The Kabachnik-Fields reaction accelerated in external magnetic field

Article abstract of DOI:10.1002/hc.21149

The significant acceleration in the Kabachnik-Fields reaction in an external magnetic field has been observed. The phenomenon is explained by the proper orientation of substrate molecules forced by external magnetic field. Diamagnetic dipoles are repulsed to the center by both electromagnet poles, being simultaneously arranged. This phenomenon may then promote the acceleration of the reaction.

Full text of DOI:10.1002/hc.21149

Heteroatom Chemistry
Volume 00, Number 0, 2014
The Kabachnik–Fields Reaction Accelerated in
External Magnetic Field
Rafał Karpowicz,1 Jarosław Lewkowski,1 Ewa Mie˛kos´,2
and Marek Zielin´ski2
1Department of Organic Chemistry, Faculty of Chemistry, University of Ło´dz´, Tamka 12, 91-403
Ło´dz´, Poland
2Department of Inorganic and Analytical Chemistry, Faculty of Chemistry, University of Ło´dz´,
Tamka 12, 91-403 Ło´dz´, Poland
Received 15 July 2013; revised 21 February 2014
line N-oxide in an external magnetic field [2–5]
ABSTRACT: The significant acceleration in the
seems to be very interesting. It was demonstrated
Kabachnik–Fields reaction in an external magnetic
that the reaction leading to 2H-isoquinolin-1-one un-
field has been observed. The phenomenon is explained
derwent the external magnetic field effect, whereas
by the proper orientation of substrate molecules
the one leading to 8,9-dihydro-5-oxa-7-aza-benzo-
forced by external magnetic field. Diamagnetic dipoles
cycloheptene did not. Different results were obtained
are repulsed to the center by both electromag-
for the photoisomerization of 1–cyano-isoquinoline
net poles, being simultaneously arranged. This phe-
N-oxide [5].
nomenon may then promote the acceleration of
It was also demonstrated that high magnetic
ꢀC
the reaction.
2014 Wiley Periodicals, Inc. Het-
field (B = 8 T) influences the growth of benzophe-
none crystals [6]. The X-ray structure of crystals
demonstrated the orthorhombic needles, which, in
the absence of magnetic field, were oriented in ran-
dom directions, whereas in the presence of high
magnetic field needles’ long axes tended to stay per-
pendicular to the direction of magnetic field. The
degree of orientation depends on the magnetic flux
density of the field.
Magnetic field also influences the structure of
surface of an electrode modified by organic poly-
mers; for example, electropolymerization of diamag-
netic o–phenylenediamine on platinum occurred
more efficiently in a magnetic field of B = 6 T [7].
All above-mentioned examples concerned with
either a physical process of solidification [6] or typi-
cal radical reactions [2–5,7], whereas intermediates
were paramagnetic and applied external magnetic
field acted in rather predictable way. Our team con-
tributed to this topic too while studying the action of
constant magnetic field on properties of alloys and
other materials [8,9].
eroatom Chem. 00:1–8, 2014; View this article online
at wileyonlinelibrary.com. DOI 10.1002/hc.21149
INTRODUCTION
The constant magnetic field found its important ap-
plication in polymer, material, or fuel industry to
improve, e.g., properties of water and fuels by main-
taining appropriate magnetic dipoles of liquids so
that it change flow properties [1].
Some examples of the influence of external con-
stant magnetic field on organic reactions were also
reported, and the photoisomerization of isoquino-
Correspondence to: Jarosław Lewkowski; e-mail: jlewkow@
uni.lodz.pl. Marek Zielin´ski; e-mail: zielmark@chemia.uni.
lodz.pl.
In memoriam of Professor Romuald Skowron´ski.
Supporting Information is available in the online issue at
www.wileyonlinelibrary.com.
ꢀC
2014 Wiley Periodicals, Inc.
1

2
Karpowicz et al.
It seemed interesting that what would be the
nates (between 20 and 26 ppm) to signal of dimethyl
phosphite (a doublet around 11.5 ppm).
effect of moderate magnetic field of B = 1 T on
the reaction of the typical nonradical, ionic mech-
anism. Therefore, we have investigated the influence
of external magnetic field on the Kabachnik–Fields
reaction.
The results were really astonishing because, in
all studied cases, reactions carried out in a magnetic
field allowed us to isolate aminophosphonates 3Aa–
3Bf at much more higher yields than reactions car-
ried out in classical thermal conditions (Table 1).
Moreover, the 31P NMR monitoring revealed
that reactions in magnetic field occurred much
faster, i.e., achieving higher conversion rates in
a short time. The reaction of thiophene (1d)
with benzylamine (2A) as well as the reac-
tion of furfural (1c) with p–toluidine (2B) and
dimethyl phosphite gave the best results and demon-
strated the most distinctive difference in con-
version rates between a reaction under constant
magnetic field and classical thermal reaction. In
the first case, dimethyl N-benzylamino(2-thienyl)-
methylphosphonate (3Ad) was formed in 50% after
73 h of heating accompanied by the magnetic
field and only in 16% under classical conditions.
