Photochemistry of halogenated benzene derivatives. Part VI. Photoreactions of tetra-and pentachlorophenols in water–acetonitrile mixtures

1985 ◽  
Vol 63 (2) ◽  
pp. 469-475 ◽  
Author(s):  
Ghulam Ghaus Choudhry ◽  
Frans W. M. van der Wielen ◽  
G. R. Barrie Webster ◽  
Otto Hutzinger
Keyword(s):  
Benzene Ring ◽  
Reductive Dechlorination ◽  
Benzene Derivatives ◽  
Aqueous Acetonitrile ◽  
Acetonitrile Solutions

Laboratory photochemical studies of aqueous acetonitrile solutions of some polychlorinated phenols (PCPs) such as 2,3,4,5-tetrachlorophenol (2,3,4,5-Cl4-Pn) (1), 2,3,4,6-Cl4-Pn (2), 2,3,5,6-Cl4-Pn (3), and pentachlorophenol (Cl5-Pn) (4) at λ > 285 nm have been carried out for 6 and 24 h exposure times. All the investigated PCPs underwent reductive dechlorination. This process was dependent not only upon the position of OH group but also upon the relative positions of the Cl substituents on the benzene ring. The Cl4-Pn 2 (and 3) and Cl5-Pn (4) also yielded photoproducts of molecular formulae C8H4Cl3NO (M+• = 235) and C8H3Cl4NO (M+• = 269), respectively. Furthermore, phenol 3 is unique amongst the investigated PCPs; in addition to the above mentioned photoproducts, it yielded hexa-, hepta-, and octachlorodihydroxybiphenyl(s) as well as heptachlorohydroxydiphenyl ether.

Anodic behaviour of limonene in low aqueous acetonitrile solutions of Cl−

1988 ◽  
Vol 66 (7) ◽  
pp. 1757-1762 ◽  
Author(s):  
J. A. Caram ◽  
M. E. Martins ◽  
E. G. Gros ◽  
C. M. Marschoff
Keyword(s):  
Water Content ◽  
Aqueous Acetonitrile ◽  
Pt Electrodes ◽  
Acetonitrile Solutions ◽  
Anodic Behaviour ◽  
Derivatives Of ◽  
Reaction Routes

The anodic behaviour of limonene on Pt electrodes was studied in LiCl solutions in acetonitrile with low water content. It was found that cis-6-acetamido-p-menth-1,8-diene is formed with acceptable yields. This compound is of interest as a potential intermediate for obtaining oxidation derivatives of limonene. Other products, among them the new compound 8-acetamido-2,4,8-trimethyl-4-chloromethyl-3-aza-bicyclo[3.3.1]non-2-ene, were identified. Reaction routes are proposed.

scholarly journals Ring Contraction Reactions of a Non-Benzenoid Aromatic Cation and a Neutral Homoaromatic System into Benzene Derivatives

2021 ◽  
Author(s):  
Demelza Lyons ◽  
An Huy Dinh ◽  
Nhan Nu Hong Ton ◽  
Reece Crocker ◽  
Binh Khanh Mai ◽  
...  
Keyword(s):  
Organic Chemistry ◽  
Benzene Ring ◽  
Benzene Derivatives ◽  
Ring Contraction ◽  
Chemistry Research ◽  
Synthetic Utility ◽  
Aromatic Ions ◽  
Benzyl Halides ◽  
Tropylium Salts ◽  
Ring Contraction Reaction

Aromaticity is one of the most intriguing concepts in organic chemistry. Simple and extended benzenoid aromatic systems have been very well established in undergraduate textbooks, and there are also mentions of non-benzenoid aromatic structures such as cyclopropenium, cyclopentadienide and cycloheptatrienylium (tropylium) ions. However, the structural relationship and the comparison of stabilization energy of such aromatic ions to benzene ring have been rarely studied and remained an underexplored area of advanced organic chemistry research. To contribute some insights into this topic, we focused on the chemical transformation, namely a ring contraction reaction, of the tropylium ion to benzene ring in this work. With an approach combining computational studies with experimental reactions, we also aim to turn this transformation into a synthetically useful tool. Indeed, this work led to the development of a new synthetic protocol, which involved an oxidative ring-contraction of tropylium ion, to formally introduce the phenyl ring onto a range of organic structures. Furthermore, the homoaromatic cycloheptatrienyl precursors of tropylium salts used in these reactions can also be rearranged to valuable benzhydryl or benzyl halides, enriching the synthetic utility of this ring-contraction protocol.

