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1.
Mik V Szüčová L Smehilová M Zatloukal M Doležal K Nisler J Grúz J Galuszka P Strnad M Spíchal L 《Phytochemistry》2011,72(8):821-7251
The first isolated cytokinin, 6-furfurylaminopurine (kinetin or Kin), was identified almost 55 years ago. Its biological effects on plant cells and tissues include influences on such processes as gene expression, cell cycle, chloroplast development, chlorophyll biosynthesis, stimulation of vascular development, delay of senescence, and mobilization of nutrients. In the present study we prepared a series of eight N9-substituted Kin derivatives, and characterized them with available physicochemical methods such as CI+ mass spectrometry and 1H NMR spectroscopy. All compounds were tested in three classical cytokinin bioassays: a tobacco callus assay, an Amaranthus assay, and a senescence assay with excised wheat leaves. The ability of the compounds to interact with Arabidopsis cytokinin receptors CRE1/AHK4 and AHK3 was tested in a bacterial receptor assay. Prepared derivatives with certain substitutions of the N9-atom of the purine moiety enhanced the cytokinin activity of the parent compound in the bioassays to a remarkable degree but negatively affected its perception by CRE1/AHK4 and AHK3. The ability of compounds to delay the senescence of excised wheat leaves in both dark and light conditions, was highly correlated with their ability to influence membrane lipid peroxidation, which is a typical symptom of senescence. Our results were corroborated by gene expression profiling of those genes involved in cytokinin metabolism and perception, plant senescence, and the stress response, and suggest that prepared kinetin derivatives might be used as potent anti-senescence agents. 相似文献
2.
《Bioorganic & medicinal chemistry》2020,28(2):115230
Cytokinins are naturally occurring substances that act as plant growth regulators promoting plant growth and development, including shoot initiation and branching, and also affecting apical dominance and leaf senescence. Aromatic cytokinin 6-benzylaminopurine (BAP) has been widely used in micropropagation systems and biotechnology. However, its 9-glucoside (BAP9G) accumulates in explants, causing root inhibition and growth heterogenity. To overcome BAP disadvantages, a series of ring-substituted 2′-deoxy-9-(β)-d-ribofuranosylpurine derivatives was prepared and examined in different classical cytokinin bioassays. Amaranthus, senescence and tobacco callus bioassays were employed to provide details of cytokinin activity of 2′-deoxy-9-(β)-d-ribosides compared to their respective free bases and ribosides. The prepared derivatives were also tested for their recognition by cytokinin receptors of Arabidopsis thaliana AHK3 and CRE1/AHK4. The ability of aromatic N6-substituted adenine-2′-deoxy-9-(β)-d-ribosides to promote plant growth and delay senescence was increased considerably and, in contrast to BAP, no loss of cytokinin activity at higher concentrations was observed. The presence of a 2′-deoxyribosyl moiety at the N9-position led to an increase in cytokinin activities in comparison to the free bases and ribosides. The antioxidant capacity, cytotoxicity and effect on the MHV-68 gammaherpesvirus strain were also examined. 相似文献
3.
Recently we reported 6-(2-hydroxy-3-methylbenzylamino)purine (PI-55) as the first molecule to antagonize cytokinin activity at the receptor level. Here we report the synthesis and in vitro biological testing of eleven BAP derivatives substituted in the benzyl ring and in the C2, N7 and N9 positions of the purine moiety. The ability of the compounds to interact with Arabidopsis cytokinin receptors AHK3 and CRE1/AHK4 was tested in bacterial receptor and in live-cell binding assays, and in an Arabidopsis ARR5:GUS (Arabidopsis response regulator 5) reporter gene assay. Cytokinin activity of the compounds was determined in classical cytokinin biotests (tobacco callus, wheat leaf senescence and Amaranthus bioassays). 6-(2,5-Dihydroxybenzylamino)purine (LGR-991) was identified as a cytokinin receptor antagonist. At the molecular level LGR-991 blocks the cytokinin receptor CRE1/AHK4 with the same potency as PI-55. Moreover, LGR-991 acts as a competitive inhibitor of AHK3, and importantly shows reduced agonistic effects in comparison to PI-55 in the ARR5:GUS reporter gene assay and in cytokinin bioassays. LGR-991 causes more rapid germination of Arabidopsis seeds and increases hypocotyl length of dark-grown seedlings, which are characteristics of plants with a reduced cytokinin status. LGR-991 exhibits a structural motive that might lead to preparation of cytokinin antagonists with a broader specificity and reduced agonistic properties. 相似文献
4.
