Cytokinin metabolism in Narcissus bulbs: chilling promotes acetylation of zeatin riboside

2003 ◽  
Vol 30 (5) ◽  
pp. 525 ◽  
Author(s):  
David S. Letham ◽  
Noel G. Smith ◽  
David A. Willcocks
Keyword(s):  
Leaf Development ◽  
Base Plate ◽  
Zeatin Riboside ◽  
Side Chain ◽  
Free Base ◽  
Summer Dormancy ◽  
Narcissus Pseudonarcissus ◽  
Base Plates ◽  
Cytokinin Bioassays ◽  
Related Compounds

The levels of the cytokinins zeatin, dihydrozeatin and N6-(isopent-2-enyl)adenine and the corresponding 9-ribosides were determined in whole Narcissus pseudonarcissus L. bulbs after onset of summer dormancy, and after storage of the dormant bulbs at 4 or 15°C under moist conditions. The cytokinin level was increased at both temperatures; the dominant cytokinin at 15°C was zeatin riboside but at 4°C the free base, zeatin, was the principal cytokinin. The metabolism of 3H-labelled zeatin, zeatin riboside and 6-benzylaminopurine was studied in scales and base plates excised from bulbs previously held at 4 or 15°C. The chilling treatment promoted conversion of [3H]zeatin riboside to O-acetylzeatin riboside (an unusual cytokinin metabolite) in the excised base plate and inhibited 9-riboside formation from 6-benzylaminopurine. Chilling also promoted formation of O-acetylzeatin riboside from [3H]zeatin in excised scale tissue. Endogenous O-acetylzeatin and O-acetylzeatin riboside were concentrated in the base plate. Relative to zeatin riboside, O-acetylzeatin riboside was degraded to adenosine and related compounds less rapidly in the leaf cluster. Since acetylation of the zeatin side chain enhances activity in cytokinin bioassays, O-acetylzeatin riboside may play a role in leaf development following chilling of Narcissus bulbs.

Conformational studies of some 5,9-dimethyl-6,7-benzomorphan diastereoisomers and related compounds

1969 ◽  
Vol 47 (19) ◽  
pp. 3623-3630 ◽  
Author(s):  
A. F. Casy ◽  
A. P. Parulkar
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Piperidine Ring ◽  
Free Base ◽  
Conformational Studies ◽  
Related Compounds

The proton magnetic resonance characteristics of some α/β diastereoisomeric 5,9-dimethyl-6,7-benzomorphans are reported for free base, hydrohalide, and methiodide forms, and differences between α- and β-signals are interpreted in terms of the piperidine ring fragment of the β-salts adopting skew-boat conformations. The steric course of quaternization of benzomorphan isomers is discussed from results of alkylations using trideuteriomethyl iodide and other experiments. A possible correlation between conformational and potency differences in analgesically active benzomorphan diastereoisomers and related compounds is discussed.

Direct side-chain acylamination of 4-picoline 1-oxides and related compounds

1979 ◽  
pp. 956 ◽  
Author(s):  
Rudolph A. Abramovitch ◽  
Dorota A. Abramovitch ◽  
Piotr Tomasik
Keyword(s):  
Side Chain ◽  
Related Compounds

ChemInform Abstract: DIRECT SIDE-CHAIN ACYLAMINATION OF 4-PICOLINE 1-OXIDES AND RELATED COMPOUNDS

1980 ◽  
Vol 11 (9) ◽  
Author(s):  
R. A. ABRAMOVITCH ◽  
D. A. ABRAMOVITCH ◽  
P. TOMASIK
Keyword(s):  
Side Chain ◽  
Related Compounds

Thermally Optimum Natural Convection Cooled Longitudinal-Plate Heat Sinks With Horizontal Base Plates

2001 ◽  
Author(s):  
K. K. Sikka ◽  
C. George
Keyword(s):  
Natural Convection ◽  
Heat Sink ◽  
Base Plate ◽  
Heat Sinks ◽  
Geometrical Parameters ◽  
Plate Heat ◽  
Horizontal Orientation ◽  
Fin Spacing ◽  
Base Plates ◽  
Weakly Dependent

