Synlett, Inhaltsverzeichnis Synlett 2025; 36(05): 531-535DOI: 10.1055/a-2352-4950 letter Base-Promoted Reaction between N-Acyl Benzotriazoles and p-Toluenesulfonylmethyl Isocyanide (TosMIC): A Facile Synthesis of 4,5-Disubstituted Oxazoles Hui You , Daming Liu , Mengni Pan , Yue Shen , Yang Li , Wanfang Li ∗ Artikel empfehlen Abstract Artikel einzeln kaufen Alle Artikel dieser Rubrik Abstract We herein developed a base-promoted cyclization reaction between N-acyl benzotriazoles and p-toluenesulfonylmethyl isocyanide (TosMIC) to afford 4,5-disubstituted oxazoles. In the presence of 3 equiv of K3PO4, the two readily available starting materials reacted in N,N-dimethylformamide at 80 °C to give 28 examples of 4-tosyl-5-aryl, -alkyl, or -alkenyl-substituted oxazoles in moderate to high yields. Key words Key wordsoxazole synthesis - N-acyl benzotriazole - p-toluenesulfonylmethyl isocyanide Volltext Referenzen References and Notes 1a Turchi IJ. Oxazoles . 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Then the mixture was allowed for stirring at 80 °C for 12 h. After cooling to room temperature, the mixture was diluted with 5 mL water and extracted with EtOAc (3 × 3 mL). The combined organic phase was washed with brine, dried over anhydrous Na2SO4, and concentrated by rotoevaporation. The desired product was purified by flash column chromatography (petroleum ether (PE)/EtOAc). 5-(Thiophen-2-yl)-4-tosyloxazole (3r) The compound was isolated as a white solid (49.1 mg, 80%) by flash column chromatography (PE/EtOAc, 10:1). 1H NMR (500 MHz, CDCl3): δ = 8.09 (d, J = 2.6 Hz, 1 H), 7.92 (d, J = 8.3 Hz, 2 H), 7.76 (s, 1 H), 7.56 (d, J = 3.9 Hz, 1 H), 7.31 (d, J = 8.1 Hz, 2 H), 7.20–7.15 (m, 1 H), 2.40 (s, 3 H). 13C NMR (126 MHz, CDCl3): δ = 148.4, 148.0, 145.0, 137.1, 133.2, 131.4, 130.3, 129.8, 128.2, 127.9, 126.4, 21.6. HRMS (ESI+): m/z [M + Na]+ calcd for C14H11NO3S2Na: 328.0078; found: 328.0078. 5-(Furan-2-yl)-4-tosyloxazole (3s) The compound was isolated as a white solid (41.6 mg, 72%) by flash column chromatography (PE/EtOAc, 10:1). 1H NMR (500 MHz, CDCl3): δ = 7.92 (d, J = 8.4 Hz, 2 H), 7.80 (s, 1 H), 7.62 (d, J = 1.0 Hz, 1 H), 7.57 (d, J = 3.5 Hz, 1 H), 7.32 (d, J = 8.1 Hz, 1 H), 6.61 (dd, J = 3.6, 1.8 Hz, 1 H), 2.41 (s, 3 H). 13C NMR (126 MHz, CDCl3): δ = 148.8, 145.2, 145.1, 144.0, 140.4, 137.1, 133.5, 129.8, 128.0, 116.1, 112.5, 21.6. 5-(4-Ethylthiazol-5-yl)-4-tosyloxazole (3t) The compound was isolated as a white solid (39.0 mg, 64%) by flash column chromatography (PE/EtOAc, 10:1). 1H NMR (500 MHz, CDCl3): δ = 8.93 (s, 1 H), 7.95 (s, 1 H), 7.87 (d, J = 8.3 Hz, 2 H), 7.41 (dt, J = 6.3, 3.4 Hz, 1 H), 7.32 (d, J = 8.1 Hz, 2 H), 2.55 (s, 3 H), 2.41 (s, 3 H). 13C NMR (126 MHz, CDCl3): δ = 156.7, 155.3, 150.5, 145.4, 145.0, 137.9, 136.5, 129.9, 128.2, 125.7, 114.6, 21.6, 17.0. HRMS (ESI+): m/z [M + Na]+ calcd for C14H12N2O3S2Na: 343.0187; found: 343.0185. 19a Qu E, Li S, Bai J, Zheng Y, Li W. Org. Lett. 2022; 24: 58 19b Zhu R, Li Y, Shen Y, Pan M, Dong W, Li W. Org. Chem. Front. 2024; 11: 2095 20 Mathiyazhagan AD, Anilkumar G. Org. Biomol. Chem. 2019; 17: 6735 Zusatzmaterial Zusatzmaterial Supporting Information