Mik V Szüčová L Spíchal L Plíhal O Nisler J Zahajská L Doležal K Strnad M 《Bioorganic & medicinal chemistry》2011,19(23):7244-7251
Rational design is one of the latest ways how to evaluate particular activity of signal molecules, for example cytokinin derivatives. A series of N(6)-[(3-methylbut-2-en-1-yl)amino]purine (iP) derivatives specifically substituted at the N9 atom of purine moiety by tetrahydropyran-2-yl, ethoxyethyl, and C2-C4 alkyl chains terminated by various functional groups were prepared. The reason for this rational design was to reveal the relationship between specific substitution at the N9 atom of purine moiety of iP and cytokinin activity of the prepared compounds. The synthesis was carried out either via 6-chloro-9-substituted intermediates prepared originally from 6-chloropurine, or by a direct alkylation of N9 atom of N(6)-[(3-methylbut-2-en-1-yl)amino]purine. Selective reduction was implemented in the preparation of compound N(6)-[(3-methylbut-2-en-1-yl)amino]-9-(2-aminoethyl-amino)purine (12) when 6-[(3-methylbut-2-en-1-yl)amino]-9-(2-azidoethyl)purine (7) was reduced by zinc powder in mild conditions. The prepared derivatives were characterized by C, H, N elemental analyses, thin layer chromatography (TLC), high performance liquid chromatography (HPLC), melting point determinations (mp), CI+ mass spectral measurement (CI+ MS), and by (1)H NMR spectroscopy. Biological activity of prepared compounds was assessed in three in vitro cytokinin bioassays (tobacco callus, wheat leaf senescence, and Amaranthus bioassay). Moreover, the perception of prepared derivatives by cytokinin-sensitive receptor CRE1/AHK4 from Arabidopsis thaliana, as well as by the receptors ZmHK1 and ZmHK3a from Zea mays, was studied in a bacterial assay where the response to the cytokinin treatment could be specifically quantified with the aim to reveal the way of the perception of the above mentioned derivatives in two different plant species, that is, Arabidopsis, a model dicot, and maize, a model monocot. The majority of cytokinin derivatives were significantly active in both Amaranthus as well as in tobacco callus bioassay and almost inactive in detached wheat leaf senescence assay. N9-Substituted iP derivatives remained active in both in vitro bioassays in a broad range of concentrations despite the fact that most of the derivatives were unable to trigger the cytokinin response in CRE1/AHK4 and ZmHK1 receptors. However, several derivatives induced low but detectable cytokinin-like activation in maize ZmHK3a receptor. Compound 6-[(3-methylbut-2-en-1-yl)amino]-9-(tetrahydropyran-2-yl)purine (1) was also recognized by CRE1/AHK4 at high concentration ≥ 50 μM. 相似文献
5.
Mark A. Sprecker Alan G. Morrice Bruce A. Gruber Nelson J. Leonard Ruth Y. Schmitz Folke Skoog 《Phytochemistry》1976,15(5):609-613
We have synthesized and compared the cytokinin activities in the tobacco bioassay of a series of benzologs of 6-(3-methyl-2-butenylamino)purine (N6-(Δ2-isopentenyl)adenine) (1a) and 6-benzylaminopurine (N6-benzyl-adenine) (1c). The linear benzo analogs 8-(3-methyl-2-butenylamino)imidazo[4,5-g]quinazoline (2b) and 8-benzyla-minoimidazo[4,5-g]quinazoline (2c) are active, while 9-(3-methyl-2-butenylamino)imidazo[4,5-f]quinazoline (3b) and 6-(3-methyl-2-butenylamino)imidazo[4,5-h]quinazoline (4b) are slightly active and 9-benzylaminoimidazo[4,5-f]-quinazoline (3c) and 6-benzylaminoimidazo[4,5-h]quinazoline (4c) are inactive. Compounds 2b and 2c represent the first examples of active cytokinins containing a tri-heterocyclic moiety. The above series of compounds demonstrates structural factors that affect cytokinin activity. These compounds also have interesting fluorescence properties which could render them useful as probes to study the mechanism of cytokinin action. 相似文献
6.
