PAPER
A Versatile and Efficient Synthesis of Substituted Pyridinones
1745
Table 6 1H and 13C NMR Data of Compounds 13-16 (continued)
Product
1H NMR (CDCl3),
13C NMR (CDCl3),
J (Hz)
J (Hz)
14a
1.52 [s, 9 H, C(CH3)3], 2.28 (s, 3 H, CH3), 2.46 (dd, 1 H, J =
4.7, 15.9 Hz, CHHC=O), 2.62 (dd, 1 H, J = 13.9, 15.9 Hz,
21.2 (CH3), 28.3 [C(CH3)3], 43.5 (CH2C=O), 56.6 (CH),
80.5 [C(CH3)3], 106.7 (HN–C=C), 124.8, 126.8, 128.8,
CHHC=O), 4.66 (dd, 1 H, J = 4.7, 13.9 Hz, CH), 5.72 (br s, 1 130.4 (CHAr), 134.9, 141.3 (CAr), 163.7 (CO2t-Bu),
H, NH), 7.21–7.33 (m, 4 H, C6H4Cl) 165.7 (HN–C=C), 187.1 (C=O),
14b
1.23 (t, 3 H, J = 7.5 Hz, CH2CH3), 1.48 [s, 9 H, C(CH3)3], 2.31 12.9 (CH2CH3), 27.4 (CH2CH3), 28.2 [C(CH3)3], 43.2
(dd, 1 H, J = 5.2, 15.9 Hz, CHHC=O), 2.43 (dd, 1 H, J = 12.8, (CH2C=O), 55.9 (CH), 80.3 [C(CH3)3], 105.4 (HN–C=C),
15.9 Hz, CHHC=O), 2.58 (m, 2 H, CH2CH3), 4.56 dd, 1 H, J = 124.8 126.7, 128.5, 130.2 (CHAr), 134.6, 141.5 (CAr),
5.2, 12.8 Hz, CH), 6.55 (br s, 1 H, NH), 7.16–7.26 (m, 4 H,
C6H4Cl)
165.7 (CO2t-Bu), 169.1 (HN–C=C), 187.5 (C=O)
15a
15b
1.50 [s, 9 H, C(CH3)3], 2.30 (s, 3 H, CH3), 2.49 (dd, 1 H, J =
5.3, 15.9 Hz, CHHC=O), 2.61 (dd, 1 H, J = 12.5, 15.9 Hz,
CHHC=O), 4.73 (dd, 1 H, J = 5.3, 12.5 Hz, CH), 6.79 (br s, 1 135.0 (CAr), 148.4, 149.8 (CHAr), 164.7 (CO2t-Bu),
H, NH), 7.29 (dd, 1 H, J = 4.9, 7.8 Hz, ArH), 7.68 (d, 1 H, J = 165.6 (HN–C=C), 187.0 (C=O)
7.8 Hz, ArH), 8.52 (m, 2 H, ArH)
21.3 (CH3), 28.4 [C(CH3)3], 42.9 (CH2C=O), 54.3 (CH),
80.5 [C(CH3)3], 106.2 (HN–C=C), 123.9, 134.4 (CHAr),
1.27 (t, 3 H, J = 7.5 Hz, CH2CH3), 1.53 [s, 9 H, C(CH3)3], 2.42 13.0 (CH2CH3), 27.4 (CH2CH3), 28.2 [C(CH3)3], 42.8
(dd, 1 H, J = 5.7, 15.9 Hz, CHHC=O), 2.51 (dd, 1 H, J = 11.7, (CH2C=O), 54.0 (CH), 80.4 [C(CH3)3], 105.7 (HN–C=C),
15.9 Hz, CHHC=O), 2.55 (m, 2 H, CH2CH3), 4.75 (dd, 1 H,
123.8 134.3 (CHAr), 135.2 (CAr), 148.2, 149.6 (CHAr),
J = 5.7, 11.7 Hz, CH), 5.81 (br s, 1 H, NH), 7.33 (dd, 1 H, J = 165.6 (CO2t-Bu), 168.9 (HN–C=C), 187.2 (C=O)
4.9, 7.8 Hz, ArH), 7.70 (d, 1 H, J = 7.8 Hz, ArH), 8.58 (m, 2
H, ArH)
16
1.51 [s, 9 H, C(CH3)3], 2.71 (s, 3 H, CH3), 2.39 (dd, 1 H, J =
11.2, 15.8 Hz, CHHC=O), 2.52 (dd, 1 H, J = 5.1, 15.8 Hz,
21.5 (CH3), 28.3 [C(CH3)3], 39.4 (CH2Ph), 40.5
(CH2C=O), 52.8 (CH), 79.9 [C(CH3)3], 104.8 (HN–C=C),
CHHC=O), 2.85 (dd, 1 H, J = 8.4, 13.4 Hz, CHHPh), 2.91 (dd, 126.9, 128.7, 129.1 (CHAr), 136.3 (CAr), 164.7 (CO2t-
1 H, J = 6.1, 13.4 Hz, CHHPh), 3.84 (m, 1 H, CH), 5.43 (br s, Bu), 165.8 (HN–C=C), 188.3 (C=O)
1 H, NH), 7.17–7.36 (m, 5 H, C6H5)
2-Alkyl and 2-Aryl-6-alkyl-1,2-dihydro-1H-pyridin-4-one
17,18,19,20; General Procedure
and 13C NMR data of 17,18,19,20 are recorded in Table 7. Satisfac-
tory microanalyses were obtained for 17a,b,18a,b,19a,b,20 C
0.40, H 0.18, N 0.20.
