title: Ugi/Robinson-Gabriel reactions directed toward the synthesis of 2,4,5-trisubstituted oxazoles.
abstract: This Letter discloses a novel concise synthesis of a series of 2,4,5-trisubstituted oxazoles via a tandem Ugi/Robinson-Gabriel sequence. Herein, 2,4-dimethoxybenzylamine1was used as an ammonia equivalent in combination with arylglyoxal3and supporting Ugi reagents, an isonitrile and carboxylic acid. As such the product of the acid treated Ugi intermediate is ideally configured to undergo a Robinson-Gabriel cyclodehydration reaction to yield the desired oxazole scaffold5.
authors.affiliation: Department of Pharmacology and Toxicology, College of Pharmacy, BIO5 Oro Valley, The University of Arizona, 1580 E. Hanley Blvd., Oro Valley, AZ 85737, USA.
authors.forename: Arthur Y
authors.initials: AY
authors.lastname: Shaw
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Xu
authors.forename: Christopher
authors.initials: C
authors.lastname: Hulme
keywords: 2,4,5-Trisubstituted oxazoles; Multicomponent reactions; Robinson–Gabriel reaction; Ugi reaction; Vilsmeier–Haack reaction
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