Darstellung und Eigenschaften von Derivaten des 4,5-Benzo-2,3-dihydro- \ ,3-diborols/ Synthesis and Properties of Derivatives of the 4,5-Benzo-2,3-dihydro-1,3-diborole

1993 ◽  
Vol 48 (1) ◽  
pp. 68-71 ◽  
Author(s):  
Hartmut Schulz ◽  
Thomas Deforth ◽  
Walter Siebert
Keyword(s):  
Sandwich Complexes ◽  
Methyl Group ◽  
H Nmr ◽  
Derivatives Of

Reactions of 1,2-bis(trimethyIstannyl)benzene (4) with bis(dichIoroboryl)methane derivatives (Cl2B)2CHR1 (R1 = H ,Me) lead to the formation of the 4,5-benzo-1,3-dichloro-2,3-dihydro-1,3-diboroles 2a,b.Substitution of chlorine in 2a,b by a methyl group using A1Me3 yields the 4,5-benzo-1,3-dimethyl-2,3-dihydro-1,3-diboroles 2c,d, of which 2c is thermally labile. Complexation of 2c,d with [(C5H5)Co(C2H4)2] did not give the expected sandwich complexes 6c,d, but the formation of the triple-decker 7d was observed. The paramagnetic 7d and the diamagnetic 7d+, obtained by oxidation with Ag+BF4-, were studied by 1H NMR .

The influence of structure on the methyl group dynamics of polymorphic complexes: 6,6′-dimethyl-2,2′-dipyridyl with halo derivatives of benzoquinone acids

CrystEngComm ◽  
2020 ◽  
Vol 22 (41) ◽  
pp. 6811-6821
Author(s):  
Magdalena Rok ◽  
Marcin Moskwa ◽  
Przemysław Dopieralski ◽  
Wojciech Medycki ◽  
Michaela Zamponi ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Neutron Scattering ◽  
Computational Methods ◽  
Group Dynamics ◽  
Molecular Complexes ◽  
Methyl Group ◽  
H Nmr ◽  
Derivatives Of ◽  
Methyl Group Dynamics

The structural analysis, neutron scattering, 1H NMR and computational methods combined to investigate new molecular complexes.

The allyl and benzyl groups as hydrogen bond acceptors in derivatives of 2-allylphenol and 2-benzylphenol

1979 ◽  
Vol 57 (22) ◽  
pp. 3005-3009 ◽  
Author(s):  
Ted Schaefer ◽  
Rudy Sebastian ◽  
Timothy A. Wildman
Keyword(s):  
Hydrogen Bond ◽  
Free Energy ◽  
Nmr Spectra ◽  
Conformational Preference ◽  
Methyl Group ◽  
H Nmr ◽  
Coupling Parameters ◽  
Derivatives Of

The 1H nmr spectra of 2-allylphenol, 2-allyl-6-methylphenol, 2-allyl-6-chlorophenol, and 2-benzyl-4-chlorophenol are analyzed in some detail. It is shown that, relative to a methyl group, the allyl and benzyl moieties, respectively, favor a cis orientation by 1570 ± 250 J/mol and 900 ± 220 J/mol in free energy at 305 K in CCl4 solution. These numbers appear to be independent of the CCl4 solvent. Coupling parameters within the allyl group in these molecules and in propene and allylbenzene show some regularities but are probably not reliable indicators of the allyl conformational preference, at least in the absence of a model allowing for hindered rotor state populations.

7-O-Alkyl derivatives of daunomycinone

1984 ◽  
Vol 49 (1) ◽  
pp. 313-319 ◽  
Author(s):  
Věra Přikrylová ◽  
Petr Sedmera ◽  
Josef V. Jizba ◽  
Jindřich Vokoun ◽  
Helena Lipavská ◽  
...  
Keyword(s):  
H Nmr ◽  
Toluenesulfonic Acid ◽  
Alkyl Derivatives ◽  
Derivatives Of

Reaction of daunomycinone (I) with alcohols and p-toluenesulfonic acid produces a mixture (~3 : 1) of its (7S)- and (7R)-O-alkyl derivatives II-IX. According to the 1H NMR evidence, the alicyclic ring exists in the 9H8 conformation in (7R)-O-alkyl derivatives, on the contrary to (7S)-epimers and 7-epi-daunomycinone that adopt the 8H9 conformation.