Kopecný D Sebela M Briozzo P Spíchal L Houba-Hérin N Masek V Joly N Madzak C Anzenbacher P Laloue M 《Journal of molecular biology》2008,380(5):886-899
Cytokinin oxidases/dehydrogenases (CKOs) mediate catabolic regulation of cytokinin levels in plants. Several substrate analogs containing an unsaturated side chain were studied for their possible inhibitory effect on maize CKO (ZmCKO1) by use of various bioanalytical methods. Two allenic derivatives, N6-(buta-2,3-dienyl)adenine (HA-8) and N6-(penta-2,3-dienyl)adenine (HA-1), were identified as strong mechanism-based inhibitors of the enzyme. Despite exhaustive dialysis, the enzyme remained inhibited. Conversely, substrate analogs with a triple bond in the side chain were much weaker inactivators. The crystal structures of recombinant ZmCKO1 complexed with HA-1 or HA-8 were solved to 1.95 Å resolution. Together with Raman spectra of the inactivated enzyme, it was revealed that reactive imine intermediates generated by oxidation of the allenic inhibitors covalently bind to the flavin adenine dinucleotide (FAD) cofactor. The binding occurs at the C4a atom of the isoalloxazine ring of FAD, the planarity of which is consequently disrupted. All the compounds under study were also analyzed for binding to the Arabidopsis cytokinin receptors AHK3 and AHK4 in a bacterial receptor assay and for cytokinin activity in the Amaranthus bioassay. HA-1 and HA-8 were found to be good receptor ligands with a significant cytokinin activity. Nevertheless, due to their ability to inactivate CKO in the desired time intervals or developmental stages, they both represent attractive compounds for physiological studies, as the inhibition mechanism of HA-1 and HA-8 is mainly FAD dependent. 相似文献
7.
Immunodetection and Identification of N-(o-Hydroxybenzylamino)Purine as a Naturally Occurring Cytokinin in Populus x canadensis Moench cv Robusta Leaves
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A highly specific and sensitive enzyme-linked immunosorbent assay (ELISA) was developed for 9-β-d-ribofuranosyl-N6-(o-hydroxybenzylamino)purine [(oOH)[9R]BAP] and structurally related cytokinins. As little as 3 femtomoles of the compound could be detected by this method. Cross-reactivity studies demonstrated the specificity of four polyclonal antibodies for (oOH)[9R] BAP and its free base in preference to a range of natural cytokinins and other purines. After evaluating the method by internal standardization employing [2-3H](oOH)[9R]BAP of high specific radioactivity as recovery marker by dilution analyses and by immunohistograms, it was possible to apply ELISA to quantify (oOH)[9R]BAP in plant extracts. In addition to (oOH)[9R]BAP, an unknown cytokinin reacting with the same antibody was detected in high performance liquid chromatography-fractionated extracts of mature Populus × canadensis Moench cv Robusta. The structure of the new compound was determined by gas chromatography-mass spectrometry and finally confirmed by synthesis as N6-(o-hydroxybenzylamino)purine. 相似文献
8.
