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New Easy Approach to the Synthesis of 2,5-Disubstituted and 2,4,5-Trisubstituted 1,3-Oxazoles. The Reaction of 1-(Methylthio)acetone with Nitriles

Supporting Info

Antonio Herrera,^† Roberto Martínez-Alvarez,*^† Pedro Ramiro,^† Dolores Molero,^‡ and John Almy^§

Departamento de Qumica Orgnica, Facultad de Ciencias Qumicas, Universidad Complutense, E-28040 Madrid, Spain, CAI de RMN, Facultad de Ciencias Qumicas, Universidad Complutense, E-28040 Madrid, Spain, and Department of Chemistry, California State University, Stanislaus, Turlock, California 95382

J. Org. Chem., 2006, 71 (8), pp 3026–3032

DOI: 10.1021/jo052619v

Publication Date (Web): March 18, 2006

†

Departamento de Química Orgánica, Universidad Complutense.

To whom correspondence should be addressed. Phone: +34913944325. Fax: +34913944103.

‡

CAI de RMN, Universidad Complutense.

California State University.

, rma@quim.ucm.es

Abstract

The reaction of 1-(methylthio)acetone with different nitriles in the presence of triflic anhydride led to the one-pot formation of 2-substituted 5-methyl-4-methylthio-1,3-oxazoles in good yield. 1,2- and 1,4-Bisozaxolyl-substituted benzenes were obtained when the reaction was carried out using aromatic dinitriles. The methylthio group at the C4 position of the oxazole ring was easily removed with Raney nickel to form 2-substituted 5-methyl-1,3-oxazoles in good yields. 4-Methylsulfonyl derivatives were prepared by the oxidation of the MeS group with m-CPBA. The proposed mechanism for the formation of oxazoles involves an unstable 1-(methylthio)-2-oxopropyl triflate, which was detected from the low-temperature NMR spectra.

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