3-Aminoquinazoline–phosphine ligands and their ruthenium(II) complexes: application in catalytic hydrogenation and transfer hydrogenation reactions

Article abstract of DOI:10.1007/s11243-018-0213-9

3-Aminoquinazolinone–phosphine proligands (5a–e) and their Ru(II) complexes (6a–e) were prepared and characterized by NMR (¹H, ¹³C, ³¹P{¹H}), FTIR and microanalysis. The 3-aminoquinazolinone–phosphine ligands were found to coordinate with the Ru(II) center via their phosphorus and nitrogen atoms. The Ru(II) complexes were applied as catalysts for the hydrogenation and transfer hydrogenation of prochiral ketones. The results showed that these complexes are efficient transfer hydrogenation catalysts.

Full text of DOI:10.1007/s11243-018-0213-9

Transition Metal Chemistry
https://doi.org/10.1007/s11243-018-0213-9
3‑Aminoquinazoline–phosphine ligands and their ruthenium(II)
complexes: application in catalytic hydrogenation and transfer
hydrogenation reactions
Mustafa Kemal Yılmaz2 · Mustafa Keleş1
Received: 15 November 2017 / Accepted: 29 January 2018
© Springer International Publishing AG, part of Springer Nature 2018
Abstract
3-Aminoquinazolinone–phosphine proligands (5a–e) and their Ru(II) complexes (6a–e) were prepared and characterized
by NMR (1H, 13C, 31P{1H}), FTIR and microanalysis. The 3-aminoquinazolinone–phosphine ligands were found to coor-
dinate with the Ru(II) center via their phosphorus and nitrogen atoms. The Ru(II) complexes were applied as catalysts for
the hydrogenation and transfer hydrogenation of prochiral ketones. The results showed that these complexes are efcient
transfer hydrogenation catalysts.
Introduction
their metal complexes, especially ruthenium complexes, act
as catalysts and are applied in hydrogenation and transfer
hydrogenation reactions to reduce or saturate organic com-
pounds [10–13].
Ruthenium(II) complexes and their catalytic applications are
important in the synthesis of biologically active compounds
for pharmaceutical, natural and industrial applications [1].
Hydrogenation is one of these applications and serves as a
useful method for the reduction of carbonyl compounds to
their corresponding secondary alcohols. Hydrogenation is
generally performed by two methods [2–4]. The frst pro-
cedure uses high pressure with molecular H2 [5], while
the second is performed using isopropyl alcohol or formic
acid as the hydrogen source [6]. The second method is eco-
friendly, is safer and shows high selectivity compared to
hydrogenation methods involving high pressure. The hydro-
genation reactions are carried out in the presence of transi-
tion metal catalysts, whose efciency is a critical factor in
securing high product yields. Phosphine ligands are known
to increase the catalytic activity of hydrogenation reactions
[7–9]. In particular, after Noyori’s research on hydrogena-
tion with the chiral P2N2 ligand, researchers have continued
to explore the use of ligands which combine soft phospho-
rus and hard nitrogen atoms. Such PN-based ligands and
In the present study, 3-aminoquinazolinones were synthe-
sized from α-hydroxy acids or α-amino acids, as described
in the literature [14], and 3-aminoquinazolinone–phosphine
proligands were obtained by the reactions of 2-(diphe-
nylphosphino)benzaldehyde with these 3-aminoquina-
zolinones. The corresponding Ru(PN)2Cl2 (6a–e) complexes
were synthesized from these iminophosphine proligands
(5a–e). Spectroscopic analysis showed that the 3-amino-
quinazolinone–phosphine proligands coordinate the Ru(II)
center via their phosphorus and nitrogen atoms. All the
Ru(PN)2Cl2 complexes were investigated as catalysts for
hydrogenation and transfer hydrogenation (TH) reactions
as catalysts.
Results and discussion
3-Aminoquinazolinones (4a–e) were prepared from L-lactic
acid 1a, L-mandelic acid 1b, L-valine 1c, L–t-leucine 1d
and L-phenyl alanine 1e via a three step synthesis [15, 16]
(Scheme 1).