Monitoring the encapsulation of chlorin e6 derivatives into polymer carriers by NMR spectroscopy

2019 ◽  
Vol 23 (11n12) ◽  
pp. 1576-1586 ◽  
Author(s):  
Sara Pfister ◽  
Luca Sauser ◽  
Ilche Gjuroski ◽  
Julien Furrer ◽  
Martina Vermathen
Keyword(s):  
Relaxation Time ◽  
Nmr Spectroscopy ◽  
Core Region ◽  
Chlorin E6 ◽  
Polypropylene Glycol ◽  
Polymer Carriers ◽  
H Nmr ◽  
Line Shape Analysis ◽  
Dynamic Methods ◽  
Derivatives Of

The encapsulation of five derivatives of chlorin e6 with different hydrophobicity and aggregation properties into a series of five poloxamer-type triblock copolymer micelles (BCMs) with varying numbers of polyethylene and polypropylene glycol (PEG, PPG) units was monitored using 1H NMR spectroscopy. NMR chemical shift and line shape analysis, as well as dynamic methods including diffusion ordered spectroscopy (DOSY) and T1 and T2 relaxation time measurements of the chlorin and the polymer resonances, proved useful to assess the chlorin–BCM compatibility. The poloxamers had high capability to break up aggregates formed by chlorins up to intermediate hydrophobicity. Physically entrapped chlorins were always localized in the BCM core region. The loading capacity correlated with chlorin polarity for all poloxamers among which those with the lowest number of PPG units were most efficient. DOSY data revealed that relatively weakly aggregating chlorins partition between the aqueous bulk and micellar environment whereas more hydrophobic chlorins are well retained in the BCM core region, rendering these systems more stable. T1 and T2 relaxation time measurements indicated that motional freedom in the BCM core region contributes to encapsulation efficiency. The BCM corona dynamics were rather insensitive towards chlorin entrapment except for the poloxamers with short PEG chains. The presented data demonstrate that 1H NMR spectroscopy is a powerful complementary tool for probing the compatibility of porphyrinic compounds with polymeric carriers such as poloxamer BCMs, which is a prerequisite in the development of stable and highly efficient drug delivery systems suitable for medical applications like photodynamic therapy of tumors.

Mechanistische Untersuchungen zum reversiblen Gleichgewicht von metallorganischen Tripeldecker- und Sandwichkomplexen des Typs [Bis{(η5-CpR)Co}-μ-{η4:η4-aren}] und [(η5-CpR)Co(η6-aren)] / Mechanistic Studies towards the Reversible Equilibrium between Metal Organic Triple Decker and Sandwich Complexes [Bis{(η5 -CpR)Co}-μ-{η4 :η4-arene}] and [{(η5-CpR)Co(η6-arene)]

1998 ◽  
Vol 53 (11) ◽  
pp. 1267-1272 ◽  
Author(s):  
Jörg J. Schneider ◽  
Dirk Wolf
Keyword(s):  
Ligand Exchange ◽  
Sandwich Complexes ◽  
Valuable Metal ◽  
H Nmr ◽  
Synthetic Utility ◽  
Metal Organic ◽  
Arene Ligand ◽  
Benzene Toluene

The arene ligand exchange mechanism of slipped arene triple deckers [Bis{(η5-CpR)Co}-μ-{η4:η4-arene}] (R = Me5, 1,2,4 tri-tert butyl, arene = benzene, toluene) 1 was studied by 1H-NMR spectroscopy for different concentrations and solvents. It has been found that triple deckers of type 1 decompose slowly in solution. A unique equilibrium, between these triple deckers and the mixed sandwich complexes [(η6-arene)Co(η5-CpR)] and 14 e [(η5-Cp)Co]solv fragments generated in situ by decomposition o f 1 exists. In addition to this equilibrium arene lability of the thus formed mixed sandwich complex type has been detected by NMR making slipped triple deckers 1 ideal single source compounds for the generation of two [(η5-Cp)Co] fragments in one reaction step. Such fragments are valuable metal ligand components with high synthetic utility in organometallic chemistry.

