Tandem Migration–Carboalkoxylation of o-Isocyanophenyl Acetals Leading to Benzoxazoles
摘要:
An efficient approach to benzoxazoles via tandem migration carboalkoxylation of o-isocyanophenyl acetals has been developed. Both a Lewis acid and base are essential for this reaction, and the BF3 center dot OEt2/2,4,6-collidine combination is the best choice for cooperative transformation.
New acridine derivatives have been prepared via Ullman condensation involving benzoxazole (5) and 2-bromo-benzoic acid. Linear products were obtained. The structure of oxazolo[4,5-b]acridine was determined by NMR spectroscopy.
US4873338A
申请人:——
公开号:US4873338A
公开(公告)日:1989-10-10
US5476849A
申请人:——
公开号:US5476849A
公开(公告)日:1995-12-19
US5514676A
申请人:——
公开号:US5514676A
公开(公告)日:1996-05-07
The vicarious nucleophilic substitution of hydrogen and related reactions in nitrobenzoxazoles
作者:Mieczysław Ma̧kosza、Jacek Stalewski
DOI:10.1016/0040-4020(95)00351-8
日期:1995.6
6-nitrobenzoxazoles 3 and 4 react with nucleophiles exclusively at C-2, giving ring opening products. If position 2- is blocked with phenyl substituent the reaction takes place in the carbocyclic ring affording the VNS products. 2-Methylthio-5-nitrobenzoxazole 7 and its 6-nitro isomer 8 give products which result from addition of a nucleophile to the carbocyclic ring (VNS) as well as to the heterocyclic ring