Novel topoisomerase I inhibitors. Syntheses and biological evaluation of phosphorus substituted quinoline derivates with antiproliferative activity

Article abstract of DOI:10.1016/j.ejmech.2018.02.058

This work describes the synthesis of 1,2,3,4-tetrahydroquinolinylphosphine oxides, phosphanes and phosphine sulfides as well as that of quinolinylphosphine oxides and phosphine sulfides, which were synthesized in good to high overall yield. The synthetic

Full text of DOI:10.1016/j.ejmech.2018.02.058

Accepted Manuscript
Novel topoisomerase I inhibitors. Syntheses and biological evaluation of phosphorus
substituted quinoline derivates with antiproliferative activity
Concepción Alonso, María Fuertes, Endika Martín-Encinas, Asier Selas, Gloria
Rubiales, Cinzia Tesauro, Birgitta K. Knudssen, Francisco Palacios
PII:
S0223-5234(18)30195-8
10.1016/j.ejmech.2018.02.058
EJMECH 10235
DOI:
Reference:
To appear in: European Journal of Medicinal Chemistry
Received Date: 21 September 2017
Revised Date: 6 February 2018
Accepted Date: 16 February 2018
Please cite this article as: Concepció. Alonso, Marí. Fuertes, E. Martín-Encinas, A. Selas, G. Rubiales,
C. Tesauro, B.K. Knudssen, F. Palacios, Novel topoisomerase I inhibitors. Syntheses and biological
evaluation of phosphorus substituted quinoline derivates with antiproliferative activity, European Journal
of Medicinal Chemistry (2018), doi: 10.1016/j.ejmech.2018.02.058.
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to
our customers we are providing this early version of the manuscript. The manuscript will undergo
copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please
note that during the production process errors may be discovered which could affect the content, and all
legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT
Novel Topoisomerase I Inhibitors. Syntheses
and Biological Evaluation of Phosphorus
Substituted Quinoline Derivates with
Antiproliferative Activity
Concepción Alonso,a* María Fuertes,a Endika Martín-Encinas,a Asier Selas,a Gloria
Rubiales,a Cinzia Tesauro,b Birgitta K. Knudssenb and Francisco Palacios a,*
a
Departamento de Química Orgánica I, Facultad de Farmacia and Centro de
Investigación Lascaray (Lascaray Research Center). Universidad del País Vasco/Euskal
Herriko Unibertsitatea (UPV/EHU). Paseo de la Universidad 7, 01006 Vitoria-Gasteiz,
Spain.
b
Department of Molecular Biology and Genetics and Interdisciplinary Nanoscience
Center (iNANO), Aarhus University, Aarhus 8000, Denmark.

ACCEPTED MANUSCRIPT
Novel Topoisomerase I Inhibitors. Syntheses and
Biological Evaluation of Phosphorus Substituted
Quinoline Derivates with Antiproliferative Activity.
Concepción Alonso,a,* María Fuertes,a Endika Martín-Encinas,a Asier Selas,a Gloria Rubiales,a
Cinzia Tesauro,b Birgitta K. Knudssenb and Francisco Palaciosa,*
a
Departamento de Química Orgánica I, Facultad de Farmacia and Centro de Investigación
Lascaray (Lascaray Research Center). Universidad del País Vasco/Euskal Herriko Unibertsitatea
(UPV/EHU). Paseo de la Universidad 7, 01006 Vitoria-Gasteiz, Spain.
b
Department of Molecular Biology and Genetics and Interdisciplinary Nanoscience Center
(iNANO), Aarhus University, Aarhus 8000, Denmark.
Keywords: Phosphorated Quinolines, Topoisomerase I, Enzyme inhibition, Antiproliferative
effect
Abbreviations: CCK8, cell counting kit; CPT, camptothecin; CPTs, camptothecin derivatives;
DDQ, dichloro-5,6-dicyanobenzoquinone; equiv, equivalents; HDAr, hetero-Diels-Alder
reaction; MCR, multicomponent reaction; SDS, sodium dodecyl sulfate; Top1, topoisomerase I;
TLC, thin layer chromatography.
1

ACCEPTED MANUSCRIPT
ABSTRACT. This work describes the synthesis of 1,2,3,4-tetrahydroquinolinylphosphine
oxides, phosphanes and phosphine sulfides as well as that of quinolinylphosphine oxides and
phosphine sulfides, which were synthesized in good to high overall yield. The synthetic route
involves a multicomponent reaction of (2-phosphine-oxide)-, 2-phosphine- or (2-phosphine-
sulfide)-aniline, aldehydes and olefins and allows the selective generation of two stereogenic
centres in a short, efficient and reliable synthesis. The selective dehydrogenation of 1,2,3,4-
tetrahydroquinolinylphosphine oxides and phosphine sulfides leads to the formation of
corresponding phosphorus substituted quinolines. Some of the products which were prepared
showed excellent activity as topoisomerase I (Top1) inhibitors. In addition, prolonged effect of
the most potent compounds is maintained with the same intensity even after three minutes of the
beginning of the enzymatic reaction. The cytotoxic effect on cell lines derived from human lung
adenocarcinoma (A549), human ovarian carcinoma (SKOV03) and human embryonic kidney
(HEK293) was also screened. 1,2,3,4-Tetrahydroquinolinylphosphine oxide 6g with an IC50
value of 0.25±0.03 ꢀM showed excellent activity against the A549 cell line in vitro, while
1,2,3,4-tetrahydroquinolinylphosphane 9c with an IC50 value of 0.08±0.01 ꢀM and 1,2,3,4-
tetrahydroquinolinylphosphine sulfide derivative 10f with an IC50 value of 0.03±0.04 ꢀM are
more active against the A549 cell line. Moreover, selectivity towards cancer cell (A549) over
non-malignant cells (MRC5) has been observed. According to their structure, they may be
excellent antiproliferative candidates.
1. Introduction
Currently some cancer chemotherapies focus on inducing damage to the DNA of cancer cells. In
this regard, it should be noted that human topoisomerase (hTop1) has become an important target
2

ACCEPTED MANUSCRIPT
in the discovery of anti-cancer drugs. This ubiquitous nuclear enzyme reduces superhelical stress
as well as other topological consequences generated in the separation of DNA strands in
metabolic processes such as replication, transcription and recombination [1]. Increased Top1
activity is observed in cancer cells compared to that observed in healthy cells, which leads to a
higher rate of replication. In this sense, Top1 inhibitors are usually the basis of some
chemotherapeutic combinations in the treatment of a broad spectrum of tumors [2]. Among the
most representative of Top1 inhibitor drugs there is camptothecin (CPT, Figure 1) and its
derivatives (CPTs) which are currently used in the systemic treatment of colon, ovarian and
small-cell lung cancers [1b, 3]. However, when being used in cancer therapy, these derivatives
carry certain drawbacks, such as lactone instability in blood plasma and cancer cell resistance
[4].
Figure 1. Structures of camptothecin and several novel synthesized antiproliferative
phosphorated (tetrahydro)quinolines I.
Among other features, camptothecin and its derivatives show several fused heterocycles in their
structural analysis. Moreover, with regard to the proposed inhibition mechanism of Top1, the
presence of flat or quasi-flat polycyclic heterocycles seems to be relevant in the effectiveness of
the antiproliferative activity [5]. Nitrogenated quinoline compounds show, in fact, an interesting
biological activity with this target [6]. Recently [7a], fluorescein hydrazones [7b], indeno[1,2-
3

ACCEPTED MANUSCRIPT
b]pyridines derivatives [7c,d], benzofuro[3,2-b]pyridines [7e], and benzimidazoles [7f] have
been reported as Top1 inhibitors. In this sense, the Povarov reaction [8] is a highly atom-
economic tool for the incorporation of nitrogen into chemical compounds, such as quinolines.
Furthermore, in the search of a methodology for the preparation of molecules with high
molecular diversity, multicomponent reactions (MCRs) represent a versatile alternative where
lower costs, shorter reaction time and less energy are needed [9]. MCRs have been successfully
applied in medicinal chemistry [10], and therefore the multicomponent version of the Povarov
reaction may interestingly be considered as a powerful tool for the preparation of nitrogen
derivatives with excellent regioselectivity.
Organophosphorus derivatives are interesting compounds from a biological point of view,
since it is known that phosphorus substituents may affect the reactivity of heterocycles and
regulate important biological functions [11]. In this context, antibiotics such as phosphinothricin,
fosfomycin, fosfidomycin or dehydrophos [12a] have been described. Thus, from
cyclophosphamide [12b] discovered in 1954 as an anticancer drug [12c] and used to treat
leukemia and different cancers to brigatinib [12d], which contains a phosphine oxide substitute
attached to an aryl group, recently approved in the USA for the treatment of metastatic non-small
cell lung cancer (NSCLC) [12e], a large number of compounds containing phosphorus have been
described [11]. The development of new strategies for the preparation of aminophosphonates
[13], phosphinated [14] or phosphorylated azaheterocycles [15] implies the incorporation of
organophosphorus functionalities in simple synthons. For example, the diphosphonylation of
quinolines leads to tetrahydroquinolines [16]. Some phosphorated derivatives of
fluoroquinolones (ciprofloxacin, norfloxacin, sparfloxacin) are characterized by a greater
biological activity than the original drugs [17].
4

