Reactions of α-haloaldehydes with triethyl phosphorotrithioite

Article abstract of DOI:10.1007/s11176-005-0202-5

Triethyl phosphorotrithioite reacts with linear and cyclic α-mono- and α,α-dihaloaldehydes by the Perkow reaction scheme to form O-vinyl phosphorotrithioates. It was established that catalytic amounts of zinc chloride much accelerate the reaction. 2005 Pl

Full text of DOI:10.1007/s11176-005-0202-5

Russian Journal of General Chemistry, Vol. 75, No. 2, 2005, pp. 225 229. Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 2, 2005,
pp. 253 257.
Original Russian Text Copyright
2005 by Guseinov, Valiullina, Batyeva, Burangulova, Asadov, Sinyashin.
Reactions of -Haloaldehydes with Triethyl Phosphorotrithioite
F. I. Guseinov, R. Zh. Valiullina, E. S. Batyeva,
R. N. Burangulova, Kh. A. Asadov, and O. G. Sinyashin
Kazan State Technological University, Kazan, Tatarstan, Russia
Received June 17, 2003
Abstract Triethyl phosphorotrithioite reacts with linear and cyclic -mono- and , -dihaloaldehydes by
the Perkow reaction scheme to form O-vinyl phosphorotrithioates. It was established that catalytic amounts
of zinc chloride much accelerate the reaction.
Reactions of thioesters of P(III) acids with carbonyl
compounds are sufficiently thoroughly studied [1 3].
However, reactions of normal thioesters of phos-
phorous acids with -halocarbonyl compounds have
scarcely been explored. As shown in [4, 5], reactions
of mixed O,S-esters of phosphorous acids with chloral
involve the P O bond and leave out the P S bond;
therewith, the products of the reactions of trialkyl
phosphorotrithioites with chloral have not been
identified.
gested that bisphosphorylated product IIIa has a Z
structure and compound IIIb, an E structure. That
means that the vinyl proton is cis to the phosphinoyl
group.
The 31P NMR spectra of compounds IIIa and IIIb
contain by two signals at
6 (IIIa) or 16 (IIIb) and
P
112 ppm, which provides evidence for the presence
of phosphinoyl and phosphinothioyl fragments in the
molecule.
To confirm the structure of the obtained com-
pounds, independent synthesis of bisphosphorylated
product IIIb was performed by the reaction of enolate
IV with phosphorus sulfochloride and ethanethiol.
With the purpose of establishing the pathway of
the reaction and the nature of the products we have
studied the reaction of triethyl phosphorotrithioite (I)
with various -haloaldehydes.
Ph
It was found that the major products of the reaction
of compound I with functionalyzed -haloaldehydes
are O-vinyl esters of phosphorotrithioic acid. Phos-
phoryl-substituted mono- and dihaloaldehydes IIa IIc
react with phosphorotrithioite I at 100 110 C.
CH~~~ONa + PCl3
(EtO)2P
S
IV
Ph
O
C H ~~~ O PCl2
S
(EtO)2P
O
OPB(SEt)2
S
X
X
Hlg
V
P(SEt)3 +
(RO)2PA
O
H
(RO)2P CHO
I
Ph
2HSEt
2Et3N
O
C H ~~~ O P(SEt)2
(EtO)2P
O
IIa IIc
IIIa, IIIb
S
IIIb
R = i-Pr, X = Hlg = Cl (a); R = Et, X = Ph, Hlg = Cl (b),
Br (a).
Intermediate phosphorothioic dichloride V was not
1
isolated pure and characterized in situ by the H and
31P NMR spectra of the reaction mixture. Hence, the
1
In the H NMR spectra of compounds IIIa, IIIc,
31P NMR spectrum contains two signals at
16
P
the vinyl proton signal is observed at 7.6 7.8 ppm
and 55 ppm, assigned to the phosphinoyl and dichlo-
rophosphinothioyl fragments of compound V, respec-
tively [8].
3
as a doublet (3JP H 12 Hz, JP H 12.5 Hz). Based on
A
B
3
the results in [6, 7], where the doublet with JPH
12 18 Hz was assigned to the methylene proton cis
3
to the phosphinoyl group and the doublet with JPH
The vinyl proton of compound V appears in the
41 Hz, to the corresponding trans-proton, we sug-
1H NMR spectrum of the reaction mixture as a
1070-3632/05/7502-0225 2005 Pleiades Publishing, Inc.

