J = 4.7, 1.0 Hz, 1H), 8.07 (dt, J = 8.0, 1.0, Hz, 1H), 7.94 (dq, J =
4.8, 1.0 Hz, 1H), 7.81 (dt, J = 8.0, 1.9, Hz, 1H), 7.73 (dt, J = 7.5,
1.8 Hz, 1H), 7.58 (dt, J = 8.0, 0.9 Hz, 1H), 7.35 (ddd, J = 7.6,
4.8, 1.1 Hz, 1H), 7.15 (d, J = 8.6 Hz, 2H), 7.03–7.06 (m, 3H), 2.35
(s, 3H), 1.95–2.02 (m, 1H), 1.77–1.85 (m, 1H), 1.38–1.47 (m, 1H),
1.11 (t, J = 7.6 Hz, 3H), 0.90 (t, J = 5.5 Hz, 3H), 0.87–0.93 (m, 1H);
13C NMR (100 MHz, CD3COCD3) d (ppm) 180.9, 162.6, 155.2,
150.4, 149.0, 148.8, 137.5, 136.8, 136.1, 134.6, 133.3, 128.4, 126.0,
124.0, 123.2, 121.6, 121.4, 107.0, 63.0, 21.6, 20.3, 19.4, 7.8, 7.3;
HRMS (TOF-ESI): 424.2125 (M+1); Anal. Calcd for C26H26N5O:
424.2137 (M+1).
180 (100), 230 (100), 396 (3%, M+1); Anal. Calcd for C24H21N5O:
C 72.89, H 5.35, N 17.71; Found: C 72.68, H 5.30, N 17.82.
5-(3-[1,2,3]Triazolo[1,5-a]pyridyl)-1-(4-methoxyphenyl)-3,3-di-
◦
methyl-4-(2-pyridyl)pyrrol-2-one 5c. 92%, mp 202–203 C; IR v
1
(cm-1) 1712, 1638, 1620, 1587, 1554, 1512; H NMR (400 MHz,
CDCl3) d (ppm) 8.61 (d, J = 7.0 Hz, 1H), 8.56 (d, J = 4.1 Hz, 1H),
7.26–7.24 (m, 1H), 7.19 (d, J = 9.0 Hz, 1H), 7.06–7.08 (m, 1H),
7.03 (dd, J = 8.9, 1.9 Hz, 2H), 6.99 (t, J = 6.8 Hz, 1H), 6.91 (td, J =
6.9, 1.0 Hz, 1H), 6.83 (d, J = 7.7 Hz, 1H), 6.73 (d, J = 8.9 Hz, 2H),
3.71 (s, 3H), 1.69 (s, 6H); 13C NMR (100 MHz, CDCl3) d (ppm)
182.5, 158.5, 153.5, 149.3, 135.6, 132.4, 130.8, 129.6, 128.5, 127.8,
126.3, 125.4, 123.8, 121.3, 117.4, 115.5, 114.0, 55.3, 49.3, 23.7; MS
(ESI): 412 (M+1); Anal. Calcd for C24H21N5O2: C 70.06, H 5.14,
N 17.02; Found: C 69.91, H 5.34, N 17.07.
3¢,6a¢-Di(2-pyridyl)-4¢-p-tolyl-4¢H-spiro[cyclohexane-1,6¢-pyrro-
◦
lo[3,2-c]pyrazol]-5¢-one 4h. 88%, 156–157 C; IR v (cm-1) 1752,
1639, 1581; 1H NMR (400 MHz, CD3COCD3) d (ppm) 8.47 (dq,
J = 4.8, 1.0 Hz, 1H), 8.05 (dd, J = 8.0, 1.0, Hz, 1H), 7.95 (dq, J = 4.7,
1.0 Hz, 1H), 7.83 (dt, J = 7.9, 1.8, Hz, 1H), 7.72 (dt, J = 7.6, 1.8 Hz,
1H), 7.58 (dt, J = 8.0, 1.0 Hz, 1H), 7.35 (ddd, J = 7.6, 4.8, 1.1 Hz,
1H), 7.15 (d, J = 8.6 Hz, 2H), 7.08 (d, J = 8.6 Hz, 2H), 7.05 (ddd,
J = 7.6, 4.8, 1.1 Hz, 1H), 2.36 (s, 3H), 1.71–1.82 (m, 4H), 1.62–1.64
(m, 1H), 1.34–1.55 (m, 5H); 13C NMR (100 MHz, CD3COCD3) d
(ppm) 181.5, 161.9, 155.2, 150.3, 149.1, 149.0, 137.4, 136.7, 136.1,
134.6, 133.2, 128.4, 126.0, 124.0, 123.7, 121.6, 121.5, 107.0, 60.4,
30.6, 25.5, 22.6, 22.03, 22.01, 20.4; HRMS (TOF-ESI): 436.2132
(M+1); Anal. Calcd for C27H26N5O: 436.2137 (M+1).
