3PO synthesis

Yield: 57%

Reaction Conditions:

with sodium acetate in acetic acidReflux;

Steps:

Synthesis of (E)-3-(pyridin-3-yl)-1-(pyridin-4-yl)prop-2-en-1-one (3PO)
To a solution of 884 mg (8.26 mmol, 1.00 mol eq) nicotinaldehyde1 and 1.00 g (8.26 mmol, 1.00 mol eq) ofpyridinylethanone 2 in 2 ml of glacial acetic acid, 1.12 g(13.7 mmol, 1.65 mol eq) of AcONa was added. The mixturewas heated to reflux overnight. Afterwards TLC analysisconfirmed only a spot for a new product. The reactionwas cooled down, 10 ml of water added and the mixturehas been stirred within 2 h at RT. Obtained solid materialwas filtered off, washed on a filter by H2O(2 × 10 ml)and dried on the air. The crude product (1.25 g) wascrystallised from 10 ml of boiled EtOH to yield 989 mg(4.71 mmol, 57%) of 3 (3PO) after standing at RT andlater on in a refrigerator overnight (Scheme 2). Obtained3PO (Fig. 2) forms pale yellow solid material. M.p.:144.4-145.9 °C [EtOH] (lit.: 146-147 °C [H2O]) (Durindaet al. 1966).1H-NMR (600 MHz, DMSO-d6): δ 9.00 (d,1H, J(B2,B4) = 1.8 Hz, H-CB(2)), 8.83 (d, 2H,J(A2,A3) = 6.0 Hz, 2 × H-CA(2)), 8.61 (dd, 1H,J(B5,B6) = 4.7 Hz, J(B4,B6) = 1.5 Hz, H-CB(6)),8.33 (ddd, 1H, J(B4,B5) = 7.9 Hz, J(B2,B4) = 1.8 Hz,J(B4,B6) = 1.5 Hz, H-CB(4)), 7.98 (d, 1H,J(CH = CH) = 15.8 Hz, -CH = C(2)HCO-), 7.97 (d,2H, J(A2,A3) = 6.0 Hz, 2 × H-CA(3)), 7.79 (d, 1H,J(CH = CH) = 15.8 Hz, -C(3)H = CHCO-), 7.51 (dd, 1H,J(B4,B5) = 7.9 Hz, J(B5,B6) = 4.7 Hz, H-CB(5)).13C-NMR (150 MHZ, DMSO-d6): δ 189.4 (C = O),151.8 CB(6), 151.3 (2 × CA(2)), 151.0 CB(2), 143.7 CA(4),142.7 (-C(3)H = CHCO-), 135.8 CB(4), 130.7 CB(3),124.5 CB(5), 123.8 (-CH = C(2)HCO-), 122.1 (2 × CA(3)).FT-IR (solid, cm-1): 2109 (w), 2082 (w), 1912 (w),1671 (s), 1606 (s), 1583(s), 1552 (s), 1473 (m), 1415 (s),1353 (m), 1303 (s), 1218 (s), 1120 (m), 1096 (m), 1021(s), 982 (s), 878 (m), 836 (m), 793 (s).MS (ESI m/z): 211.1 [M + H]+.Anal. Calcd for C13H10N2O(210.23): C, 74.27; H, 4.79;N, 13.33. Found: C, 74.02; H, 4.89; N, 13.48.

References:

Murár, Miroslav;Horvathová, Jana;Moravčík, Roman;Addová, Gabriela;Zeman, Michal;Boháč, Andrej [Chemical Papers,2018,vol. 72,# 12,p. 2979 - 2985]