226
GUSEINOV et al.
7.7 ppm (3JPH 12.5 Hz). Linear (VIa,
doublet at
the nature of the halogen. The reaction with chlorine-
substituted carbonyl compound IIb is complete within
8 h. On replacement of chlorine by the more readily
leaving bromine (aldehyde IIc) the reaction time is
halved.
P
VIb) and cyclic (VII) carbonyl-containing mono- and
dichloroaldehydes also react with triethyl phosphoro-
trithioite along the Perkow scheme.
O
O
R
Cl
R
Cl
Note that in all the reactions of -haloaldehydes
with triethyl phosphorotrithioite we isolated, along
with O-vinyl phosphorotrithioates, such by-products
as trietyl phosphorotrithioate and triethyl phosphoro-
tetrathioate whose formation is characteristic of reac-
tions of trialkyl phosphorotrithioites with carbonyl
compounds [2].
+ P(SEt)3
C H ~~~ O P ( S E t ) 2
Cl
CHO
S
VIa, VIb
VIIIa, VIIIb
R = Ph (a), EtO (b).
Cl
C H ~~~ O P ( S E t ) 2
S
+ P(SEt)3
O
O
CHO
It is known [1,2] that reactions of S-esters of P(III)
acids with carbonyl compounds are actively catalyzed
with acids (specifically, HCl). In this connection we
have studied the reaction of triethyl phosphorotri-
thioite with haloaldehyde VIa in the presence of
equimolar amount of hydrogen chloride, which pro-
ceeds just at room temperature and leads to formation
of vinyl phosphate VIIIa. In this case, the yield of
the product increases by 13%.
O
O
VII
IX
1
The H NMR spectra of compounds VIIIa and
VIIIb show a =CH O proton signal at 8 ppm as a
3
doublet with JPH 12.5 Hz. The methine proton of
thiophosphate IX appears as two triplets at
3
7.55 ppm (4JHH 2.5 Hz and JPH 12.5 Hz).
The phosphorus signals of the thiophosphoryl
The progress of the reaction of triethyl phosphoro-
trithioite with aldehyde VII in the presence of equi-
molar amount of hydrogen chloride was controlled by
groups are observed at
112 [VIIIb and IX] and
P
93 ppm [VIIIa].
1
means of 31P and H NMR spectroscopy. In the 31P
The IR spectra of O-vinyl phosphorotrithioates III,
VIII, and IX agree with the proposed structure. The
NMR spectrum, signals at P 188 and 211 ppm appear.
They are characteristic of diethyl phosphorodithiote
and ethyl phosphorodichloridothioite, respectively. In
1
absorption band at 650 690 cm relates to stretching
vibrations of the P=S group, the narrow band at 1620
1
the 1H NMR spectrum, the signal at
9.5 ppm,
1660 cm , to the C=C bond, and the band at 1695
1
1710 cm , to the C=O group. The P=O group of bis-
characteristic of the aldehyde proton, disappears and
signals at 5.2 and 12.5 ppm appear, assigned to the
>CH and OH protons of thioacetal X. As the tempera-
phosphoryl compounds IIIa and IIIb absorbs at
1
1260 cm .
188 and
The structure of the synthesized O-vinyl phospho-
P
rotrithioates suggests formation of geometric isomers.
1
But the H and 31P NMR spectra show that the reac-
tion proceeds stereoselectively to form a single isomer.
However, the structure of the isolated isomer is im-
possible to assign unambiguously with the spectral
evidence in hand.
1
Analysis of the 31P and H NMR spectra of the
reaction mixtures shows that the rate of formation of
O-vinyl phosphorotrithioates depends on the nature
of the -substituents in the carbonyl compounds.
Hence, the most electophilic dichloroacetic aldehydes
IIa and VIa, VIb react with thiophosphite I for 1 h.
