"on water" palladium catalyzed diastereoselective boronic acid addition to structurally diverse cyclopropane nitriles

Article abstract of DOI:10.1039/d0ob00077a

An efficient palladium catalyzed diastereoselective addition of arylboronic acids to complex spirocyclopropyl dinitriles is developed in the presence of a catalytic amount of 4-dodecylbenzenesulphonic acid (DBSA) as a Br?nsted acid surfactant in aqueous media. The protocol is also found to be highly effective when different types of nitrile compounds and organo-boron compounds are used. The overall reaction has been found to be very cost efficient since it requires low catalyst loading, mild thermal energy and short reaction time. Wide substrate scope, operational simplicity, good to excellent product yield, and use of green solvents make the reaction a practical route to transform nitrile into a keto functionality in biorelevant heterocyclic scaffolds. The scale-up synthesis of the target scaffolds can also be achieved with ease which also signifies the practicability of this protocol. This journal is

Full text of DOI:10.1039/d0ob00077a

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“On water” palladium catalyzed diastereoselective
boronic acid addition to structurally diverse
cyclopropane nitriles†
Cite this: DOI: 10.1039/d0ob00077a
Dwaipayan Das, Prasun Mukherjee and Asish R. Das
*
An efficient palladium catalyzed diastereoselective addition of arylboronic acids to complex spirocyclo-
propyl dinitriles is developed in the presence of a catalytic amount of 4-dodecylbenzenesulphonic acid
(DBSA) as a Brønsted acid surfactant in aqueous media. The protocol is also found to be highly effective
when different types of nitrile compounds and organo-boron compounds are used. The overall reaction
has been found to be very cost efficient since it requires low catalyst loading, mild thermal energy and
short reaction time. Wide substrate scope, operational simplicity, good to excellent product yield, and use
of green solvents make the reaction a practical route to transform nitrile into a keto functionality in biore-
levant heterocyclic scaffolds. The scale-up synthesis of the target scaffolds can also be achieved with
ease which also signifies the practicability of this protocol.
Received 14th January 2020,
Accepted 19th October 2020
DOI: 10.1039/d0ob00077a
rsc.li/obc
the literature, there are only a handful examples of transition
metal catalyzed synthesis of ketones,8 and in most of the cases
Introduction
The keto functionality can be found in numerous bioactive simple nitriles are used as substrates. The very first attempt
compounds1 and natural products.2 It is also one of the key was made by Larock et al. via the reaction between arylboronic
functional groups in countless organic transformations.3 acids and nitrile compounds in the presence of a palladium
Installation of a carbonyl group in organic scaffolds may be catalyst.8a,b Furthermore, Lu et al. extended the scope using
achieved via Friedel–Crafts acylation,4 oxidation of secondary different reactants.8c Recently, Sarkar et al. have performed
alcohols,5 Weinreb ketone synthesis6 and other protocols this type of palladium catalyzed addition reaction with pyra-
involving the addition of organometallic reagents (Grignard or zole tethered ligands for the synthesis of aryl ketones and
organo-lithium reagents) to nitriles.7 However, these method- 3-acylindoles.8d Murakami et al. and Miura et al. have parallelly
ologies cannot be useful to install a keto functionality in a established the reaction through the use of a rhodium
complex organic molecule because of poor tolerance against catalyst.8e–f,i–j Some groups are also using the concept to syn-
harsh reaction conditions. Additionally, these methods are thesize small heterocyclic molecules via the metal catalyzed
plagued with additional disadvantages such as stoichiometric addition of arylboronic acid to nitriles followed by their inter-
amount of reagents, hazardous chemical compounds, tedious or intramolecular cyclization (Scheme 1).9 But the majority of
reaction conditions and poor chemo-selectivity. In view of the these procedures involve simple nitrile molecules, toxic
immense importance of the keto containing complex hetero- organic solvents or binary solvents and drastic conditions.
cyclic skeleton, we wish to transform the nitrile functionality Thus, there is enough urgency for robust transition metal cata-
present in our previously synthesized cyclopropane nitriles lysis to obtain highly functionalized ketones. Herein, we wish
into the corresponding ketones under relatively mild con- to disclose a practical route to construct synthetically and bio-
ditions. Transition metal catalyzed formation of ketones can logically important ketones via the reaction between boronic
be realized as a practical route in synthetic chemistry due to acid with highly functionalized cyclopropane nitriles in the
their commercial importance along with catalytic efficacy. In presence of a catalytic amount of DBSA as a Brønsted acid
combined surfactant using water as the sole solvent.
