Mechanism of C
N migration of CO2Alk groups Russ.Chem.Bull., Int.Ed., Vol. 52, No. 10, October, 2003
2265
tion was added dropwise to hexane. Precipitated crystals were
dried in vacuo. Lowꢀmelting hygroscopic white crystals were
obtained in 65% yield. Found (%): C, 46.91; H, 5.76; N, 6.23.
C17H25N2O9Cl. Calculated (%): C, 46.79; H, 5.73; N, 6.42.
1H NMR, δ: 1.16—1.19, 1.25 (both m, 3 H each, NCH2CH3);
1.35 (t, 6 H, OCH2CH3, J = 7.2 Hz); 3.31—3.39, 3.52—3.57
(both m, 2 H each, NCH2CH3); 4.38 (m, 4 H, OCH2CH3); 6.57
(s, 1 H, CH—N); 8.21 (m, 1 H, CH), 8.57 (d, 1 H, CH, J =
6.8 Hz), 9.02 (s, 1 H, CH), 9.11 (m, 1 H, CH), Py.
NCH2CH3); 4.14, 4.21 (both q, 2 H each, OCH2CH3, J =
7.2 Hz); 7.31 (t, 2 H, CH, J = 7.6 Hz), 7.45 (d, 2 H, CH, J =
7.6 Hz), 7.75 (t, 1 H, CH, J = 7.6 Hz), Ph; 8.16 (d, 1 H, CH,
J = 8.0 Hz); 7.16 (m, 1 H, CH), 8.65 (m, 2 H, CH), Py.
IR, ν/cm–1
(C—C(O)Et).
: 1714 (N—C(O)OEt), 1641 (C(O)N), 1580
1ꢀ[Methoxycarbonylꢀ(NꢀmethoxycarbonylꢀNꢀphenylcarbaꢀ
moyl)methyl]pyridinium perchlorate (7a). Phenyl isocyanate
(0.71 g, 6.0 mmol) was added to ylide 4a (0.25 g, 1.2 mmol)
dissolved in CDCl3 (1 mL), and the mixture was left at ∼20 °C
for 5 days. Then the reaction mixture was added dropwise with
stirring to petroleum ether. A precipitate formed was filtered off,
washed with ether, and stored in vacuo. The product was obꢀ
tained in 99% yield (0.44 g). 70% HClO4 (0.17 g) was added to
the obtained unpurified ylide dissolved in a minimum amount of
ethanol, and the mixture was slightly heated until a yellow preꢀ
cipitate dissolved. Then the resulting transparent colorless mixꢀ
ture was added dropwise to a stirred mixture of diethyl and
petroleum ethers. A precipitate formed was filtered off and
washed with ether. A crystalline substance with m.p. 88—91 °C
was obtained in 84.3% yield (0.43 g). Found (%): C, 47.43;
H, 3.91; N, 6.55. C17H17O9N2Cl. Calculated (%): C, 47.66;
H, 3.97; N, 6.54. 1H NMR, δ: 3.78, 3.93 (both s, 3 H each,
CH3); 7.38 (m, 5 H, CH), 7.51 (s, 1 H, CH), Ph; 7.97 (t, 1 H,
CH, J = 7.6 Hz), 8.47 (m, 2 H, CH), 8.85 (d, 2 H, CH, J =
5.6 Hz), Py.
NꢀEthoxycarbonylcarbamoylꢀNꢀ(4ꢀnitrophenyl)ethoxyꢀ
carbonylmethylpyridinium methanesulfonate (7b). An equimolar
amount of MeSO2OH was added dropwise to a stirred solution
of ylide 6a (0.10 g, 0.25 mmol) in CH2Cl2 (2 mL). The resulting
colorless solution was concentrated, and a solid residue was
washed with ether and recrystallized from an ether—THF mixꢀ
ture. The yield was 70%, m.p. 120—122 °C. Found (%): C, 47.47;
H, 4.72; N, 7.93; S, 6.64. C20H23N3O10S. Calculated (%):
C, 48.29; H, 4.66; N, 8.45; S, 6.44. 1H NMR, δ: 1.18, 1.31
(both t, 3 H each, OCH2CH3, J = 7.2 Hz); 2.78 (s, 3 H, CH3S);
4.25—4.45 (m, 4 H, OCH2CH3); 7.68, 8.25 (both d, 2 H each,
CH, Ph, J = 8.8 Hz); 7.99 (s, 1 H, CH); 8.02 (m, 2 H, CH), 8.52
(t, 1 H, CH, J = 7.6 Hz); 9.27 (d, 2 H, CH, J = 5.6 Hz), Py. IR,
ν/cm–1: 1750 (C(O)OEt); 1711, (N—C(O)OEt).
3ꢀ(N,NꢀDiethylaminocarbonyl)ꢀ(NꢀphenylꢀNꢀethoxycarboꢀ
nylcarbamoyl)ethoxycarbonylmethylpyridinium iodide (11).
35% HCl was added dropwise to a solution of ylide 8 (0.4 g,
0.88 mmol) in acetonitrile (5 mL) until the mixture became
colorless. Then an equimolar amount of NaI (0.132 g) dissolved
in acetonitrile was added to the reaction mixture. A residue was
filtered off and concentrated in vacuo. The resulting salt was
washed with a hexane—acetone mixture and precipitated from
acetone to hexane. A yellow crystalline substance with m.p.
