricultural fugicidal activity.Besides, a facile aldol condensation of a-phenylene sulfide-y-butyrolactone and paraformaldehyde promoted by sodium methoxide in methanol was found, and it has a practical application value.