ACCEPTED MANUSCRIPT
With these considerations in mind, we believe that the development of new hybrid molecules
[18] incorporating a phosphine, phosphine sulfide or phosphine oxide group in the heterocyclic
ring of a tetrahydroquinoline and/or a quinoline structure may be privileged scaffolds for
pharmaceuticals and may improve the antiproliferative cytotoxic properties with respect to other
biologically active structures. This fact could be due to an improvement in π-π* stacking
interactions with the DNA base pairs [1].
Bearing all this in mind, the development of highly selective methodologies to provide
efficient and fast access to phosphorous heterocycles containing a skeleton of quinolines I
(Figure 1) represents an interesting challenge in organic chemistry, due to the potential interest
of these molecules not only in synthetic but also in medicinal chemistry.
2. Results and Discussion
2.1 Chemistry
The phosphine-oxide substituted quinoline derivatives were synthesized by a two-step Povarov
type [4+2]-cycloaddition reaction. Therefore, 2-(diphenylphosphine oxide)aldimines 4, prepared
in situ by reaction of 2-(diphenylphosphine oxide)aniline 1 and aldehydes 2, were reacted with
styrenes 3 in the presence of 2 equivalents of BF3·Et2O in refluxing chloroform (Scheme 1,
Route
A).
After
reaction
completion,
the
corresponding
endo-1,2,3,4-
tetrahydroquinolinylphosphine oxides 6 were selectively obtained with good yields in a regio-
and stereospecific way (Chart 1). The formation of (1,2,3,4-tetrahydroquinolin-8-yl)phosphine
oxide 6 may be explained through a regio- and stereoselective [4+2]-cycloaddition reaction
between aldimine 4, obtained from amine 1, aldehydes 2, and olefins 3, followed by a
prototropic tautomerization of adduct 5. Subsequent dehydrogenation of 1,2,3,4-
5

ACCEPTED MANUSCRIPT
tetrahydroquinolines 6 with 2 equivalents of DDQ in CHCl3 produced the corresponding
quinolinylphosphine oxides 7 (Scheme 1, Chart 1). The formation of compounds 7 was
1
determined by H NMR spectroscopy where upfield signals corresponding to the protons of
tetrahydroquinoline ring of starting compounds 6 disappeared and only aromatic signals were
observed.
Scheme 1. Syntheses of 1,2,3,4-tetrahydroquinolinylphosphine oxides
quinolinylphosphine oxides 7.
6
and
Alternatively, same compounds 6 can be directly obtained by a multicomponent (MCR) protocol.
In this sense, the three components (phosphine oxide amine 1, aldehydes 2 and styrenes 3 were
reacted in the presence of the Lewis acid (BF3·Et2O) and the corresponding endo-
quinolinylphosphine oxide 6 were regio- and diastereoselectively obtained (Scheme 1, Route B,
Chart 1).
The methodology tolerates a wide range of electron-releasing and electron-withdrawing aromatic
aldehydes, even fluorinated ones which allow the preparation of fluoro containing compounds,
interesting substrates from a biological point of view [19]. As far as we know, this strategy
6

ACCEPTED MANUSCRIPT
represents the first example for the preparation of disubstituted 1,2,3,4-tetrahydroquinolines 6
and quinolines 7 containing a phosphine oxide group.
Chart 1. Structures of 1,2,3,4-tetrahydroquinolinylphosphine oxides 6 and quinolinylphosphine
oxides 7 obtained (aIsolated yield obtained byRoute A. bIsolated yield obtained by Route B).
Afterwards, with the aim of expanding the diversity in substitution of quinoline derivatives, the
phosphino substituted quinolines were synthesized by multicomponent Povarov type [4+2]-
cycloaddition
reaction
as
shown
in
Scheme 2.
First,
the endo-1,2,3,4-
tetrahydroquinolinylphosphanes 9 were regioselectively obtained by reaction between 2-
(diphenylphosphino)aniline 8, aldehydes 2a (R = C6H5) and /or 2b (R = 4-CF3C6H4) and styrene
7

ACCEPTED MANUSCRIPT
3a (R1 = H) in the presence of 2 equivalents of BF3·Et2O in refluxing chloroform (Scheme 2,
Route A) and led to the formation of the corresponding tetrahydroquinolines 9a and 9b (Chart 2)
in a regioselective fashion.
In a similar way to that reported in the case of 1,2,3,4-tetrahydroquinolinylphosphine oxides 6
(Scheme 1, vide supra), the formation of 1,2,3,4-tetrahydroquinolinylphosphane 9 may be
explained through a regio- and stereoselective [4+2]-cycloaddition reaction between aldimine,
obtained from aldehyde 2 and amine 8, and the corresponding olefin 3, followed by a prototropic
tautomerization.
Scheme 2. Syntheses of 1,2,3,4-tetrahydroquinolinylphosphanes 9, 1,2,3,4-tetrahydro-
quinolinylphosphine sulfides 10 and quinolinylphosphine sulfides 12.
In order to increase the diversity of the process, the reaction was extended to a substituted
styrene containing an electron-withdrawing substituent (fluorine) such as p-fluorostyrene 3b (R1
= 4-F), since several recently approved drugs contain fluorine in their structure [19], and a
substituted styrene containing an electron-donating group such as p-methylstyrene 3c (R1 = 4-
Me). It is noteworthy that when substituted olefins on the aromatic ring are used, more stable
1,2,3,4-tetrahydroquinolinylphosphanes 9 could be obtained and isolated with better yields [20].
When using p-fluorostyrene 3b and p-methylstyrene 3c corresponding 1,2,3,4-
8

ACCEPTED MANUSCRIPT
tetrahydroquinolinylphosphanes 9c-f were obtained with good yields (Scheme 2, Route A, Chart
2).
Chart 2. Structures of 1,2,3,4-tetrahydroquinolinylphosphanes 9 obtained by Povarov reaction.
Due to the instability of 1,2,3,4-tetrahydroquinolinylphosphanes 9 [21] and because phosphine
sulfides constitute an important class of organophosphorus compounds with potential biological
activity [11], we explored whether these 1,2,3,4-tetrahydroquinolinylphosphine sulfides 10 may
be directly obtained by using a phosphine sulfide amine 11 through a multicomponent protocol.
In this case, the three components (phosphine sulfide amine 11, aldehydes 2 and olefins 3,
Scheme 2, Route B) were mixed in the presence of the Lewis acid (BF3·Et2O), and
corresponding endo-1,2,3,4-tetrahydroquinolinylphosphine sulfides 10 were regioselectively
obtained in refluxing chloroform during 48 hours.
As before, the formation of 1,2,3,4-tetrahydroquinolinylphosphine sulfides 10 may be explained
through a regio- and stereoselective [4+2]-cycloaddition reaction between aldimines, initially
generated by condensation reaction of phosphine sulfide amine 11 and aldehydes 2, and olefins 3
followed
by
a
prototropic
tautomerization.
Aromatization
of
1,2,3,4-
9

ACCEPTED MANUSCRIPT
tetrahydroquinolinylphosphine sulfides 10, which appeared in some cases as a minor component
in the sulfurization reaction of heterocycles 9, was performed by treatment with 2 equivalents of
DDQ in toluene under microwave irradiation for 1 hour. In this manner, the corresponding
quinolinylphosphine sulfides 12 were obtained with good yields (Scheme 2, Chart 3).
Chart 3. Structures of 1,2,3,4-tetrahydroquinolinylphosphine sulfides 10 and
quinolinylphosphine sulfides 12 obtained (aa small amount (9%) of aromatized compound 12a was also
b
c
obtained; a small amount (5%) of aromatized compound 12c was also obtained; isolated yields obtained from
amine 11; dobtained along with tetrahydroqueinoline 10c).
The methodology represents an easy and efficient strategy for the preparation of functionalized
quinoline derivatives containing phosphorus substituents and tolerates a wide range of aromatic
aldehydes with electron-releasing and electron-withdrawing substituents. Regarding phosphorus
substitution, a wide variety of derivatives, such as phosphine, phosphine oxide and phosphine
sulfide derivatives, can be prepared. The biological behavior of prepared compounds as Top1
inhibitors and as antiproliferative agents was studied.
10

ACCEPTED MANUSCRIPT
2.2 Biological results and discussion
2.2.1. Inhibition of topoisomerase I. The inhibitory effect of the synthesized derivatives on
human Topoisomerase type I (hTop1) was investigated. A conventional supercoiled plasmid
relaxation assay was used to determine if the newly synthesized phosphorous heterocycles,
namely 1,2,3,4-tetrahydroquinolinylphosphine oxides 6 and quinolinylphosphine oxides 7,
1,2,3,4-tetrahydroquinolinylphosphanes 9, 1,2,3,4-tetrahydroquinolinylphosphine sulfides 10 and
quinolinylphosphine sulfides 12 inhibit hTop1 activity and therefore the transformation of
supercoiled plasmid DNA into the relaxed one (Table 1). In these experiments compound
samples were mixed with enzyme followed by addition of supercoiled plasmid DNA substrate
and continued incubation for increasing time periods (15 seconds, 45 seconds, 1 minute and 3
minutes). The reaction was terminated by the addition of SDS. DNA relaxation products were
then resolved by gel electrophoresis in 1% agarose gel and visualized by gel red staining.
Camptothecin was used as a positive control (Figure 2).
Figure 2. Inhibition of Top1 activity along the time (15”, 45”, 1’ and 3’) by compounds 7e, 9a
and 10a and camptothecin at 80 µM: lanes 1-3, DNA+Top1+DMSO; lanes 4-7,
DNA+Top1+camptothecin 80µM; lanes 8-11, DNA+Top1+7e 80µM; lanes 12-15,
DNA+Top1+9a 80µM; lanes 16-19, DNA+Top1+10a 80µM; lane 20, control DNA. Reaction
samples were mixed with enzyme at 37 ºC before adding the supercoiled DNA substrate and
separated by electrophoresis on a 1% agarose gel, and then stained with gel red, and
photographed under UV light as described in the Top1 mediated DNA relaxation assay; Sc,
supercoiled DNA.
11