After 79 h, aminophosphonate 3Ad was formed
in 70% under the magnetic field and 28% un-
der classical conditions (Fig. 1). The case of the
reaction with furfural (1c) with p–toluidine (2B)
and dimethyl phosphite gave similarly impres-
sive results. Dimethyl N-(p-methyl-phenyl)amino(2-
furyl)methylphosphonate (3Bc) was formed in 50%
after 28 h of heating with magnetic field and
only in 29% under classical conditions. After 55 h,
aminophosphonate 3Bc was formed in 70% under
the magnetic field and in 40% under classical condi-
tions and after 100 h, 80% and 48%, under magnetic
field and classical conditions, respectively (Fig. 2).
RESULTS AND DISCUSSION
For the first investigation, we have chosen the
Kabachnik–Fields reaction because of two reasons.
First, the products of the Kabachnik–Fields reac-
tion, i.e., aminophosphonic derivatives, despite their
old history are still en vogue, which is recently con-
cluded by Kafarski [10]; it is much of interest to
find a more efficient method for their synthesis.
The second reason is a highly pragmatic one, the
Kabachnik–Field reaction is very easy to monitor by
the 31P NMR spectroscopy, which is an easy tool, so
that we chose it for its simplicity.
That is why we performed the Kabachnik–Fields
reaction for six representative aldehydes 1a–f with
two representative amines 2A–B and dimethyl phos-
phite (Scheme 1). Reactions were carried out in re-
fluxing acetonitrile in a magnetic field of B = 1 T and,
to compare, reactions in classical thermal conditions
were launched simultaneously (see Figs. S1–S3 in
the Supporting Information). Both reactions were
simultaneously monitored by the 31P NMR spec-
troscopy at certain intervals of time. Samples were
taken at the same time, and 31P NMR spectra were
recorded simultaneously ( 5 min), so that the con-
version rates could be estimated by comparing inte-
grations of peaks assigned to formed aminophospho-
O
OCH3
OCH3
O
H
P
Δ or Δ-m.f.
OCH3
R2 NH2
R1 CHO
P
R1
+
+
OCH3
CH3CN
HN R2
1a-f
2A-B
3Aa-Bf
R1 = a: Ph, b: ferrocenyl, c: 2-furyl, d: 2-thienyl, e: 2-phenylethenyl, f: c-Hex
R2 = A: CH2Ph, B: 4-methylphenyl
SCHEME 1 Kabachnik–Fields reaction with dimethyl phosphite, amines 2A–B, and aldehydes 1a–f with or without constant
magnetic field.
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Kabachnik–Fields Reaction Accelerated in External Magnetic Field
3
TABLE 1 Results of the Kabachnik–Fields Reaction in External Magnetic Field (B = 1 T) and Classical Thermal Conditions
(B = 0 T)
R1
R2
Time of Reaction (h)
B = 1 T Yield (%) (Mass [g])
B = 0 T Yield (%) (Mass [g])
Ph (a)
CH2Ph (A)
52
28
55
79
73
28
52
28
105
76
70 (1.07)
75 (1.55)
71 (1.05)
59 (0.92)
68 (1.13)
73 (1.14)
74 (1.13)
69 (1.42)
64 (0.95)
73 (1.14)
69 (1.15)
71 (1.10)
30 (0.46)
64 (1.32)
55 (0.81)
22 (0.34)
53 (0.88)
58 (0.91)
68 (1.04)
64 (1.32)
39 (0.58)
63 (0.98)
56 (0.93)
63 (0.95)
Fc (b)
CH2Ph (A)
2-Furyl (c)
2-Thien (d)
PhCH=CH (e)
c-Hex (f)
Ph (a)
CH2Ph (A)
CH2Ph (A)
CH2Ph (A)
CH2Ph (A)
p-CH3-C6H4 (B)
p-CH3-C6H4 (B)
p-CH3-C6H4 (B)
p-CH3-C6H4 (B)
p-CH3-C6H4 (B)
p-CH3-C6H4 (B)
Fc (b)
2-Furyl (c)
2-Thien (d)
PhCH=CH (e)
c-Hex (f)
100
25
80
70
60
50
40
30
20
10
0
4
6,5
28
31
49
Time (h)
Conversion rates estimated at given intervals of time for
52
55
73
76
79
FIGURE
1
a
reaction of benzylamine 2A with 2-
thiophenecarboxaldehyde 1d and dimethyl phosphite at B = 1 T (ꢀ) and 0 T (ꢁ).
