RODINA et al.
1884
2,2,5,5-Tetramethyl-4-{[tris(dimethylamino)-λ5-
was added, and the mixture was heated for 7 h under
reflux. The mixture was cooled, and the precipitate
was filtered off and washed with benzene. Yield of
phosphonium iodide V 17 mg (3.5%), mp 178–184°C
[7]. The solvent was distilled off from the filtrate to
obtain initial phosphazine IVa. Yield 0.41 g (79%),
mp 170–173°C (decomp.), Rf 0.29 (petroleum ether–
diethyl ether, 10:1).
phosphanylidene]hydrazono}tetrahydrofuran-3-one
(IIIc) was synthesized from 2.06 g (0.013 mol) of
hexamethylphosphorous triamide (IIb) and 2.19 g
(0.013 mol) of diazo ketone Ia in anhydrous diethyl
ether. Yield 3.4 g (80%), orange crystals, mp 105–
107°C (from Et2O). 1H NMR spectrum, δ, ppm: 1.32 s
(6H, CH3), 1.42 s (6H, CH3), 2.74 d (18H, CH3N,
3JPH = 10 Hz). Found, %: C 50.83; H 9.02; N 21.10.
C14H30N5O2P. Calculated, %: C 50.73; H 9.14; N 21.13.
Reaction of phosphazines IIIa and IVa with
aldehydes (general procedure). A 15-ml flask was
thoroughly dried and charged with 0.215 g (0.5 mmol)
of phosphazine IIIa or its solution in 1.5–2 ml of
benzene (in the reaction with benzaldehyde), 1.5–2 ml
of freshly distilled acetaldehyde or 0.053 g (0.5 mmol)
of benzaldehyde was added (acetaldehyde was added
until the mixture turned homogeneous), and the mix-
ture was left to stand for 24 h at 18–20°C, the progress
2,2:5,5-Bis(pentamethylene)-4-{[tris(dimethyl-
amino)-λ5-phosphanylidene]hydrazono}tetrahydro-
furan-3-one (IIId) was obtained from 1.3 g (8.0 mmol)
of phosphine IIb and 1.9 g (7.7 mmol) of diazo ketone
Ib. Yield 2.9 g (92%), orange crystals, mp 113–115°C
(from hexane). Found, %: C 58.33; H 9.22; N 16.70.
C20H38N5O2P. Calculated, %: C 58.36; H 9.32; N 17.02.
1
of the reaction being monitored by TLC and H NMR
Thermal isomerization of phosphazine IIIa.
Compound IIIa, (1.0 g, 2.3 mmol), was placed in a test
tube equipped with a reflux condenser and was heated
for 8–10 min at 140°C on an oil bath. The material
melted at 105–110°C, solidified, and melted again on
heating to 169–173°C.
spectroscopy. Unreacted aldehyde and the solvent were
distilled off under reduced pressure, the residue was
treated with benzene–petroleum ether (~10:1; 3×
10 ml) to separate triphenylphosphine oxide, and the
solvent was removed to isolate azine VIa or VIb.
2,2,5,5-Tetramethyl-4-[(triphenyl-λ5-phospha-
nylidene)hydrazono]tetrahydrofuran-3-one (IVa)
(high-melting isomer). Yield 1.0 g (100%), yellow
crystals, mp 174–175°C (decomp.; from anhydrous
methanol), Rf 0.29 (petroleum ether–diethyl ether,
10:1). H NMR spectrum, δ, ppm: 1.46 s (6H, CH3),
1.84 s (6H, CH3). Found, %: C 72.50; H 6.20; N 6.43.
C26H27N2O2P. Calculated, %: C 72.55; H 6.28; N 6.51.
In the reactions of phosphazine IVa with acetalde-
hyde and benzaldehyde under analogous conditions, as
well as in the reaction of IVa with benzaldehyde on
heating in boiling benzene for 24 h, no azine VIa or
IVb was formed, and only the initial reactants were
1
1
detected in the reaction mixture by H NMR spectros-
copy.
4-Ethylidenehydrazono-2,2,5,5-tetramethyltetra-
hydrofuran-3-one (VIa). Yield 55% (according to the
1H NMR data), Rf 0.46 (petroleum ether–diethyl ether,
Reaction of phosphazine IIIa with methyl iodide.
A solution of 0.85 g (6 mmol) of freshly distilled meth-
yl iodide in 3 ml of benzene was added to a solution of
1.27 g (3 mmol) of isomer IIIa in 10 ml of anhydrous
benzene, and the mixture was heated to the boiling
point. After several minutes, the precipitate was fil-
tered off, washed with anhydrous benzene, and dried in
a vacuum desiccator. Yield of methyl(triphenyl)phos-
phonium iodide (V) 1.05 g (87%), mp 184–185°C [7].
The solvent was distilled off from the filtrate under
reduced pressure (1–2 mm) to isolate 0.53 g of com-
pound Ia. According to the TLC data, the latter con-
tained impurities of the corresponding hydrazone and
triphenylphosphine oxide.
1
1:1). H NMR spectrum, δ, ppm: 1.35 s (6H, CH3),
1.55 s (6H, CH3), 2.13 d (3H, CH3, J = 5.6 Hz), 7.92 q
(1H, CH=N, J = 5.6 Hz).
4-Benzylidenehydrazono-2,2,5,5-tetramethyl-
tetrahydrofuran-3-one (VIb). Yield 68% (according
1
to the H NMR data), mp 94–96°C (from benzene),
1
Rf 0.64 (petroleum ether–diethyl ether, 1:1). H NMR
spectrum, δ, ppm: 1.41 s (6H, CH3), 1.67 s (6H, CH3),
7.49 m (3H, m-H, p-H), 7.83 d (2H, o-H, J = 6.5 Hz),
8.54 s (1H, CH=N).
1
The H and 13C NMR spectra were recorded on
a Bruker AM-300 spectrometer at 300 and 75.5 MHz,
respectively, using CDCl3 as solvent and TMS as inter-
nal reference. The progress of reactions was monitored
by TLC on Silufol UV-254 plates. The elemental com-
positions were determined on a Heraeus CHNO Rapid
Reaction of phosphazine IVa with methyl iodide.
High-melting isomer IVa, 0.5 g (1.2 mmol), was
dissolved in 15 ml of benzene on heating, a solution of
0.34 g (2.4 mmol) of methyl iodide in 3 ml of benzene
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 43 No. 12 2007