ACCEPTED MANUSCRIPT
Table 1. Top1 inhibitory activity of quinolinylphosphine oxides 6 and 7, quinolinylphosphanes 9
and quinolinylphosphine sulfides 10 and 12.
Top1 Inhibitiona
Entry Compound
R
R1
15 s
1 min
3 min
1
Camptothecin (CPT)
Ph
++
++
Θ
6a
6b
6c
2
H
H
++
++
++
++
+
Θ
Θ
3
4-F-C6H4
4-CF3-C6H4
2-pyridyl
2-MeO-C6H4
1-naphthyl
4-F-C6H4
Ph
4
H
+
Θ
6d
6e
5
H
+++
+++
++
+++
+++
++
++
+
+++
++
+
6
H
6f
7
H
6g
6h
7a
8
4-F
4-Me
H
++
+
9
+
Θ
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Ph
++
++
+
Θ
7b
7c
4-F-C6H4
4-CF3-C6H4
2-pyridyl
2-MeO-C6H4
1-naphthyl
4-F-C6H4
Ph
H
+
+
H
+
+
Θ
7d
7e
H
++
++
+++
+++
++
Θ
Θ
H
+++
+++
++
++
++
Θ
7f
H
7g
7h
9a
4-F
4-Me
H
Θ
Θ
Ph
+++
++
+++
++
+++
+++
+++
++
+++
Θ
+++
++
+++
+++
+++
++
+++
Θ
9b
9c
4-CF3-C6H4
4-F-C6H4
Ph
H
4-F
4-Me
4-Me
4-Me
H
+++
+++
+++
++
9d
9e
4-F-C6H4
4-MeO-C6H4
Ph
9f
10a
10b
10c
10d
10e
10f
12a
12b
12f
+++
Θ
4-CF3-C6H4
4-F-C6H4
3,4-F2-C6H3
2-naphthyl
4-F-C6H4
Ph
H
H
+
+
+
H
++
++
+++
+++
++
+++
+
++
+++
+++
Θ
H
+++
+++
+++
+++
+
4-F
H
4-CF3-C6H4
H
+++
4-F-C6H4
4-F
+
a The activity of the compounds to inhibit Top1 relaxation was expressed semiquantitatively as follows: Θ, no activity;
+, weak activity; ++ similar activity to camptothecin; +++ strong activity. See Supporting information for quantitative
values of % inhibition (Table 1.SI).
12

ACCEPTED MANUSCRIPT
Top1 inhibitory activity was tested by detecting the conversion of supercoiled DNA (Sc, Figure
2) to its relaxed form in the presence of the purified enzyme and expressed in semiquantitative
fashion relative to the Top1 inhibitory activity of camptothecin (Table 1). As shown in Figure 2,
Top1 relaxes supercoiled DNA even in the presence of DMSO (Figure 2, lanes 1-3). On the other
hand, CPT inhibits the relaxation, as indicated by the increased intensity of the band
corresponding to the supercoiled DNA (Figure 2, lanes 4-7). And on the basis of the results of
the relaxation assays (Figure 2, lanes 4-19, Table 1), we conclude that some of the tested
compounds inhibited Top1 relaxation more potently than camptothecin when added at the same
concentration. For instance, phosphine oxide derivatives with aromatic or electron-donating
substituents present higher inhibitory activity than CPT (Table 1), such as tetrahydroquinolines
6d (R = 2-pyridyl, R1 = H, entry 5) and 6e (R = 2-MeOC6H4, R1 = H, entry 6) or quinolines 7e (R
= 2-MeOC6H4, R1 = H, entry 14) and 7f (R = 2-naphthyl, R1 = H, entry 15). However, in
phosphine or phosphine sulfide derivatives electron-withdrawing substituents present the highest
potency. Therefore, tetrahydroquinolinylphosphane 9a (R = Ph, R1 = H, entry 18), 9c (R = 4-
FC6H4, R1 = 4-FC6H4, entry 20) and phosphine sulfides 10a (R = Ph, R1 = H, entry 24), 10e (R =
2-naphthyl, R1 = H, entry 28), 10f (R = 4-FC6H4, R1 = 4-FC6H4, entry 29), 12a (R = Ph, R1 = H,
entry 30), 12b (R = 4-CF3C6H4, R1 = H, entry 31) resulted to be more potent than CPT in
inhibiting Top1 enzymatic activity. In addition, relaxation assays of compounds 6d, 9a, 9c, 9d,
10a, 10e, 10f and 12b after 3 minutes of enzymatic reaction have been performed at lower
different concentrations as 60, 40, 20 and 10 µM (see Supporting Information, Table 2.SI). And
it is noteworthy that some of those potent compounds, such as 6d, 9d, 9e, 10e, 10f and 12b, are
able to inhibit Top1 activity even at such a low concentration as 20 and 10 at µM (Table 2.SI,
entries 2, 5, 6, 8, 9, 10).
13

ACCEPTED MANUSCRIPT
Remarkably, longer effect on those compounds presenting greater inhibition than that observed
for the natural inhibitor, CPT, must be pointed out. It is well known that CPT binds reversibly to
Top1 and that the cleavage complexes reverse within minutes as seen in lane 7 [6]. The quick
detachment from the topoisomerase I-cleaved DNA complex represents one of the disadvantages
of CPT based anticancer drugs which imposes long infusions [22]. As it can be observed in
Table 1, the most potent compounds (Table 1, entries 5, 6, 14, 15, 18, 20, 21, 22, 24, 28, 29, 31)
the potent effect on inhibiting Top1 activity is maintained with the same intensity even after 3
minutes the enzymatic reaction starts. In other words, these compounds show their ability to
prevent relaxation of supercoiled DNA with high potency over prolonged period, representing an
advantage with respect to CPT as it may reduce the amount and frequency of drug
administration. And it is noteworthy that these compounds are not only more potent than CPT
after 3 minutes of enzymatic reaction but are also able of inhibiting the action of the Top1 after
that time even at low concentrations.
2.2.2. In Vitro Cytotoxicity. The cytotoxicity of the newly synthesized 1,2,3,4-
tetrahydroquinolinylphosphine oxides 6 and quinolinylphosphine oxide derivatives 7, 1,2,3,4-
tetrahydroquinolinylphosphanes 9, 1,2,3,4-tetrahydroquinolinylphosphine sulfides 10 and
quinolinylphosphine sulfides 11 was evaluated in vitro by testing their antiproliferative activities
against several human cancer cell lines: A549 (carcinomic human alveolar basal epithelial cell),
SKOV03 (human ovarian carcinoma) and HEK293 (human embryonic kidney). Cell counting kit
(CCK-8) assay was employed to assess growth inhibition and, cell proliferation inhibitory
activities of the compounds are listed in Table 2 as IC50 values.
14

ACCEPTED MANUSCRIPT
Table 2. Antiproliferative activity of quinolinylphosphine oxides 6 and 7, quinolinylphosphanes
9, quinolinylphosphine sulfides 10 and 12.
Cytotoxicity IC50 (µM)a
Entry Compound
R
R1
lung
ovarian
kidney
A549
SKOV03
HEK293
MRC-5
1
camptothecin
Ph
(1.0±0.06)·10-3 (5.5±0.01)·10-3 (5.6±2.04)·10-4
-
6a
6b
6c
2
H
H
1.72±0.20
2.69±0.31
0.50±0.06
3.80±1.21
0.21±0.03
3.57±0.31
0.25±0.03
1.20±0.12
1.21±0.68
2.26±0.21
1.03±0.16
2.93±0.27
3.11±0.65
6.32±1.09
3.82±0.42
7.65±0.90
0.6±2.1
>50
24.09±2.02
>50
>50
26.50±4.52
28.00±2.02
14.83±2.56
16.26±1.11
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
3
4-F-C6H4
4-CF3-C6H4
2-pyridyl
2-MeO-C6H4
1-naphthyl
4-F-C6H4
Ph
4
H
6d
6e
5
H
19.07±3.56
>50
6
H
6f
7
H
>50
6g
6h
7a
8
4-F
4-Me
H
17.79±5.45
>50
23.88±4.05
28.0±2.26
13.77±1,47
17.17±2.98
19.37±1,08
12.01±0.98
24.13±1.76
54.37±6.46
12.46±0.87
8.97±0.54
>50
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Ph
14.46±2.27
8.16±1.99
15.19±0.81
17.31±1.33
13.06±1.80
>50
7b
7c
4-F-C6H4
4-CF3-C6H4
2-pyridyl
2-MeO-C6H4
1-naphthyl
4-F-C6H4
Ph
H
H
7d
7e
H
H
7f
H
7g
7h
9a
4-F
4-Me
H
6.77±0.85
17.38±1.58
>50
Ph
9b
9c
4-CF3-C6H4
4-F-C6H4
Ph
H
16.17±4.9
0.08±0.01
0.11±0.01
0.25±0.12
2.48±0.96
0.16±0.01
0.22±0.01
0.27±0.05
0.08±0.03
0.27±0.05
0.03±0.02
>50
>50
>50
4-F
4-Me
4-Me
>50
>50
9d
9e
>50
>50
4-F-C6H4
>50
>50
9f
4-MeO-C6H4 4-Me
>50
>50
10a
10b
10c
10d
10e
10f
12a
12b
12f
Ph
H
H
>50
>50
4-CF3-C6H4
4-F-C6H4
3,4-F2-C6H3
2-naphthyl
4-F-C6H4
Ph
>50
>50
H
>50
>50
H
>50
>50
H
>50
>50
4-F
H
>50
>50
>50
>50
4-CF3-C6H4
H
>50
>50
>50
4-F-C6H4
4-F
>50
>50
>50
aThe cytotoxicity IC50 values listed are the concentrations corresponding to 50% growth inhibition.
15