90
80
70
60
50
40
30
20
10
0
4
7
8
28 31 49 52
55 73 76 79 97 100 105
Time (h)
FIGURE 2 Conversion rates estimated at given intervals of time for a reaction of p-toluidine 2B with 2-furfural 1c and dimethyl
phosphite at B = 1 T (ꢀ) and 0 T (ꢁ).
The formation of dimethyl N-benzylamino
(phenyl)-methylphosphonate (3Aa) is also highly
promoted by the presence of magnetic field as com-
pared to a classical thermal reaction. After 8 h
of heating under constant magnetic field, the con-
version reached 60%, whereas classical heating al-
lowed the system to produce 19% aminophospho-
nate 3Aa only. When a magnetic field forced sys-
tem to form 3Aa in 90% during 52 h, a classical
thermal reaction occurred at 39% conversion rate
only (Fig. 3). Similar results were also obtained
for other reactions, but a distinctive difference was
Heteroatom Chemistry DOI 10.1002/hc

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Karpowicz et al.
100
90
80
70
60
50
40
30
20
10
0
1
2
3
4
6
8
25
28
30
49
52
Time (h)
FIGURE 3 Conversion rates estimated at given intervals of time for a reaction of benzylamine 2A with benzaldehyde 1a and
dimethyl phosphite at B = 1 T (ꢀ) and 0 T (ꢁ).
100
90
80
70
60
50
40
30
20
10
0
4
7
25 28 31 49 52 55 73 76 79 100
Time (h)
FIGURE 4 Conversion rates estimated at given intervals of time for a reaction of p-toluidine 2B with cinnamaldehyde 1e and
dimethyl phosphite at B = 1 T (ꢀ) and 0 T (ꢁ).
also observed for the reaction with p-toluidine 2B
with cinnamaldehyde 1e and dimethyl phosphite
(Fig. 4).
All these results tend to state that the Kabachnik–
Fields reaction of a known ionic mechanism [11]
occurs much better when apart from heating, a con-
stant magnetic field is applied. Therefore, the con-
stant magnetic field has an accelerating effect on this
reaction. Why?
It is known that the thermal energy is necessary
to accelerate the velocity of substrate molecules to
increase the reaction rate for slow reactions, whereas
the magnetic field did not change the velocity of var-
ious chemical species [1]. However, the magnetic
field changes the direction of atoms’ or molecules’
movement and causes orientation of their magnetic
moments in a given direction, i.e., a certain orien-
tation of their magnetic dipoles [1]. But there is
no comprehensive theoretical model that accounts
for the magnetic field effects on chemical processes,
despite the observation that the external magnetic
field actually has a significant effect on the chemi-
cal and biochemical systems [12]. Of course, some
attempts were made to construct models explaining
how an applied weak magnetic field might influence
the steady state of a nonequilibrium chemical sys-
tem. It was assumed that external magnetic field can
have an effect on the rates of radical reactions oc-
curring in a system leading to drastic changes in
the properties of chemical systems such as tempera-
ture and reagent concentration [10]. It is concluded
that though the energy of magnetic interactions is
small, under certain conditions relatively weak mag-
netic fields can significantly affect the rates of chem-
ical reactions with the participation of paramagnetic
particles [12,13].
We did not find any study in the literature de-
scribing the action of magnetic field on diamag-
netic systems. However, Li et al. [14] suggested
that effects of an applied magnetic field on chem-
ical reactions are due to the fact that applied mag-
netic field can have an orientational effect on some
Heteroatom Chemistry DOI 10.1002/hc

Kabachnik–Fields Reaction Accelerated in External Magnetic Field
5
and it seems that the proper orientation of sub-
strate molecules, which is forced by external mag-
netic field, plays a key role, as it forces a shorter
distance between molecules. Further investigations
will focus on the influence of external magnetic field
on other Mannich-type reactions.
a: B = 0
b: B = 1 T
B
N
N
N
N
B
S
S
S
S
N
S
EXPERIMENTAL
General
Diamagnetic molecule
Diamagnetic dipole
Acetonitrile (Aldrich, Poznan´, Poland) was routinely
distilled and dried prior to use. Aldehydes, amines,
and dimethyl phosphite (Aldrich) were used as re-
Magnetic dipole
moment vector
1
ceived. H and 31P NMR spectra were recorded on
B
Magnetic induction
vector
a Bruker Avance III 600 MHz apparatus operat-
ing at 600 MHz (1H NMR), 150 MHz (13C NMR),
and 243 MHz (31P NMR). In two cases (3Ab and
3Ad), 13C NMR spectra were recorded on a Var-
ian Gemini 2000BB 200 MHz apparatus operating
at 50 MHz. Elemental analyses were performed in
the Microanalysis Lab, the Centre of Molecular and
Macromolecular Studies Polish Academy of Science
(PAS), in Ło´dz´, Poland. Melting points were mea-
sured in a MelTemp II apparatus and were uncor-
rected.