The decreased electrophilicity of the carbonyl carbon
atom in monohaloacetaldehydes IIb, IIc and VII
results in that these compounds fail to react without
catalyst under prolonged heating (14 16 h), while in
the presence of zinc chloride the reaction is complete
within 4 8 h. The rate of the reaction of triethyl phos-
phorotrithioite with haloaldehydes also depends on
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REACTIONS OF -HALOALDEHYDES WITH TRIETHYL PHOSPHOROTRITHIOITE
227
VII to form thioacetal X. As the temperature rises,
thioacetal X reacts with diethyl phosphorochlorido-
dithioite to give an unstable phosphite which decom-
poses into unsaturated thioester XI and phosphoro-
chloridodithioate XII according to the known scheme
[9].
OP(SEt)2
Cl
SEt
OP(SEt)2
X + ClP(SEt)2
O
O
O
+
S
CH SEt + (EtS)2P(O)Cl
O
O
O
R
Cl
XI
XII
We failed to isolate compounds XI and XII pure
because of their close boiling points.
trum shows signals at
93 and 63.3 ppm, character-
P
istic of triethyl phosphorotetrathioate and triethyl
phosphorotrithioate, and a weak signal at P 112 ppm,
assignable to O-vinyl phosphorotrithioate XIII.
As the reaction of phosphorothioites with chloral
in the presence of catalysts has not so far been studied,
we turned to the reaction of triethyl phosphorotri-
thioite with chloral in the presence of catalytic
amounts of zinc chloride. After heating of the reaction
1
In the H NMR spectrum of the reaction mixture
we observed, along with the signals at 1.3 (CH3)
and 2.9 ppm ( SCH2 ), a singlet at 5.5 ppm, related
to the proton of chloral dithioacetal XIV, and a weak
doublet at 7.05 ppm (3JPH 12.5 Hz), characteristic of
the proton at the double bond of O-vinyl phosphoro-
trithioate XIII.
mixture at 100 C for 1 h, signals at
188 and
P
210 ppm appear in the 31P NMR spectrum, belonging
to diethyl phosphorochloridodithioite and ethyl phos-
phorodichloridothioite. Evidently, because of the
steric overloading of the carbonyl carbon atom, the
halogenophilic attack of phosphorus on the chlorine
atom, leading to formation of phosphorochlorido-
Fractionation of the reaction mixture of phosphoro-
trithioite I with chloral gave thioacetal XIV in 35%
yield and triethyl phosphorotrithioate in 41% yield.
thioites, takes place. In addition, the 31P NMR spec-
SEt
CCl3 CHO + P(SEt)3
[Cl2C=CH~~~OP(SEt)2] + CCl3CH
S
+ P(SEt)3
O
SEt
XIII
XIV
1
Hence, we established that triethyl phosphorotri-
thioite reacts with -halocarbonyl compounds by the
Perkow scheme to form O-vinyl phosphorotrithioates.
Addition of a catalytic amount of zinc chloride to the
The H NMR spectra were measured on a Tesla BM-
567 (100 MHz) against internal HMDS. The 31P
NMR spectra were obtained on a Bruker MSL-400
spectrometer (162 MHz) against external 85% phos-
phoric acid.
reaction mixture of phosphorotrithioite
I
with
-monohaloaldehydes significantly accelerates the re-
action but does not alter its direction.
Functionalyzed haloaldehydes II, VI, and VII were
prepared according to the procedures in [10].
The spectral characteristics and elemental analyses
of the resulting products are listed in the table.
S,S-Diethyl O-[2-(diisopropoxyphosphinoyl)-2-
phenylvinyl]phosphorotrithioate (IIIa). A mixture
of 4.28 g of phosphorotrithioite I and 5.5 g of al-
dehyde IIa was heated at 100 C for 1 h. Product IIIa
was purified from admixtures (triethyl phosphorotri-
thioate, triethyl phosphorotetrathioate) by film distilla-
tion [spiral temperature 120 C (0.05 mm Hg)]. Film
distillation of the residue [spiral temperature 150 C
EXPERIMENTAL
The IR spectra were recorded on a UR-20 spectro-
1
meter in the range 400 3800 cm for liquid films
or suspensions in Vaseline oil between KBr plates.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 75 No. 2 2005

228
GUSEINOV et al.
IR and 1H and 31P NMR spectra elemental analyses of compounds III, VIII, and IX
1H NMR spectrum [(CD3)2CO], , ppm 31P NMR spectrum,
1
Comp. no.