Department of Chemistry, University of Calcutta 92, A. P. C. Road, Kolkata-700009,
India. E-mail: ardchem@caluniv.ac.in, ardas66@rediffmail.com;
Tel: +913323501014, +919433120265; Fax: +913323519754
†Electronic supplementary information (ESI) available: Copies of 1H and 13C
Results and discussion
NMR spectra and X-ray crystallographic data for compounds 4a and 5g. CCDC
We employed spirocyclopropylpyrazolone and barbiturate
dicarbonitriles for this transformation. Initially, 1a and
1952896 and 1952797. For ESI and crystallographic data in CIF or other elec-
tronic format see DOI: 10.1039/d0ob00077a
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Table 2 Ligands used for optimization
aqueous medium in the presence of dioxane as a co-solvent at
100 °C using Pd(OAc)2 and L2 with 1.0 equivalent of 1a and
2.0 equivalents of 3a (Table 1, entry 1) in search of 4a′. Despite
the low conversion of the starting material, we isolated the
newly formed compound. After complete characterization, it
was found to be product 4a from the reaction between boronic
acid and one of the two nitriles of the starting spirocyclopro-
pane. It is worth mentioning that no trace of 4a′ was obtained
Scheme 1 Transition metal catalyzed transformation of nitriles into
ketones.
phenylboronic acid (3a) were chosen as the model reactants during this reaction which is supported by the fact that 4a was
for optimizing the reaction conditions. Several Brønsted acids observed as a single spot during TLC and also NMR studies
(Table 1) and ligands (Table 2) were employed during this revealed the absence of any isomeric peaks. On detecting the
investigation. Initially, the reaction was performed in an excellent diastereoselectivity of this reaction, we immediately
Table 1 Screening of catalysts, ligands, acids and solvents and optimization of reaction conditionsa
Entry
Catalyst (mol%)
Ligand (mol%)
Brønsted acid (equiv.)
Solvent
Temp. (°C)
Time (h)
Yield of 4ab (%)
1c
Pd(OAc)2 (5)
Pd(OAc)2 (5)
Pd(OAc)2 (5)
Pd(OAc)2 (10)
Pd(OAc)2 (5)
Pd(OAc)2 (5)
Pd(OAc)2 (5)
Pd(OAc)2 (5)
Pd(OAc)2 (5)
Pd(OAc)2 (5)
Pd(OAc)2 (5)
Pd(OAc)2 (5)
Pd(OAc)2 (5)
Pd(OAc)2 (5)
Pd(OAc)2 (5)
Pd(OAc)2 (3)
Pd(OAc)2 (3)
Pd(OAc)2 (2)
—
L2 (5)
L2 (5)
L2 (5)
L2 (10)
L2 (5)
L2 (5)
L2 (5)
L2 (5)
L2 (5)
L2 (5)
L2 (5)
L2 (5)
L2 (5)
L2 (5)
L2 (5)
L2 (3)
L2 (3)
L2 (2)
—
AcOH (2.0)
TfOH (2.0)
AcOH (2.0)
AcOH (2.0)
AcOH (2.0)
AcOH (2.0)
TFA (2.0)
AcOH (1.1)
TfOH (1.1)
PTSA (1.1)
PTSA (1.1)
PTSA (1.1)
PTSA (1.1)
DBSA (1.1)
DBSA (0.2)
DBSA (0.2)
DBSA (2.0)
DBSA (0.2)
DBSA (0.2)
DBSA (0.2)
DBSA (0.2)
DBSA (0.2)
1,4-Dioxane + H2O (1 : 1)
1,4-Dioxane + H2O (1 : 1)
1,4-Dioxane + H2O (1 : 1)
1,4-Dioxane + H2O (1 : 1)
DMSO + H2O (2 : 1)
NMP + H2O (2 : 1)
1,4-Dioxane + H2O (1 : 1)
1,4-Dioxane + H2O (1 : 1)
1,4-Dioxane + H2O (1 : 1)
1,4-Dioxane + H2O (1 : 1)
1,4-Dioxane + H2O (1 : 1)
THF + H2O (1 : 1)
THF + H2O (1 : 1)
H2O
H2O
H2O
H2O
H2O
H2O
H2O
H2O
H2O
100
100
100
100
130
130
100
100
100
100
90
90
80
90
90
90
90
90
3.0
2.0
3.0
3.0
2.0
2.0
3.0
3.0
2.0
2.0
2.0
2.0
4.0
2.0
2.0
2.0
2.0
2.0
24.0
20.0
20.0
20.0
20
13
20
22
10
12
10
34
25
40
52
76
54
90
94
96
88
72
—
—
—
—
2c
3c
4c
5c
6c
7c
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Reflux
Reflux
Reflux
Reflux
FeCl3 (20)
Yb(OTf)3 (20)
Cu(OTf)2 (20)
—
—
—
a All the reactions were carried out with 1a (0.5 mmol) and 2a (0.6 mmol) in 3 mL of the solvent or solvent mixture. b Isolated yields of 4a and 4a′
were not obtained in every case. c 2.0 equiv. of phenylboronic acid (3a) were used instead of 1.2 equiv.