5-(3-[1,2,3]Triazolo[1,5-a]pyridyl)-1-(4-chlorophenyl)-3,3-dim-
ethyl-4-(2-pyridyl)pyrrol-2-one 5d. 91%, mp 208–209 ◦C; IR v
1
(cm-1) 1720, 1620, 1583, 1526; H NMR (400 MHz, CDCl3) d
(ppm) 8.63 (d, J = 7.1 Hz, 1H), 8.58 (d, J = 4.1 Hz, 1H), 7.27 (brs,
1H), 7.19 (d, J = 8.6 Hz, 2H), 7.16 (d, J = 9.0 Hz, 1H), 7.09 (d,
J = 6.6 Hz, 1H), 7.05 (d, J = 8.7 Hz, 2H), 7.03 (brs, 1H), 6.94 (td,
J = 6.9, 1.1 Hz, 1H), 6.84 (brs, 1H), 1.68 (s, 6H); 13C NMR (100
MHz, CDCl3) d (ppm) 182.0, 153.3, 149.4, 135.8, 133.7, 132.8,
132.3, 130.1, 129.9, 128.8, 128.4, 128.1, 126.6, 125.5, 124.0, 121.5,
117.3, 115.7, 49.5, 23.7; MS (CI): 416 (M+1); Anal. Calcd for
C23H18ClN5O: C 66.43, H 4.36, N 16.84; Found: C 66.52, H 4.60,
N 16.84.
General procedure for the reaction of b-lactam carbenes 2 with
3,6-di(2-pyridyl)tetrazine 3 in xylene
5-(3-[1,2,3]Triazolo[1,5-a]pyridyl)-1-(4-bromophenyl)-3,3-dim-
ethyl-4-(2-pyridyl)pyrrol-2-one 5e. 80%, mp 205–206 ◦C; IR v
Under nitrogen atmosphere, the mixture of spiro[b-lactam-4,2¢-
oxadiazolines] 1 (1.5 mmol) and 3,6-di(2-pyridyl)tetrazine 3 (1
mmol) was heated in refluxing xylene (50 mL) for 3–12 h.
After removal of the solvent under vacuum, the residue was
chromatographed on a silica gel column eluting with a mixture of
petroleum ether and ethyl acetate from 10 : 1 to pure ethyl acetate
to give products 5-triazolo[1,5-a]pyridylpyrrol-2-ones 5 in 75–92%
yields. Products 5 were further purified by recrystallization in ethyl
acetate and petroleum ether.
1
(cm-1) 1720, 1635, 1583, 1561; H NMR (400 MHz, CDCl3) d
(ppm) 8.56 (d, J = 7.0 Hz, 1H), 8.50 (d, J = 4.4 Hz, 1H), 7.27 (d,
J = 8.6 Hz, 2H), 7.20 (bs, 1H), 7.08 (d, J = 8.9 Hz, 1H), 7.01(t,
J = 6.6 Hz, 1H), 6.95 (brs 1H), 6.92 (d, J = 8.6 Hz, 2H), 6.87
(t, J = 6.9 Hz, 1H), 6.76 (brs 1H), 1.61 (s, 6H); 13C NMR (100
MHz, CDCl3) d (ppm) 181.9, 153.2, 149.3, 135.9, 134.2, 132.3,
131.8, 130.1, 129.8, 128.7, 128.0, 126.6, 125.6, 124.0, 121.6, 120.9,
117.3, 115.7, 49.5, 23.7; MS (ESI): 460 (M+1); Anal. Calcd for
C23H18BrN5O: C 60.01, H 3.94, N 15.21; Found: C 59.75, H 3.87,
N 15.18.