* Mustafa Keleş
mkeles@osmaniye.edu.tr
The 3-aminoquinazolinone–phosphine proligands
(5a–e) were synthesized by reaction of 2-(diphenylphos-
phino)benzaldehyde with 3-aminoquinazolinones (5a–e) as
shown in Scheme 2. They were characterized by elemental
1
Department of Chemistry, Faculty of Arts and Sciences,
Osmaniye Korkut Ata University, 80000 Osmaniye, Turkey
2
Department of Chemistry, Faculty of Arts and Sciences,
1
analysis, FTIR, and H, 13C, 31P{1H} NMR spectroscopy.
Mersin University, 33343 Mersin, Turkey
Vol.:(0123456789)
1 3

Transition Metal Chemistry
O
O
O
N
R
O
R
R
ii
iv
iii
i,
R
OH
Cl
N
O
OAc
O
O
X
OH NH2
OAc
1a-e
2a-e
4a-e
3a-e
R= Me, X=OH (a); R= Ph, X= NH2 (b); R= iPr, X=NH2 (c)
R= tBu, X=NH2 (d); R= Bn, X=OH (e)
Scheme 1 Preparation of the 3-aminoquinazolinones 4a–e. i) 4.0 equiv. AcCl (for 1a and 1b); 4.0 equiv. NaNO2, AcOH (for 1c–e), RT; ii) 3.0
equiv. SOCl2, DMF, RT; iii) 2.2 equiv. methyl 2-aminobenzoate, Et2O, RT; iv) 5.0 equiv. NH2NH2, EtOH, 150 °C
Scheme 2 Preparation of the
3-aminoquinazolinone–phos-
phine proligands and their
Ru(II) complexes
O
5a R= CH3
5b R= Ph
O
N
N
ethanol
+
PPh2 5c R= iPr
5d R= tBu
N
R
Ph
R
N
P
Ph
N
O
OH
5e R= Bn
OH NH2
4a-e
toluene
reflux
[Ru(p-cymene)2Cl2]2
6a R= CH3
6b R= Ph
6c R= iPr
Bu
6e R= Bn
Cl
Ru
Cl
P
N
P
6d R= t
N
In the IR spectra of the free proligands, peaks due to the
ν(N–H) and ν(C = O) stretching vibrations of the amines and
aldehydes were absent, being replaced by the imine group
ν(N = CH) stretching at 1607–1603 cm−1 (1607 (5a), 1603
(5b), 1607 (5c), 1606 (5d) and 1606 (5e) cm−1). The cor-
responding ν(N = CH) stretching vibrations of the Ru(II)
complexes were observed at 1603–1569 cm−1, indicating
that Ru is coordinated by the imine nitrogen [17]. The P-Ph
bands for the Ru(II) complexes (6a–e) were observed at
show a single peak, shifted upfeld compared to 2-(diphe-
nylphosphino)benzaldehyde at − 15.35 (5a), − 16.26 (5b),
− 16.18 (5c), − 16.35 (5d) and − 15.44 (5e) ppm [21, 22].
The 31P NMR spectra of the Ru(PN)Cl2 complexes were
observed at 59.60 (6a), 59.61 (6b), 52.57 (6c), 61.00 (6d)
and 59.62 ppm (6e). Hence, the 31P NMR peaks were shifted
downfeld upon complexation, consistent with coordination
of the P atoms to the metal [23, 24]. Overall, the spectro-
scopic data clearly showed that the ligands do not coordinate
to the metal via the aliphatic hydroxide, which would confer
chirality on the complexes, despite the fact that the reactions
were carried out at diferent temperatures with several bases.
On the other hand, from the 31P NMR spectra of 6a–e, the
peaks observed at 26.71–26.97 ppm showed that the phos-
phorus was partially oxidized during the purifcation of the
compounds or the NMR measurements.