To a stirred soln of tetrahydropyridinone 13, 14, 15 or 16 (5 mmol),
in CH2Cl2 (10 mL), was added TFA (3.85 mL, 50 mmol), and the
mixture was heated at 50 °C. After completion (4 h monitored by
TLC analysis), the reaction mixture was neutralized with sat. aq
K2CO3 and extracted with CH2Cl2 (2 20 mL). The combined or-
ganic fractions were dried (CaCl2) and concentrated in vacuo. The
crude product was chromatographed on silica gel eluting with vari-
able amounts of EtOAc–MeOH to give the pure compound. The 1H
17b
IR (KBr),: 3218, 3060, 2965, 2925, 2878, 1616, 1601, 1532, 1450,
1351, 1264, 1237, 1107, 769, 702 cm–1.
Table 7 1H and 13C NMR Data of Compounds 17a 18, 19, 20
Product
1H NMR (CDCl3),
13C NMR (CDCl3),
, J (Hz)
, J (Hz)
17b
1.19 (t, 3 H, J = 7.6 Hz, CH2CH3), 2.28 (q, 2 H, J = 7.6 Hz,
CH2CH3), 2.42 (dd, 1 H, J = 4.9, 16.2 Hz, CHHC=O), 2.62
11.7 (CH2CH3), 27.8 (CH2CH3), 43.4 (CH2C=O), 57.9
(CH), 97.2 (C=CH), 126.5, 128.1, 128.7 (CHAr), 140.2
(dd, 1 H, J = 14.5, 16.2 Hz, CHHC=O), 4.67 (dd, 1 H, J = 4.9, (CAr), 167.8 (C=CH), 191.9 (C=O)
14.5 Hz, CH), 5.04 (s, 1 H C=CH), 5.15 (br s, 1 H, NH), 7.31–
7.40 (m, 5 H, C6H5)
18a
18b
1.98 (s, 3 H, CH3), 2.47 (dd, 1 H, J = 4.8, 16.0 Hz,
21.2 (CH3), 43.2 (CH2C=O), 57.9 (CH), 99.9 (C=CH),
CHHC=O), 2.60 (dd, 1 H, J = 14.2, 16.0 Hz, CHHC=O), 4.69 124.6, 126.8, 128.6, 130.6 (CHAr), 134.8, 142.2 (CAr),
(dd, 1 H, J = 4.8, 14.2 Hz, CH), 4.98 (s, 1 H, C=CH), 5.34 (br 162.4 (C=CH), 191.5 (C=O)
s, 1 H, NH), 7.24–7.39 (m, 5 H, C6H5)
1.19 (t, 3 H, J = 7.6 Hz, CH2CH3), 2.29 (q, 2 H, J = 7.6 Hz,
CH2CH3), 2.37 (dd, 1 H, J = 5.0, 16.1 Hz, CHHC=O), 2.50
11.7 (CH2CH3), 27.9 (CH2CH3), 43.4 (CH2C=O), 57.6
(CH), 97.8 (C=CH), 124.8, 126.7, 128.4, 130.2 (CHAr),
(dd, 1 H, J = 13.8, 16.1 Hz, CHHC=O), 4.62 (dd, 1 H J = 5.0, 134.6 142.4 (CAr), 167.7 (C=CH), 191.5 (C=O)
13.8 Hz, CH), 4.98 (s, 1 H, C=CH), 5.63 (br s, 1 H, NH),
7.24–7.36 (m, 4 H, C6H4Cl)
Synthesis 2002, No. 12, 1740–1746 ISSN 0039-7881 © Thieme Stuttgart · New York