Abstract Longitudinal-plate fin heat sinks are optimized under natural convection conditions for the horizontal orientation of the heat sink base plate. The thermal performance of the heat sinks is numerically modeled. The fin height, thickness and spacing and heat sink width are systematically varied. The numerical results are validated by experimentation. Results show that the thermal resistance of a heat sink minimizes for a certain number of fins on the base plate. The fin spacing-to-length ratio at which the minimum occurs is weakly dependent on the fin height and thickness and heat sink width. The flow fields reveal that the minimum occurs for the heat sink geometry in which the number of fins are maximized such that the flow velocity as the air exits the fins is fully developed. A correlation of the heat transfer with the heat sink geometrical parameters is also developed.

Synthesis of Vinca Alkaloids and Related Compounds. XXVI. An Unusual Side-chain Elimination from Indole Nucleus

Heterocycles ◽  
1985 ◽  
Vol 23 (11) ◽  
pp. 2843 ◽  
Author(s):  
Csaba Szántay ◽  
M�ia Incze ◽  
Ferenc S葉i ◽  
Zsuzsanna Kardos-Balogh
Keyword(s):  
Side Chain ◽  
Vinca Alkaloids ◽  
Related Compounds

New GaN Power-Electronics Packaging Solutions: A Thermal Analysis using Raman Thermography

2010 ◽  
Vol 2010 (1) ◽  
pp. 000446-000449
Author(s):  
M. Faqir ◽  
A. Manoi ◽  
T. Mrotzek ◽  
S. Knippscheer ◽  
M. Massiot ◽  
...  
Keyword(s):  
Base Plate ◽  
Heat Diffusion ◽  
Heat Extraction ◽  
Dramatic Improvement ◽  
High Electron ◽  
Operation Condition ◽  
Thermal Dynamics ◽  
Diamond Composite ◽  
Base Plates ◽  
Device Operation

Raman thermography measurements were performed on AlGaN/GaN multi-finger high electron mobility transistors (HEMTs) to determine their channel temperature at various power levels. The devices were mounted on both silver diamond composite and CuW base plates, in order to benchmark the thermal performance of novel diamond composite base plates compared to traditional materials. We illustrate that AlGaN/GaN HEMT devices mounted on silver diamond composite base plates show peak temperatures which are 50% lower than the peak temperatures exhibited by devices mounted on traditional CuW base plates. This is a dramatic improvement in terms of heat extraction, as basis to enabling longer device life-times and better performances. In addition, time-resolved Raman thermography measurements were carrier out to obtain thermal dynamics of devices on the silver-diamond base plate and on heat diffusion during pulsed device operation. This time-dependent information is of great importance for reliability and failure analyses, as pulsed operation of a HEMT is a typically device operation condition. Finite-element thermal simulations were performed for comparison with the experimental results, and good agreement with the experimental data was obtained.

Structure and Conformation of Photosynthetic Pigments and Related Compounds 9 On the Structure and Macrocycle Conformation of Two Copper(II) Rhodochlorin Derivatives and Two Related Rhodoporphyrins

1995 ◽  
Vol 50 (6) ◽  
pp. 969-981 ◽  
Author(s):  
Mathias O. Senge ◽  
Karin Ruhlandt-Senge ◽  
Shwn-Ji H. Lee ◽  
Kevin M. Smith
Keyword(s):  
Crystal Structure ◽  
Acetic Acid ◽  
Formic Acid ◽  
Photosynthetic Pigments ◽  
Dimethyl Ester ◽  
Substituent Effects ◽  
Crystal Data ◽  
Free Base ◽  
The Mean ◽  
Related Compounds