ACCEPTED MANUSCRIPT
The tested compounds displayed a broad spectrum of antiproliferative activity against the cancer
cell lines tested in culture. We first focused on those compounds containing a phosphine oxide
group such as 1,2,3,4-tetrahydroquinolinylphosphine oxides 6 and the aromatized
quinolinylphosphine oxide derivatives 7 for our studies.
Afterwards, the corresponding 1,2,3,4-tetrahydroquinolinylphosphanes 9 were tested. And
finally the family of compounds containing a phosphine sulfide group such as 1,2,3,4-
tetrahydroquinolinylphosphine sulfides 10 and the aromatized quinolinylphosphine sulfides 12
derivatives were studied.
According to the data presented in Table 2, in general all these phosphorated derivatives present
a higher selective cytotoxicity in the human lung adenocarcinoma cell line (A549) than in the
other two cell lines, human ovarian carcinoma line (SKOV03) and human embryonic kidney cell
line (HEK293). Moreover, MRC-5 non-malignant lung fibroblasts were tested for studying
selective toxicity [23] and in contrast, none of the synthesized phosphorated compounds
exhibited any toxicity toward MRC-5 cells (Table 2).
Concerning the new compounds containing a phosphine oxide group against the A549 cell line in
vitro, 1,2,3,4-tetrahydroquinolinylphosphine oxides 6 with IC50 values between 0.21±0.03 and
3.57±0.31 ꢀM are more active than the corresponding quinolinylphosphine oxides 7 with IC50
values between 1.03±0.16 and 7.65±0.90 ꢀM, the most effective compounds being the derivative
6e (R = 2-CH3O-C6H4, R1 = H) with an IC50 value of 0.21±0.03 ꢀM, the compound 6g (R = 4-
FC6H4, R1 = 4-F) with an IC50 value of 0.25±0.03 ꢀM and the derivative 6c (R = 4-CF3C6H4, R1
= H) with an IC50 value of 0.50±0.06 ꢀM; while the quinoline 7c (R = 4-CF3C6H4, R1 = H) with
an IC50 value of 1.03±0.66 ꢀM is the most active between quinolinylphosphine oxides 7.
However, against the SKOV03 and HEK293 cell lines in vitro, quinolines 7 are more active than
16

ACCEPTED MANUSCRIPT
the corresponding 1,2,3,4-tetrahydroquinolines 6, with the highest activity in
quinolinylphosphine oxide 7g (R = 4-FC6H4, R1 = 4-F) with an IC50 value of 6.77±0.85 ꢀM in
the case of SKOV03 and in the derivative 7h (R = C6H5, R1 = 4-CH3) with an IC50 value of
8.97±0.54 ꢀM for HEK293 cell line, respectively.
Furthermore, very high selectivity was observed in the antiproliferative activity of the new
compounds containing a phosphine 9 or a phosphine sulfide group 10 and 12 against the A549
versus SKOV03 and HEK293 cell lines, and it can even be observed that the fluorinated
derivatives
presented
the
highest
cytotoxic
effects
[11].
Thus,
1,2,3,4-
tetrahydroquinolinylphosphanes 9 showed IC50 values between 0.08±0.01 and 16.17±4.39 ꢀM;
the 1,2,3,4-tetrahydroquinolinylphosphane derivative 9c (R = 4-FC6H4, R1 = 4-F) with an IC50
value of 0.08±0.01 ꢀM and compound 9d (R = C6H5, R1 = 4-CH3) with an IC50 value of
0.11±0.01 ꢀM being the most effective.
Finally, excellent results were observed for 1,2,3,4-tetrahydroquinolinylphosphine sulfides 10
most effectively being the better ones against the A549 cell line in vitro with IC50 values between
0.03±0.02 and 0.27±0.05 ꢀM. Once again, the fluorinated derivatives were the most cytotoxic,
such as tetrahydroquinoline 10f (R = 4-FC6H4, R1 = 4-F) with an IC50 value of 0.03±0.04 ꢀM and
the tetrahydroquinoline 10d (R = 3,4-F2-C6H4, R1 = H) with an IC50 value of 0.08±0.03 ꢀM.
However, no cytotoxic effect was observed for aromatic quinolinylphosphine sulfides 12.
3. Conclusions
In summary, the preparation of novel 1,2,3,4-tetrahydroquinolines and quinolines containing
phosphorus substituents such as phosphine oxide, phosphine and phosphine sulfide by using the
Povarov reaction and the development of a new family of TopI inhibitors are reported. The
17

ACCEPTED MANUSCRIPT
synthesis of 1,2,3,4-tetrahydroquinolinylphosphine oxides 6 involves either the Aza-Diels-Alder
reaction of functionalized imines 4, obtained from phosphine oxide aniline 1 with aldehydes 2,
and styrenes 3 or by means of the multicomponent reaction of phosphino oxide aniline 1,
aldehydes 2 and styrenes 3 in a regio and stereoselective fashion. Subsequent aromatization with
DDQ afforded the corresponding quinolinylphosphine oxides 7. The synthesis of 1,2,3,4-
tetrahydroquinolinylphosphanes 9 involves the multicomponent reaction of phosphinoaniline 8,
aldehydes 2 and styrenes 3. 1,2,3,4-Tetrahydroquinolinylphosphine sulfides 10 can be obtained
from anilines containing the phosphine sulfide group 11, aldehydes 2 and styrenes 3. Subsequent
aromatization of 1,2,3,4-tetrahydroquinolines 10 with DDQ afforded the corresponding
quinolinylphosphine sulfides 12.
This strategy contributes to the possibility of introducing structural diversity at different
positions of the resulting scaffold depending on the starting amines and commercial aromatic
aldehydes and olefins, and allows the preparation of quinolines with a phosphorated substituent
in its structure that could be interesting in terms of the biological activity since this fragment is
present in compounds with very interesting biological properties.
Some of the newly synthesized compounds exhibited inhibitory effects against TopI mediated
relaxation comparable to those observed for the natural inhibitor, camptothecin (CPT). To the
best of our knowledge, this is the first time that phosphino, phosphino sulfide and
quinolinylphosphine oxide derivatives have been tested as TopI inhibitors and may be considered
as new families of TopI inhibitors. The therapeutic efficacy of all the prepared derivatives was
evaluated against three different human cancer cell lines A549, SKOV03 and HEK293. The best
results were observed in A549 cell lines and very good cytotoxic effects were observed for the
1,2,3,4-tetrahydroquinolinylphosphane derivative 9c with an IC50 value of 0.08±0.01 ꢀM as well
18

ACCEPTED MANUSCRIPT
as for 1,2,3,4-tetrahydroquinolinylphosphine sulfide 10f with an IC50 value of 0.03±0.04 ꢀM and
the 1,2,3,4-tetrahydroquinolinylphosphine sulfide 10d with an IC50 value of 0.08±0.03 ꢀM.
These preliminary studies suggested that some of the newly synthesized compounds exhibited a
significant antiproliferative activity by inhibiting the growth of human tumor cell lines.
4. Experimental protocols
4.1 Chemistry
4.1.1. General experimental information
All reagents from commercial suppliers were used without further purification. All solvents were
freshly distilled before use from appropriate drying agents. All other reagents were recrystallized
or distilled when necessary. Reactions were performed under a dry nitrogen atmosphere.
Analytical TLCs were performed with silica gel 60 F254 plates. Visualization was accomplished
by UV light. Column chromatography was carried out using silica gel 60 (230-400 mesh ASTM)
or neutral alumina (70-290 mesh ASTM). Melting points were determined with an
Electrothermal IA9100 Digital Melting Point Apparatus without correction. NMR spectra were
obtained on a Bruker Avance 400 MHz and a Varian VXR 300 MHz spectrometers and recorded
1
at 25 ºC. Chemical shifts for H NMR spectra are reported in ppm downfield from TMS,
13
chemical shifts for C NMR spectra are recorded in ppm relative to internal chloroform (δ =
77.2 ppm for 13C), chemical shifts for 19F NMR are reported in ppm downfield from
fluorotrichloromethane (CFCl3). Coupling constants (J) are reported in Hertz. The terms m, s, d,
13
19
t, q refer to multiplet, singlet, doublet, triplet, quartet. C NMR, and F NMR were broadband
decoupled from hydrogen nuclei. High resolution mass spectra (HRMS) was measured by EI
method with a Agilent LC-Q-TOF-MS 6520 spectrometer. Compounds 9a,b, 9d-f, 10a,b and
12a,b were prepared as previously described [20].
4.1.2. Compounds Purity Analysis
19