Synthesis of amino acid derivatives of indole-3-acetic acid

2005 ◽  
Vol 2005 (10) ◽  
pp. 640-642 ◽  
Author(s):  
Ying Liu ◽  
Liang Zhao ◽  
Liang Liu ◽  
Lin-Yi Wei ◽  
Lu-Hua Lai
Keyword(s):  
Acetic Acid ◽  
Amino Acid ◽  
Amino Acid Derivatives ◽  
H Nmr ◽  
Derivatives Of ◽  
Indole 3 Acetic Acid

Amino acid derivatives of a modified indole-3-acetic acid have been synthesised. Fourteen new dipeptide-like compounds 3–4 were obtained and their structures were elucidated based on the IR, 1H NMR, MS spectra.

Synthesis and chemiluminescence of new derivatives of isoluminol

1987 ◽  
Vol 65 (6) ◽  
pp. 1392-1396 ◽  
Author(s):  
Alain Bélanger ◽  
Paul Brassard ◽  
Sylvie Laquerre ◽  
Yves Mérand
Keyword(s):  
Maleic Acid ◽  
Quantum Yields ◽  
Methyl Group ◽  
Derivatives Of

In an attempt to improve the sensitivity of luminescent immunoassays, we have prepared some new isoluminol, 7-(N,N-dialkylamino)-5-methyl-2,3-dihydrophthalazine-1,4-diones by means of a novel procedure involving the cycloaddition of dienamines to maleic acid derivatives. These compounds are characterized by the presence of a methyl group at C-5 and give quantum yields three to five times greater than those of the most efficient isoluminols in use at present.

scholarly journals Synthesis and biological evaluation of 4-substituted aryl-piperazine derivatives of 1,7,8,9-tetrachloro-10,10-dimethoxy-4-azatricyclo [5.2.1.02,6] dec-8-ene-3,5-dione as anti-cancer and anti-angiogenesis agents

2020 ◽  
Author(s):  
Lifang Guo ◽  
Benshan Xu ◽  
Zirui Wan ◽  
Lulu Ren ◽  
Jie Zhang ◽  
...  
Keyword(s):  
Biological Evaluation ◽  
Cytotoxic Activities ◽  
H Nmr ◽  
Chemical Structures ◽  
Piperazine Derivatives ◽  
Anti Cancer ◽  
And Migration ◽  
Anti Tumor Activity ◽  
Synthesis And Biological Evaluation ◽  
Derivatives Of

Abstract Background: A series of aryl-piperazine derivatives of 1,7,8,9-tetrachloro-10,10-dimethoxy-4-azatricyclo [5.2.1.0 2,6 ] dec-8-ene-3,5-dione were synthesized. The chemical structures of the desired compounds were identified by 1 H NMR, ESI-MS and elementary analytical. The anti-cancer and anti-angiogenesis activities of the newly synthesized compounds were evaluated by proliferation and migration assays, respectively. Results: The screening results demonstrated that compounds 2 and 5 showed potent anti-tumor activity (IC 50 values ranging from 7.1 to 15.9μM) with low cytotoxic activities (IC 50 ＞ 79.3μM). Although compound 5 showed little effects on endothelia proliferation (IC 50 =65.3μM), it indeed significantly abrogated endothelia cell migration (IC 50 =6.7μM). Conclusions: This work may impart new direction for the investigations of aryl-piperazine derivatives and lead to the development of potent novel anti-tumor and anti-angiogenesis agents.

The Dinitration of Dimethylacetanilides

2003 ◽  
Vol 2003 (5) ◽  
pp. 303-304 ◽  
Author(s):  
Inmaculada C. Rodriguez Medina ◽  
James R. Hanson
Keyword(s):  
Methyl Group ◽  
H Nmr ◽  
Nmr Methods ◽  
Steric Inhibition Of Resonance

The orientation of dinitration of the dimethylacetanilides has been examined by 1H NMR methods and a possible enhancement of the hyperconjugative influence of a methyl group has been considered as an additional factor augmenting the effect of the steric inhibition of resonance on the orientation of substitution.

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