The formation and reactions of carbanionic derivatives of methyl phosphazenes

1981 ◽  
Vol 59 (17) ◽  
pp. 2654-2664 ◽  
Author(s):  
Keith D. Gallicano ◽  
Richard T. Oakley ◽  
Norman L. Paddock ◽  
Rajendra D. Sharma
Keyword(s):  
Oxidative Coupling ◽  
Electrostatic Interactions ◽  
Ring Size ◽  
Cyclic Phosphazenes ◽  
Derivatives Of

The cyclic phosphazenes N3P3Ph4Me2, N3P3Me6, and N4P4Me8 are deprotonated by alkyllithiums. The resulting carbanions react with monofunctional electrophiles to form phosphazenes carrying the groups PCH2R (R = Me, Br, I, PhC(O), COOH AsMe2, Me3M (M = Si, Ge, Sn)). Two phosphazenyl groups can be joined either by the use of a difunctional halide or by oxidative coupling of organo-copper derivatives. The formation of the carbanions, the extent of deprotonation, substituent orientation, and the dependence of reactivity on ring size, are interpreted in terms of a balance between π-electron energies and electrostatic interactions.

scholarly journals Synthesis, Characterization, and Encapsulation of Novel Plant Growth Regulators (PGRs) in Biopolymer Matrices

2021 ◽  
Vol 22 (4) ◽  
pp. 1847
Author(s):  
Kristina Vlahoviček-Kahlina ◽  
Slaven Jurić ◽  
Marijan Marijan ◽  
Botagoz Mutaliyeva ◽  
Svetlana V. Khalus ◽  
...  
Keyword(s):  
Plant Growth ◽  
Plant Growth Regulators ◽  
Growth Regulators ◽  
Electrostatic Interactions ◽  
Growth Regulation ◽  
Field Experiments ◽  
Dimethyl Ester ◽  
Plant Growth Regulation ◽  
Derivatives Of ◽  
Growth Regulating Activity

Novel plant growth regulators (PGRs) based on the derivatives of dehydroamino acids 2,3-dehydroaspartic acid dimethyl ester (PGR1), Z-isomer of the potassium salt of 2-amino-3-methoxycarbonylacrylic acid (PGR2) and 1-methyl-3-methylamino-maleimide (PGR3) have been synthesized and their growth-regulating properties investigated. Laboratory testing revealed their plant growth-regulating activity. PGR1 showing the most stimulating activity on all laboratory tested cultures were used in field experiments. Results showed that PGR1 is a highly effective environmentally friendly plant growth regulator with effects on different crops. Biopolymeric microcapsule formulations (chitosan/alginate microcapsule loaded with PGR) suitable for application in agriculture were prepared and characterized. Physicochemical properties and release profiles of PGRs from microcapsule formulations depend on the molecular interactions between microcapsule constituents including mainly electrostatic interactions and hydrogen bonds. The differences in the microcapsule formulations structure did not affect the mechanism of PGRs release which was identified as diffusion through microcapsules. The obtained results opened a perspective for the future use of microcapsule formulations as new promising agroformulations with a sustained and target release for plant growth regulation.

scholarly journals The Fluoride Anion-Catalyzed Sulfurization of Thioketones with Elemental Sulfur Leading to Sulfur-Rich Heterocycles: First Sulfurization of Thiochalcones

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 822
Author(s):  
Grzegorz Mlostoń ◽  
Jakub Wręczycki ◽  
Katarzyna Urbaniak ◽  
Dariusz M. Bieliński ◽  
Heinz Heimgartner
Keyword(s):  
Elemental Sulfur ◽  
Fluoride Anion ◽  
Ring Size ◽  
Mild Conditions ◽  
Tetrabutylammonium Fluoride ◽  
Cesium Fluoride ◽  
Secondary Reactions ◽  
Derivatives Of