Reactions in magnetic field were carried out
with the use of the apparatus constructed in the
Division of Radio Equipment (RADIOPAN) of PAS
(Poznan´, Poland) consisting of following compo-
nents: a laboratory electromagnet with N and S pole
shoes (ER-2505 type), a electrochemical cell with a
three-electrode system, a PZP-80 control device for
the electromagnet, a stable current source for the
electromagnet, a Hall sensor for a constant magnetic
field, and a Hall teslameter (TH-26 type) (Figs. S1–S4
in the Supporting Information).
FIGURE 5 Arrangement of a diamagnetics molecule, when
(a) no external magnetic field was applied and (b) external
magnetic field of B = 1 T was applied.
organic polymers and biological molecules, which
enhance mass transfer and morphological changes
in organic films [14], and we took this suggestion as
a basis for our consideration.
In diamagnetic substances, the resultant mag-
netic moments are zero, so, when external magnetic
field is not applied, no magnetic organization oc-
curs [15, 16]. However, external constant magnetic
field is able to induce certain magnetic dipole mo-
ments in diamagnetic organic molecules, and their
value is proportional to magnetic field induction [1].
These dipoles are arranged in such a way that their
magnetic dipole moment vector is oriented in the op-
posite direction to the vector B. If a magnetic dipole
of a diamagnetic substance is considered as an ele-
mental magnet of poles N i S, it arranges in such a
way that its pole N will be facing to the electromag-
net pole S and the dipole pole S is facing to the elec-
tromagnet pole N (Fig. 5). Diamagnetic dipoles are
repulsed to the center by both poles of an electro-
magnet, being simultaneously arranged. This phe-
nomenon may then promote the acceleration of the
reaction.
General Procedure for the Synthesis of
Aminophosphonates 3Aa–3Bf
An appropriate aldehyde 1a–f (5 mmol), amine
2A–B (5 mmol), and dimethyl phosphite (5 mmol,
0.55 g) were dissolved in 30 mL of acetonitrile in
two independent reaction vessels equipped with re-
flux condensers. One of the vessels was placed be-
tween poles of an electromagnet and was heated
with a heat gun (see Figs. S1–S4 in the Support-
ing Information), and the other was heated with
a magnetic stirrer. Both solutions were then re-
fluxed during the day and stirred at room temper-
ature overnight. At certain intervals, both reactions
were monitored by 31P NMR, i.e., 0.5 mL samples
were taken simultaneously from each reaction; to
each sample, 0.5 mL of CDCl3 was added, 31P NMR
CONCLUSIONS
We have demonstrated the significant accelerat-
ing effect of the constant magnetic field on the
Kabachnik–Fields reaction. As far as can be ascer-
tained, this is the first example of a nonradical reac-
tion, which was accelerated when external magnetic
field was applied. The described phenomena is de-
scribed in the patent application [17]. We tried to
find a reasonable explanation for this phenomenon,
Heteroatom Chemistry DOI 10.1002/hc

6
Karpowicz et al.
nondecoupled spectra were recorded at nearly the
same time ( 5 min), and conversion rates were es-
timated by comparing of integrations. Results are
presented in Tables S1 and S2 in the Support-
ing Information. After the reaction was considered
to be accomplished, a solvent was evaporated, the
residue dissolved in dichloromethane washed with
saturated, aqueous NaHCO3, an organic layer was
dried and evaporated to obtain residues contain-
ing almost pure aminophosphonate 3Aa–Bf, which
were chromatographed on silica gel and eluted with
ethyl an acetate–hexane (4:1) solvent system. All new
aminophosphonates 3Ab, 3Ad, and 3Af as well as
for C20H24FeNO3P: C, 58.13; H, 5.85; N, 3.39. Found:
C, 58.06; H, 5.90; N, 3.43.
Dimethyl N-Benzylamino(2-furyl)methyl-
phosphonate (3Ac)
1
Y = 71% (1.05 g). Yellow oil. H NMR (CDCl3, 600
MHz): δ (ppm) 7.69–7.68 (m, 5Hfur, 1H); 7.57.43–7.42
(m, PhH, 2H); 7.39–7.36 (m, PhH, 2H); 7.33–7.29
3
(m, PhH, 4H); 6.50–6.49 (m, Hfur, 1H); 6.42–6.41
4
2
(m, Hfur, 1H); 4.23 (d, JPH = –19.8 Hz, CHP, 1H);
2
3
3.88 (d, JHH = –13.2 Hz, CH2Ph, 1H); 3.83 (d, JPH
1
2
3Bb, 3Bd, and 3Bf were characterized by H, 31P,
= 10.8 Hz, POCH3, 3H); 3.65 (d, JHH = –13.2 Hz,
and 13C NMR spectroscopy, and their purity was
confirmed by elemental analyses. Data of known syn-
thesized aminophsophonates are described in the
literature, and their identity was confirmed by 1H
and 31P NMR spectroscopy, and melting point mea-
surements, which were compared with the literature
data [18–22]. Yields of reactions carried out under
influence of magnetic field are also given.
