10410-35-2Relevant articles and documents
Benzofuran Derivatives. Part 4. Synthesis of Benzofurans and 2,3,4,5-Tetrahydro-1-benzoxepin-3,5-diones
Suzuki, Tsuneo,Tanemura, Kiyoshi,Horaguchi, Takaaki,Shimimizu, Takahachi,Sakakibara, Tohru
, p. 423 - 429 (2007/10/02)
By treatment of ethyl 4- or 5-substituted 2-acetylphenoxyacetates 1 with potassium hydroxide in dry dioxane, benzofurans 2-7 and 2,3,4,5-tetrahydro-1-benzoxepin-3,5-diones 8 were obtained.The relative yields of benzofurans 2-7 and 2,3,4,5-tetrahydro-1-benzoxepin-3,5-diones 8 varied with the types of 4- or 5-substituents.The electron-donating 4-methoxyl group favored the formation of benzoxepins.On the other hand, electron-withdrawing substituents such as the 4-nitro group favored the formation of benzofurans.When esters 1 were treated with sodium amide,2,3-dihydrobenzofurans 2 were obtained exclusively regardless of 4- or 5-substituents.
Thermal Rearrangement of 2-Methyl-2-(2'-acetoxy-5'-methylphenyl)oxirane
Dhekne, Vijay V.,Rao, A. S.
, p. 852 - 855 (2007/10/02)
Thermal rearrangement of 2-methyl-(2'-acetoxy-5'-methylphenyl)oxirane (2) at 160 deg C for 1 hr furnishes a mixture of 2-(2'-hydroxy-5'-methylphenyl)propenyl acetate (4), 3,5-dimethylbenzofuran (11), 2-(2'-acetoxy-5'-methylphenyl)-propenyl acetate (5), 2-hydroxy-5-methylacetophenone (13), (+/-)-2,3-dihydro-3α,5-dimethylbenzofuran-2β-ol (14) and (+/-)-2,3-dihydro-3β,5-dimethylbenzofuran-2β-ol (15).Evidences in support of E-geometry at the ethylenic linkage of enolester (4) are presented.Treatment of 4 with alkali in the presence of air furnishes 13.Oxidation of a mixture of 14 and 15 gives 2,3-dihydro-3,5-dimethylbenzofuran-2-one (19). 3,5-Dimethylbenzofuran (11) has been prepared from 4.Thermal rearrangement of 2-methyl-(2'-acetoxy-5'-bromophenyl)oxirane (27) furnishes 5-bromo-3-methylbenzofuran (12) in good yield.