1
1436–1472 cm−1 [18, 19]. In the H NMR spectra of the
proligands, multiplets at 8.56–7.00 ppm were assigned
to the phenyl protons. The azomethine protons (HC = N)
appeared at 9.88 (5a), 9.59 (5b), 9.90 (5c), 10.00 (5d) and
9.92 (5e) ppm as a doublet, with a coupling constant of
around JPH = 6.0 Hz; the peak was shifted downfeld to
9.83–10.90 ppm as a singlet after coordination to the Ru(II)
center. Peaks at diferent values around at 5.30–1.62 ppm
were assigned to the OH protons of both the free proligands
and their complexes [20]. In the 13C NMR spectra, azome-
thine carbons of the proligands were observed between
165.0 and 166.0 ppm, while the aromatic carbon signals
were observed at 159–117 ppm. The 31P NMR spectra of
all of these 3-aminoquinazolinone–phosphine proligands
Transfer hydrogenation reactions
For a series of complexes, both the chemical nature of the
substituents and their positions can infuence their cata-
lytic activities. Therefore, a series of Ru(II) complexes,
substituted with both aliphatic and aromatic groups having
1 3

Transition Metal Chemistry
diferent electronic and steric efects on the 3-aminoquina-
zolinone skeleton, were investigated in transfer hydrogena-
tion reactions. To evaluate the efciency of these Ru(II)
complexes (6a–e) for transfer hydrogenation reactions, we
have chosen acetophenone as a model substrate. Normally, in
a typical transfer hydrogenation reaction, a base is used for
generation of a highly active dihydride complex. This serves
to deprotonate the isopropyl alcohol, resulting in an alkoxide
ion that undergoes β-elimination at the Ru–H active center
[2]. In order to determine the efect of base on the transfer
hydrogenation reaction, we examined both inorganic and
organic bases (NaOH, KOtBu and Et3N). We did not obtain
signifcant yields with KOtBu or Et3N; however, NaOH gave
acceptable yields. When the reaction was carried out in the
absence of a base, no products were obtained.
investigated under 10 bar H2 pressure for 24 h using 1% mol
of complex 6a. The results are presented in Table 2.
The use of ethanol or isopropanol as solvent failed to
achieve a signifcant conversion. However, when metha-
nol was used as solvent, the activity of the catalysts was
increased, which can be explained by the higher polarity
(εEtOH = 25, εiPrOH = 20 and εMeOH = 33) [26]. As given
in Table 2, under 10 bar hydrogen pressure, the reduction
of acetophenone to secondary alcohol gave very low yield.
Therefore, in order to improve the yield, the hydrogen pres-
sure was increased to 40 bar. Herein, we chose a substrate to
catalyst (S/C) ratio of 100/1 and the racemic products were
analyzed by GC (Table 3).
As shown in Table 3, diferent yields were obtained from
the hydrogenation of acetophenone (72%), 2-methoxyaceto-
phenone (99 and 97%) and 3-methoxyacetophenone (95%,
entries 4, 6, 10 and 12) under 40 bar H2 pressure. We con-
clude that long reaction times and high pressures of H2 are
required for optimum yields.
The reaction temperature is an important parameter for
the transfer hydrogenation of prochiral ketones, so we also
tested diferent temperatures (82, 60, 40 and 25 °C). For the
reaction with NaOH in 2-propanol, as the temperature was
decreased from 82 °C to room temperature, both the yield
and conversion decreased dramatically, such that poor results
were obtained at low temperatures. Subsequent experiments
were therefore carried out at 82 °C (Scheme 3).
Experimental
Our frst investigation was into the reduction of bromo-
and chloro-acetophenones with electron-withdrawing groups
to secondary alcohols. Bromo-acetophenones were reduced
to the corresponding secondary alcohols in good yields at
82 °C (Table 1, entries 4, 5 and 6). The same situation was
observed with chloro-acetophenones, as shown in Table 1
entries 7–9. The electron-withdrawing efect of these groups
reduces the electron density on the carbonyl group, increas-
ing the afnity of the active ruthenium center for the sub-
strate and so accelerating the catalytic reaction. As expected,
the transfer hydrogenation of acetophenones with ring acti-
vating methyl and methoxy groups on the aromatic ring gave
moderate yields (Table 1, entries 10 and 11). It can be con-
cluded that electron-donating groups on the aryl ring of the
ketones tend to slow the catalytic hydride transfer [2, 25].