CH2Ph, 1H); 3.59 (d, JPH = 10.8 Hz, POCH3, 3H).
3
31P NMR (CDCl3, 243 MHz): δ (ppm) 25.75 [19].
Dimethyl N-Benzylamino(2-thienyl)methyl-
phosphonate (3Ad)
1
Y = 59% (0.92 g). Yellow oil. H NMR (CDCl3, 600
MHz): δ (ppm) 7.39–7.38 (m, PhH, 2H); 7.34–7.32
5
3
(m, PhH, Hthioph, 3H); 7.28–7.25 (m, PhH, Hthioph
,
4
Dimethyl N-Benzylamino(phenyl)methyl-
phosphonate (3Aa)
2H); 7.09 (dd, J = 5.4 and 3.6 Hz, Hthioph, 1H);
2 2
4.36 (d, JPH = –24.0 Hz, 1H, CHP); 3.88 (d, JHH
=
3
−13.2 Hz, CH2Ph, 1H); 3.87 (d, JPH = 10.8 Hz, 3H,
1
Y = 70% (1.07 g). Yellow oil. H NMR (CDCl3, 600
3
POCH3); 3.56 (d, JPH = 10.8 Hz, 3H, POCH3); 3.48
MHz): δ (ppm) 7.43–7.42 (m, PhH, 2H); 7.39–7.36
(d, JHH = –13.2 Hz, CH2Ph, 1H). 13C NMR (CDCl3,
2
(m, PhH, 2H); 7.33–7.29 (m, PhH, 4H); 7.25–7.23
50 MHz): δ (ppm) 137.31 (Cphen-CH2); 131.40 (d,
2JPC = 8.5 Hz, C2thioph-C-P); 127.92 (C4thioph); 127.81
(Cphen-H); 127.09 (Cphen-H); 126.01 (Cphen-H); 125.69
(C5thioph); 124.62 (C4thioph); 58.47 (d, 3JPC = 12.0 Hz,
CH2); 57.17 (d, 1JPC = 165.0 Hz, C–P); 52.55 (d, 2JPC
2
(m, PhH, 2H); 4.05 (d, JPH = –19.8 Hz, CHP, 1H);
2
3
3.80 (d, JHH = –13.2 Hz, CH2Ph, 1H); 3.73 (d, JPH
2
= 10.8 Hz, POCH3, 3H); 3.55 (d, JHH = –13.2 Hz,
3
CH2Ph, 1H); 3.54 (d, JPH = 10.8 Hz, POCH3, 3H).
31P NMR (CDCl3, 243 MHz): δ (ppm) 25.75 [18].
2
= 7.0 Hz, P–O–C); 51.60 (d, JPC = 7.0 Hz, P–O–C).
31P NMR (CDCl3, 243 MHz): δ (ppm) 23.96. Anal.
calcd for C14H18NO3PS: C, 54.01; H, 5.83; N, 4.50.
Found: C, 54.08; H, 5.95; N, 4.55.
Dimethyl N-Benzylamino(ferrocenyl)methyl-
phosphonate (3Ab)
1
Y = 75% (1.55 g). Brown oil. H NMR (CDCl3, 600
MHz): δ (ppm) 7.45–7.43 (m, PhH, 2H); 7.38–7.36
Dimethyl N-Benzylamino(2-phenylethenyl)
methyl-phosphonate (3Ae)
(m, PhH, 2H); 7.30–7.28 (m, PhH, 1H); 4.29–4.28 (m,
2
1H, C5H4); 4.27–4.25 (m, 1H, C5H4); 4.22 (d, JHH
1
= –13.2 Hz, CH2Ph, 1H); 4.18–4.17 (m, 1H, C5H4);
Y = 68% (1.13 g). Yellow oil. H NMR (CDCl3, 600
4.15–4.14 (m, 1H, C5H4); 4.07 (s, 5H, C5H5); 4.06
MHz): δ (ppm) 7.43–7.39 (m, PhH, 2H); 7.36–7.34
2
2
(d, JHH = –13.2 Hz, CH2Ph, 1H); 3.76 (d, JPH = –
11.0 Hz, 1H, CHP); 3.71 and 3.67 (2d, 3JPH = 10.8 Hz,
2×3H, POCH3). 13C NMR (CDCl3, 50 MHz): δ (ppm)
(m, PhH, 2H); 7.33–7.31 (m, PhH, 4H); 7.28–7.24
4
4
(m, PhH, 2H); 6.62 (ddd, JHH = 1.2 Hz, JPH
=
3
4.8 Hz, JHH = 15.6 Hz, CH = CH, 1H); 6.15 (ddd,
138.68 (Cphen-CH2); 127.30 (Cphen-H); 127.21 (Cphen
-
3JPH = 5.4 Hz, 3JHH = 6.6 Hz, 3JHH = 15.6 Hz, CH =