74—76 °C was obtained in 98% yield (0.42 g). Found (%):
N, 6.74. C24H30N3O6I. Calculated (%): N, 7.20. 1H NMR, δ:
1.11 (t, 3 H, NCH2CH3, J = 7.0 Hz); 1.19 (t, 3 H, NCH2CH3,
J = 7.2 Hz); 1.24 (t, 3 H, OCH2CH3, J = 6.8 Hz); 1.34 (t, 3 H,
OCH2CH3, J = 7.2 Hz); 3.31, 3.52 (both m, 2 H each,
NCH2CH3); 4.47—4.13 (m, 4 H, OCH2CH3); 7.41—7.34 (m,
3 H, CH); 7.46—7.44 (m, 2 H, CH), Ph; 8.13 (s, CHN); 8.18
(m, 1 H, CH); 8.55 (d, 1 H, CH, J = 8.9 Hz); 9.05 (s, 1 H, CH);
9.89 (d, 1 H, CH, J = 6.0 Hz). IR, ν/cm–1: 1740 (CHCO2Et),
1709 (NCO2Et), 1639, (C(O)NEt2).
Pyridinium [NꢀethoxycarbonylꢀNꢀ(4ꢀnitrophenyl)carbaꢀ
moyl]ethoxycarbonylmethylide (6a). pꢀNitrophenyl isocyanate
(1.5 g, 12.6 mmol) was added to ylide 1 (2 g, 8.44 mmol) disꢀ
solved in CHCl3, and the solution was left at ∼20 °C for 1 day.
Then the solvent was evaporated, a residue was dissolved in a
minimum amount of acetone, and the resulting solution was left
for 16 h in a refrigerator. Yellow crystals formed were filtered off.
The yield of the product was 62%, m.p. 58—60 °C. Found (%):
C, 56.97; H, 4.73; N, 10.44. C19H19N3O7. Calculated (%):
C, 56.86; H, 4.77; N, 10.47. 1H NMR, δ: 1.12, 1.30 (both t,
3 H each, OCH2CH3, J = 7.2 Hz); 4.05, 4.28 (both q, 2 H each,
OCH2CH3, J = 7.2 Hz); 7.71, 8.17 (both d, 2 H each, CH, Ph,
J = 8.2 Hz); 7.85 (m, 2 H, CH), 8.26 (t, 1 H, CH, J =
7.6 Hz), 8.63 (d, 2 H, CH, J = 5.6 Hz), Py. 13C NMR,
δ: 10.6 (OCH2CH3); 55.6 (OCH2CH3); 57.6 (OCH2CH3);
103.4 (C(–)); 121.7—122.2 (Ph); 124.7 (CH); 135.7
(N—C (Ph)); 138.4 (CH); 145.1 (CH); 150.0 (159.0 (NCO2Et);
160.2 (CO2Et). IR, ν/cm–1
:
1591 (C—C(O)OEt); 1720
(N—C(O)OEt).
Pyridinium [NꢀethoxycarbonylꢀNꢀ(4ꢀethoxycarbonylpheꢀ
nyl)carbamoyl]ethoxycarbonylmethylide (6b). pꢀEthoxycarbonylꢀ
phenyl isocyanate (1.6 g, 8.4 mmol) was added to ylide 1 (1.0 g,
4.2 mmol) dissolved in CHCl3, and the resulting mixture was
left for 1 day at ∼20 °C in a closed flask. Then the reaction
mixture was added with stirring to petroleum ether, and an oil
precipitated was separated and stored in vacuo. The oil was
dissolved in an acetone—ether mixture, and the resulting soluꢀ
tion was left for several days in a refrigerator. Crystals with m.p.
105—107 °C were obtained in 52.2% yield (0.94 g). Found (%):
C, 62.42; H, 5.60; N, 6.53. C22H24O7N2. Calculated (%):
C, 61.68; H, 5.61; N, 6.54. 1H NMR, δ: 1.14, 1.27, 1.35 (all t,
3 H each, OCH2CH3, J = 7.2 Hz); 4.06, 4.24, 4.32 (all q,
2 H each, OCH2CH3, J = 7.2 Hz); 7.58 (d, 2 H, CH, Ph, J =
8.2 Hz); 7.78 (m, 2 H, CH), 8.18 (t, 1 H, CH, J = 7.6 Hz), 8.61
(d, 2 H, CH, J = 5.6 Hz), Py. IR, ν/cm–1: 1727 (Ph—C(O)OEt);
1706 (N—C(O)OEt); 1598 (CO2Et conjug.).
3ꢀ(N,NꢀDiethylaminocarbonyl)pyridinium (Nꢀethoxycarboꢀ
nylꢀNꢀphenylcarbamoyl)ethoxycarbonylmethylide (10). Phenyl
isocyanate (0.54 g, 4.5 mmol) was added to ylide 8 (0.5 g,
1.5 mmol) dissolved in anhydrous CH2Cl2, and the mixture was
left at ∼20 °C for 5 days. Then the reaction mixture was added
dropwise with stirring to a mixture of diethyl and petroleum
ethers, and the resulting solution was left to stay in cold for
several hours. A precipitate formed was filtered off, washed with
ether, and stored in vacuo. A yellow crystalline substance was
obtained in 94% yield (0.64 g), m.p. 125—127 °C. Found (%):
C, 62.92; H, 6.40; N, 9.11. C24H29N3O6. Calculated (%):
C, 63.30; H, 6.37; N, 9.23. 1H NMR, δ: 1.15—1.29 (m, 6 H,
CH2CH3); 1.21 (t, 3 H, OCH2CH3, J = 7.6 Hz); 1.25 (t, 3 H,
OCH2CH3, J = 7.2 Hz); 3.33, 3.53 (both m, 2 H each,