Fluoride anion was demonstrated as a superior activator of elemental sulfur (S8) to perform sulfurization of thioketones leading to diverse sulfur-rich heterocycles. Due to solubility problems, reactions must be carried out either in THF using tetrabutylammonium fluoride (TBAF) or in DMF using cesium fluoride (CsF), respectively. The reactive sulfurizing reagents are in situ generated, nucleophilic fluoropolysulfide anions FS(8−x)−, which react with the C=S bond according to the carbophilic addition mode. Dithiiranes formed thereby, existing in an equilibrium with the ring-opened form (diradicals/zwitterions) are key-intermediates, which undergo either a step-wise dimerization to afford 1,2,4,5-tetrathianes or an intramolecular insertion, leading in the case of thioxo derivatives of 2,2,4,4-tetramethylcyclobutane-1,3-dione to ring enlarged products. In reactions catalyzed by TBAF, water bounded to fluoride anion via H-bridges and forming thereby its stable hydrates is involved in secondary reactions leading, e.g., in the case of 2,2,4,4-tetramethyl-3-thioxocyclobutanone to the formation of some unexpected products such as the ring enlarged dithiolactone and ring-opened dithiocarboxylate. In contrast to thioketones, the fluoride anion catalyzed sulfurization of their α,β-unsaturated analogues, i.e., thiochalcones is slow and inefficient. However, an alternative protocol with triphenylphosphine (PPh3) applied as a catalyst, offers an attractive approach to the synthesis of 3H-1,2-dithioles via 1,5-dipolar electrocyclization of the in situ-generated α,β-unsaturated thiocabonyl S-sulfides. All reactions occur under mild conditions and can be considered as attractive methods for the preparation of sulfur rich heterocycles with diverse ring-size.

Strukturvergleich bei 9,10-Dihydro-9,10-anthrylen-Verbindungen des Magnesiums und des Alkylaluminiums / Comparison between the Structures of 9,10-Dihydro-9,10-anthrylene Compounds of Magnesium and Alkylaluminium

1985 ◽  
Vol 40 (11) ◽  
pp. 1504-1510 ◽  
Author(s):  
Herbert Lehmkuhl ◽  
Abdul Shakoor ◽  
Klaus Mehler ◽  
Carl Krüger ◽  
Yi-Hung Tsay
Keyword(s):  
Ring Size ◽  
Coordination Geometry ◽  
Chemical Behaviour ◽  
Trimethylsilyl Derivatives ◽  
Derivatives Of

In magnesium as well as in aluminium derivatives of anthracene (1−4, 8) and its trimethylsilyl derivatives (5, 6 and 11), the metals occupy the axial positions at C9 and CIO, to form five-, seven- or ten-membered metallacycles, respectively, in 1−3, 5, 6 and 11. It appears that the metalla-ring size, and thus the coordination geometry of the bridging metal is of influence upon the chemical behaviour.

scholarly journals Salt effects on the conformational behavior of 5-substituted 1,3-dioxanes

2003 ◽  
Vol 75 (5) ◽  
pp. 589-599 ◽  
Author(s):  
Eusebio Juaristi ◽  
G. A. Rosquete-Pina ◽  
M. Vázquez-Hernández ◽  
A. J. Mota
Keyword(s):  
Conformational Analysis ◽  
Metal Ions ◽  
Electrostatic Interactions ◽  
Inorganic Salts ◽  
Conformational Behavior ◽  
Anomeric Effect ◽  
Biological Processes ◽  
Polar Substituents ◽  
Derivatives Of

Since their introduction by E. L. Eliel nearly four decades ago, derivatives of 1,3-dioxane have proved useful in conformational analysis. Examples are discussed, where 5-polar substituents permit the evaluation of fundamental phenomena such as attractive and repulsive gauche effects, electrostatic interactions, and stereoelectronic effects. By the same token, 2-substituted 1,3-dioxanes, 1,3-dithianes, and 1,3-oxathianes are useful frameworks for the study of the anomeric effect and the associated structural and spectroscopic manifestations, such as the so-called Perlin effects. In view of the varied and essential involvement of metal ions and inorganic salts in biological processes, 5-substituted 1,3-dioxanes are presently being examined in the presence of Li+, Na+, K+, Ag+, Mg2+, Ca2+, Ba2+, and other cations, with the aim to increase the understanding of biomolecular properties in vivo.