David Kopečný Pierre Briozzo Hana Popelková Marek Šebela Radka Končitíková Lukáš Spíchal Jaroslav Nisler Catherine Madzak Ivo Frébort Michel Laloue Nicole Houba-Hérin 《Biochimie》2010
Cytokinin oxidase/dehydrogenase (CKO) is a flavoenzyme, which irreversibly degrades the plant hormones cytokinins and thereby participates in their homeostasis. Several synthetic cytokinins including urea derivatives are known CKO inhibitors but structural data explaining enzyme–inhibitor interactions are lacking. Thus, an inhibitory study with numerous urea derivatives was undertaken using the maize enzyme (ZmCKO1) and the crystal structure of ZmCKO1 in a complex with N-(2-chloro-pyridin-4-yl)-N′-phenylurea (CPPU) was solved. CPPU binds in a planar conformation and competes for the same binding site with natural substrates like N6-(2-isopentenyl)adenine (iP) and zeatin (Z). Nitrogens at the urea backbone are hydrogen bonded to the putative active site base Asp169. Subsequently, site-directed mutagenesis of L492 and E381 residues involved in the inhibitor binding was performed. The crystal structures of L492A mutant in a complex with CPPU and N-(2-chloro-pyridin-4-yl)-N′-benzylurea (CPBU) were solved and confirm the importance of a stacking interaction between the 2-chloro-4-pyridinyl ring of the inhibitor and the isoalloxazine ring of the FAD cofactor. Amino derivatives like N-(2-amino-pyridin-4-yl)-N′-phenylurea (APPU) inhibited ZmCKO1 more efficiently than CPPU, as opposed to the inhibition of E381A/S mutants, emphasizing the importance of this residue for inhibitor binding. As highly specific CKO inhibitors without undesired side effects are of major interest for physiological studies, all studied compounds were further analyzed for cytokinin activity in the Amaranthus bioassay and for binding to the Arabidopsis cytokinin receptors AHK3 and AHK4. By contrast to CPPU itself, APPU and several benzylureas bind only negligibly to the receptors and exhibit weak cytokinin activity. 相似文献
9.
A new cytokinin was isolated from mature leaves of poplar. Its structure was determined by UV and MS and confirmed by synthesis as 6-(o-hydroxybenzylamino)-9-β-d-ribofuranosylpurine. This cytokinin has medium activity in the soybean callus test but shows high activity in the radish leaf senescence test. 相似文献
10.
《Bioorganic & medicinal chemistry letters》2014,24(13):2905-2908
A series of novel pyrazolo[3,4-b]pyridine and pyrimidine functionalized 1,2,3-triazole derivatives 8a–g and 9a–g were prepared starting from 6-trifluoromethylpyridine-2(1H)one 2 via selective O-alkylation, followed by cyclisation using hydrazine hydrate to obtain 6-(trifluoromethyl)-1H-pyrazolo[3,4-b]pyridin-3-amine 4. Compound 4 was diazotized followed by reaction with sodium azide, resulted in 3-azido-6-(trifluoromethyl)-1H-pyrazolo[3,4-b]pyridine 5. Compound 5 was further cyclized with N-/O-propargylated pyrimidine derivatives under Sharpless conditions and obtained compounds 6 and 7, respectively. Each set of compounds 6 and 7 were alkylated with different alkyl halides and obtained respective products 8 and 9. All the products were screened for cytotoxicity against four human cancer cell lines such as A549-Lung (CCL-185), MCF7-Breast (HTB-22), DU145-Prostate (HTB-81) and HeLa-Cervical (CCL-2), compounds 9d, 9e and 9f which showed promising activity have been identified. The products were also screened for antimicrobial, anti bio-film and MBC activities. Promising compounds in each case have been identified. 相似文献
11.
Maninder Minu Ananda Thangadurai Sharad Ramesh Wakode Shyam Sundar Agrawal Balasubramanian Narasimhan 《Bioorganic & medicinal chemistry letters》2009,19(11):2960-2964
Antimicrobial activity of synthesized 2,3-disubstituted-3,3a,4,5,6,7-hexahydro-2H-indazole derivatives indicated that 3-(4-chlorophenyl)-2-(4-nitrophenylsulfonyl)-3,3a,4,5,6,7-hexahydro-2H-indazole (6) and 3-(4-fluorophenyl)-2-(4-nitrophenylsulfonyl)-3,3a,4,5,6,7-hexahydro-2H-indazole (20) were the most active compounds. Further, the results of QSAR studies indicated the importance of topological parameters 2χ and 2χv in defining the antimicrobial activity of hexahydroindazoles. 相似文献
12.