H); 126.01 (Cphen-H); 84.46 (Cferr-CH); 67.50 (d, 3JPC
= 2.5 Hz, Cferr); 67.36 (C5H5); 66.59 (Cferr); 66.54
CH, 1H); 4.07 (ddd, JHH = 1.2 Hz, JHH = 6.6 Hz,
4
3
2JPH = –25.8 Hz, CHP, 1H); 3.80 (d, JPH = 10.8 Hz,
3
3
1
(Cferr); 64.87 (d, JPC = 2.5 Hz, Cferr); 53.52 (d, JPC
POCH3, 3H); 3.79 (d, 2JHH = –13.2 Hz, CH2Ph, 1H);
2
= 157.5 Hz, C–P); 52.37 (d, JPC = 8.5 Hz, P–O–C);
3.77 (d, 3JPH = 10.8 Hz, POCH3, 3H); 3.76 (d, 2JHH
=
52.21 (CH2); 52.25 (d, JPC = 7.5 Hz, P–O–C). 31P
−13.2 Hz, CH2Ph, 1H). 31P NMR (CDCl3, 243 MHz):
δ (ppm) 25.86 [20].
2
NMR (CDCl3, 243 MHz): δ (ppm) 24.85. Anal. calcd
Heteroatom Chemistry DOI 10.1002/hc

Kabachnik–Fields Reaction Accelerated in External Magnetic Field
7
for C20H24FeNO3P: C, 58.13; H, 5.85; N, 3.39. Found:
C, 57.85; H, 5.67; N, 3.59.
Dimethyl N-Benzylamino(cyclohexyl)methyl-
phosphonate (3Af)
1
Y = 73% (1.14 g). Yellow oil. H NMR (CDCl3, 600
MHz): δ (ppm) 7.36–7.35 (m, PhH, 2H); 7.32–7.30
(m, PhH, 2H); 7.26–7.23 (m, PhH, 1H); 4.02 (d,
Dimethyl N-(p-Methylphenyl)amino(2-furyl)-
methylphosphonate (3Bc)
2
2JHH = –13.2 Hz, CH2Ph, 1H); 3.87 (dd, JHH
=
4
−13.2 and JPH = 1.8 Hz, CH2Ph, 1H); 3.78 and
Y = 64% (0.95 g). Mp: 79–81°C. Lit [21]: 83–85°C;
1H NMR (CDCl3, 600 MHz): δ (ppm) 7.39–7.38 (m,
5Hfur, 1H); 6.96 and 6.59 (AAꢁXXꢁ system, 3JHH = 8.4
and 4JHH = 1.8 and 4JHH = 1.2 Hz, p-C6H4, 2 × 2H);
3
3.75 (2d, JPH = 10.8 Hz, 2 × 3H, POCH3); 2.77
3
3
(dd, JPH = 14.4 and JHH = 4.2 Hz, 1H, NH); 1.88–
1.76 (m, cHex, 4H); 1.69–1.61 (m, cHex, 2H); 1.49–
1.42 (m, cHex, 1H); 1.32–1.16 (m, cHex, 4H). 13C
NMR (CDCl3, 150 MHz): δ (ppm) 140.06 (Cphen-CH2);
128.36 (Cphen-H); 128.23 (Cphen-H); 127.02 (Cphen-H);
3
4
7.38–7.37 (m, Hfur, 1H); 7.33–7.32 (m, Hfur, 1H);
2
4.88 (d, JPH = −24.0 Hz, CHP, 1H); 3.81 and 3.63
3
(2d, JPH = 10.8 Hz, POCH3, 2 × 3H); 2.12 (s, CH3,
1
3
59.35 (d, JPC = 140.9 Hz, C–P); 53.39 (d, JPC
=
3H). 31P NMR (CDCl3, 243 MHz): δ (ppm) 22.69.
2
4.4 Hz, CH2); 52.41 (d, JPC = 7.1 Hz, P–O–C);
2
2
52.30 (d, JPC = 7.5 Hz, P–O–C); 39.23 (d, JPC
=
4.5 Hz, C1c-hex-P); 30.82 (d, JPC = 11.7 Hz, C2
-
3
c-hex
Dimethyl N-(p-Methylphenyl)amino(2-thienyl)-
methylphosphonate (3Bd)
P); 28.29 (d, JPC = 4.1 Hz, C3c-hex-P); 26.55 (Cc-hex);
26.36 (Cc-hex); 26.14 (Cc-hex). 31P NMR (CDCl3, 243
MHz): δ (ppm) 30.88. Anal. calcd for C16H26NO3P:
C, 61.72; H, 8.42; N, 4.50. Found: C, 61.77; H, 8.43;
N, 4.66.
