A Convenient Synthesis of Alkyl Heteroarylpyruvates

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• 1H NMR spectra were recorded on a Varian M 360 L spectrometer with TMS as internal standard. All melting points are uncorrected and were taken on a Kofler micro hot stage. Microanalyses were obtained on a Perkin-Elmer Analyzer 240 C.
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• The 1H NMR data for the compounds in this work are: 2 (DMSO-d6) keto form: δ 1.35 (t, 3H, CH2CH−3), 4.30 (q, 2H, CH−2Me), 4.15 (s, 2H, CH−2CO), 7.25 (d, 2H, H3, H5,), 8.65 (d, 2H, H2, H6,), JH2,H3, = JH5,H6, = 5.0 Hz. Enol form: δ 1.40 (t, 3H, CH2CH−3), 4.35 (q, 2H, CH−2Me), 6.45 (s, 1H, CH=), 6.90–7.10 (broad s, 1H, OH), 7.70 (d, 2H, H3, H5,), 8.65 (d, 2H, H2,H6,), JH2,H3, = JH5,H6, = 5.0 Hz. 3: (CDCl3) δ 1.40 (t, 3H, CH2CH−3), 4.50 (q, 2H, CH−2Me), 6.50 (s, 1H, -CH=), 7.20 (d, 1H, H5,), 8.80 (d, 1H, H6,), 9.20 (s, 1H, H2,), 13.2–15.2 (broad s, 1H, OH), J5′,6′ = 5.0 Hz. 4: (CDCl3) δ 1.40 (t, 3H, CH2CH−3), 2.60 (s, 3H, 6′-Me), 4.40 (q, 2H, CH−2Me), 6.40 (s, 1H, -CH=), 7.00 (s, 1H, H5,), 9.00 (s, 1H, H2,). 5: (CDCl3) δ 1.4 (t, 3H, CH3CH−3), 4.4 (q, 2H, CH−2CH3), 6.65 (s, 1H, -CH=), 8.4–8.8 (m, 3H, H3, H4, H5,), 10.8–12.5 (broad s, 1H, OH), J5′,6′ = 2.0 Hz. 6: (CDCl3) δ 1.40 (t, 3H, CH2CH−3), 4.40 (q, CH−2CH3), 6.40 (s, 1H, -CH=), 7.10 (d, 1H, H3,), 7.3–7.8 (m, 5H, H5′ H6′ H7′ H8′ OH), 8.00 (d, 1H, H4,), JH3′H4′ = 8.0 Hz. 7: (CDCl3) δ 1.40 (t, 3H, CH2CH−3), 4.45 (q, 2H, CH−2CH3), 6.85 (s, 1H, -CH=), 7.3–7.8 (m, 2H, H5′ H6′), 7.8–8.3 (m, 2H, H4′, H7′), 10.7–11.3 (broad s, 1H, OH). 8: (CDCl3) δ 1.40 (t, 3H, CH2CH−3), 4.35 (q, 2H, CH−2CH3), 4.35 (q, 2H, CH−2H3), 6.60 (s, 1H, -CH=), 7.1–7.8 (m, 3H, H3′, H4′, H5′), 8.30 (d, 1H, H6′), 14.2–14.4 (broad s, 1H, OH). J5′,6′ = 5.0 Hz.
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