Randy Ortíz-Castro Eduardo Valencia-Cantero José López-Bucio 《Plant signaling & behavior》2008,3(4):263-265
Accumulating evidence indicates that plant growth promoting rhizobacteria (PGPR) influence plant growth and development by the production of phytohormones such as auxins, gibberellins, and cytokinins. Little is known on the genetic basis and signal transduction components that mediate the beneficial effects of PGPRs in plants. We recently reported the identification of a Bacillus megaterium strain that promoted growth of A. thaliana and P. vulgaris seedlings. In this addendum, the role of cytokinin signaling in mediating the plant responses to bacterial inoculation was investigated using A. thaliana mutants lacking one, two or three of the putative cytokinin receptors CRE1, AHK2 and AHK3, and RPN12 a gene involved in cytokinin signaling. We show that plant growth promotion by B. megaterium is reduced in AHK2-2 single and double mutant combinations and in RPN12. Furthermore, the triple cytokinin-receptor CRE1-12/AHK2-2/AHK3-3 knockout was insensitive to inoculation in terms of growth promotion and root developmental responses. Our results indicate that cytokinin receptors play a complimentary role in plant growth promotion by B. megaterium.Key words: Arabidopsis, plant growth stimulation, root development, rhizobacteria 相似文献
13.
Rut Beyerle-Pfnür Stefan Jaworski Bernhard Lippert Helmut Schöllhorn Ulf Thewalt 《Inorganica chimica acta》1985,107(3):217-222
The preparation is reported of [(NH3)3Pt(9- MeA)] X2 (9-MeA = 9-methyladenine) with XCl (1a) and XClO4 (1b) and of trans-[(OH)2Pt(NH3)3- (9-MeA)]X2 with XCl (2a) and XClO4 (2b), and the crystal structure of 1b. [(NH3)3Pt(C6H7N5)](ClO4)2 crystallizes in space group P21/n with a = 20.810(7) Å, b = 7.697(3) Å, c = 10.567(4) Å, β = 91.57(6)°, Z = 4. The structure was refined to R = 0.054, Rw = 0.063. In all four compounds Pt coordination is through N7 of 9-MeA, as is evident from 3J coupling between H8 of the adenine ring and 195Pt. Pt(II) and Pt(IV) complexes can be differentiated on the basis of different 3J values, larger for Pt(II) than for Pt(IV) by a factor of 1.57 (av). In Me2SO-d6, hydrogen bonding occurs between Cl? and C(8)H of 9-MeA as weil as between Cl? and the NH3 groups in the case of the Pt(II) complex 1a. Protonation of the 9-MeA ligands was followed using 1H NMR spectroscopy and pKa values for the N1 protonated 9-MeA ligands were determined in D2O. They are 1.9 for 1a and 1.8 for 2a, which compares with 4.5 for the non-platinated 9-MeA. Possible consequences for hydrogen bonding with the complementary bases thymine or uracil are discussed briefly. Protonation of the OH groups in the Pt(IV) complexes has been shown not to occur above pH 1. 相似文献
14.
P.A.J. Gorin 《Carbohydrate research》1973,27(2):309-323
Benzyl 2-[(benzyloxycarbonyl)methylamino]-2-deoxy-α-D-mannopyranoside (10) and its furanose isomer (9), the derived N-methyloxazolidinones 11 and 6, benzyl 2-[(benzyloxycarbonyl)methylamino]-2-deoxy-β-D-glucofuranoside (15) and methyl 2-deoxy-2-methylacetamido-β-D-galactofuranoside (20), were prepared from appropriate diethyl dithioacetals. They were considered the most suitable starting materials for synthesis of O-methyl-2-deoxy-2-methylamino-hexoses because of their ease of preparation and the presence of suitable blocking groups. Oxazolidinones were prepared from N-benzyloxycarbonyl derivatives of 2-amino-2-deoxy-D-mannose by using methanolic sodium methoxide. Their use in preparation of 2-deoxy-2-methyl-amino derivatives is discussed. The Kuhn reagent was used in these syntheses for N-methylating amides. However, certain amides containing comparatively bulky substituents in the vicinity of the NH group are resistant to methylation. 相似文献
15.
