Dichloro(diisopropylamino)phosphonio[5(4H )oxopyrazol-4-ylide-5-one]: Synthesis and Properties 457
tert-butylamine (0.3 g; 4 mmol) and triethylamine
(0.09 g; 5 mmol) and triethylamine (1 g; 10 mmol)
was added. The solvent was removed in vacuo after
24 h, and toluene was added to the residue. The pre-
cipitate of triethylamine hydrochloride was filtered
off. The product was obtained by crystallization from
10 to 15 ml of a mixture of heptane/benzene (2:1).
(0.6 g; 6 mmol) in 10 ml of benzene was added. Af-
ter 4 days the precipitate formed was filtered off, the
solvent from the reaction mixture was removed in
vacuo, and the residue was dried in vacuo. The oily
residue solidified on standing and was washed with
petroleum ether and dried.
5-Ethoxy-3-methyl-1-phenyl-1H-pyrazol-4-yl-
phosphonic Dichloride (13)
4-[(Diisopropylamin(2,2-dimethylhydrazino)-
dimethylphosphorohydrazonoyl]-3-methyl-1-
phenyl-1H-pyrazol-5-ol (8)
To a solution of the dichlorophosphine A (3.03 g;
10 mmol) in 20 ml of benzene a solution of chlo-
rine (0.85 g; 12 mmol) in 25 ml of carbon tetrachlo-
ride was added dropwise with stirring within 1 h at
−30◦C. At that temperature the reaction mixture was
stirred for 1 h, and then it was allowed to warm to
ambient temperature. The 31P NMR spectrum of the
reaction mixture revealed a signal at −68.4 ppm cor-
responding to the tetrachlorophosphorane 12. SO2
was bubbled through the reaction mixture for 0.5 h.
The solvent was removed under reduced pressure.
The residue was dissolved in petroleum ether and
filtered. The solvent was evaporated, and the residue
was dried in vacuo.
To a solution of the P,P-dichloroylide 3 (1.87 g;
5 mmol) in 20 ml of benzene a mixture of N,N-
dimethylhydrazine (0.6 g; 10 mmol) and triethyl-
amine (1 g; 10 mmol) in 10 ml of benzene was added.
After 1 h the precipitate was filtered off, the sol-
vent was removed from the filtrate in vacuo, and the
residue was dissolved in 15 ml of benzene. The prod-
uct was isolated from the solution by precipitation
with portions of 7 ml of petroleum ether and was
crystallized from 15 ml of octane.
5-Hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl-
N,N-diisopropylphosphonamidic Chloride
Hydrochloride (9)
4-[(5-Ethoxy-3-methyl-1-phenyl-1H-pyrazol-4-
yl)(4-morpholinyl)phosphoryl]morpholine (14)
To a solution of the P,P-dichloroylide 3 (1.87 g;
5 mmol) in 10 ml of acetonitrile a solution of water
(0.09 g; 5 mmol) in 5 ml of acetone was added. The
mixture was heated, and a colorless precipitate was
immediately formed. After 0.5 h the precipitate was
filtered off. The product was purified by recrystal-
lization from a mixture of dichloromethane/benzene
(3:10).
Morpholine (1.75 g; 20 mmol) in 15 ml of benzene
was added to a solution of 13 (1.6 g; 5 mmol) in 15 ml
of benzene. After 2 h the morpholine hydrochloride
formed was filtered off. The solvent was evaporated
under reduced pressure and a solid residue was left.
The product was purified by reprecipitation with
heptane from benzene.
1-(Diisopropylamino)-3,8-dimethyl-5-phenyl-
1,5-dihydro-1λ5-pyrazolo[4,3-e][1,3,4]-
oxazaphosphorin-1-one (11a)
X-Ray Structure Determination of 11b
Crystal data: Monoclinic, space group P21/c, a =
To a solution of the P,P-dichloroylide 3 (1.87 g;
5 mmol) in 30 ml of acetonitrile a mixture of water
(0.09 g; 5 mmol) and triethylamine (1 g; 10 mmol)
was added. The precipitate formed was filtered off
and was dissolved in benzene. A newly formed pre-
cipitate was filtered off, and the solvent was removed
from the filtrate in vacuo. The product was obtained
from the residue by recrystallization from 15 ml of
heptane.
˚
7.950(2), b = 15.651(3), c = 18.370(4) A, β =
3
◦
−3
˚
99.79(3) , U = 2252.9 A , Z = 4, Dx = 1.246 Mg m ,
F(000) = 896, µ = 0.15 mm−1, T = −100◦C.
Data collection: A crystal ca. 0.8 × 0.4 × 0.35 mm was
used to register 4288 intensities (Mo Kꢀ radiation,
2ꢁmax 50◦) on a Stoe STADI-4 diffractometer.
Structure refinement: The structure was refined
anisotropically against F2 (program SHELXL-97, G.
M. Sheldrick, University of Go¨ttingen) to wR2 0.059,
R1 0.151 for 276 parameters and 3979 independent
1-(Diisopropylamino)-8-methyl-5,8-diphenyl-
1,5-dihydro-1λ5-pyrazolo[4,3-e][1,3,4]-
oxazaphosphorin-1-one (11b)
−3
˚
reflections; max. ꢀρ = 0.49 eA , S = 1.07. Hydrogen
atoms were included using a riding model or rigid
methyl groups.
To a solution of the P,P-dichloroylide 3 (1.87 g;
5 mmol) in 20 ml of benzonitrile a mixture of water