4
1
Y = 73% (1.14 g). Mp: 104–106°C; H NMR (CDCl3,
3
4
600 MHz): δ (ppm) 7.22 (dd, JHH = 4.8 and JHH
=
=
1.5 Hz, 1H, 5Hthioph); 7.15 (dd, 3JHH = 3.3 and 4JHH
3
1.1 Hz, 1H, Hthioph); 6.98–6.95 (m, 3H, part of
4
AAꢁXXꢁ system p-C6H4 and Hthioph); 6.59 (part of
AAꢁXXꢁ system, JHH = 8.4 and JHH = 1.8 Hz and
3
4
Dimethyl N-(p-Methylphenyl)amino(phenyl)-
methylphosphonate (3Ba)
4JHH = 1.8 Hz, 2 × 2H, p-C6H4); 5.03 (d, JPH
=
=
2
3
−24.0 Hz, 1H, CHP); 3.78 and 3.62 (2d, JPH
Y = 74% (1.13 g). Mp: 68–71°C. Lit [21]: 69–70°C;
10.8 Hz, 2 × 3H, POCH3); 2.20 (s, CH3, 3H). 13C
1H NMR (CDCl3, 600 MHz): δ (ppm) 7.47–7.45 (m,
2
NMR (CDCl3, 150 MHz): δ (ppm) 143.59 (d, JPC
=
PhH, 2H); 7.34–7.32 (m, PhH, 2H); 7.28–7.25 (m,
13.6 Hz, C2thioph-C-P); 139.74 (Cphen-NH); 129.78
3
PhH, 1H); 6.91 and 6.52 (AAꢁXXꢁ system, JHH
=
5
4
4
(Cphen-H); 128.43 (Cphen-CH3); 127.14 (d, JPC
=
8.4 and JHH = 1.8 Hz and JHH = 1.8 Hz, p-C6H4,
3.2 Hz, C5thioph); 126.23 (d, JPC = 7.2 Hz, C3thioph);
3
2
2 × 2H); 4.77 (d, JPH = –24.0 Hz, CHP, 1H); 3.75
125.40 (d, JPC = 3.4 Hz, C4thioph); 114.25 (Cphen-H);
4
and 3.48 (2d, 3JPH = 10.8 Hz, POCH3, 2 × 3H); 2.18
(s, CH3, 3H). 31P NMR (CDCl3, 243 MHz): δ (ppm)
25.12.
1
2
52.12 (d, JPC = 158.0 Hz, C–P); 54.13 (d, JPC
=
2
7.4 Hz, P–O–C); 53.80 (d, JPC = 6.8 Hz, P–O–C);
20.38 (CH3). 31P NMR (CDCl3, 243 MHz): δ (ppm)
23.25. Anal. calcd for C14H18NO3PS: C, 54.01; H,
5.83; N, 4.50. Found: C, 53.92; H, 5.86; N, 4.66.
Dimethyl N-(p-Methylphenyl)amino(ferrocenyl)-
methylphosphonate (3Bb)
1
Y = 69% (1.42 g). Mp: 167–169°C; H NMR (CDCl3,
Dimethyl N-(p-Methylphenyl)amino(2-phenyl-
ethenyl)methylphosphonate (3Be)
600 MHz): δ (ppm) 7.05 and 6.72 (AAꢁXXꢁ system,
2
3JHH = 8.4 Hz, 2 × 2H, p-C6H4); 4.46 (d, JPH
=
1
–16.2 Hz, 1H, CHP); 4.32–4.30 (m, 2H, C5H4); 4.21–
4.19 (m, 2H, C5H4); 4.09 (s, 5H, C5H5); 4.01–3.99
Y = 69% (1.15 g). Yellow oil. H NMR (CDCl3, 600
MHz): δ (ppm) 7.40–7.36 (m, PhH, 2H); 7.33–7.32
3
(m, 1H, NH); 3.67 and 3.62 (2d, JPH = 10.2 Hz, 2
(m, PhH, 2H); 7.26–7.24 (m, PhH, 1H); 6.94 and 6.65
× 3H, POCH3); 2.26 (s, CH3, 3H). 13C NMR (CDCl3,
(AAꢁXXꢁ system, JHH = 8.4 and JHH = 1.8 Hz and
3
4
3
4
150 MHz): δ (ppm) 144.84 (d, JPC = 6.0 Hz, Cphen
-
4JHH = 1.8 Hz, p-C6H4, 2 × 2H); 6.74 (ddd, JHH
=
4
3
NH); 129.97 (Cphen-H); 127.82 (Cphen-CH3); 113.75
1.2 Hz, JPH = 4.8 Hz, JHH = 15.6 Hz, CH = CH,
2
(Cphen-H); 85.51 (d, JPC = 6.6 Hz, Cferr-CH); 68.79
1H); 6.28 (ddd, 3JPH = 5.4 Hz, 3JHH = 6.6 Hz, 3JHH
=
3
4
(C5H5); 68.64 (d, JPC = 4.1 Hz, Cferr); 68.18 (Cferr);
15.6 Hz, CH = CH, 1H); 4.77 (ddd, JHH = 1.2 Hz,
3JHH = 6.6 Hz, 2JPH = –25.8 Hz, CHP, 1H); 3.84 and
67.86 (Cferr); 65.99 (d, 3JPC = 1.7 Hz, Cferr); 53.91 (d,
2JPC = 6.8 Hz, P–O–C); 53.25 (d, 2JPC = 7.1 Hz, P–O–
3
3.82 (2d, JPH = 10.8 Hz, POCH3, 2 × 3H); 2.26 (s,
C); 52.19 (d, 1JPC = 161.0 Hz, C–P); 20.42 (CH3). 31
P
CH3, 3H). 31P NMR (CDCl3, 243 MHz): δ (ppm) 24.81
NMR (CDCl3, 243 MHz): δ (ppm) 23.94. Anal. calcd
[22].