Zatloukal M Gemrotová M Dolezal K Havlícek L Spíchal L Strnad M 《Bioorganic & medicinal chemistry》2008,16(20):9268-9275
The synthesis of a new group of 2-X-6-anilinopurines, including compounds with potential cytokinin-like activities, with various substitutions (X=H, halogen, amino, methylthio or nitro) on the phenyl ring is described. The prepared compounds have been characterized using standard physico-chemical methods, and the influence of individual substituents on biological activity has been compared in three different bioassays, based on the stimulation of tobacco callus growth, retention of chlorophyll in excised wheat leaves and the dark induction of betacyanin synthesis in Amaranthus cotyledons. The biological activity of the prepared compounds was also assessed in receptor assays, in which the ability of the compounds to activate the cytokinin receptors AHK3 and AHK4/CRE1 was studied. Finally, the interactions of the compounds with the Arabidopsis cytokinin oxidase/dehydrogenase AtCKX2 (heterologously expressed) were investigated. Systematic testing led to the identification of two very potent inhibitors of AtCKX2: 2-chloro-6-(3-methoxyphenyl)aminopurine and 2-fluoro-6-(3-methoxyphenyl)aminopurine. 相似文献
16.
Treatment of (Z)-3-deoxy-1,2:5,6-di-O-isopropylidine-3-C-(methoxycarbonyl)-methylene-α-d-ribo-hexofuranose (1) with diazomethane in ether afforded the unstable Δ1- and Δ2-pyrazolines 2 and 2a. High-pressure hydrogenation of the latter compounds over Raney nickel afforded a mixture of amines 3, 5, 7, and 9 (in 80% yield), which were separated by chromatography. Acetylation of these compounds yielded the N-acetyl derivatives 4, 6, 8, and 10. X-Ray analysis of compounds 8 and 10 showed them to be spiro-3,4′-(R)-(3-deoxy-1,2:5,6-di-O-isopropylidine-α-d-ribo-hexofuranose)-3′-(R)-[and 3′-(S)]-acetamido-2′-pyrrolidinone, respectively. The structures of compounds 4 and 6 (determined by chemical means) were the corresponding spiro-3,4′-(S)-3′-(R)-acetamido-2′-pyrrolidinone and 3′-(S)-acetamido-2′-pyrrolidinone, respectively. 相似文献
17.
《Bioorganic & medicinal chemistry》2014,22(12):3072-3082
Structure–activity relationships of 2-alkynyladenine derivatives were explored by varying substituents at the 9-, 8- and 2-positions of the purine moiety in order to optimize A2A adenosine receptor antagonist activity in vitro. A propargyl group at the 9-position was found to be important for A2A antagonist activity, and the introduction of a halogen, aryl, or heteroaryl at the 8-position further enhanced activity. A series of 8-substituted 2-alkynyl-N9-propargyladenine derivatives exhibited potent antagonist activity, with IC50 values in the low nM range. Compound 4a from this series was found to be orally active at a dose of 3 mg/kg in a mouse catalepsy model and a 6-hydroxydopamine-lesioned rat model of Parkinson’s disease. 相似文献
18.
C. A. Auer 《Journal of Plant Growth Regulation》1996,15(4):201-206
The effects of cytokinins on the in vitro growth of the roots of Arabidopsis thaliana seedlings were examined. Root growth was inhibited in a manner dependent upon the type of cytokinin compound, the cytokinin concentration, the Arabidopsis genotype, and the duration of exposure to cytokinin. For the cytokinins N
6-benzyladenine (BA), isopentenyl adenine (iP), or dihydrozeatin (DHZ), the concentration required for 50% root growth inhibition differed for each cytokinin and in each of three Arabidopsis genotypes tested. iP was the most active cytokinin in inhibiting the root growth of the Ler-0 genotype, whereas iP and BA had equal activity when tested with the Col-2 and Columbia genotypes. DHZ had the lowest activity of the three cytokinins tested in all three genotypes. A brief 1-day exposure of seeds to a root-inhibiting concentration of BA increased root growth compared with seedlings grown without BA; exposure to BA for 3–6 days inhibited root growth. BA metabolism was evaluated after 6 h and 1, 3, and 6 days in Columbia seedlings. BA, N
6-benzyladenosine (BAR), and N
6-benzyladenosine-5-monophosphate (BAMP) decreased with time, whereas N
6-benzyladenine-7--d-glucopyranoside (BA-7-G) and N
6-benzyladenine-9--d-glucopyranoside (BA-9-G) accumulated in the growing seedlings. Seven aromatic cytokinins were compared at 5 m for their effect on Col-3 root growth. BA, BAR, N
6-(m-hydroxybenzylamino)adenine, and N
6-(o-hydroxybenzylamino)adenine were highly effective in inhibiting root growth, whereas N
6-(p-hydroxybenzylamino)adenine produced only a slight decrease in root growth. BA-7-G and BA-9-G did not affect root growth.Abbreviations BA
N
6-benzyladenine
- iP
isopentenyl-adenine
- DHZ
dihydrozeatin
- BAR
N
6-benzyladenosine
- BAMP
N
6-benzyladenosine 5-monophosphate
- BA-7-G
N
6-benzyladenine-7--d-glucopyranoside
- BA-9-G
N
6-benzyladenine-9--d-glucopyranoside
-
m-OH BA
N
6-(m-hydroxybenzylamino)adenine
-
o-OH BA
N
6-(o-hydroxybenzylamino)adenine
-
p-OH BA
N
6-(p-hyrdoxybenzylamino)adenine
- HPLC
high performance liquid chromatography
- gFW
grams fresh weight 相似文献
19.