ACCEPTED MANUSCRIPT
All synthesized compounds were analyzed by HPLC to determine their purity. The analyses were
performed on Agilent 1260 infinity HPLC system (C-18 column, Hypersil, BDS, 5 ꢀm, 0.4
mm×25 mm) at room temperature. All the tested compounds were dissolved in dichloromethane,
and 5ꢀL of the sample was loaded onto the column. Ethanol and heptane were used as mobile
phase, and the flow rate was set at 1.0 mL/min. The maximal absorbance at the range of 190−400
nm was used as the detection wavelength. The purity of all the tested compounds (compounds 6,
7, 9, 10 and 12) is >95%, which meets the purity requirement by the Journal.
4.1.3.1. (2-Aminophenyl)diphenylphosphine oxide (1). To
a
solution of (2-
nitrophenyl)diphenylphosphine oxide [24] (10 mmol, 3.233 g) in methanol (15 mL), one spoon
of RANEY® Nickel (approx. 5 g) was added. The reaction was stirred for 2 h a 80 psi with a H2
containing balloon attached. The reaction mixture was filtered off through a pad of celite and
evaporated to dryness to obtain 2.903 g of (2-aminophenyl)diphenylphosphine oxide 1 (99%) as
a yellow solid; mp 167-168 ºC (methanol). 1H NMR (300 MHz, CDCl3) δ: 4.87 (ws, 2 H, NH2),
6.58-6.80 (m, 3 H), 7.22-7.27 (m 1 H), 7.46-7.67 (m, 10 H) ppm. 13C NMR (75 MHz, CDCl3): δ
: 111.7 (d, 1Jcp = 105.8 Hz, C), 116.5 (d, 3Jcp = 12.6 Hz, HC), 116.8 (d, 3Jcp = 8.6 Hz, HC), 128.5-
133.4 (m, 12 HC and 2 C), 152.6 (d, 2Jcp = 4.5 Hz, C) ppm. 31P NMR (120 MHz, CDCl3): δ: 36.7
ppm. HRMS (EI): calculated for C18H16NOP [M]+ 293.0970; found 293.0984.
4.1.3.2. General procedure for the preparation of aldimines (4). To a solution of (2-
aminophenyl)diphenylphosphine oxide 1 (10 mmol, 2.933 g) in CHCl3 (30 mL) was added the
corresponding aldehyde (10 mmol). The mixture was stirred under nitrogen at the opportune
1
31
temperature until consumption of starting materials was checked by H NMR and/or P NMR
and/or 19F NMR spectroscopy. The reaction product is unstable during distillation and/or
chromatography and was used without purification for the following reactions.
4.1.3.2.1. 2-(Benzylideneaminophenyl)diphenylphosphine oxide (4a). The general procedure
1
was followed using benzaldehyde (10 mmol, 1.016 mL) and heated to reflux for 24 h. H NMR
crude reaction mixture (300 MHz, CDCl3) δ: 6.93-6.97(m, 1H), 7.22-7.61 (m, 14 H), 7.69-7.97
(m, 5 H), 8.03 (s, 1 H); 31P NMR crude reaction mixture (120 MHz, CDCl3) δ: 29.0 ppm.
4.1.3.2.2. 2-(4-Fluorobenzylideneaminophenyl)diphenylphosphine oxide (4b). The general
procedure was followed using 4-fluorobenzaldehyde (10 mmol, 1.079 mL) and heated to reflux
20

ACCEPTED MANUSCRIPT
1
for 12 h. H NMR crude reaction mixture (300 MHz, CDCl3) δ: 6.66-6.74 (m, 1 H), 6.87-7.87
(m, 17 H), 8.01 (s, 1 H) 31P NMR crude reaction mixture (120 MHz, CDCl3) δ: 28.6 ppm; 19F
NMR crude reaction mixture (282 MHz, CDCl3): δ = - 107.8 ppm.
4.1.3.2.3. 2-(4-Trifluoromethylbenzylideneaminophenyl)diphenylphosphine oxide (4c). The
general procedure was followed using 4-trifluoromethylbenzaldehyde (10 mmol, 1.339 mL) and
heated to reflux for 12 h. 1H NMR crude reaction mixture (300 MHz, CDCl3) δ: 7.06-7.08 (m, 1
H), 7.15-7.96 (m, 17 H), 8.02 (s, 1 H) ppm; 31P NMR crude reaction mixture (120 MHz, CDCl3)
δ: 28.6 ppm; 19F NMR crude reaction mixture (282 MHz, CDCl3): δ = - 63.3 ppm.
4.1.3.2.4. Diphenyl-2-(pyridin-2-ylmethylen)aminophenylphosphine oxide (4d). The general
procedure was followed using 2-pyridinecarboxaldehyde (10 mmol, 0.9512 mL) and heated to
reflux for 24 h. 1H NMR crude reaction mixture (300 MHz, CDCl3) δ: 6.58-7.91 (m, 17 H), 8.29
(s, 1 H), , 8.57 (d, 3JHH = 5.0 Hz, 1 H) ppm; 31P NMR crude reaction mixture (120 MHz, CDCl3)
δ: 28.6 ppm.
4.1.3.3. Synthesis of 1,2,3,4-tetrahydroquinolinylphosphine oxides
6
and/or
quinolinylphosphine oxides 7 by Povarov reaction.
4.1.3.3.1. General procedure A. Reaction of imines 4 with styrenes 3. Styrene 3 (12 mmol)
and 1 equivalent of BF3·Et2O (10 mmol, 1.230 mL) were added to a solution of the in situ
prepared aldimine 4 (10 mmol) in CHCl3 (25 mL). The mixture was stirred at the appropriate
1
temperature until TLC, 31P NMR and H NMR spectroscopy indicated the disappearance of
aldimine. The reaction mixture was washed with 2M aqueous solution of NaOH (50 mL) and
water (50 mL), extracted with dichloromethane (2 x 25 mL), and dried over anhydrous MgSO4.
The removal of the solvent under vacuum afforded and oil that was purified by silica gel flash
column chromatography using a gradient elution of 10-70% ethyl acetate in hexane to afford
products 6 and/or 7.
4.1.3.3.2. General procedure B. Multicomponent reaction (MCR). A mixture of (2-
Aminophenyl)diphenylphosphanoxide 1 (10 mmol, 2.933 g), freshly distilled aldehyde 2 (10
mmol) styrene 3 (12 mmol) and 1 equivalent of BF3·Et2O (10 mmol, 1.230 mL) in CHCl3 (25
mL) and in the presence of molecular sieves (4Å) in CHCl3 (25 mL), was stirred and heated at
21

ACCEPTED MANUSCRIPT
1
reflux until TLC, 31P NMR and H NMR analysis indicated the consumption of starting
materials. The molecular sieves were removed by filtration and the resulting solution was diluted
with methylene chloride (50 mL), washed with a solution of NaOH 2M (50 mL) and water (50
mL), extracted with methylene chloride (2 x 20 mL), and dried over anhydrous MgSO4. Removal
of solvent under vacuum led to an solid that was purified by flash column chromatography on
silica gel using a gradient of elution of 5-70% ethyl acetate in hexane to afford products 6 and/or
7.
4.1.3.3.4. (2,4-Diphenyl-1,2,3,4-tetrahydroquinolin-8-yl)diphenylphosphine oxide (6a). The
general procedure A was followed using aldimine 4a (10 mmol) prepared in situ and styrene 3a
(12 mmol, 1.374 mL) for 2.5 h at room temperature, affording 4.334 g (90%) of a white solid
identified as 6a, mp 132-133 ºC (ethyl acetate/hexane). When the general procedure B was
followed using benzaldehyde 2a (10 mmol, 1.016 mL) and styrene 3a (12 mmol, 1.374 mL) for 1
h at room temperature, 3.251 g (67%) of 6a were obtained. 1H NMR (400 MHz, CDCl3) δ: 2.06
3
3
2
(ddd, JHH = 12.7 Hz, JHH = 11.7 Hz, JHH = 12.7 Hz, 1 H, CH2) 2.28-2.31 (m, 1 H, CH2), 4.29
(dd, 4JHH = 4.2 Hz, 3JHH = 12.5 Hz, 1 H, CH), 4.77 (dd, 4JHH = 3.2 Hz, 3JHH = 11.7 Hz, 1 H, CH),
6.33 (ddd, 3JHH = 7.6 Hz, 3JHH = 7.5 Hz, 4JHP = 2.9 Hz, 1 H), 6.63 (d, 3JHH = 7.6 Hz, 1 H), 6.66 (d,
13
3JHH = 7.5 Hz, 1 H), 7.08-7.86 (m, NH and 20 H) ppm; C {1H} NMR (75 MHz, CDCl3) δ:
1
40.9 (CH2), 44.7 (HC), 56.7 (HC), 110.3 (d, JCP = 105.6 Hz, C), 114.6 (d, 3JCP = 13.8 Hz, HC),
2
125.9-133.3 (m, 22 HC y 3 C), 143.8 (C), 144.1 (C), 150.0 (d, JCP = 4.6 Hz, C) ppm; 31P NMR
(120 MHz, CDCl3) δ: 36.4 ppm. HRMS (EI) calculated for C33H28NOP [M]+ 485.1909; found
485.1914. Purity 95.94% (EtOH/Heptane = 10/90, Rt = 4.848 min).
4.1.3.3.5.
(2-(4-Fluorophenyl)-4-phenyl-1,2,3,4-tetrahydroquinolin-8-yl)diphenylphosphine
oxide (6b). The general procedure A was followed using aldimine 4b (10 mmol) prepared in situ
and styrene 3a (12 mmol, 1.374 mL) for 42 h. The mixture was refluxed affording compounds
6b (2.417 g, 48%) as a yellow oil (Rf = 0.52, 50:50 hexane/EtOAc) and 7b (0.400 g, 8%) as a
yellow solid mp 219-220 ºC (ethyl acetate/hexane). When the general procedure B was followed
using 4-fluorobenzaldehyde (10 mmol, 1.079 mL) and styrene 3a (12 mmol, 1.374 mL) for 24 h
1
heated to reflux only compound 7b (3.444 g, 69%) was obtained. Data for 6b: H NMR (300
3
3
2
MHz, CDCl3) δ: 1.85 (ddd, JHH = 12.8 Hz, JHH = 11.4 Hz, JHH = 12.7 Hz, 1 H, CH2), 2.08-2.12
22