The Responses of Onion and Lily Mitosis to Coumarin and Parasorbic Acid

1947 ◽  
Vol 23 (3-4) ◽  
pp. 292-297
Author(s):  
IVOR CORNMAN
Keyword(s):  
Aqueous Solution ◽  
Benzene Ring ◽  
Lactone Ring ◽  
Saturated Solution ◽  
Saturated Aqueous Solution ◽  
Benzene Derivatives ◽  
Binucleate Cells

1. In Allium and Lilium roots, saturated aqueous solution of coumarin produced a disruption of the metaphase typical of many benzene derivatives, viz. suppression of the spindle, splitting and shortening of the chromosomes, with retarded division of the centromere. The resultant polyploid nuclei and binucleate cells resumed division when the roots were returned to water. 2. Saturated solution of parasorbic acid slowed Allium mitosis, but caused no abnormalities. 3. Both coumarin and parasorbic acid eventually prevented the inception of mitosis, and this suppression of prophases persisted for several hours after removal of the agent. 4. The results are in agreement with prior evidence that in some configurations the benzene ring disrupts mitosis whereas the lactone ring inhibits growth.

Carbon-13 Substituent-Induced Chemical Shifts: Monosubstituted Benzene Derivatives

1992 ◽  
Vol 57 (3) ◽  
pp. 497-507 ◽  
Author(s):  
Otto Exner ◽  
Miloš Buděšínský
Keyword(s):  
Benzene Ring ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
The Other ◽  
Correlation Equations ◽  
Benzene Derivatives ◽  
Complex Mechanism ◽  
Monosubstituted Benzene ◽  
Resonance Effects ◽  
Other Hand

Carbon-13 NMR spectra of twelve monosubstituted benzene derivatives were measured in deuterochloroform. Together with the literature data a set of 35 systematically chosen substituents was obtained on which some thirty correlation equations were tested. As anticipated only substituent chemical shifts (SCS) in the position 4 are controlled by inductive and resonance effects, and can be correlated by dual substituent parameters (DSP). For the other positions DSP were not successful and more sophisticated equations are not much telling. On the other hand, the direct relations between two series of SCS are usually more precise and simple to understand. It is concluded that SCS in benzene ring need not be controlled by too complex mechanism but simply by different factors than by inductive and resonance effects.

Poly (SNS) Quantitative Electrosynthesis and Electrodissolution

1993 ◽  
Vol 328 ◽  
Author(s):  
T. F. Otero ◽  
E. Brillas ◽  
J. Carrasco ◽  
A. Figueras
Keyword(s):  
Conducting Polymers ◽  
Thick Films ◽  
Industrial Applications ◽  
Cathodic Reduction ◽  
Acetonitrile Solution ◽  
Aqueous Acetonitrile ◽  
Acetonitrile Solutions

ABSTRACTThe electrogeneration and electrodissolution of poly (SNS) have been improved by using aqueous acetonitrile solutions having a 1% (ν/ν) of water constant. Compact, adherent and thick films (until 0.4 Mg cm-2) were galvanostatically electrogenerated. The electrodeposited (oxidized) polymer is insoluble in 0.1 M L?CIO4 aqueous acetonitrile solution and solubilizes by cathodic reduction. Both, electrogeneration and electrodissolution, are faradaic processes. Those facts mimic electrodeposition and electroerosion of metals and their concomitant industrial applications. New technological possibilities using polymers in electrophotography, electroreprography, electropolishing, electro-erosion and electromachining are open through polymeric electrodissolution altogether to a new processible way, through the obtained solution, for the conducting polymers.

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