Effects Of Chloro Substituents Research Articles

Allylic Polymers II. Effects of Chloro-Substituents on Copolymerization of Allyl Chloroacetates with Vinyl Acetate

Allylic Polymers II. Effects of Chloro-Substituents on Copolymerization of Allyl Chloroacetates with Vinyl Acetate

ChemInform Abstract: Addition of Diphenyldiazomethane to Unsubstituted and Chloro‐Substituted 1,4‐Benzoquinones. Effects of Chloro Substituents on the Addition Modes.

AbstractThe reaction of the differently chloro‐substituted 1,4‐benzoquinones (I) or (VII) with diphenyldiazomethane (II) leads to two sorts of products: (III)‐(V) and (IX), (X) arise from addition of (II) to the C=C double bonds of (I) or (VII) in the first reaction step, whereas (VI) and (XI) result from addition to the C=O double bond.

Addition of Diphenyldiazomethane to Unsubstituted and Chloro-Substituted 1,4-Benzoquinones. Effects of Chloro Substituents on the Addition Modes

Abstract Unsubstituted 1,4-benzoquinone (1a) reacted with diphenyldiazomethane (DDM) at the C=C double bonds to give dihydroxy-3H-indazole (2a) and its benzhydryl ether (3a) together with benzodipyrazole derivative (4a). Similarly, reactions of 2-chloro- and 2,3-dichloro-1,4-benzoquinones (1b and 1c) with DDM yielded the corresponding dihydroxy-3H-indazoles (2b, 2b′, and 2c) and their benzhydryl ethers (3b, 3b′, and 3c) along with 5–13% benzophenone (6). On the other hand, reaction of 2,6-dichloro-1,4-benzoquinone (1e) with DDM gave bicyclic 5e and tricyclic diones (7e), together with benzophenone dimethyl acetal (9) in the presence of added methanol. In the same conditions, 2,3,5-trichloro-1,4-benzoquinone (1f) provided bicyclic dione (5f) and 9. Formation of 6 and 9 was interpreted as arising from the hydrolysis and methanolysis of the 1:1 betaine intermediates given by the addition of DDM to the quinonoid C=O double bonds. The C=O addition increased with increasing chlorine substituents.

Tetrahedral intermediates 4. The effect of chloro-substituents on the kinetics of the breakdown of hemiorthoesters

1-Hydroxy-2-chloromethyl-1,3-dioxolane (4) and 1-hydroxy-2-dichloromethyl-1, 3-dioxolane (5) have been detected as intermediates by1H NMR spectroscopy in the hydration of respectively 2-chloromethylene-1, 3-dioxolane and 2-dichloromethylene-1, 3-dioxolane in aqueous acetonitrile. The kinetics of the breakdown of (4) and (5) into ethylene glycol monochloroacetate and monodichloroacetate have been studied by uv spectroscopy and values ofkH+,kHO-, andkH2O evaluated. It was found that the introduction of chlorosubstituents into 2-hydroxy-2-methyl-1, 3-dioxolane caused a decrease inkH+ and increase inkH2O- and little change inkH2Ofor its breakdown. The mechanisms of these reactions are discussed. Present

Degradation of methoxylated benzoic acids by a Nocardia from a lignin-rich environment: significance to lignin degradation and effect of chloro substituents.

Strain A81 of Nocardia corallina hydroxylates or demethylates p-anisic acid to p-hydroxybenzoic acid and isovanillic acid. It demethylates veratric acid to a mixture of vanillic and isovanillic acids. These are both demethylated to protocatechuic acid, which undergoes ring cleavage to afford beta-carboxy-cis-cis-muconic acid. The intermediacy of protocatechuic acid in the catabolic pathway of veratric acid was confirmed by blocking ring cleavage with an additional substituent in the ring: 5-chlorovanillic acid was demethylated to 5-chloro-protocatechuic acid, which accumulated. Chloro substituents in the ring of other methoxylated benzoic acids also arrested their normal metabolism by the Nocardia: an ortho-chloro substituent thwarted both demethylation and ring-opening. ortho-Hydroxylation of p-methoxybenzoic acid to isovanillic acid was unaffected by a chlorine ortho to the methoxyl group. Washed whole cells of veratric acid-grown N. corallina A81 produced no detected structural changes in an isolated lignin. The implications of this observation are discussed.

Degradation of Methoxylated Benzoic Acids by a Nocardia from a Lignin-Rich Environment: Significance to Lignin Degradation and Effect of Chloro Substituents

Strain A81 of Nocardia corallina hydroxylates or demethylates p-anisic acid to p-hydroxybenzoic acid and isovanillic acid. It demethylates veratric acid to a mixture of vanillic and isovanillic acids. These are both demethylated to protocatechuic acid, which undergoes ring cleavage to afford beta-carboxy-cis-cis-muconic acid. The intermediacy of protocatechuic acid in the catabolic pathway of veratric acid was confirmed by blocking ring cleavage with an additional substituent in the ring: 5-chlorovanillic acid was demethylated to 5-chloro-protocatechuic acid, which accumulated. Chloro substituents in the ring of other methoxylated benzoic acids also arrested their normal metabolism by the Nocardia: an ortho-chloro substituent thwarted both demethylation and ring-opening. ortho-Hydroxylation of p-methoxybenzoic acid to isovanillic acid was unaffected by a chlorine ortho to the methoxyl group. Washed whole cells of veratric acid-grown N. corallina A81 produced no detected structural changes in an isolated lignin. The implications of this observation are discussed.

The effect of chloro-substituents on the rate of nitrogen inversion in 1-phthalimidoaziridines

Phthalimidoaziridines (I) show temperature-dependent 1H n.m.r. spectra. The coalescence temperatures for several 2- and 3-substituted phthalimidoaziridines have been found to lie in the range 75—125°. However, in the case of the 2,3-dichloro-derivatives, the coalescence temperatures are below 0°.