Pyrimidin-/thiazol-/thiazolin-ylidenamidothiophosphoric dichlorides

Article abstract of DOI:10.1002/hc.10170

Nine new amidodichlorothiophosphorus(V) derivatives incorporating pyrimidine, thiazole, and thiazoline rings were obtained by sulfurization of the corresponding aminodichlorophosphines generated in situ from the reaction of the respective N-alkyl-2-aminoc

Full text of DOI:10.1002/hc.10170

Heteroatom Chemistry
Volume 14, Number 6, 2003
P
yrimidin-/Thiazol-/Thiazolin-
ylidenamidothiophosphoric
Dichlorides
Vijaya Kabra, Neelima Gupta, Sama Jain, and Varsha Saxena
Department of Chemistry, University of Rajasthan, Jaipur 302 004, India
Received 28 February 2003; revised 13 March 2003
compounds are available in literature. Elemental
ABSTRACT: Nine new amidodichlorothiophospho-
sulfur has been used in solution, or in a sealed
rus(V) derivatives incorporating pyrimidine, thiazole,
◦
tube at temperature above 100 C, for the sulfuriza-
and thiazoline rings were obtained by sulfurization
tion of dichlorophosphites to give dichlorothiophos-
of the corresponding aminodichlorophosphines gener-
phates [14–16]. The sulfurization of N-dichlorophos-
ated in situ from the reaction of the respective N-alkyl-
phinotriphenylphosphazene has been achieved by
2
-aminocycloiminium halide with PCl in the presence
3
treatment with elemental sulfur [17]. The sulfuriza-
tion of alkylphosphonous dichloride with elemental
sulfur has been carried out in an exothermic reaction
in the presence of anhydrous aluminium chloride
as catalyst [18]. The oxidation of bisdichlorophos-
phinylphenylamine has also been carried out by the
addition of sulfur in the presence of aluminium chlo-
of triethylamine. These pyrimidin-/thiazol-/thiazolin-
ylidenamidothiophosphoric dichlorides were isolated
as stable crystalline solids and are well characterized
by elemental analysis, NMR, and mass spectroscopy.
ꢀ
5
C
2003 Wiley Periodicals, Inc. Heteroatom Chem 14:498–
02, 2003; Published online in Wiley InterScience
(
www.interscience.wiley.com). DOI 10.1002/hc.10170
◦
ride at 150 C [19]. However, during the sulfurization
of cycloalkanephosphonic acid dichloride, quanti-
tative yields could be obtained by using Sn(IV) or
Ti(IV) chloride as a catalyst in place of aluminium
chloride [20,21]. In some cases, for the oxidation of
dichlorophosphites, thiophosphoryl chloride at 125–
INTRODUCTION
Dichlorothiophosphorus(V) derivatives have found a
significant place in literature [1] as versatile synthons
for obtaining a wide variety of important organo-
phosphorus compounds ranging from deoxynucleo-
side/nucleotide esters [2–4], phosphorus contain-
ing crown ethers [5,6], functionalized phosphorus
◦
◦
1
55 C [22] or sulfur monochloride at 15–20 C have
been used as sulfurizing agent [23]. In an isomer-
ization reaction, dichlorothiophosphites have been
converted into thiophosphonic acid dichlorides by
◦
5
heating at ∼300 C [24–27].
macrocycles [7], dithioxo-ꢀ -phosphorane [8], thio-
Recently we have developed a facile method
for the preparation of N-alkylcycloiminylidenami-
nodichlorophosphines from the reaction of N-alkyl-
phosphoramide esters having flame retardant prop-
erties [9] to the compounds having insecticidal and
nematocidal properties [10–13]. A number of meth-
ods for the sulfurization of dichlorophosphorus(III)
compounds to form dichlorothiophosphorus(V)
2
-aminocycloiminium halides with phosphorus
trichloride in the presence of triethylamine [28–
0]. We now report the sulfurization of these pre-
3
cursors with elemental sulfur at room tempera-
ture, leading to cycloiminylidenamidothiophospho-
ric dichlorides. These compounds can be used
as synthons for preparing amidothiophosphate
Correspondence to: Vijaya Kabra; e-mail: sgkabra@jpl.dot.net.in.
Contract grant sponsor: CSIR, New Delhi.
Contract grant number: 01(1610)/99/EMR-II.
c 2003 Wiley Periodicals, Inc.
ꢀ
4
98