Materials and methods
All reactions were carried out under an inert atmosphere
using conventional Schlenk glassware. Solvents were dried
using established procedures and then immediately distilled
under argon prior to use [27]. The 3-aminoquinazolinones
[15, 16] and 2-(diphenylphosphino)benzaldehyde [28] were
prepared as described in the literature. Microanalyses were
obtained with a LECO CHNS 932 instrument. IR spectra
were recorded with a PerkinElmer RX1 spectrophotome-
ter in the range between 4000 and 650 cm−1. All 1H NMR
(400.1 MHz) and 31P{1H} NMR (162.0 MHz) spectra were
recorded at 25 °C with DMSO-d6 and CDCl3 on a Bruker
NMR spectrometer. The 13C NMR spectra were taken on
a Varian Mercury 100.6 MHz NMR spectrometer. The
31P{1H} NMR spectra were recorded with complete pro-
ton decoupling and referenced with 85% H3PO4 as external
standard. The reaction products were analyzed with a Perki-
nElmer Clarus 500 series gas chromatograph equipped with
a fame ionization detector and a 30 m × 0.25 mm × 0.25 μm
flm thickness β-Dex capillary column. Thin-layer chroma-
tography was used for monitoring the reactions.
Hydrogenation reactions
The Ru(II) complexes (6a–e) were also investigated for the
hydrogenation of various acetophenones. Preliminary opti-
mization of the reaction conditions was investigated for the
hydrogenation of acetophenone. The system was initially
P r e p a r a t i o n o f 3 ‑ ( 2 ‑ ( d i p h e n y l p h o s p h i n o )
benzylideneamino)‑2‑(1‑hydroxyethyl) quinazolin‑4(3H)‑one
(5a) A mixture of p-toluenesulfonic acid (10 mg), 2-(diphe-
nylphosphino)benzaldehyde (282 mg, 0,974 mmol) and
3-amino-2-(S)-1-hydroxyethyl)-3H-quinazolin-4-one
(100 mg, 0,487 mmol) in ethanol (10 mL) and heated at
120 °C for 12 h. The reaction was cooled and analyzed by
O
OH
R= -Br
-Cl
6a-e
-CH3
-OCH3
R
R
IPA, NaOH
Scheme 3 Catalytic transfer hydrogenation of acetophenone deriva-
tives
1 3

Transition Metal Chemistry
Table 1 Transfer hydrogenation of acetophenones with Ru(II) catalysts
O
OH
6a-e
IPA, NaOH
R
R
Yieldc(%) (TON)d
6c
Entry
1
Substrate
Product
6a
6b
6d
6e
O
OH
87 (435)
78 (390)
82 (410)
39a (195)
26b (130)
96 (480)
98 (490)
82 (410)
98 (490)
66a (330)
38b (190)
98 (490)
≥99 (495)
97 (485)
96 (480)
84a (420)
34c (170)
≥99 (495)
≥99 (495)
98 (490)
O
O
OH
OH
2
3
4
5
6
44a (220)
17b (85)
92 (460)
98 (490)
97(485)
53a (265)
13b (65)
97 (485)
98 (490)
96 (480)
Br
O
O
Br
OH
OH
Br
Br
O
OH
OH
Br
Br
O
7
≥99 (495) ≥99 (495) ≥99 (495) ≥99 (495)
≥99 (495)
98 (490)
99 (495)
19 (95)
Cl
O
Cl
OH
8
99 (495)
96 (480)
≤5 (25)
98 (490)
95 (475)
6 (30)
96 (480)
97 (485)
8 (40)
99 (495)
99 (495)
12 (60)
Cl
Cl
O
OH
OH
OH
9
Cl
Cl
O
10
O
11
41(205)
39 (195)
60 (300)
68 (340)
78 (390)
1 3

Transition Metal Chemistry
Table 1 (continued)
Yieldc(%) (TON)d
6c
Entry
12
Substrate
Product
6a
6b
6d
6e
O
OH
76 (380)
73 (365)
92 (460)
23 (115)
90 (450)
33 (165)
92 (460)
OCH3
OCH3
O
OH
13
8 (40)
6 (30)
23 (115)
H3CO
H3CO
Reaction conditions: substrate (2 mmol), catalyst (0.004 mmol), IPA (3 mL), NaOH (0.1 mmol), 24 h.