IR spectrum, , cm
(J, Hz)
P, ppm
IIIa
564 (PS), 652 (P=S), 695 (CCl), 995 1.25 m (18H, 6CH3), 2.9 m (4H,
(POC), 1261 (P=O), 1625 (C=C)
2SCH33), 4.6 m (2H, 2OCH), 7.6 d.d (1H,
6, 112
3
A
B
=CH, JP H 12, JP H 12.5)
555 (PS), 689 (P=S), 1024 (POC), 1.3 m (12H, 4CH3), 3.0 m (4H, 2SCH3),
1261 (P=O), 1640 (C=C) 4.1 q, (4H 2OCH2), 7.4 s (5H, Ph),
IIIb
6, 111.7
93
3
3
A
B
7.7 d.d (1H, =CH, JP H 12, JP H 12.5)
VIIIa 558 (PS), 660 (P=S), 690 (CCl), 1199 1.3 m (6H, 2CH3), 2.9 m (4H, 2SCH3),
(POC), 1654 (C=C), 1694 (C=O), 3033 7.4 s (5H, Ph), 8.0 d (1H, =CH, 3JPH 12.5)
(Ph)
VIIIb 556 (PS), 665 (P=S), 704 (CCl), 1066 1.3 m (9H, 6CH3), 2.9 m (4H, 2SCH3),
(POC), 1634 (C=C), 1725 (C=O) 4.2 m (2H, OCH2), 8.0 d (1H, =CH, 3JPH
12.5)
112
IX
574 (PS), 659 (P=S), 1020 (POC), 1.3 t (6H, 2CH3), 2.9 m (4H, 2SCH3),
1678 (C=C), 1752 (C=O) 3.1 t (2H, CH2), 4.3 t (2H, OCH2),
112
3
4
7.55 d.t (1H, =CH, JPH 12.5, JHH 2.5)
Table (Contd.)
of finely cut metallic sodium, 1.5 l of diethyl ether,
and 10 ml of absolute ethanol (for initiation of the
reaction). The addition rate was such that the tempera-
ture of the reaction mixture was maintained at a tem-
perature of no higher than 5 C. After the addition had
been complete, the reaction mixture was kept for 1 h
at a decreased temperature, then for 3 days at room
temperature, and, finally, for 1.5 h in ether under
reflux. Enolate IV precipitated and was filtered off,
washed with ether (3 100), and dried in a water-jet-
pump vacuum at 40 60 C. Dry enolate IV is a fine
cream-colored powder. Yield 250 g (90%).
Found, %
Calculated, %
Comp.
no.
Formula
P
Cl
P
Cl
IIIa
14.47
14.05
8.41
8.29 C12H25ClO4P2S3 14.53
8.32
IIIb
VIIIa
VIIIb
IX
C16H26O4P2S3
9.55 C13H16ClO2PS3
14.09
8.46
9.69
9.19 10.53 C9H16ClO3PS3
10.35 C9H16O3PS3
9.27 10.61
10.40
(0.05 mm Hg)] gave 3.83 g (45%) of the target pro-
S,S-Diethyl O-[2-(diethoxyphosphinoyl)-2-
phenylvinyl]phosphorotrithioate (IIIb). Enolate IV,
5.56 g, was added to a cold (0 C) solution of 3.39 g
of phosphorus sulfochloride in 10 ml of ether. The
addition rate was such that the temperature of the re-
action mixture was maintained at a temperature of no
higher than 5 C. After the addition had been complete,
the reaction mixture was stirred for 1 h with cooling
duct, n2D0 1.5060.
S,S-Diethyl O-[2-(diethoxyphosphinoyl)-2-
phenylvinyl] phosphorotrithioate (IIIb). a. A mix-
ture of 4.28 g of phosphorotrithioite I and 5.81 g of
aldehyde IIb was heated at 100 110 C for 8 h in the
presence of a catalytic amount of zinc chloride. Distil-
lation of the reaction mixture gave 5.89 g (67%) of
product IIIb, bp 145 148 C (0.05 mm Hg), nD20
1.5432.
