Resorcinol allyl ethers

Rapid Claisen rearrangement of allyl phenyl ether and meta-substituted derivatives has been reported to occur with poor regioselectivity at 250 °C in dicationic ionic liquids, especially (24).23 Claisen rearrangement of resorcinol allyl ethers (25) was found to have poor regioselectivity under thermal or microwave conditions, but it was further found that selectivity for the 6-substituted product (26) over (27) could be improved to 13 1 using boron trichloride and an appropriately protected ether (25 ... 

The extent of C-alkylation as a side reaction in etherification varies about 1% of allyl 2-allylphenyl ether is formed when phenol is used in the acetone and potassium carbonate method with allyl bromide with cinnamyl bromide or 7,7-dimethylallyl bromide the extent of C-alkylar tion is greater.16 A complicated mixture of C- and O-alkylation products results from the treatment of phenol with 4-bromo-2-hexene and 4-chloro-2-hexene. 9 4-Hexenylresordnol has been obtained in about 40% yield from the reaction of l-bromo-2-hexene, resorcinol, and potassium carbonate in boiling acetone.99 An appreciable amount of C-alkylation occurs when 2,6-dimethyIphenol is treated with allyl bromide and sodium ethoxide in ethanol.70 Since, in general, the ampunt of C-alkylation is greatly increased by carrying out the alkylation on the sodium salt of the phenol in benzene,16 this method is unsuitable for the preparar tion of allyl aryl ethers. 

Curious about these strained products, we wondered if more rigid starting structure could be used for the Adler-Becker/Diels-Alder sequence (Scheme 10). We decided to see if chromanones could be substituted with benzofuian stractures. SUylation of resorcinol 44 was followed by bromination and cyclizatiOTi to form benzofuran 46. As shown previously, triahylatiOTi and allyl ether deprotection yielded ketone 47, which was subsequently reduced to the benzylic alcohol however, this required much harsher conditions than those in the chromanone series (LiAlHj vs. NaBHj). Although less efficient than the chromanone derivative, the Adler-Becker oxidation proceeded to provide epoxy benzofuranone 48... 

As a related reaction, Rawal carried out intramolecular vinylation of 2-bromoallyl ether of electron-rich resorcinol 72 and obtained the benzofurans 73 and 74 in equal amounts by ortho and para substitutions when the Herrmann catalyst (XVIII-1) was used. Cleavage of the allyl ether to give resorcinol (75) is a side reaction, whose amount increases when Pd(PPh3)4 is used as a catalyst. Similarly the indoles 77 and 78 were synthesized in 1 1 ratio from 76 [19]. 

Tribromophenyl allyl ether flame retardant, polyamides Ethylenebis dibromonorbornane dicarboximide Melamine cyanurate Octabromodiphenyl oxide Phosphorus, red Polystyrene, brominated Resorcinol bis (diphenylphosphate) flame retardant, polybutylenes Tetrabromobisphenol A, bis (2,3-dibromopropyl ether) flame retardant, polyester fabrics Methylphosphonic acid, bis [(5-ethyl-2-methyl-2-oxido-1,3,2-dioxaphosphorinan-5-yl) methyl] ester... 

Tetrabromobisphenol A bis (allyl ether) Tri (P,P -dichloroisopropyl) phosphate flame retardant, unsaturated polyesters Zinc molybdate flame retardant, upholstery Ammonium octamolybdate flame retardant, urethane foams Pentabromodiphenyl oxide flame retardant, vinyl Resorcinol bis (diphenylphosphate) flame retardant, vinyl film Diphenyl octyl phosphate flame retardant, vinyl foam t-Butylphenyl diphenyl phosphate flame retardant, vinyl nitrile foam t-Butylphenyl diphenyl phosphate flame retardant, vinyl resins Trioctyl phosphate flame retardant, vinyl sheeting Diphenyl octyl phosphate flame retardant, wall coverings Ammonium octamolybdate flame retardant, wall coverings high risk buildings... 

The alkylation of benzene by propan-l-ol and AICI3 in hexane or cyclohexane has been studied over the temperature range -40 to -f-100°C by n.m.r. spectroscopy. Structures of the several products of alkylation of mesitylene with 3,5-di-t-butyl-4-hydroxybenzyl alcohol and of resorcinol and its methyl ethers with a-butylbenzyl alcohol plus orthophosphoric acid have been elucidated. Allylation of guaiacol by allyl alcohol and an acid catalyst is... 

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