aBase: KOtBu
bBase: Et3N
c GC yield of the corresponding alcohol
dTON: mol of product/mol of catalyst
Table 3 Hydrogenation reaction of acetophenone and derivativesa
Table 2 Infuence of solvents and temperature on the reduction of
acetophenone with 6aa
Entry Catalyst Substrate
Yield (%)b
Entry
Solvent
T (°C)
Conv. (%)b
10 bar H2 40 bar H2
1
2
3
4
5
Methanol
Methanol
Methanol
iPrOH
50
60
80
60
80
10
27
68
NR
3
1
6a
NR
5
Ethanol
2
3
4
5
6
6b
6c
6d
6e
6a
NR
15
46
15
16
≤ 5
45
72
16
99
aReaction conditions: acetophenone (2 mmol), 6a (0.1 mmol), solv.
(3 mL), H2:10 bar, 24 h. NR: no reaction
bProducts were analyzed by GC
TLC [ethylacetate:hexane/1:5]. The solvent was evaporated
under reduced pressure until dryness and the residue was
dissolved in CH2Cl2. The solution was washed with NaHCO3
followed by H2O and the organic phase was dried with
Na2SO4. The crude product, obtained by evaporation of the
solvent, was purifed by chromatography on silica gel using
1:9 ethylacetate:hexane as an eluent. Yield 101 mg (44%),
m.p.: 130–131 °C (dec.). 1H NMR (400.2 MHz, CDCl3): δ
(ppm) 9.88 (d, 1H, JPH = 5.8 Hz, HC = N), 8.12 (m, 2H,
ArCH), 7.52 (m, 2H, ArCH), 7.44–7.21 (m, 12H, ArCH),
6.84 (m, 2H, ArCH), 4.84 (m, 1H, CH), 4.35 (s, OH), 1.34
(d, 3H, J = 6.4 Hz, CH3). 13C NMR (100.6 MHz, CDCl3):
δ (ppm) 165.5 (d, JPC = 19.2 Hz, N = CH), 158.7–121.6
(Ar), 65.4 (CH), 22.1 (CH3). 31P{1H} NMR (162.0 MHz,
CDCl3): δ (ppm) − 15.35 (s). FTIR (KBr, cm−1): 3451 (OH);
1687 (C = O); 1607 (C = N); 1435 (P-Ph). Anal. calcd. for
C29H24N3O2P: C, 72.95; H, 5.07; N, 8.80%. Found: C, 73.33;
H, 5.29; N, 8.47%.
7
8
9
10
11
6b
6c
6d
6e
6a
9
9
NR
≤ 5
80
52
≤ 5
59
97
58
12
13
14
15
6b
6c
6d
6e
45
NR
79
60
95
69
77
69
aReaction conditions: substrate (2 mmol), cat. (0.004 mmol), 24 h.
NR: no reaction
bGC yield of the corresponding alcohol
The other proligands 5b–5e were prepared by the same
procedure.
1 3

Transition Metal Chemistry
3‑(2‑(Diphenylphosphino)benzylideneamino)‑2‑(hydroxy(ph
Preparation of Ru(II) complexes (6a–e)
enyl)methyl)quinazolin‑4(3H)‑one (5b) Yield 74 mg (37%),
1
m.p.: 161–163 °C (dec.). H NMR (400.2 MHz, CDCl3):
Complex 6a
δ (ppm) 9.59 (d, 1H, JPH = 6.01 Hz, HC = N), 8.20–7.00
(m, ArH, 23H), 4.20 (s, 1H, CH), 1.62 (s, OH). 13C NMR
(100.6 MHz, CDCl3): δ (ppm) 165.3 (d, JPC = 19.2 Hz,
N = CH), 145.50–117.0 (Ar), 68.4 (CH). 31P{1H} NMR
(162.0 MHz, CDCl3): δ (ppm) − 16.26 (s). FTIR (KBr,
cm−1): 3301 (OH); 1682 (C = O); 1603 (C = N); 1432 (P–
Ph). Anal. calcd. for C34H26N3O2P: C, 75.68; H, 4.86; N,
7.79%. Found: C, 76.73; H, 5.09; N, 8.47%.