Heteroatom Chemistry DOI 10.1002/hc

8
Karpowicz et al.
[3] Hata, N. Chem Lett 1978, 1359–1362.
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603–606.
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1997, 84, 435–436.
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38, 1771–1778.
[9] Zielin´ski, M. Mater Chem Phys 2013, 141, 370–377.
[10] Kafarski, P. In XIVth Symposium on Advances in
Heteroorganic Chemistry, Ło´dz´, Poland, November
18, 2011.
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2010, 124, 168–172.
Dimethyl N-(p-Methylphenyl)amino(cyclohexyl)-
methylphosphonate (3Bf)
1
Y = 71% (1.10 g). Mp: 118–120°C; H NMR (CDCl3,
600 MHz): δ (ppm) 6.97 and 6.56 (AAꢁXXꢁ system,
3JHH = 8.4 Hz, 2 × 2H, p-C6H4); 3.71 and 3.67 (2d,
2
3JPH = 10.8 Hz, 2 × 3H, POCH3); 3.61 (dd, JPH
=
3
–18.6 and JHH = 4.2 Hz, 1H, CHP); 2.23 (s, CH3,
3H); 1.96–1.94 (m, cHex, 1H); 1.88–1.85 (m, cHex,
1H); 1.76–1.71 (m, cHex, 3H); 1.63–1.61 (m, cHex,
1H); 1.31–1.09 (m, cHex, 5H). 13C NMR (CDCl3, 150
3
MHz): δ (ppm) 145.27 (d, JPC = 5.7 Hz, Cphen-NH);
129.83 (Cphen-H); 127.15 (Cphen-CH3); 113.29 (Cphen
-
=
H); 56.39 (d, 1JPC = 150.5 Hz, C–P); 53.34 (d, 2JPC
2
6.8 Hz, P–O–C); 52.33 (d, JPC = 7.2 Hz, P–O–C);
2
3
39.97 (d, JPC = 5.6 Hz, C1c-hex-P); 30.90 (d, JPC
=
11.3 Hz, C2c-hex-P); 28.39 (d, JPC = 4.7 Hz, C3
-
4
c-hex
P); 26.29 (Cc-hex); 26.17 (Cc-hex); 26.01 (Cc-hex); 20.33
(CH3). 31P NMR (CDCl3, 243 MHz): δ (ppm) 27.91.
Anal. calcd for C16H26NO3P: C, 61.72; H, 8.42; N,
4.50. Found: C, 61.42; H, 8.30; N, 4.65.
[15] Orchard, F. Magnetochemistry; Oxford University
Press: New York, 2007.
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[19] Thirupathi Reddy, Y.; Narsimha Reddy, P.; Sunil
Kumar, B.; Rajput, P.; Sreenivasulu, N.; Rajitha,
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ACKNOWLEDGMENT
We wish to express our great thanks to Professor
Ryszard B. Nazarski for his fruitful scientific discus-
sions and friendly assistance.
[20] Manjula, A.; Vittal Rao, B.; Neelakantan, P. Synth
Commun 2003, 33, 2963–2969.
[21] Mu, X.-J.; Lei, M.-Y.; Zou, J.-P.; Zhang, W. Tetrahe-
dron Lett 2006, 47, 1125–1127.
[22] Palacios, F.; Vicario, J.; Maliszewska, A.; Aparicio, D.
J Org Chem 2007, 72, 2682–2685.
REFERENCES
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Heteroatom Chemistry DOI 10.1002/hc