The effect of ring size in N-benzoyl saturated heterocyclic amides

1981 ◽  
Vol 34 (11) ◽  
pp. 2307 ◽  
Author(s):  
CW Fong ◽  
HG Grant
Keyword(s):  
Crystal Structure ◽  
Ring Size ◽  
Intramolecular Exchange ◽  
Derivatives Of ◽  
Exchange Data

The structures of the N-benzoyl derivatives of aziridine, azetidine, pyrrolidine, piperidine, hexamethyleneimine and heptamethyleneimine in solution have been investigated by 13C n.m.r. spectroscopy. In conjunction with literature crystal structure and dynamic intramolecular exchange data, it has been concluded that N-benzoylaziridine and N-benzoylazetidine possess pyrimidal nitrogen atoms in solution. The N-benzoyl derivatives of pyrrolidine, �piperidine, hexamethyleneimine and heptamethyleneimine have planar or near planar nitrogen atoms.

scholarly journals Synthesis, Characterization and Encapsulation of Novel Plant Growth Regulators (PGRs) in Biopolymer Matrices

2020 ◽  
Author(s):  
Kristina Vlahoviček-Kahlina ◽  
Slaven Jurić ◽  
Marijan Marijan ◽  
Botagoz Mutaliyeva ◽  
Svetlana Khalus ◽  
...  
Keyword(s):  
Plant Growth ◽  
Plant Growth Regulators ◽  
Growth Regulators ◽  
Electrostatic Interactions ◽  
Growth Regulation ◽  
Field Experiments ◽  
Dimethyl Ester ◽  
Plant Growth Regulation ◽  
New Compounds ◽  
Derivatives Of

Abstract Novel plant growth regulators (PGRs) based on the derivatives of dehydroamino acids (2,3-dehydroaspartic acid dimethyl ester, Z-isomer of the potassium salt of 2-amino-3-methoxycarbonylacrylic acid and 1-methyl-3-methylamino-maleimide) have been synthesized and their growth-regulating properties investigated. Laboratory testing and field experiments revealed new compounds are highly effective environmentally friendly plant growth regulators with effects on different crops. Biopolymeric microcapsule formulations (chitosan/alginate microcapsule loaded with PGR) suitable for application in agriculture were prepared and characterized. Physicochemical properties and release profiles of PGRs from microcapsule formulations depend on the molecular interactions between microcapsule constituents including mainly electrostatic interactions and hydrogen bonds. The differences in the microcapsule formulations structure did not affect the mechanism of PGRs release which was identified as diffusion through microcapsules. The obtained results opened a perspective for the future use of microcapsule formulations as new promising agroformulations with a sustained and target release for plant growth regulation.

Partition coefficients and ultraviolet absorption maxima for the cinnamoyl derivatives of some long-chain and large-ring amines

1970 ◽  
Vol 48 (8) ◽  
pp. 1340-1343 ◽  
Author(s):  
D. J. Currie ◽  
H. L. Holmes
Keyword(s):  
Nitrogen Atom ◽  
Chain Length ◽  
Partition Coefficients ◽  
The Other ◽  
Ring Size ◽  
Amide Nitrogen ◽  
Derivatives Of ◽  
Limiting Value ◽  
Long Chain ◽  
Amide Nitrogen Atom

Partition coefficients of the title compounds in the system cyclohexane–water do not increase steadily with increasing chain length or ring size but level off to a limiting value. Reasons are advanced to account for this observation. Absorption maxima, on the other hand, are not influenced by the size of the ring or the length of the chain but are dependent only upon the degree of substitution on the amide nitrogen atom.

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