To a solution of [Ru(p-cymene)Cl2]2 (306 mg, 1 mmol) in
dry toluene (10 mL), compound 5a (960 mg, 2.1 mmol)
was added. The mixture was stirred for 12 h at refux. The
solvent was removed under reduced pressure until dry-
ness, giving a dark red solid, which was crystallized from
CH2Cl2/hexane mixture. Yield 1.015 g (90%), mp.: 191 °C
(dec.). 1H NMR (400.2 MHz, CDCl3): δ (ppm) 9.87 (s, 2H,
N = CH), 7.89–7.28 (m, ArH, 36H), 5.30 (s, OH), 4.93 (m,
2H, CH), 2.70 (s, 6H, CH3). 31P{1H} NMR (162.0 MHz,
CDCl3): δ (ppm) 59.60 (s). FTIR (KBr, cm−1): 3426 (OH);
1678 (C = O); 1592 (C = N); 1436 (P–Ph). Anal. calcd. for
C58H48Cl2N6O4P2Ru: C: 61.81, H: 4.29, N: 7.46%. Found:
C: 62.34, H: 4.09, N: 7.02%.
3‑(2‑(Diphenylphosphino)benzylideneamino)‑2‑(1‑hydrox
y‑2‑methylpropyl)quinazolin‑4(3H)‑one (5c) Yield 65 mg
1
(30%), m.p.: 118–120 °C (dec.). H NMR (400.2 MHz,
CDCl3): δ (ppm) 9.90 (d, 1H, JPH = 6.00 Hz, HC = N),
8.32–7.00 (m, 18H, ArH), 4.24 (d, J = 7.6 Hz, 1H, CH), 2.68
(m, 1H, CH), 1.62 (br, OH), 1.80 (s, 6H, CH3). 13C NMR
(100.6 MHz, CDCl3): δ (ppm) 165.5 (d, JPC = 19.2 Hz,
N = CH), 158.7–121.6 (Ar), 65.4 (CH), 23.0 (CH3). 31P{1H}
NMR (162.0 MHz, CDCl3): δ (ppm) − 16.18 (s). FTIR
(KBr, cm−1): 3426 (OH); 1683 (C = O); 1607 (C = N); 1434
(P–Ph). Anal. calcd. for C31H28N3O2P: C, 73.65; H, 5.58; N,
8.31%. Found: C, 74.45; H, 5.86; N, 8.86%.
The other complexes 6b–d were prepared by the same
procedure.
Complex 6b
Yield 913 mg (73%), m.p.: 210 °C (dec.), dark red solid.
1H NMR (400.2 MHz, CDCl3): δ (ppm) 10.15 (s, 2H,
N = CH), 8.56–7.28 (m, ArH, 46H), 5.17 (s, 2H, CH),
1.67 (s, OH). 31P{1H} NMR (162.0 MHz, CDCl3): δ
(ppm) 59.61 (s). FTIR (KBr, cm−1): 3386 (OH); 1681
(C = O); 1592 (C = N); 1468 (P–Ph). Anal. calcd. for
C68H52Cl2N6O4P2Ru: C: 65.28, H: 4.19, N: 6.72%. Found:
C: 66.02, H: 4.30, N: 6.10%.
3‑(2‑(Diphenylphosphino)benzylideneamino)‑2‑(1‑hydro
xy‑2,2‑dimethylpropyl)quinazolin‑4(3H)‑one (5d) Yield
138 mg (66%), m.p.: 144 °C (dec.). 1H NMR (400.2 MHz,
CDCl3): δ (ppm) 10.00 (d, 1H, JPH = 6.24 Hz, HC = N),
8.20–7.10 (m, 18H, ArH), 4.91 (s, OH), 3.63 (s, 1H, CH),
0.82 (s, 9H, CH3). 13C NMR (100.6 MHz, CDCl3): δ (ppm)
165.0 (d, JPC = 19.2 Hz, N = CH), 159.7–127.0 (Ar), 73.0
(CH), 23.0 (CH3). 31P{1H} NMR (162.0 MHz, CDCl3): δ
(ppm) − 16.35 (s). FTIR (KBr, cm−1): 3423 (OH); 1684
(C = O); 1606 (C = N); 1434 (P–Ph). Anal. calcd. for
C32H30N3O2P: C, 73.97; H, 5.82; N, 8.09%. Found: C, 73.93;
H, 6.09; N, 8.43%.
