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Dehydrative Cyclization Catalyzed by the Combination of Molybdenum(VI) Oxides and Benzoic Acids: First Synthesis of the Antitumour Substance BE‐70016
Author(s) -
Sakakura Akira,
Umemura Shuhei,
Kondo Rei,
Ishihara Kazuaki
Publication year - 2007
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.200600550
Subject(s) - chemistry , catalysis , ammonium molybdate , toluene , molybdenum , yield (engineering) , medicinal chemistry , benzoic acid , derivative (finance) , oxazoline , organic chemistry , raw material , materials science , economics , financial economics , metallurgy
Abstract The dehydrative cyclization of N‐ ( o‐ hydroxybenzoyl)threonine derivative 1a is efficiently promoted by the combined use of molybdenum(VI) oxides and benzoic acids bearing electron‐withdrawing substituents. In the presence of ammonium molybdate [(NH 4 ) 2 MoO 4 , 10 mol %] and pentafluorobenzoic acid (C 6 F 5 CO 2 H; 10 mol %), dehydrative cyclization of 1a was conducted in toluene under azeotropic reflux conditions to give 2‐( o‐ hydroxyphenyl)oxazoline 2a in 76 % yield. Furthermore, the first total synthesis of the antitumour substance BE‐70016 was achieved using the catalytic dehydrative cyclization of 1a as a key reaction.