Supplementary material

BF3˙SiO2 is a simple and efficient Lewis acid catalysts for the one-pot synthesis of polyfunctionalized piperidin-4-ones

Someshwar D. Dindulkar ● Paramasivam Parthiban ● Yeon Tae Jeong*

1H NMR and 13C NMR data of literature compounds 1, 2, 6, 12 and 14.

trans-3-Methyl-cis-2,6-diphenylpiperidin-4-one (1, C18H19NO)

White solid, m.p.: 86-88 oC; 1H NMR (400 MHz, CDCl3): δ = 7.45 (t, J = 6.2 Hz, 4H, H-2'a/2'e, H-6'a/6'e), 7.37-7.24 (m, 6H, remaining phenyl protons), 4.08 (dd, J = 2.9, 11.7 Hz, H-6a), 3.61 (d, J = 10.6 Hz, H-2a), 2.76-2.59 (m, H-3a, H-5a, H-5e), 2.09 (br s, NH), 0.83 (d, J = 6.9 Hz, CH3 at C-3) ppm; 13C NMR (100.52 MHz, CDCl3): δ = 209.59 (C-4), 142.81, 141.94 (C-2'/6'), 128.68, 128.57, 126.56 (remaining phenyl carbons), 68.48 (C-2), 61.60 (C-6), 51.71 (C-3), 50.95 (C-5), 10.23 (CH3 at C-3) ppm.

trans-3-Methyl-cis-2,6-bis(4-methoxyphenyl)piperidin-4-one (2, C20H23NO3)

Yellow solid, m.p.: 138-140 oC; 1H NMR (400 MHz, CDCl3): δ = 7.36 (dd, J = 2.2, 8.6 Hz, 4H, H-2'a/2'e, H-6'a/6'e), 6.87 (q, J = 6 Hz, 4H, H-2'b/2'd, H-6'b/6'd), 4.01 (dd, J = 2.9, 11.7 Hz, H-6a), 3.80 (s, OCH3), 3.78 (s, OCH3), 3.55 (d, J = 10.2 Hz, H-2a), 2.70-2.55 (m, H-3a, H-5a, H-5e), 1.96 (br s, NH), 0.82 (d, J = 6.5 Hz, CH3 at C-3) ppm; 13C NMR (100.52 MHz, CDCl3): δ = 210.12 (C-4), 159.23, 159.11 (C-2'c/6'c), 135.08, 134.21 (C-2'/6'), 128.76, 127.68 (C-2'a/2'e, C-6'a/6'e), 113.96, 113.84 (C-2'b/2'd, C-6'b/6'd), 67.86 (C-2), 60.99 (C-6), 55.30 (OCH3), 51.84 (C-3), 51.08 (C-5), 10.25 (CH3 at C-3) ppm.

trans-3-Ethyl-cis-2,6-diphenylpiperidin-4-one (6, C19H21NO)

White solid, m.p.: 109-111 oC; 1H NMR (400 MHz,CDCl3): δ = 7.47-7.42 (m, 4H, H-2'a/2'e, H-6'a/6'e), 7.37-7.24 (m, 6H, remaining phenyl protons), 4.06 (dd, J = 3.1, 11.5 Hz, H-6a), 3.71 (d, J = 10.2, Hz, H-2a), 2.72 (t, J = 12.2 Hz, H-3a), 2.61-2.56 (m, H-5a, H-5e), 2.04 (br s, NH), 1.61-1.50 (m, CH of Et at C-3), 1.17-1.11 (m, CH' of Et at C-3), 0.77 (t, J = 7.5 Hz, CH3 of Et at C-3) ppm; 13C NMR (100.52 MHz, CDCl3): δ = 209.17 (C-4), 142.81, 141.91 (C-2'/6'), 128.64, 128.57, 127.88 (remaining phenyl carbons), 66.79 (C-2), 61.80 (C-6), 58.49 (C-3), 51.59 (C-5), 17.93 (CH2 of Et at C-3), 12.31 (CH3 of Et at C-3) ppm.

trans-3-Isopropyl-cis-2,6-diphenylpiperidin-4-one (12, C20H23NO)

White solid, m.p.: 126-128 oC; 1H NMR (400 MHz,CDCl3): δ = 7.48 (d, J = 7.3 Hz, 2H, H-2'a/2'e), 7.41 (d, J = 7.3 Hz, 2H, H-6'a/6'e), 7.37-7.23 (m, 6H, remaining phenyl protons), 4.09 (dd, J = 3.1, 11.5 Hz, H-6a), 3.98 (d, J = 10.6 Hz, H-2a), 2.67 (m, H-3a, H-5a), 2.55 (dd, J = 3.1, 13.7 Hz, H-5e), 1.95 (br s, NH), 1.67-1.62 (m, CH of iPr at C-3), 1.02 (d, J = 6.9 Hz, CH3 of iPr at C-3), 0.88 (d, J = 6.9 Hz, CH3' of iPr at C-3) ppm; 13C NMR (100.52 MHz, CDCl3): δ = 208.89 (C-4), 142.90, 142.20 (C-2'/6'), 128.68, 128.63, 126.57 (remaining phenyl carbons), 64.76 (C-2), 61.24 (C-6), 61.13 (C-3), 52.02 (C-5), 25.98 (CH of iPr at C-3), 21.06 (CH3 of iPr at C-3), 17.72 (CH3' of iPr at C-3) ppm.

trans-3,5-dimethyl-cis-2,6-diphenylpiperidin-4-one (14,C19H21NO)

White solid, m.p.: 133-135 oC; 1H NMR (400 MHz,CDCl3): δ = 7.43 (d, J = 7.3 Hz, 4H, H-2'a/6'a, H-2'e/6'e), 7.34-7.22 (m, 6H, remaining phenyl protons), 3.60 (d, J = 10.2 Hz, H-2ª, H-6a), 2.81-2.74 (m, H-3a, H-5a), 2.05 (br s, NH), 0.82 (d, J = 6.6 Hz, CH3 at C-3 and C-5) ppm; 13C NMR (100.52 MHz, CDCl3): δ = 211.14 (C-4), 142.04 (C-2'/6'), 128.50, 127.94, 127.75 (remaining phenyl carbons), 68.87 (C-2, C-6), 52.05 (C-3, C-5), 10.57 (CH3 at C-3 and C-5) ppm.