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Monatshefte für Chemie - Chemical Monthly

, Volume 149, Issue 4, pp 721–722 | Cite as

Correction to: Regioselective synthesis of pyridines by redox alkylation of pyridine N-oxides with malonates

  • Miran Lemmerer
  • Christopher J. Teskey
  • Daniel Kaiser
  • Nuno Maulide
Correction
  • 213 Downloads

Correction to: Monatsh Chem  https://doi.org/10.1007/s00706-017-2081-y

The original version of this article unfortunately contained mistakes. In section “General procedure” some numbers were missing. The corrected text is given below.

General procedure

All flasks and stirrer bars were flame dried before use. To the N-oxide (0.2 mmol, 1.0 equiv.), dissolved in 2 cm3 dichloromethane was added Tf2O (0.3 mmol, 1.5 equiv.) at 0 °C. In another flask, a suspension of NaH (0.7 mmol, 3.5 equiv.) in 1 cm3 tetrahydrofuran was cooled to 0 °C and the malonate (0.7 mmol, 3.5 equiv.) was added. After 15 min, the malonate solution was added to the activated N-oxide solution and the mixture was stirred at room temperature for 1 h. The reaction was quenched with NH4Cl solution and the aqueous phase was extracted with dichloromethane. The combined organic layers were washed with brine before being dried over MgSO4. The solvents were removed under reduced pressure and the crude product was purified by column chromatography.

Dibenzyl 2-(2,6-dimethylpyridin-4-yl)malonate (6a, C24H23NO4)

The product was prepared according to the general procedure. Purification by column chromatography (EtOAc:heptane = 1:1) yielded the product (41.0 mg, 53%) as a pale yellow solid. 1H NMR (400 MHz, CDCl3): δ = 7.28–7.20 (m, 10H), 6.88 (s, 2H), 5.11 (dd, J = 12.0, 18.1 Hz, 4H), 4.56 (s, 1H), 2.43 (s, 6H) ppm; 13C NMR (101 MHz, CDCl3): δ = 167.0, 158.4, 141.5, 135.1, 128.7, 128.7, 128.4, 120.9, 67.9, 57.3, 24.6 ppm; IR: \(\bar{\nu }\) = 3064, 3033, 2955, 2922, 1732, 1605, 1569, 1497, 1453, 1375, 1297, 1140 cm−1; HRMS (ESI): m/z calculated for [M + H]+ 390.1700, found 390.1701.

Diethyl 2-(2,6-dimethylpyridin-4-yl)-2-fluoromalonate (6b, C14H18FNO4)

The product was prepared according to the general procedure. Purification by column chromatography (EtOAc:heptane = 1:3) yielded the product (34.3 mg, 61%) as a pale yellow liquid. 1H NMR (400 MHz, CDCl3): δ = 7.19 (s, 2H), 4.33 (q, J = 7.1, 4H), 2.56 (s, 6H), 1.32 (t, J = 7.1 Hz, 6H) ppm; 13C NMR (101 MHz, CDCl3): δ = 164.9 (d, J = 25.0 Hz), 158.3, 142.4 (d, J = 22.4 Hz), 116.8 (d, J = 9.0 Hz), 93.2 (d, J = 202.9 Hz), 63.4, 24.8, 14.0 ppm; 19F NMR (659 MHz, CDCl3): − 165.2 ppm; IR: \(\bar{\nu }\) = 2983, 2927, 1753, 1604, 1569, 1445, 1412, 1369, 1270, 1230, 1174, 1105, 1044, 1010 cm−1; HRMS (ESI): m/z calculated for [M + H]+ 284.1293, found 284.1292.

Diethyl 2-(2-cyanoethyl)-2-(2,6-dimethylpyridin-4-yl)malonate (6c, C17H22N2O4)

The product was prepared according to the general procedure. Purification by column chromatography (EtOAc:heptane = 1:1) yielded the product (48.4 mg, 76%) as a pink liquid. 1H NMR (400 MHz, CDCl3): δ = 6.90 (s, 2H), 4.32–4.24 (m, 4H), 2.61–2.57 (m, 2H), 2.54 (s, 6H), 2.37–2.33 (m, 2H), 1.28 (t, J = 7.1 Hz, 6H) ppm; 13C NMR (125 MHz, CDCl3): δ = 168.8, 158.6, 145.0, 119.0, 118.9, 62.6, 61.3, 32.0, 24.8, 14.0, 13.5 ppm; IR: \(\bar{\nu }\) = 2982, 2937, 2249, 1728, 1603, 1564, 1445, 1368, 1254, 1188, 1079, 1016 cm−1; HRMS (ESI): m/z calculated for [M + H]+ 319.1652, found 319.1651.

Diethyl 2-(2,6-dimethylpyridin-4-yl)-2-methylmalonate (6d, C15H21NO4)

The product was prepared according to the general procedure. Purification by column chromatography (EtOAc:heptane = 1:1) yielded the product (33.6 mg, 60%) as a pale yellow liquid. 1H NMR (400 MHz, CDCl3): δ = 6.94 (s, 2H), 4.25 (m, 4H), 2.52 (s, 6H), 1.81 (s, 3H), 1.26 (t, J = 7.2 Hz, 6H) ppm; 13C NMR (101 MHz, CDCl3): δ = 170.7, 157.9, 147.8, 119.1, 62.1, 58.6, 24.8, 22.2, 14.1 ppm; IR: \(\bar{\nu }\) = 2982, 1728, 1604, 1564, 1447, 1414, 1377, 1253, 1181, 1105, 1017 cm−1; HRMS (ESI): m/z calculated for [M + H]+ 280.1543, found 280.1543.

