Regioselective electro-bromination of benzofuran (2) was achieved successfully by an adequate choice of solvents and bromide salts to afford 5-bromobenzofuran (1), 5,7-dibromobenzofuran (3), and 2,3-dibromo-2,3-dihydrobenzofuran (4), respectively. Upon electrolysis of benzofuran (2) in AcOH/H2O (100/1) containing NH4Br, substitution at the C(5)-position of benzofuran (2) proceeded smoothly to afford 5-bromobenzofuran (1). After passage of totally 4 F/mol of electricity in a similar medium, 5,7-dibromobenzofuran (3) was obtained as a sole product. On the other hand, electrolysis of benzofuran (2) in CH2Cl2/H2O (1/1) and/or AcOH/H2O (10/1) in the presence of either NaBr or NH4Br afforded 2,3-dibromo-2,3-dihydrobenzofuran (4), exclusively.
METHOD OF FORMING POLYARYL POLYMERS
申请人:Dow Global Technologies LLC
公开号:US20150031847A1
公开(公告)日:2015-01-29
In a method of forming a polyacetal or polyketal, a specific acetal- or ketal-containing bis(aryl)acetal is coupled with itself or a comonomer in the presence of a catalyst and a base. The polymerization reaction tolerates hydroxyl and other functional groups on the bis(aryl)acetal. Among other applications, the polyacetals and polyketals are useful components of photoresist compositions.
US8962779B2
申请人:——
公开号:US8962779B2
公开(公告)日:2015-02-24
Simonis; Wenzel, Chemische Berichte, 1900, vol. 33, p. 422
作者:Simonis、Wenzel
DOI:——
日期:——
Fries; Moskopp, Justus Liebigs Annalen der Chemie, 1910, vol. 372, p. 196