ACCEPTED MANUSCRIPT
(m, 1 H, CH2), 4.11 (dd, 3JHH = 4.1 Hz, 3JHH = 12.8 Hz, 1 H, CH), 4.58 (dd, 3JHH = 2.3 Hz, 3JHH
=
11.4 Hz, 1 H, CH), 6.23-6.29 (m, 1 H), 6.53 (d, 3JHH = 7.6 Hz, 1 H), 6.57 (d, 3JHH = 7.5 Hz, 1 H),
6.70-6.76 (m, 2H), 6.85-6.90 (m, 2 H), 7.08 (s, 1 H, NH), 7.11-7.23 (m, 5 H), 7.32-7.69 (m, 10
H) ppm; 13C NMR {H} (75 MHz, CDCl3) δ: 41.1 (CH2), 44.7 (CH), 56.2 (CH), 111.2 (d, 1JCP =
105.5 Hz, C), 114.8 (d, 3JCP = 13.8 Hz, HC), 115.3 (d, 3JCF = 21.3 Hz, 2 HC), 126.1 (d, 3JCP = 8.0
Hz, C),127.0 (HC), 128.7 (d, 2JCP = 4.9 Hz, HC), 128.8-132.0 (m, 13 HC), 132.3 (d, 1JCP = 104.8
Hz, C), 132.6 (2 HC), 132.9 (HC), 133.1 (d, 1JCP = 104.8 Hz, C), 133.6 (HC), 139.6 (d, 4JCF = 2.5
Hz, C), 144.1 (C), 149.9 (d, 2JCP = 3.5 Hz, C), 162.5 (d, 1JCF = 244.6 Hz, C) ppm; 31P NMR (120
MHz, CDCl3) δ: 36.4 ppm; 19F NMR (282 MHz, CDCl3) δ: -116.0 to -115.9 (m) ppm. HRMS
(EI): calculated for C33H27FNOP [M]+ 503.1814; found C33H23FNOP [-4H]+ 499.1500. Purity
97.83% (EtOH/Heptane = 10/90, Rt = 6.304 min). See data for compound 7b (vide infra).
4.1.3.3.6.
(4-Phenyl-2-(4-trifluoromethylphenyl)-1,2,3,4-tetrahydroquinolin-8-yl)
diphenylphosphine oxide (6c). The general procedure A was followed using compound 4c (10
mmol) prepared in situ and styrene 3a (12 mmol, 1.374 mL) for 1 h at room temperature,
1
affording 4.425 g (80%) of 6c as a white solid mp 199-201 ºC (ethyl acetate/hexane). H NMR
(400 MHz, CDCl3) δ: 1.97 (ddd, 3JHH = 12.0 Hz, 3JHH = 12.4 Hz, 2JHH = 12.5 Hz, 1 H, CH2), 2.22-
2.27 (m, 1 H, CH2), 4.23 (dd, 3JHH = 12.4 Hz, 3JHH = 4.0 Hz, 1 H, CH), 4.78 (dd, 3JHH = 12.0 Hz,
3JHH = 2.7 Hz, 1 H, CH), 6.36-6.42 (m, 1 H), 6.64 (d, 3JHH = 7.6 Hz, 1 H), 6.69 (d, 3JHH = 7.5 Hz,
13
1 H), 7.11-7.79 (m, NH and 19 H) ppm; C NMR {H} (75 MHz, CDCl3) δ: 40.8 (CH2), 44.7
1
3
1
(HC), 56.5 (HC), 111.4 (d, JCP = 105.2 Hz, C), 115.3 (d, JCP = 13.6 Hz, HC), 124.3 (q, JCF =
2
3
272.1 Hz, CF3), 125.6 (d, JCP = 3.5 Hz, HC), 126.1 (d, JCP = 8.1 Hz, C), 126.5-128.8 (m, 13
2
1
HC), 129.6 (q, JCF = 32.3 Hz, C), 131.9-132.4 (m, 6 HC and C) 132.9 (d, JCP = 105.2 Hz, C),
133.1 (HC), 143.9 (C), 148.1 (C), 149.7 (d, 2JCP = 4.5 Hz, C) ppm; 31P NMR (120 MHz, CDCl3)
δ: 36.5 ppm; 19F NMR (282 MHz, CDCl3) δ: - 62.8 ppm. HRMS (EI): calculated for
C34H27F3NOP [M]+ 553.1782; found 553.1802. Purity 97.84% (EtOH/Heptane = 10/90, Rt =
3.709 min).
4.1.3.3.7. (4-Phenyl-2-(pyridin-2-yl)-1,2,3,4-tetrahydroquinolin-8-yl)diphenylphosphine oxide
(6d). The general procedure A was followed using aldimine 4d (10 mmol) prepared in situ and
styrene 3a (12 mmol, 1.374 mL) for 6.5 h at room temperature affording 3.309 g (68%) of 7d as
23

ACCEPTED MANUSCRIPT
a yellow solid, mp 110-112 ºC (ethyl acetate/hexane). When the general procedure B was
followed using 2-pyridinecarboxaldehyde (10 mmol, 0.951 mL) and styrene 3a (12 mmol, 1.374
mL) for 24 h heated to reflux compound 6d (3.357 g, 69%) was obtained. 1H NMR (400 MHz,
CDCl3) δ: 1.97 (ddd, 3JHH = 12.5 Hz, 3JHH = 11.4 Hz, 2JHH = 12.5 Hz, 1 H, CH2), 2.45-2.52 (m, 1
H, CH2), 4.27 (dd, 3JHH = 12.5 Hz, 3JHH = 4.6 Hz, 1 H, CH), 4.84 (dd, 3JHH = 11.3 Hz, 3JHH = 3.3
3
3
4
Hz, 1 H, CH), 6.38 (ddd JHH = 7.6 Hz, JHH = 7.6 Hz, JHP = 3.0 Hz, 1 H), 6.63-6.74 (m, 2 H),
6.96 (d, 3JHH = 7.9 Hz, 1 H), 7.17-7.81 (m, NH and 18 H), 8.45 (d, 3JHH = 7.4 Hz, 1 H) ppm; 13C
NMR {H} (75 MHz, CDCl3) δ: 39.1 (CH), 44.6 (CH2), 57.9 (CH), 111.0 (d, 1JCP = 105.6 Hz, C),
3
115.1 (d, 3JCP = 13.9 Hz, HC), 119.6 (HC), 122.2 (HC), 126.2 (d, JCP = 7.9 Hz, C), 126.8 (HC),
1
128.2-132.1 (m, 15HC and C), 133.3 (d, JCP = 104.8 Hz, C), 133.4 (2HC), 137.2 (HC), 144.3
2
31
(C), 148.9 (HC), 149.9 (d, JCP = 4.5 Hz, C), 162.7 (C) ppm; P NMR (120 MHz, CDCl3) δ:
37.0 ppm. HRMS (EI): calculated for C32H27N2OP [M]+ 486.1861; found 486.1869. Purity
99.48% (EtOH/Heptane = 10/90, Rt = 6.045 min).
4.1.3.3.8. (2-(2-Methoxyphenyl)-4-phenyl-1,2,3,4-tetrahydroquinolin-8-yl)diphenylphosphine
oxide (6e). The general procedure B was followed using o-anisaldehyde (10 mmol, 1.208 mL)
and styrene 3a (12 mmol, 1.374 mL) for 36 h heated to reflux affording compound 6e (4.692 g,
91%) as a white solid, mp 233-235 ºC (ethyl acetate/hexane). 1H NMR (400 MHz, CDCl3) δ:
3
1.75 (ddd, 3JHH = 12.5 Hz, JHH = 11.1 Hz, 2JHH = 12.5 Hz, 1 H, CH2), 2.28-2.33 (m, 1 H, CH2),
3.68 (s, 3 H, OCH3), 4.15 (dd, 4JHH = 4.2 Hz, 3JHH = 12.5 Hz, 1 H, CH), 5.03 (dd, 4JHH = 3.1 Hz,
3JHH = 11.1 Hz, 1 H, CH), 6.25 (ddd 3JHH = 7.6 Hz, 3JHH = 7.4 Hz, 4JHP = 2.9 Hz, 1 H), 6.51-6.75
(m, 5 H), 6.89 ( s, NH) 7.03-7.73 (m, 16 H) ppm; 13C NMR {H} (75 MHz, CDCl3) δ: 38.0
1
(CH2), 44.8 (HC), 50.0 (OCH3), 55.4 (HC), 110.2 (HC) 110.9 (d, JCP = 105.6 Hz, C), 114.4 (d,
2
3JCP = 13.8 Hz, HC), 121.0 (HC), 125.8-133.8 (m, 19 HC and 4 C), 144.5 (C), 150.5 (d, JCP =
4.6 Hz, C), 156.5 (C) ppm; 31P NMR (120 MHz, CDCl3) δ: 36.3 ppm. HRMS (EI): calculated for
C34H30NO2P [M]+ 515.2014; found 515.2022. Purity 98.19% (EtOH/Heptane = 10/90, Rt =
4.636 min).
4.1.3.3.9. (2-(Naphthalen-1-yl)-4-phenyl-1,2,3,4-tetrahydroquinolin-8-yl)diphenylphosphine
oxide (6f). The general procedure B was followed using 1-naphthaldehyde (10 mmol, 1.358 mL)
and and styrene 3a (12 mmol, 1.374 mL) heated to reflux for 48 h affording compound 6f (3.482
1
g, 65%) as a white solid, mp 267-269 ºC (ethyl acetate/hexane). H NMR (400 MHz, CDCl3) δ:
24

