Purines. XXXIII. Syntheses and cytokinin activities of both enantiomers of 1'-methylzeatin and their 9-.BETA.-D-ribofuranosides.
作者:Tozo FUJII、Taisuke ITAYA、Satoshi MATSUBARA
DOI:10.1248/cpb.37.1758
日期:——
The structures and absolute configurations of the cytokinins 1'-methylzeatin and its 9-riboside, both secreted by Pseudomonas syringae pv savastanoi, have been established as [R-(E)]-2-methyl-4-(9H-purin-6-ylamino)-2-penten-1-ol[(1'R)-2] and [R-(E)]-N-(4-hydroxy-1, 3-dimethyl-2-butenyl)adenosine [(1''R)-4], respectively, as a result of the chiral syntheses of (1'R)- and (1'S)-1'-methylzeatins [(1'R)-2 and (1'S)-2] and of their 9-β-D-ribofuranosides [(1''R)-4 and (1''S)-4] from D- and L-alanines. These zeatin derivatives were tested for cytokinin activity in the tobacco callus and the lettuce seed germination bioassays. The "natural" enantiomer (1'R)-2 was found to be as active as zeatin (1) itself and more active than its 9-riboside [(1''R)-4]. The "unnatural" enantiomer (1'S)-2 and its 9-riboside [(1''S)-4] were less active than the corresponding natural cytokinins, (1'R)-2 and (1''R)-4, respectively.
Synthesis and Absolute Configuration of the Green Alga Cytokinin 2-Hydroxy-1'-methylzeatin
作者:Tozo Fujii、Masashi Ohba、Tsuyoshi Haneishi、Satoshi Matsubara、A. H. Abad Farooqi、Y. N. Shukla
DOI:10.3987/com-91-5920
日期:——
The correctness of the gross structure of the marine green alga cytokinin 2-hydroxy-1'-methylzeatin (1) has been confirmed as a result of the chiral syntheses of (1'R)-1 and (1'S)-1. An indirect comparison of the cytokinin activity of the natural cytokinin with those of the synthetic enantiomers suggests that the R configuration may be assigned to the natural one unless it would be racemic.
FUJII, TOZO;ITAYA, TAISUKE;MATSUBARA, SATOSHI, CHEM. AND PHARM. BULL., 37,(1989) N, C. 1758-1763
作者:FUJII, TOZO、ITAYA, TAISUKE、MATSUBARA, SATOSHI
DOI:——
日期:——
Asymmetric Syntheses of α-Methyl γ-Amino Acid Derivatives
this reaction; syn-products were formed from the E-alkenes, while the Z-isomers gave anti-target materials, both with high diastereoselectivities. This study featured asymmetric catalysis to elaborate opticallyactive substrates into more stereochemically complex chirons; we suggest that the approach used, optimization of stereocontrol by varying peripheral aspects of the substrate, tends to be easier