70401-56-8

Upstream product

• 493-09-4 benzo-1,4-dioxane 
• 187737-37-7 propene 
• 493-08-3 chromane 
• 27890-67-1 6-methylene-cyclohexa-2,4-dienone 
• 861009-82-7 acetic acid-(2-methallyl-phenyl ester) 
• 6627-85-6 (2-allyl-phenoxy)-acetic acid 
• 10178-53-7 1-bromo-2-((2-methylallyl)oxy)benzene 

Relevant academic research and scientific papers

Radical Hydrodehalogenation of Aryl Bromides and Chlorides with Sodium Hydride and 1,4-Dioxane

A practical method for radical chain reduction of various aryl bromides and chlorides is introduced. The thermal process uses NaH and 1,4-dioxane as reagents and 1,10-phenanthroline as an initiator. Hydrodehalogenation can be combined with typical cyclization reactions, proving the nature of the radical mechanism. These chain reactions proceed by electron catalysis. DFT calculations and mechanistic studies support the suggested mechanism.

Thermal Decomposition of Chroman. Reactivity of o-Quinone Methide

The gas phase thermal decomposition of 3,4-dihydro-2H-1-benzopyran (chroman, 1) has been studied between 760 and 1110 K in different bath gases and hydrogen donors. In nitrogen, the unimolecular rate parameters are k1 (s-1) = 1015.3 exp(-263 (kJ mol-1)/RT). The activation energy is slightly higher than the bond dissociation energy (BDE) of the phenoxylic C - O bond. The decomposition starts with elimination of ethene and formation of 6-methylene-2,4-cyclohexadien-1-one (o-quinone methide, 2). Quinone methides are important intermediates in the chemistry of lignin. In the high temperature range (860-980 K) 2 decomposes cleanly into CO, benzene, and small amounts of fulvene, obeying k2 (s-1) = 1014.8 exp(-281 (kJ mol-1)/RT. Reverse radical disproportionation of 2 with toluene is mainly responsible for o-cresol formation. In cis-2-butene at 770 K, exclusively cis-2,3-dimethylchroman is formed. This stereospecificity suggests a concerted retro-Diels - Alder mechanism and is not compatible with the high Arrhenius parameters, indicative of a stepwise, biradical mechanism.

Photoelectron transfer induced decarboxylation of substituted carboxylic acids across a liquid/liquid interface

Methylene blue photocatalyzed electron transfer reactions of some phenoxyacetic acid derivatives and N-phenylglycine across a liquid/liquid interface led to their efficient decarboxylation. Nanosecond laser flash photolysis studies of this process, in a reverse micellar system of Aerosol- OT (AOT)-benzene-water indicated that the liquid/liquid interface acts as a barrier in controlling the energy wasting back electron transfer. Intramolecular C-C bond forming reactions of these radicals were utilized for the synthesis of various chroman derivatives.

Photochemical electron transfer across a liquid/liquid interface: Methylene Blue-sensitized decarboxylation of substituted carboxylic acids

Methylene Blue photocatalyzed electron transfer reactions of some substituted carboxylic acids across the water/benzene interface lead to efficient decarboxylation of these acids and the utility of this procedure has been demonstrated by the synthesis of some dihydrobenzopyran and dihydrobenzofuran derivatives.

Thermal Decomposition of 2,3-Dihydro-1,4-benzodioxin and 1,2-Dimethoxybenzene

Rates and mechanisms of decomposition of 2,3-dihydro-1,4-benzodioxin (1) and 1,2-dimethoxybenzene (27) have been investigated in the gas phase near atmospheric pressure between 750 and 900 K in a tubular flow reactor in a large excess of radical trapping agents.The following rate expressions for decomposition have been determined: log kt/s-1 (1) = 15.7 - (271 kJ mol-1/2.303 RT); log kt/s-1 (27) = 15.7 - (251 kJ mol-1/2.303 RT).The main decomposition routes for 1 are the formation of o-benzoquinone (2) and 2-methyl-1,3-benzodioxole (7) through a biradical intermediate.The measured activation energy is 20 kJ mol-1 above the required C-O bond dissociation energy.Compound 2 rapidly loses CO to form cyclopenta-2,4-dien-1-one (6) which after dimerisation decomposes mainly into 3-phenylprop-2-enal (12) and indenols (14).The main product of the thermolysis of 27 is o-hydroxybenzaldehyde (33).The O-methyl bond is weakened by 16 kJ mol-1 compared to methoxybenzene as a result of the o-methoxy-substitution.

Rate Constants for the Cyclisation of Some Aryl Radicals bearing Unsaturated ortho-Substituents

Rate constants and Arrhenius parameters have been determined for ring-closure of o-alkenyl- and o-alkenyloxy-aryl radicals, and for deuterium atom transfer from tributyltin deuteride.