Diethyl 2-allyl-2-(2,6-dimethylpyridin-4-yl)malonate (7a, C17H23NO4)

The product was prepared according to the general procedure. Purification by column chromatography (EtOAc:heptane = 1:3) yielded the product (43.6 mg, 71%) as a pale yellow liquid. 1H NMR (400 MHz, CDCl3): δ = 7.01 (s, 2H), 5.75–5.64 (m, 1H), 5.08 (m, 1H), 5.04(s, 1H), 4.29–4.16 (m, 4H), 3.00 (d, J = 7.1 Hz, 2H), 2.52 (s, 6H), 1.25 (t, J = 7.1, 6H) ppm; 13C NMR (101 MHz, CDCl3): δ = 169.5, 157.8, 146.3, 132.5, 119.7, 119.4, 62.4, 62.0, 40.3, 24.8, 14.1 ppm; IR: \(\bar{\nu }\) = 2981, 2926, 1729, 1602, 1563, 1443, 1414, 1367, 1295, 1270, 1230, 1196, 1162 cm−1; HRMS (ESI): m/z calculated for [M + H]+ 306.1700, found 306.1703.

Diethyl 2-allyl-2-(4-methylpyridin-2-yl)malonate (7b, C16H21NO4)

The product was prepared according to the general procedure. Purification by column chromatography (EtOAc:heptane = 1:10) yielded the product (48.8 mg, 84%) as a pale yellow liquid. 1H NMR (400 MHz, CDCl3): δ = 8.39 (dd, J = 0.5, 5.0 Hz, 1H), 7.56 (app t, J = 0.7 Hz, 1H), 7.01–6.99 (m, 1H), 5.82–5.75 (m, 1H), 5.04–4.99 (m, 2H), 4.27–4.20 (m, 4H), 3.12 (d, J = 7.2 Hz, 2H), 2.36 (s, 3H), 1.24 (t, J = 7.1 Hz, 6H) ppm; 13C NMR (101 MHz, CDCl3): δ = 169.9, 156.6, 148.6, 147.1, 133.6, 124.8, 123.5, 118.6, 65.3, 61.7, 40.4, 21.4, 14.1 ppm; IR: \(\bar{\nu }\) = 2980, 2936, 1729, 1601, 1444, 1298, 1195 cm−1; HRMS (ESI): m/z calculated for [M + H]+ 292.1543, found 292.1543.

Diethyl 2-allyl-2-(4-phenylpyridin-2-yl)malonate (7c, C21H23NO4)

The product was prepared according to the general procedure. Purification by column chromatography (EtOAc:heptane = 1:10) yielded the product (48.0 mg, 68%) as a pale yellow liquid. 1H NMR (400 MHz, CDCl3): δ = 8.59 (dd, J = 0.7, 5.1 Hz, 1H), 7.88 (dd, J = 0.7, 1.7 Hz, 1H), 7.65–7.63 (m, 2H), 7.48–7.41 (m, 4H), 5.86–5.79 (m, 1H), 5.06–5.02 (m, 2H), 4.30–4.24 (m, 4H), 3.17 (d, J = 7.1 Hz, 2H), 1.26 (t, J = 7.1 Hz, 6H) ppm; 13C NMR (125 MHz, CDCl3): δ = 169.8, 157.2, 149.2, 148.5, 138.6, 133.3, 129.2, 129.1, 127.3, 122.4, 120.7, 119.0, 65.5, 61.8, 40.5, 14.2 ppm; IR: \(\bar{\nu }\) = 3062, 2980, 2935, 1729, 1594, 1547, 1467, 1225, 1036 cm−1; HRMS (ESI): m/z calculated for [M + H]+ 354.1700, found 354.1699.

Diethyl 2-allyl-2-(4-cyanopyridin-2-yl)malonate (7d, C16H18N2O4)

The product was prepared according to the general procedure. Purification by column chromatography (EtOAc:heptane = 1:10) yielded the product (10.3 mg, 17%) as a pale yellow liquid. 1H NMR (400 MHz, CDCl3): δ = 8.72 (dd, J = 0.9, 5.0 Hz, 1H), 7.98 (app t, J = 1.3 Hz, 1H), 7.43 (dd, J = 1.3, 5.0 Hz, 1H), 5.74–5.63 (m, 1H), 5.04–5.01 (m, 2H), 4.29–4.22 (m, 4H), 3.12 (d, J = 7.3 Hz, 2H), 1.25 (t, J = 7.1 Hz, 6H) ppm; 13C NMR (101 MHz, CDCl3): δ = 169.0, 158.5, 149.6, 132.4, 126.5, 124.0, 120.5, 119.7, 116.8, 65.3, 62.2, 40.3, 14.1 ppm; IR: \(\bar{\nu }\) = 3077, 2981, 2933, 2239, 1730, 1594, 1467, 1299, 1168, 1044 cm−1; HRMS (ESI): m/z calculated for [M + Na]+ 325.1159, found 325.1157.

The original article has been corrected.

Copyright information

© Springer-Verlag GmbH Austria, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Institute of Organic ChemistryUniversity of ViennaViennaAustria

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