ACCEPTED MANUSCRIPT
3
3
2
2.11 (ddd, JHH = 12.7 Hz, JHH = 11.3 Hz, JHH = 12.5 Hz, 1 H, CH2), 2.48-2.55 (m, 1 H, CH2),
3
3
4.39 (dd, JHH = 12.7 Hz, 3JHH = 4.3 Hz, 1 H, CH), 5.56 (dd, JHH = 11.3 Hz, 3JHH =2.7 Hz, 1 H,
3
3
CH), 6.40 (ddd JHH = 7.6 Hz, JHH = 7.5 Hz, 4JHP = 3.0 Hz, 1 H), 6.66-6.75 (m, 2 H), 7.16-7.99
13
(m, NH and 22 H) ppm; C NMR {H} (75 MHz, CDCl3) δ: 39.3 (CH2), 45.1 (HC), 52.9 (HC),
1
3
111.4 (d, JCP = 105.5 Hz, ), 114.8 (d, JCP = 13.8 Hz, HC), 120,5 (C), 122.5 (HC), 122.8 (HC),
3
125.4 (HC), 125,9 (HC), 126.1 (HC), 126.3 (d, JCP = 7.8 Hz, C), 126.9 (HC), 127,8 (HC),
128.5-129.0 (m, 6 HC), 130.7 (C), 131.8-133.9 (m, 11 HC and 2 C arom), 139.3 (C), 144.3 (C),
2
31
150.3 (d, JCP = 4.6 Hz, C) ppm; P NMR (120 MHz, CDCl3) δ: 36.3 ppm. HRMS (EI):
calculated for C37H30NOP [M]+ 535.2065; found 535.2076. Purity 98.32% (EtOH/Heptane =
10/90, Rt = 4.360 min).
4.1.3.3.10. (2,4-Bis(4-fluorophenyl)-1,2,3,4-tetrahydroquinolin-8-yl)diphenylphosphine oxide
(6g). The general procedure B was followed using 4-fluorobenzaldehyde (10 mmol, 1.079 mL)
and 4-fluorostyrene 3b (12 mmol, 1.437 mL), heated to reflux for 24 h affording compound 6g
1
(2.295 g, 44%) as a whit solid, mp 183-185 ºC (ethyl acetate/hexane). H NMR (400 MHz,
CDCl3) δ: 1.90 (ddd, 3JHH = 12.4 Hz, 3JHH = 11.3 Hz, 2JHH = 12.7 Hz, 1 H, CH2), 2.14-2.20 (m, 1 H,
CH2), 4.22 (dd, 3JHH = 12.4 Hz, 3JHH = 4.3 Hz, 1 H, CH), 4.70 (dd, 3JHH = 11.3 Hz, 3JHH =3.2 Hz,
1 H, CH), 6.37 (ddd 3JHH = 7.6 Hz, 3JHH = 7.4 Hz, 4JHP = 3.0 Hz, 1 H), 6.62-7.19 (m, NH and 11
13
H), 7.44-7.78 (m, 9 H) ppm; C NMR {H} (75 MHz, CDCl3) δ: 41.3 (CH2), 44.0 (HC) 56.2
1
3
3
(HC), 111.3 (d, JCP = 105.5 Hz, C), 114.9 (d, JCP = 13.8 Hz, HC), 115.4 (d, JCF = 21.3 Hz, 2
HC), 115.6 (d, 3JCF = 21.3 Hz, 2 HC), 125.8 (d, 3JCP = 8.0 Hz, C), 127.6-133.6 (m, 16 HC and 2 C
4
4
2
arom), 139.6 (d, JCF = 3.1 Hz, C), 139.8 (d, JCF = 3.2 Hz, C), 149.9 (d, JCP = 4.6 Hz, C), 161.8
1
1
31
(d, JCF = 242.1 Hz, FC), 162.1 (d, JCF = 245.0 Hz, FC) ppm; P NMR (120 MHz, CDCl3) δ:
36.3 ppm; 19F NMR (282 MHz, CDCl3) δ: - 116.6 to -116.4 (m), -116.0 to -115.9 (m) ppm.
HRMS (EI): calculated for C33H26F2NOP [M]+ 521.172; found 521.1727. Purity 98.95%
(EtOH/Heptane = 10/90, Rt = 4.119min).
4.1.3.3.11. (2-Phenyl-4-(p-tolyl)-1,2,3,4-tetrahydroquinolin-8-yl)diphenylphosphine oxide (6h).
The general procedure B was followed using benzaldehyde (10 mmol, 1.016 mL) and 1- methyl-
4-vinylbenzene 3b (12 mmol, 1.575 mL), heated to reflux for 48 h affording compound 6h
1
(3.045 g, 61%) as a light orange solid, mp 223-225 ºC (ethyl acetate/hexane). H NMR (400
MHz, CDCl3) δ: 1.90-2.25 (m, 2 H, CH2), 2.33 (s, 3 H CH3), 4.19 (dd, 3JHH = 12.4 Hz, 3JHH = 4.0
25

ACCEPTED MANUSCRIPT
Hz, 1 H, CH), 4.71 (dd, 3JHH = 11.4 Hz, 3JHH =3.4 Hz, 1 H, CH), 6.35 (ddd 3JHH = 7.8 Hz, 3JHH
=
7.4 Hz, 4JHP = 2.8 Hz, 1 H), 6.57-6.68 (m, 2 H), 6.99-7.78 (m, NH and 19 H) ppm; 13C NMR {H}
(75 MHz, CDCl3) δ: 21.2 (CH3), 41.0 (CH2), 44.4 (HC) 57.0 (HC), 111.0 (d, 1JCP = 108.0 Hz, C),
114.8 (d, 3JCP = 11.7 Hz, HC), 126.1-133.6 (m, 21 HC and 3 C arom), 136.4 (C), 141.2 (C), 143.9
2
31
(C), 150.0 (d, JCP = 3.6 Hz, C) ppm; P NMR (120 MHz, CDCl3) δ: 36.4 ppm. HRMS (EI):
calculated for C34H30NOP [M]+ 499.2065; found 499.2077. Purity 97.16% (EtOH/Heptane =
10/90, Rt = 4.326 min).
4.1.3.4. General Procedure for the Preparation of quinolinylphosphine oxides 7 by
Dehydrogenation with DDQ: To a solution of the corresponding tetrahydroquinoline 6 (1
mmol) in CHCl3 (7 mL) was added DDQ (0.545 g, 2 mmol), and the mixture was heated to
reflux for 2 h. The removal of the solvent under vacuum afforded and oil, diethyl ether was
added and the resulting solid was removed by filtration. The filtrate was removed under vacuum
and the crude solid was purified by recrystallization on ether.
4.1.3.4.1. (2,4-Diphenylquinolin-8-yl)diphenylphosphine oxide (7a). The general procedure was
employed with 6a (0.485 g, 1 mmol) to afford 7a (0.419 g, 87% yield) as a white solid; m.p.
178-180 °C (ethyl acetate/hexane). 1H NMR (300 MHz, CDCl3) δ: 7.16-7.57 (m, 17 H), 7.77 (s,
1 H), 7.91 (dd, 3JHP = 12.3 Hz, 3JHH = 7.8 Hz, 4 H), 8.09 (d, 3JHH = 8.4 Hz, 1 H), 8.61 (dd, 3JHP =
3
13
13.7 Hz, JHH = 6.9 Hz, 1 H) ppm; C NMR {H} (75 MHz, CDCl3) δ: 119.2 (HC), 125.9 (C)
126.0 (d, 3JCP = 13.1 Hz, HC), 127.7-132.3 (m, 1 C and 21 HC), 134.0 (d, 1JCP = 108.8 Hz, 2 C),
3
2
137.9 (d, JCP = 7.0 Hz, HC), 138.0 (C), 138.5 (C), 148.1 (d, JCP = 5.6 Hz C), 149.6 (C), 155.8
(C) ppm; 31P NMR (120 MHz, CDCl3) δ: 29.4 ppm. HRMS (EI): calculated for C33H24NOP [M]+
481.1596; found 481.1589. Purity 95.74% (EtOH/Heptane = 10/90, Rt = 6.609 min).
4.1.3.4.2. (2-(4-Fluorophenyl)-4-phenylquinolin-8-yl)diphenylphosphine oxide (7b). The
general procedure was employed with 6b (0.504 g, 1 mmol) to afford 7b (0.375 g, 75% yield) as
a white solid; m.p. 219-220 °C (ethyl acetate/hexane). 1H NMR (300 MHz, CDCl3) δ: 6.84-6.88
3
(m, 2 H), 7.27-7.54 (m, 14 H), 7.65 (s, 1 H), 7.80-7.85 (m, 4 H), 8.02 (d, JHH = 8.4 Hz, 1 H),
3
3
4
13
8.46 (ddd, JHP = 13.8 Hz, JHH = 7.2 Hz, JHH = 2.0 Hz, 1 H) ppm; C NMR {H} (75 MHz,
CDCl3) δ: 115.4 (d, 2JCF = 22.1 Hz, 2 HC), 118.9 (HC), 125.8 (d, 3JCP = 7.6 Hz, C), 125.9 (d, 3JCP
= 13.1 Hz, HC), 128.2-132.3 (m, 1 C and 18 HC), 134.1 (d, 1JCP = 108.2 Hz, 2 C), 134.7 (d, 4JCF
26