Complex 6c
Yield 993 mg (84%), m.p.: 243 °C (dec.), brown solid.
1H NMR (400.2 MHz, CDCl3): δ (ppm) 10.15 (s, 2H,
N = CH), 8.29–7.28 (m, ArH, 36H), 4.51 (s, 2H, CH), 4.51
(s, OH), 3.48 (m, 2H, CH), 1.91 (s, 12H, CH3). 31P{1H}
NMR (162.0 MHz, CDCl3): δ (ppm) 52.57 (s). FTIR (KBr,
cm−1): 3418 (OH); 1680 (C = O); 1603 (C = N); 1468
(P–Ph). Anal. calcd. for C62H56Cl2N6O4P2Ru: C: 62.94,
H: 4.77, N: 7.10%. Found: C: 63.85, H: 4.70, N: 6.90%.
3‑(2‑(Diphenylphosphino)benzylideneamino)‑2‑(1‑hydrox
y‑2‑phenylethyl)quinazolin‑4(3H)‑one (5e) Yield 140 mg
(71%), m.p.: 156 °C (dec.). 1H NMR (400.2 MHz, CDCl3):
δ (ppm) 9.92 (d, 1H, JPH = 5.96 Hz, HC = N), 8.25–7.13 (m,
23H, ArH), 4.91 (d, 1H, J = 9.7 Hz, CH), 4.24 (s, OH), 3.74
(d, 1H, J = 9.7 Hz, CH). 13C NMR (100.6 MHz, CDCl3):
δ (ppm) 166.0 (d, JPC = 19.2 Hz, N = CH), 139.0–126.0
(Ar), 71.4 (CH), 41.0 (CH3). 31P{1H} NMR (162.0 MHz,
CDCl3): δ (ppm) − 15.44 (s). FTIR (KBr, cm−1): 3423 (OH);
1684 (C = O); 1606 (C = N); 1434 (P–Ph). Anal. calcd. for
C35H28N3O2P: C, 75.94; H, 5.10; N, 7.59%. Found: C, 76.30;
H, 5.69; N, 8.47%.
Complex 6d
Yield 690 mg (57%), m.p.: 248 °C (dec.), brown solid.
1H NMR (400.2 MHz, CDCl3): δ (ppm) 10.90 (s, 2H,
N = CH), 8.30–7.07 (m, ArH, 36H), 5.17 (s, 2H, CH), 4.45
(s, OH), 1.90 (s, 18H, CH3). 31P{1H} NMR (162.0 MHz,
CDCl3): δ (ppm) 61.00 (s). FTIR (KBr, cm−1): 3426 (OH);
1657 (C = O); 1602 (C = N); 1472 (P–Ph). Anal. calcd.
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Transition Metal Chemistry
for C64H60Cl2N6O4P2Ru: 63.47, H:4.99, N:6.94%. Found:
C: 63.95, H: 4.97, N: 6.15%.
the ruthenium active centers, such that the nature of the sub-
stituents did not contribute to the catalytic performance.
Acknowledgements This work was supported by the Osmaniye Korkut
Ata University and the Scientifc and Technological Research Council
of Turkey (Project Number: 109T801). The authors also thank to Prof.
Dr. Sabri Ulukanlı for the synthesis of 3-aminoquinazolinones.
Complex 6e
Yield 844 mg (66%), m.p.: 230 °C (dec.), brown solid. 1H
NMR (400.2 MHz, CDCl3): δ (ppm) 9.83 (s, 2H, N = CH),
8.40–7.28 (m, ArH, 46H), 4.57 (m, 4H, CH2), 3.47 (m, 2H,
CH), 3.15 (s, OH). 31P{1H} NMR (162.0 MHz, CDCl3):
δ (ppm) 59.62 (s). FTIR (KBr, cm−1): 3429 (OH); 1672
(C = O); 1569 (C = N); 1468 (P–Ph). Anal. calcd. for
C70H56Cl2N6O4P2Ru: C: 65.73, H: 4.41, N: 6.57%. Found:
C: 66.21, H: 4.47, N: 6.24%.
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