Solution of Bromobenzophosphole 2. Phosphorus tribromide (4.2 mmol) was added dropwise to a
solution of amide 1 (4.2 mmol) [3] and triethylamine (12.6 mmol) in pyridine at 0°C (15 ml). The reaction
mixture was held for 3 h at room temperature, and used without purification for further conversions. We observe
a signal at 110.5 ppm in the 31P NMR spectrum of the reaction mixture.
5
c
1-Diethylamino-5-dimethylamino-2-(4-methylphenyl)-1-thiooxo-1,2-dihydro-1 -benzo[ ][1,2]-
λ
azaphosphol-3-one (4). Diethylamine (4.2 mmol) and then 30 min later elemental sulfur (5 mmol) were added
to the solution of bromobenzphosphole 2. After 12 h, benzene (50 ml) was added and the mixture was stirred,
then the precipitate was filtered off and the filtrate was evaporated down. The residue was chromatographed on
31
silica gel with toluene as the eluent. Yield 67%; mp 201-203°C (ethanol). P NMR spectrum (CDCl3): 63.9
1
ppm. H NMR spectrum (CDCl3), , ppm, J, Hz: 0.83 (6H, t, N(CH2CH3)2); 2.38 (3H, s, CH3; 3.02 (2H, m,
δ
3
4
4
NCH2CH3); 3.10 (6H, s, N(CH3)2); 3.22 (2H, m, NCH2CH3); 6.95 (1H, m, JHH = 8.7, JHH = 2.1, JHP = 3.9,
6-H); 7.3 (5H, m, 4-H, NC6H4CH3); 7.6 (1H, dd, 3JHH = 8.7, 3JHP = 11.7, 7-H). Found, %: N 10.73, 10.82; P 7.93,
7.95. C20H26N3OPS. Calculated, %: N 10.84; P 7.99.
a
5-Dimethylamino-1-(2-methylimidazo[1,2- ]pyridin-3-yl)-2-(4-methylphenyl)-1-thiooxo-1,2-dihydro-
5
c
2-Methylimidazo[1,2-a]pyridine (4.2 mmol) and then 30 min later
1 -benz[ ][1,2]azaphosphol-3-one (5).
λ
elemental sulfur (5 mmol) were added to the solution of bromobenzphosphole 2. After 12 h, benzene (50 ml)
was added to the reaction mixture and the mixture was stirred, then the precipitate was filtered off and the
filtrate was evaporated down, and the residue was recrystallized from toluene. Yield 35%; mp 251-253°C
(toluene). 31P NMR spectrum (CDCl3); 37.6 ppm. H NMR spectrum (CDCl3), , ppm, J, Hz: 2.16 (3H, s,
1
δ
3
3
2'-CH3); 2.30 (3H, s, NC6H4CH3); 3.16 (6H, s, N(CH3)2); 6.74 (1H, t, JHH = 7.1, 6'-H); 6.96 (2H, d, JHH = 7.9,
o-CH3C6H4); 7.00 (1H, m, 6-H); 7.10 (2H, d, 3JHH = 7.9, m-CH3C6H4); 7.32 (1H, dd, 3JHH = 7.1, 3JHH = 8.5, 7'-H);
3
3
3
7.38 (3H, br. s, 4-H); 7.61 (1-H, br. d, JHH = 8.5, 8'-H); 7.67 (1H, dd, JHH = 8.7, JHP = 11.7, 7-H); 9.1 (1-H,
br. d, 3JHH = 7.1, 5'-H). Found, %: N 12.46, 12.51; P 6.87, 6.91. C24H25N4OPS. Calculated, %: N 12.55; P 6.94.
5
c
5-Dimethylamino-2-(4-methylphenyl)-1-phenyl-1-thiooxo-1,2-dihydro-1 -benzo[ ][1,2]-azaphosphol-
λ
3-one (6). Dibromophenylphosphine (4.2 mmol) was added dropwise to a solution of amide 1 (4.2 mmol) [3]
and triethylamine (12.6 mmol) in pyridine (15 ml) at 0°C, and then the mixture was allowed to stand for 4.5 h at
room temperature. Then elemental sulfur (5 mmol) was added. After 12 h, the precipitate was filtered off,
washed with water, and recrystallized from acetonitrile. Yield 54%; mp 235-236°C (acetonitrile). 31P NMR
1
spectrum (dioxane): 56.6 ppm. H NMR spectrum (CF3COOD), , ppm, J, Hz: 2.58 (3H, s, CH3); 3.87 (6H, s,
δ
3
3
N(CH3)2); 7.2 (2H, d, JHH = 7.8, o-CH3C6H4); 7.43 (2H, d, JHH = 7.8, m-CH3-C6H4); 7.9 (5H, br. s+m,
6,7,3',4',5'-H); 8.43 (2H, m, 2',6'-H); 8.87 (1H, s, 4-H). Found, %: N 7.06, 7.11; P 7.75, 7.82. C22H21N2OPS.
Calculated, %: N 7.14; P 7.89.
The 1H and 31P NMR spectra were obtained on a Varian VXR-300.
REFERENCES
1.
2.
3.
J. A. Miles and R. W. Street, J. Org. Chem., 43, 4668 (1978).
O. Nir, M. Fridkin, and Y. Segall, Phosphorus, Sulfur, Silicon Relat. Elem., 109, 241 (1996).
V. Kmonicek, E. Svatek, J. Holubek, M. Ryska, M. Valchar, and M. Protiva, Collect. Czech. Chem.
Commun., 55, 1817 (1990).
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