Pyrimidin-/Thiazol-/Thiazolin-ylidenamidothiophosphoric Dichlorides 499
derivatives, which are expected to be potential
pesticides.
because of the presence of one additional iminium
3
1
ring nitrogen in the conjugative position. P NMR
signal of the cycloiminylidenamidothiophosphoric
dichlorides 3a–i appears at δ 50.6–68.9, the range
for a four-coordinate, pentavalent phosphorus [32].
RESULTS AND DISCUSSION
N-Alkyl-2-aminopyrimidin(thiazol/thiazolin)ium
halides 1 react with 1 equivalent of phosphorus
trichloride and 2 equivalents of triethylamine
1
H NMR
◦
at 0–5 C in methylene chloride to generate
The structures of the cycloiminylidenaminodichlo-
rophosphines 2a–d and of the cycloiminylidenami-
dothiophosphoric dichlorides 3a–i are confirmed by
the corresponding aminodichlorophosphines
2
3
1
(
δ P = 146–192) [29,30]. The intermediate pyrim-
1
idinylidenaminodichlorophosphines 2a–d have
been isolated for the first time. The reaction was
completed in 4–6 h as revealed by disappearance
H NMR studies (Table 1). As compared to that in
1a–d, the N-methylene or methyl protons in 2a–d
become shielded by ꢀδ 0.13–0.41 ppm as a result
of dichlorophosphinylation. However, sulfurization
of phosphorus of 2 does not cause any remarkable
shielding effect on N CH /CH protons in 3.
3
1
of the P NMR signal for phosphorus trichloride
in the reaction mixture. Thereafter, the oxidation
of 2 with elemental sulfur at ambient temperature
afforded the corresponding cycloiminylidenami-
dothiophosphoric dichlorides 3 in good yields
2
3
Mass Spectrum
(Scheme 1).
In case of 1a–d, the intermediate pyrimidinyli-
The mass spectrum of one representative 3c has been
recorded where, in accordance with the nitrogen
rule, the molecular ion peak is observed at m/z 317
denaminodichlorophosphines 2a–d were isolated
by carrying out the reaction in toluene. Cycloiminy-
lidenamidothiophosphoric dichlorides 3a–h were
obtained as creamish white to pale yellow, crys-
talline, sharp melting solids, stable under nitrogen
atmosphere, except 3i which was obtained as syrupy
mass.
All the products have been well characterized by
elemental analysis, NMR spectroscopy (Table 1), and
mass spectrum in one case (3c).
(
22%). However, the (M + 1) peak (m/z 318) forms
the base peak in the spectrum because of the possi-
ble acceptance of one proton by iminium nitrogen
to give more stable species B (Scheme 2). This peak
is accompanied by (M + 1) + 2 (m/z 320, 70%) and
(
M + 1) + 4 (m/z 322, 14%) peaks, consistent with
the presence of two chlorine atoms. Initial fragmen-
tation takes place by the loss of one chlorine atom
from the molecular ion, when the fragment ion (m/z
282, 40%) having one chlorine atom is accompa-
nied by the +2 peak (m/z 284, 16%). During further
fragmentation, loss of sulfur atom (m/z 250, 20%) is
favored over the loss of second chlorine atom.
31P NMR
3
1
The P NMR chemical shift of 2a–d at δ 179–
92 is in the range characteristic for halophosphine
1
derivatives [31]; however, in comparison to other re-
ported analogous aminodichloropshosphine deriva-
tives [28–30] the phosphorus is much deshielded
SCHEME 1
SCHEME 2 Mass spectral fragmentation of 3c.