5-(3-[1,2,3]Triazolo[1,5-a]pyridyl)-3,3-dimethyl-1-phenyl-4-(2-
pyridyl)pyrrol-2-one 5a. 87%, mp 192–193 ◦C; IR v (cm-1) 1716,
1622, 1582, 1562, 1518; 1H NMR (400 MHz, CD3COCD3) d (ppm)
8.86 (d, J = 7.0 Hz, 1H), 8.56 (dt, J = 3.9 Hz, 1H), 7.43 (d, J =
7.8 Hz, 1H), 7.34 (dt, J = 7.7, 1.9 Hz, 1H), 7.27 (dd, J = 9.0,
6.6 Hz, 1H), 7.19–7.23 (m, 2H), 7.10–7.16 (m, 4H), 7.07 (ddd, J =
7.5, 4.8 Hz, 1H), 6.82 (d, J = 8.1 Hz, 1H), 1.68 (s, 6H); 13C NMR
(100 MHz, CDCl3) d (ppm) 182.1, 153.3, 149.0, 136.0, 135.0, 132.4,
130.8, 129.5, 128.7, 128.3, 127.2, 127.1, 126.4, 125.4, 124.1, 121.5,
117.4, 115.6, 49.48, 23.75; MS (ESI): 382(M+1); Anal. Calcd for
C23H19N5O: C 72.42, H 5.02, N 18.36; Found: C 72.04, H 4.68, N
18.17.
5-(3-[1,2,3]Triazolo[1,5-a]pyridyl)-3,3-die◦thyl-4-(2-pyridyl)-1-
(p-tolyl)pyrrol-2-one 5f. 82%; mp 182–183 C, IR v (cm-1) 1712,
1
1623, 1585, 1514; H NMR (400 MHz, CDCl3) d (ppm) 8.53 (d,
J = 7.0 Hz, 1H), 8.48 (d, J = 4.3 Hz, 1H), 7.15 (td, J = 7.8, 1.8 Hz,
1H), 7.11 (d, J = 7.9 Hz, 1H), 7.00 (ddd, J = 8.8, 6.6, 0.8 Hz,
1H), 6.88–6.98 (m, 5H), 6.83 (td, J = 6.9, 1.2 Hz, 1H), 6.79 (d,
J = 8.0 Hz, 1H), 2.21–2.26 (m, 2H), 2.16 (s, 3H), 1.92–1.97 (m,
2H), 0.91 (t, J = 7.3 Hz, 6H); 13C NMR (100 MHz, CDCl3) d
(ppm) 181.2, 153.8, 149.5, 137.1, 135.5, 133.0, 132.5, 132.4, 129.3,
128.7, 127.2, 126.3, 125.4, 125.1, 123.6, 121.1, 117.3, 115.4, 59.9,
30.1, 21.1, 9.3; MS (CI): 424 (M+1); Anal. Calcd for C26H25N5O:
C 73.74, H 5.95, N 16.54; Found: C 73.49, H 6.29, N 16.35.
5-(3-[1,2,3]Triazolo[1,5-a]pyridyl)-3,3-dimethyl-4-(2-pyridyl)-1-
(p-tolyl)pyrrol-2-one 5b. 83%, mp 184–185 ◦C; IR v (cm-1) 1733,
1
1619, 1584, 1513; H NMR (400 MHz, CDCl3) d (ppm) 8.61 (d,
J = 7.0 Hz, 1H), 8.56 (d, J = 4.2 Hz, 1H), 7.19 (d, J = 8.9 Hz, 1H),
7.07 (d, J = 6.8 Hz, 1H), 7.04 (d, J = 4.0 Hz, 2H), 7.00 (d, J =
4.1 Hz, 2H), 6.91 (t, J = 6.6 Hz, 1H), 6.85 (brs, 1H), 2.24 (s, 3H),
1.69 (s, 6H); 13C NMR (100 MHz, CDCl3) d (ppm) 182.2, 153.5,
149.1, 137.0, 135.8, 132.4, 132.4, 130.8, 129.3, 128.5, 127.0, 126.2,
125.4, 124.0, 121.4, 117.5, 115.5, 49.4, 23.7, 21.1, 21.0; MS (EI):
5-(3-[1,2,3]Triazolo[1,5-a]pyridyl)-3-ethyl-3-methyl-4-(2-pyrid-
yl)-1-(p-tolyl)pyrrol-2-one 5g. 90%, mp 161–162 ◦C; IR v (cm-1)
1713, 1635, 1619, 1582, 1514; H NMR (400 MHz, CDCl3) d
(ppm) 8.53 (d, J = 7.0 Hz, 1H), 8.48 (dd, J = 4.8, 0.8 Hz, 1H),
7.16 (d, J = 7.6, 1H), 7.11 (d, J = 9.0 Hz, 1H), 7.00 (td, J = 7.4,
0.7 Hz, 1H), 6.89–6.94 (m, 5H), 6.83(td, J = 7.8, 1.1 Hz, 1H), 6.77
1
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The Royal Society of Chemistry 2012
Org. Biomol. Chem., 2012, 10, 970–977 | 975
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