ACCEPTED MANUSCRIPT
3
2
= 2.6 Hz, C), 137.9 (C), 137.9 (d, JCP = 7.2 Hz, HC), 148.2 (d, JCP = 5.7 Hz, C), 149.8 (C),
1
31
19
154.8 (C), 163.8 (d, JCF = 249.9 Hz, C-F) ppm; P NMR (120 MHz, CDCl3) δ:29.0 ppm; F
NMR (282 MHz, CDCl3) δ: -112.17 to -112.05 (m) ppm. HRMS (EI): calculated for
C33H23FNOP [M]+ 499.1501; found 499.1511. Purity 96.54% (EtOH/Heptane = 10/90, Rt =
6.374 min).
4.1.3.4.3. (4-Phenyl-2-(4-(trifluoromethyl)phenyl)quinolin-8-yl)diphenylphosphine oxide (7c).
The general procedure was employed with 6c (0.554 g, 1 mmol) to afford 7c (0.439 g, 80%
yield) as a yellow solid; m.p. 233-235 °C (ethyl acetate/hexane). 1H NMR (300 MHz, CDCl3) δ:
3
7.28-7.45 (m, 16 H), 7.72 (s, 1 H), 7.82 (dd, 3JHP = 12.2 Hz, 3JHH = 7.7 Hz, 4 H), 8.05 (d, JHH
=
3
3
13
8.2 Hz, 1 H), 8.47 (dd, JHP = 13.8 Hz, JHH = 7.0 Hz, 1 H) ppm; C NMR {H} (75 MHz,
CDCl3) δ: 119.3 (HC), 124.2 (q, 1JCF = 272.4 Hz, CF3), 125.6 (d, 4JCP = 3.6 Hz, HC), 126.3-132.6
1
3
(m, 20 HC and 3 C), 134.0 (d, JCP = 108.4 Hz, 2 C), 137.8 (C), 138.1 (d, JCP = 7.3 Hz, HC),
2
31
141.9 (C), 148.2 (d, JCP = 5.2 Hz, C), 150.2 (C), 154.3 (C) ppm; P NMR (120 MHz, CDCl3)
δ:28.0 ppm; 19F NMR (282 MHz, CDCl3) δ: - 62.9 ppm. HRMS (EI): calculated for
C34H23F3NOP [M]+ 549.1469; found 549.1471. Purity 96.62% (EtOH/Heptane = 10/90, Rt =
5.792 min).
4.1.3.4.4. (4-Phenyl-2-(pyridin-2-yl)quinolin-8-yl)diphenylphosphine oxide (7d). The general
procedure was employed with 6d (0.487 g, 1 mmol) to afford 7d (0.401 g, 83% yield) as a
yellow solid; m.p. 114–115 °C (ethyl acetate/hexane). 1H NMR (300 MHz, CDCl3) δ: 7.13-7.18
(m, 2 H), 7.28-7.55 (m, 14 H), 7.80-7.86 (m, 3 H), 8.09 (d, 3JHH = 8.4 Hz, 1 H), 8.34 (dd, 3JHH
=
3
7.0 Hz, 3JHH = 7.0 Hz, 1 H), 8.43 (s, 1 H), 8.51 (d, JHH = 4.0 Hz, 1 H) ppm; 13C NMR {H} (75
3
MHz, CDCl3) δ:119.5 (HC), 122.5 (HC), 124.3 (HC), 126.6 (d, JCP = 12.6 Hz, HC), 127.2 (d,
1
3JCP = 7.0 Hz, C), 128.4-132.1 (m, C and 16 HC), 134.1 (d, JCP = 108.3 Hz, 2C), 136.8 (HC),
137.7 (d, 3JCP = 8.6 Hz, HC), 138.0 (C), 148.1 (d, 2JCP = 5.5 Hz, C), 148.9 (HC), 149.9 (C), 154.9
(C), 155.5 (C) ppm; 31P NMR (120 MHz, CDCl3) δ:29.1 ppm. HRMS (EI): calculated for
C32H23N2OP [M]+ 482.1548; found 482.1549. Purity 96.79% (EtOH/Heptane = 10/90, Rt =
8.604 min).
4.1.3.4.5. (2-(2-Methoxyphenyl)-4-phenylquinolin-8-yl)diphenylphosphine oxide (7e). The
general procedure was employed with 6e (0.516 g, 1 mmol) to afford 7e (0.379 g, 74% yield) as
27

ACCEPTED MANUSCRIPT
a white solid; m.p. 267-269 °C (ethyl acetate/hexane). 1H NMR (300 MHz, CDCl3) δ: 3.80 (s, 3
H, OCH3), 6.52 (dd, J = 1.6 Hz, J = 7.6 Hz, 1 H), 6.69-6.75 (m, 1 H), 6.94 (d, 3JHH = 8.7 Hz, 1
3
3
H), 7.20-7.66 (m, 13 H), 7.89 (dd, JHP = 12.5 Hz, JHH = 7.0 Hz, 4 H), 7.96 (s, 1 H), 8.12 (d,
3
3
4
13
3JHH = 9.0 Hz, 1 H), 8.67 (ddd, JHP = 13.9 Hz, JHH = 7.1 Hz, JHH = 1.6 Hz, 1 H), ppm; C
NMR {H} (75 MHz, CDCl3) δ: 55.7 (OCH3), 111.3 (HC), 120.9 (HC), 121.0-138.5 (m, 6 C, 21
2
31
HC), 147.7 (d, JCP = 5.6 Hz C), 148.1 (C), 155.5 (C), 157.5 (C) ppm; P NMR (120 MHz,
CDCl3) δ: 29.4 ppm;31P NMR (120 MHz, CDCl3) δ: 29.3 ppm. HRMS (EI): calculated for
C34H26NO2P [M]+ 511.1701; found 511.1719. Purity 96.29% (EtOH/Heptane = 10/90, Rt =
6.181 min).
4.1.3.4.6. (2-(Naphthalen-1-yl)-4-phenylquinolin-8-yl)diphenylphosphine oxide (7f). The
general procedure was employed with 6f (0.536 g, 1 mmol) to afford 7f (0.383 g, 72% yield) as
a white solid; m.p. 263-265 °C (ethyl acetate/hexane). 1H NMR (300 MHz, CDCl3) δ: 6.85-6.88
(m, 1H), 7.18-7.91 (m, 23 H), 8.23 (d, 3JHH = 8.7 Hz, 1 H), 8.80 (ddd, 3JHP = 13.7 Hz, 3JHH = 7.2
4
13
Hz, JHH = 1.5 Hz, 1 H), ppm; C NMR {H} (75 MHz, CDCl3) δ: 123.9 (HC), 125.4 (HC),
1
3
125.7-133.2 (m, 4 C, 23 HC), 133.8 (C), 134.3 (d, JCP = 108.7 Hz, 2 C), 137.8 (d, JCP = 9.8
31
Hz, C), 138.0 (d, 3JCP = 6.7 Hz, HC), 148.3 (d, 2JCP = 6.2 Hz C), 149.0 (C), 158.1 (C) ppm; P
NMR (120 MHz, CDCl3) δ: 29.7 ppm. HRMS (EI): calculated for C37H26NOP [M]+ 531.1752;
found 531.1763. Purity 99.34% (EtOH/Heptane = 10/90, Rt = 6.313 min).
4.1.3.4.7. (2,4-Bis(4-fluorophenyl)quinolin-8-yl)diphenylphosphine oxide (7g). The general
procedure was employed with 6g (0.522 g, 1 mmol) to afford 7g (0.497 g, 96% yield) as a white
1
solid; m.p. 258-260 °C (ethyl acetate/hexane). H NMR (300 MHz, CDCl3) δ: 6.93-6.99 (m, 2
3
H), 7.23-7.66 (m, 13 H), 7.72 (s, 1 H), 7.88-7.94 (m, 4 H), 8.07 (d, JHH = 8.4 Hz, 1 H), 8.55
(ddd, 3JHP = 13.9 Hz, 3JHH = 7.0 Hz, 4JHH = 1.3 Hz, 1 H) ppm; 13C NMR {H} (75 MHz, CDCl3)
2
2
3
δ:115.6 (d, JCF = 22.0 Hz, 2HC), 116.0 (d, JCF = 21.6 Hz, 2HC), 119.1(HC), 125.9 (d, JCP =
7.2 Hz, C), 126.2 (d, 3JCP = 12.9 Hz, HC), 128.2-132.3 (m, 15 HC), 134.0 (d, 4JCF = 3.2 Hz, C),
134.1 (d, 1JCP = 108.2 Hz, 2 C), 134.7 (d, 4JCF = 3.0 Hz, C), 138.1 (d, 3JCP = 7.2 Hz, HC), 148.2
2
1
1
(d, JCP = 5.6 Hz, C), 148.8 (2C), 154.8 (C), 163.7 (d, JCF = 248.9 Hz, C-F), 164.0 (d, JCF =
31
250.0 Hz, C-F) ppm; P NMR (120 MHz, CDCl3) δ: 28.8 ppm. HRMS (EI): calculated for
C33H22F2NOP [M]+ 517.1407; found 517.1417. Purity 97.22% (EtOH/Heptane = 10/90, Rt =
6.489 min).
28