Germination inhibitor synthesis

The final steps in a total synthesis of (+ )-gloeosporone (3, a natural germination inhibitor of a fungus) required oxidation of the acetylene group of 1 to a diketone group. The oxidation was carried out in 74% yield by the catalytic Ru02 procedure of Sharpless. On liberation (pyridine-HF) of the C7-hydroxyl group, the hydroxy... 

An efficient synthesis of the fungal germination inhibitor Aitemaric Acid required an ester which survived the ruthenium catalyst used in the formation of 103.1 [Scheme 6.103. 232 Since the product 103w2 was also acid-sensitive, an ester... 

A. Furstner and co-workers devised an efficient synthesis of (-)-gloeosporone, a fungal germination inhibitor. They utilized the Keck asymmetric allylation method to create the 7(R>homoallylic alcohol subunit. The reaction of the substrate aldehyde in the presence of the in situ generated catalyst provided the product with high yield and as the only diastereomer. It is important to note that it was essential to use freshly distilled Ti(/-OPr)4 for the preparation of the catalyst in order to get high enantioselectivity and reproducible results. 

Triumferol or 4-hydroxyisoxazole (9) is the powerful seed germination inhibitor isolated from the African medicinal plant Triumfetta rhomboidea. Confirmation of its structure and its activity was obtained by synthesis through conversion of ethyl isoxazole-3-carboxylate into its acid chloride followed by reaction with MeMgBr... 

Nakatani M, Yamachika T, Tanoue T, Hase T 1985 Structures and synthesis of seed-germination inhibitors from Hibiscus rosa-sinensis. Phytochemistry 24 39-42... 

The antagonism of GA action by ABA can be seen in studies of steady-state mRNA accumulation in aleurone cells, a major site of a-amylase synthesis in germinating cereal seeds (Fig. 3). GA treatment promotes the accumulation of high levels of a-amylase, shown by immunoprecipi-tation, while ABA, alone or with GA, completely represses this accumulation. In contrast, ABA clearly promotes the accumulation of a-amylase inhibitor mRNA, as determined by specific immunoprecipi-tation, while GA alone slightly reduces the level of a-amylase inhibitor mRNA. However, GA, together with ABA, does not decrease the level... 

If a potent inhibitor of succinyl-CoA synthetase is applied to liver cells and germinating plant cells, what effect would this have on energy production and the synthesis of carbohydrate in both types of cell ... 

Seebach et al. [45] employed this procedure in the synthesis of the germination self-inhibitor gloeosporone (79). Treatment of seco acid 77 with 2 equiv of DEAD and 2 equiv of triphenylphosphine in benzene (0.005 M) for 10 min afforded the... 

Another relevant example is the total synthesis of the macrolide glacosporone, a germination self-inhibitor from the fungus Colletotrichum glocosporioides. The retrosynthetic scheme shows the important role played by the dithiane anion (Scheme 8). 

D-phenylalanine, the sterioisomer of the naturally occurring L-phenylalanine, inhibits the PAL activity. Szkutnicka and Lewak (18) found that the application of this compound to germinating seeds caused an increase in the PAL level. They attributed this to the decrease in the production of cinnamic acid and compounds derived therefrom. Similar results have been obtained by Amrhein and Gerhardt (19) with the PAL-inhibitors, L-a-aminooxy-8-phenylpropionic acid and a-aminooxyacetic acid on gherkin seedlings. They found that the synthesis of hydroxycinnamic acids was inhibited and that the PAL level increased. This increase was suppressed when tr<2 s-cinnamic acid was applied. 

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