Crystal structure analyses of (rhodochlorinato-15-acetic trimethyl ester)copper(II) 3 and (31, 32-didehydro-rhodochlorinato-15-formic acid trimethyl ester)copper(II) 4 reveal intriguing multiple macrocycle conformations of the metallochlorins in the crystal. The observed conformations range from almost planar macrocycles to distorted macrocycles with individual atoms being displaced up to 0.72 Å from the mean plane. The nonplanar macrocycles show a S4-ruffled macrocycie distortion with significant distortions for the meso-carbons and tilting of the Cb- Cb axes. A comparison with the related free base porphyrins rhodoporphyrin-15- acetic acid trimethyl ester 5 and rhodoporphyrin dimethyl ester 6 shows that the conformational distortion is due to the mixing of metal and substituent effects, hydroporphyrin character, and packing forces. Crystal data: 3, monoclinic, P21, a = 12.096(4) Å, b - 14.307(4) Å, c = 22.343(9) Å , β = 104.94(4)°, Z = 4 (2 indep. mol.), R = 0.069 for 8141 reflections with I > 2.0σ(I); 4, triclinic, P 1, a = 10.528(3) Å . b - 10.646(4) Å, c = 34.026(13) Å, α = 89.81(4)°, β = 88.72(3)°, γ = 60.38(2)°, Z = 4 (4 indep. mol.). R = 0.073 for 9446 reflections with I > 2.5σ(I); 5, triclinic, P 1̄, a = 9.591(2) Å, b = 12.959(4) Å, c = 13.453(4) Å, α = 105.86(2)°, β = 92.67(2)°, γ = 96.12(2)°, Z = 2, R = 0.060 for 4990 reflections with I > 2.5 σ(I); 6, triclinic, P 1̄, a = 8.908(4) Å, b = 12.895(5) Å, c = 13.482(6) Å , α = 102.74(3)°, β = 90.38(4)°, γ = 91.84(3)°, Z = 2, R = 0.089 for 3369 reflections with I > 2.0σ(I).

scholarly journals Cyclic Peroxides from a Two-Sponge Association of Plakortis communis-Agelas mauritiana

2013 ◽  
Vol 8 (6) ◽  
pp. 1934578X1300800
Author(s):  
Pinus Jumaryatno ◽  
Lynette K. Lambert ◽  
John N. A. Hooper ◽  
Joanne T. Blanchfield ◽  
Mary J. Garson
Keyword(s):  
2D Nmr ◽  
Side Chain ◽  
Relative Configuration ◽  
Carboxylic Acid Groups ◽  
Rp Hplc ◽  
Chemical Shift Data ◽  
New Compounds ◽  
Cyclic Peroxide ◽  
Related Compounds ◽  
Shift Data

A cyclic peroxide 1 with an unusual phenethenyl side chain, together with the known peroxide 2 with a C4-sidechain have been isolated from a two-sponge association of Plakortis communis – Agelas mauritiana (Carter, 1883) collected near Mooloolaba, South-East Queensland, Australia. Metabolite purification was complicated by the presence of the free carboxylic acid groups in 1 and 2; therefore, diazomethane treatment was undertaken to afford methyl ester 3. Following RP-HPLC purification, the ring-opened analogues 4 and 5 were also obtained. The structures of the new compounds were elucidated on the basis of their 1D and 2D NMR and MS data, and by comparison with literature data. The relative configuration of the isolated peroxides was determined by the interpretation of JH-H values and comparison of the 13C chemical shift data with literature data for related compounds. The bromopyrrole alkaloid longamide (6) was also isolated.

TRYPTAMINES, CARBOLINES, AND RELATED COMPOUNDS: PART V. 3-(α-ALKYL-β-AMINOETHYL)INDOLES

1960 ◽  
Vol 38 (4) ◽  
pp. 554-556 ◽  
Author(s):  
R. A. Abramovitch ◽  
J. M. Muchowski
Keyword(s):  
Alkyl Group ◽  
Side Chain ◽  
Related Compounds

The scope of the tryptamine synthesis via 1-oxo-1,2,3,4-tetrahydro-β-carbolines has been extended to tryptamines bearing a side-chain α-alkyl group. The preparation of 3-(2-amino-1-methylethyl)indole by this procedure is described.

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