We have synthesized 2- and 8-monosubstituted and 2,8-disubstituted derivatives of the cytokinin 6-(3-methyl-2-butenylamino)purine (N6-isopentenyladenine) and have shown the dependence of growth-promoting activity in the tobacco bioassay upon the position, number, and type of substituent. The representative substituent groups were MeS, Me, MeSO2, C6H5CH2S, HS and Cl. The 8-methyl derivative was exceptional in being more active than the unsubstituted parent compound. In general, substitution in the 8-position decreases activity less than substitution in the 2-position, with the exception of the electron-attracting methylsulfonyl. Substitution in both the 2- and 8-positions lowers the activity more than substitution at either single position on the adenine nucleus, with the exception of the 2,8-dimethyl derivative. The chloro and methylthio derivatives show activity in the same range as the methyl derivatives, and the mercapto compounds, which exist mainly as CS tautomers, show somewhat less activity than the corresponding methylthio compounds. Bulky (C6H5CH2S and MeSO2) and strongly electron-attracting (MeSO2) substituents cause relatively great reduction in cytokinin activity. 相似文献
20.
Five 2,6-di(acylamino)-2,6-dideoxy-3-O-(d-2-propanoyl-l-alanyl-d-isoglutamine)-d-glucopyranoses (lipophilic, muramoyl dipeptide analogs) were synthesized from benzyl 2-(benzyloxycarbonylamino)-3-O-(d-1-carboxyethyl)-2-deoxy-5,6-O-isopropylidene-β-dglucopyranoside (1). Methanesulfonylation of 3, derived from the methyl ester of 1 by O-deisopropylidenation, gave the 6-methanesulfonate (4). (Tetrahydropyran-2-yl)ation of 4 gave benzyl 2-(benzyloxycarbonylamino)-2-deoxy-3-O-[d-1-(methoxycarbonyl)ethyl]-6-O-(methylsulfonyl)-5-O-(tetrahydropyran-2-yl)-β-d- glucofuranoside, which was treated with sodium azide to give the corresponding 6-azido derivative (6). Condensation of benzyl 6-amino-2-(benzyloxycarbonyl-amino)-2,6-dideoxy-3-O-[d-1-(methoxycarbonyl)ethyl]-5-O-(tetrahydropyran-2-yl)-β-d-glucofuranoside, derived from 6 by reduction, with the activated esters of octanoic, hexadecanoic, and eicosanoic acid gave the corresponding 6-N-fatty acyl derivatives (8–10). Coupling of the 2-amino derivatives, obtained from compounds 8, 9, and 10 by catalytic reduction, with the activated esters of the fatty acids, gave the 2,6-(diacylamino)-2,6-dideoxy derivatives (11–15). Condensation of the acids, formed from 11–15 by de-esterification, with the benzyl ester of l-alanyl-d-isoglutamine, and subsequent hydrolysis, afforded benzyl 2,6-di(acylamino)-2,6-dideoxy-3-O-(d-2-propanoyl-l-alanyl-d-isoglutamine benzyl ester)-β-d-glucofuranosides. Hydrogenation of the dipeptide derivatives thus obtained gave the five lipophilic analogs of 6-amino-6-deoxymuramoyl dipeptide, respectively, in good yields. 相似文献