5
00 Kabra et al.
TABLE 1 Physical and NMR Data of Compounds 2 and 3
Found %a
Mol. Formula
(mol. wt.)
δ
31P
(CDCl3)
◦
δ
1H; J (Hz)b
mp ( C) Yield (%)
C
H
N
2
a
b
Syrupy
C5H Cl N P
–
–
–
179.0
3.23 (s, 3H, NCH ), 7.10–7.40
6
2
3
3
(210.01)
(m, 3H, H-4, H-5 & H-6)
3
2
140–142
65
C H Cl N P
32.02
3.35
18.45
179.0
1.52 (t, 3H,
J
= 7.1, NCH CH );
6
8
2
3
HH
3
2
3
(224.03)
(32.16) (3.59) (18.75)
4.21 (q, 2H,
J
= 7.1,
HH
NCH CH ); 6.81 (dd, 1H,
2
3
3
JHH = 7.1, 4.3, H-5); 7.95 (ddd,
3
4
1
H,
J
= 7.1,
J
= 3.5,
HH
HH
5
JPH = 2.1, H-6); 8.86
(
unresolved dd, 1H, H-4)
2
c
d
128–129
130–131
70
68
C11H10Cl N P
46.10
3.41
14.52
191.8
191.7
5.38 (s, 2H, NCH ), 6.80 (dd, 1H,
2
3
2
3
(286.09)
(46.17) (3.52) (14.68)
JHH = 5.7, 4.3, H-5); 7.47
(
s, 5H, C H5); 7.97 (unresolved
6
m, 1H, H-6); 8.82 (dd, 1H,
3
4
JHH = 4.3, JHH = 2.1, H-4)
2
C12H12Cl N P
47.96
4.01
13.92
2.34 (s, 3H, C H CH -p); 5.26
6 4 3
2
3
(300.13)
(48.02) (4.03) (14.00)
(s, 2H, NCH ), 6.65 (dd, 1H,
2
3
JHH = 7.1, 4.3, H-5); 7.22
(
s, 4H, C H CH -p); 7.79 (ddd,
6 4 3
3
4
1
H, JHH = 7.1, JHH = 3.5,
JPH = 2.1, H-6); 8.71
5
(
unresolved m, 1H, H-4)
3
a
b
108–110
115–117
60
72
C5H Cl N PS
24.71
2.41
17.24
68.9
50.6
3.74 (s, 3H, NCH ); 6.75 (dd, 1H,
6
2
3
3
3
(242.06)
(24.80) (2.49) (17.35)
JHH = 6.3, 4.4, H-5); 7.98
(
(
unresolved t, 1H, H-6); 8.75
unresolved d, 1H, H-4).
3
3
C H Cl N PS
28.03
3.09
16.31
1.39 (t, 3H,
J
= 8.5, NCH CH );
6
8
2
3
HH
3
2
3
(256.24)
(28.12) (3.15) (16.39)
4.15 (q, 2H,
J
= 8.5,
HH
NCH CH ); 6.75 (dd, 1H,
2
3
3
JHH = 5.7, 4.3, H-5); 7.93 (ddd,
3
4
1
H,
J
= 5.7,
J
= 2.8,
HH
HH
5
JPH = 2.1, H-6); 8.81 (dd, 1H,
3
4
JHH = 5.7,
J
= 2.8, H-4)
HH
3
3
c
d
110–112
115–116
75
70
C11H10Cl N PS
41.39
3.11
13.14
68.8
53.2
5.36 (s, 2H, NCH ); 6.82 (dd, 1H,
2
3
2
3
(318.16)
(41.52) (3.17) (13.20)
JHH = 5.7, 4.3, H-5); 7.49 (s,
5
H, C H5); 7.96 (ddd, 1H,
6
3
4
JHH = 5.7, JHH = 2.8,
5
3
JPH = 2.1, H-6); 8.87 (dd, 1H,
4
JHH = 5.7,
J
= 2.8, H-4)
HH
C12H12Cl N PS
43.20
3.55
12.60
2.37 (s, 3H, C H CH -p); 5.25
2
3
6 4 3
(332.19)
(43.38) (3.64) (12.65)
(s, 2H, NCH ); 6.71 (dd, 1H,
2
3
JHH = 6.3, 4.3, H-5); 7.24
3
(
(
(
(
d, 2H,
J
= 7.7, m-H); 7.32
HH
3
d, 2H, JHH = 7.7, o-H); 7.83
unresolved m, 1H, H-6); 8.70
unresolved d, 1H, H-4)
3
3
e
f
85–86
56–58
70
73
C5H7Cl N PS
22.86
2.65
10.68
57.9
52.5
1.34 (t, 3H,
J
= 7.2, NCH CH );
2
2
2
HH
3
2
3
(261.1)
(22.99) (2.70) (10.73)
3.98 (q, 2H,
J
= 7.2, NCH );
HH
2
3
6
.60 (dd, 1H, JHH = 4.7,
5
JPH = 1.7, H-5); 6.91 (dd, 1H,
3
5
JHH = 4.7,
J
= 1.7,
PH
H-4)
3
C10H Cl N PS
37.02
(37.11) (2.80)
2.76
8.52
(8.66)
5.07 (s, 2H, NCH ); 6.51 (d, 1H,
9
2
2
2
2
3
(323.6)
JHH = 4.0, H-5); 6.84 (d, 1H,
3
JHH = 4.0, H-4); 7.19–7.32
(
m, 5H, C H5)
6
(
Continued )