1
and for 3 h at room temperature. H NMR spectrum
(acetone-d6), , ppm (J, Hz): 1.3 m (6H, 2CH2), 4.0 q
3
(4H, 2OCH2), 7.3 s (5H, Ph), 7.7 d (1H, =CH, JPH
12.5 Hz). 31P NMR spectrum, P, ppm: 16; 55.7. A
day after, the reaction mixture was cooled to 0 C, a
mixture of 2.48 g of ethanethiol and 4.40 g of triethyl-
amine was added dropwise to it, and stirring was
continued at 0 5 C for 2 h and for 3 h without the
cooling bath. The precipitate that formed was filtered
off, the solvent was removed from the filtrate, and the
residue was distilled to obtain 3 g (34%) of product
IIIb, bp 145 149 C (0.05 ppm Hg), n2D0 1.5429.
b. Analogously 4.28 g of phosphorotrithioite I and
6.7 of aldehyde IIc were heated at 100 C for 4 h to
give 6.33 g (72%) of product IIIb, bp 145 148 C
(0.05 mm Hg), n2D0 1.5434.
Diethyl benzylphosphonate sodium enolate (IV).
A mixture of 148 g of ethyl formate and 228 g of di-
ethyl benzylphosphonate was added dropwise with a
vigorously stirred and cold ( 5 0 C) mixture of 23 g
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REACTIONS OF -HALOALDEHYDES WITH TRIETHYL PHOSPHOROTRITHIOITE
229
4
O-(2-Benzoyl-2-chlorovinyl) S,S-diethyl phos-
phorotrithioate (VIIIa). a. A mixture of 4.28 g of
phosphorotrithioite I and 4.34 g of aldehyde VIa was
heated at 100 C for 1 h. Product VIIIa was purified
from admixtures (triethyl phosphorotrithioate and tri-
ethyl phosphorotetrathioate) by film distillation [spiral
temperature 120 C (0.05 mm Hg)]. The residue was
treated with 5 ml of diethyl ether, and the crystals that
formed were filtered off, washed with ether, and dried
give 3.08 g (42%) of product VIIIa, decomp. point
240 C.
(1H, =CH, JHH 2.5 Hz). Compound XII (acetone-d6),
, ppm: 1.15 m (6H, 2CH3), 2.75 m (4H, 2SCH2). 31
NMR spectrum: 56 ppm.
P
P
Reaction of triethyl phosphorotrithioite with
chloral. A mixture of 4.28 g of phosphorotrithioite I
and 5.88 g of chloral was heated at 100 C in the pre-
sence of a catalytic amount of zinc chloride. 31P NMR
spectrum, P, ppm: 63 [(EtS)3P=O]. 93 [(EtS)3P=S],
112 [(EtS)2P(S)OCH=CCl2], 188 [(EtS)2PCl]. After 2
days, excess chloral was removed in a vacuum. Distil-
lation of the residue gave 2.57 g (35%) of thioacetal
XIV, bp 107 C (0.05 mm Hg), n2D0 1.5400 [1H NMR
spectrum (acetone-d6), , ppm: 1.25 t (6H, 2CH3),
2.8 m (4H, 2SCH2), 5.55 s (1H, CH<)] and 1.89 g
(41%) of triethyl phosphorotrithioate, bp 140 C (0.05
b. Through a solution of 4.28 g of phosphorotri-
thioite I and 4.34 g of aldehyde VIa in 20 ml of
methylene chloride, 0.73 g of hydrogen chloride was
bubbled at 20 C. The reaction mixture was left to
stand for 2 days, washed with water to pH 6, and
dried over CaCl2. The solvent was removed, and the
residue was subjected to film distillation. Product
VIIIa was isolated like in procedure a. Yield 4 g
(55%), crystals, decomp. point 240 C.
mm Hg), n2D0 1.5702,
62 ppm {published data [3]:
bp 174 C (10 mm Hg),PnD20 1.5709, P 61 ppm}.
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was left to stand for 2 days. 31P NMR spectrum,
,
ppm: 210, 188. Subsequent heating at 100 C for 1 Ph
and distillation gave fraction [bp 97 98 C
a
(0.05 Hg)] comprising a mixture of unsaturated thio-
1
ester XI and phosphorochloridodithioate XII. The H
NMR spectrum contains signals of two compounds.
Compound XI (acetone-d6), , ppm: 1.15 t (3H, CH3),
2.75 m (4H, CH2, SCH2), 4.20 t (2H, OCH2), 7.25 t
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 75 No. 2 2005