Pyrimidin-/Thiazol-/Thiazolin-ylidenamidothiophosphoric Dichlorides 501
TABLE 1 Continued
Found %a
Mol. Formula
(mol. wt.)
δ
31P
(CDCl3)
◦
δ
1H; J (Hz)b
mp ( C) Yield (%)
C
H
N
3
g
h
81–83
95–97
65
67
C H7Cl N PS
19.15
2.77
11.19
55.5
3.05 (s, 3H, NCH ); 3.34 (bd,
1H, H-5); 3.7 (bd, 1H, H-4)
4
2
2
2
3
(249.1)
(19.28) (2.83) (11.25)
36.90
(36.93) (3.41)
3
3
C10H11Cl N PS
3.35
8.55
(8.61)
53.4
54.7
3.29 (t, 2H,
J
= 7.1, H-5);
2
2
2
HH
3
(325.2)
3.60 (t, 2H,
.71 (s, 2H, NCH ); 7.31 (s,
H, C H5)
J
= 7.1, H-4);
HH
4
5
2
6
3i
Syrupy
C11H13Cl N PS
–
–
–
2.32 (s, 3H, C H CH -p); 3.20
2
2
2
6 4 3
3
(339.1)
(t, 2H, JHH = 7.5, H-5); 3.29
3
(
(
t, 2H, JHH = 7.5, H-4); 4.66
s, 2H, NCH ); 7.09–7.21 (m,
2
4
H, CH C H CH -p)
2 6 4 3
a
Values in parentheses represent calculated values.
b
2
a–d, 3b, 3h on Jeol FX 90Q; 3a,c–g on Brucker DPX 300; and 3i on Brucker WM400 spectrometer.
EXPERIMENTAL
N-Alkyl-2-pyrimidin-/thiazol-/thiazolin-
ylidenamidothiophosphoric Dichlorides (3a–i)
Solvents and commercial reagents were distilled and
dried by common methods before use. All experi-
ments were carried out in dry nitrogen atmosphere
using Schlenk technique. Melting points were de-
termined by capillary method and are uncorrected.
NMR spectra were recorded on a JEOL FX 90 Q
N-Alkyl-2-aminocycloiminium halide 1 (20 mmol)
was suspended in methylene chloride (40 ml) and
phosphorus trichloride (1.75 ml, 20 mmol) was
◦
added slowly with stirring at 0–5 C, followed by
a solution of triethylamine (5.6 ml, 40 mmol) in
methylene chloride (10 ml). After 5–6 h of stirring,
the reaction mixture was brought to room tem-
perature and sulfur powder (640 mg, 20 mmol)
was added to it. The resulting mixture was left for
overnight stirring, the solvent was removed in vacuo,
and residue extracted with diethyl ether (2 × 50 ml).
The combined ether extracts were concentrated and
left in refrigerator, whereupon cream to pale yellow
solid (3) separated, which was filtered and dried.
However, 3i was obtained as syrupy mass and could
not be crystallized.
3
1
1
(
P NMR at 36.23 MHz, H NMR at 89.55 MHz),
3
1
1
Brucker DPX 300 ( P NMR at 121.5 MHz, H NMR
at 300.13 MHz), or Brucker WM 400 ( P NMR at
1
3
1
1
61.7 MHz, H NMR at 399.65 MHz) spectrometer.
The chemical shifts refer to 85% H PO (external)
3
4
3
1
1
for P NMR and TMS (internal) for H NMR. The
FAB mass spectrum was recorded on Jeol SX 102
mass spectrometer. N-Alkyl-2-aminocycloiminium
salts 1 were prepared by reported [29] or analogous
method.
3
c: Mass spectrum (FAB): m/z 322 [(M + 1) + 4,
N-Alkyl-2-pyrimidinylidenamino-
dichlorophosphines (2a–d)
1
2
1
4%], m/z 321 (M + 4, 15%), m/z 320 [(M + 1) +
, 70%], m/z 319 (M + 2, 30%), m/z 318 (M + 1,
+
00%), m/z 317 (M , C11
H10Cl
2
3
N PS, 22%), m/z 284
To
aminopyrimidinium halide (20 mmol) in toluene
30 ml) was added phosphorus trichloride (1.75 ml,
0 mmol) with stirring. A solution of triethylamine
5.6 ml, 40 mmol) in toluene (10 ml) was added
slowly with continuous stirring. After stirring for
0–22 h at room temperature, the reaction mixture
a
well stirred suspension of N-alkyl-2-
(C
11
H
10
N
3
ClPS, 16%), m/z 282 (C11
m/z 252 (C11 P, 8%), m/z 250 (C11
0%), m/z 107 (C , 20%).
H10ClN
3
PS, 40%),
P,
H
10ClN
3
H
10ClN
3
(
2
(
2
5
H
5
N
3
ACKNOWLEDGMENTS
2
We are thankful to Prof. R. K. Bansal for useful
suggestions. Thanks are also due to RSIC, Lucknow,
for providing C, H, N analysis data, NMR, and mass
spectra.
was filtered, residue washed with toluene, and
solvent was removed from the filtrate in vacuo. The
residue thus obtained was extracted with diethyl
ether (2 × 50 ml). Combined ether extracts were
concentrated to 15–20 ml and left in refrigerator,
whereupon creamish white to yellow solid (2)
deposited, which was filtered and dried. 2a was
obtained as syrupy mass.
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