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began our investigation to optimize the reaction conditions for ture and use of THF as the solvent increased the yield to a
the formation of 4a in a maximum yield as the diastereo- great extent (Table 1, entries 11 and 12). Interestingly, when
selective reactions have great impact in synthetic organic we used DBSA instead of p-toluenesulfonic acid (Table 1, entry
chemistry.10
14), a further increase in the yield was observed. The absence
Then we modified the conditions by varying the amount of of any co-solvent did not affect the reaction due to the surfac-
the catalyst, ligands, additives and solvent systems (Table 1, tant property of DBSA. Generally, it forms micelles in water
entries 2–7; Table S1 (see the ESI), entries 1 and2†) but all of which act as reactors.11 Furthermore, a catalytic amount of
them did not alter the diastereoselectivity and furnished 4a. DBSA (Table 1, entry 15) was found to provide even better
We then changed the amount of phenylboronic acid (1.2 results.12 Further deviation from these conditions either by
equiv.) and the additive (1.1 equiv.) which increased the yield changing the palladium catalyst or the ligand and other
of 4a to 34% (Table 1, entry 8). The use of triflic acid instead of reagents lowered the yield (Table 1, entries 17 and 18;
acetic acid (Table 1, entry 9) however further decreased the Table S1, entries 3–7 and 10–12†). The use of a mono-pro-
yield. The use of p-toluenesulfonic acid (Table 1, entry 10) tected amino acid ligand (L4) and dppf (L5) along with palla-
resulted a slight increase in the yield. Lowering of the tempera- dium acetate was found to be unproductive (Table S1, entries 8
Table 3 Substrate scope for the synthesis of ketones from pyrazolo cyclopropane nitrilesa
a Reaction conditions: 4-methyl-7-oxo-2,6-diaryl-5,6-diazaspiro[2.4]hept-4-ene-1,1-dicarbonitrile (1a–i) or 7-oxo-2,4,6-triphenyl-5,6-diazaspiro[2.4]
hept-4-ene-1,1-dicarbonitrile (1j), arylboronic acid (1.2 mmol), 90 °C, 2 h.
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and 9†). Additionally, replacement of DBSA with aromatic and found that the desired ketones are produced in excellent yields
aliphatic carboxylic acids failed to afford 4a (Table S1, entries (Tables 3 and 4). We also examined a vast variety of phenyl-
13 and 14†). The reaction was also carried out in the presence boronic acid derivatives carrying both electron-donating and
of Lewis acids such as FeCl3, Yb(OTf)3 and Cu(OTf)2 and also electron-withdrawing functionalities. Unfortunately, alkyl and
in the absence of any metal catalyst (Table 1, entries 19–22) heterocyclic boronic acids failed to produce the corresponding
but all the attempts were in vain which essentially indicates ketones under the optimized conditions. The reason may be
the necessity of palladium salts as the effective catalyst for this the lower migratory aptitude of alkyl groups as compared to
particular transformation.
aryl groups present in boronic acid. In the case of the hetero-
With these optimized conditions, we then started to investi- cyclic counterparts, the heterocyclic scaffold may inhibit the
gate the extent and constraint of this protocol. For this objec- co-ordination of heteroaryl boronic acid with palladium. The
tive, a wide variety of 4-methyl-7-oxo-2,6-diaryl-5,6-diazaspiro reaction was found to be very compatible with the substrates
[2.4]hept-4-ene-1,1-dicarbonitrile (1a–i), 7-oxo-2,4,6-triphenyl- containing bulky substituent groups like 4-tert-butyl phenyl
5,6-diazaspiro[2.4]hept-4-ene-1,1-dicarbonitrile (1j) and 5,7- and extended aromatic groups like naphthyl and biphenyl as
dimethyl-4,6,8-trioxo-2-aryl-5,7-diazaspiro[2.5]-octane-1,1-dicar- well. However, it was found that the yields of the ketones carry-
bonitrile (2a–g) possessing electron-donating and electron- ing –NO2, –F and –CF3 groups (4i–k, 4v, 4w, 5e, 5f, and 5h) are
withdrawing groups were prepared according to the litera- slightly lower than those of their other homologues. This may
ture.13 Then these were employed for the reaction with happen due to the lower solubility of their precursor nitriles
1.2 mmol arylboronic acid in the presence of 0.2 mmol DBSA (1e, 1f, 2d, 2e, and 2g) and phenylboronic acid derivatives (3g
using 3 mol% Pd(OAc)2 and 3 mol% L2 as the catalyst system and 3k) in aqueous media. All the synthesized compounds
1
in 3 mL water (Tables 3 and 4).
were well characterized through H and 13C NMR and IR spec-
Every time, the reaction proceeded very smoothly. troscopy. Finally, the structural motifs of the synthesized com-
Furthermore, the reaction takes only 2 hours to consume the pounds were established through X-ray analysis of 4a and 5g
starting materials in all instances. In almost every case, we (Fig. 1a and b) .
Table 4 Substrate scope for the synthesis of ketones from barbiturate cyclopropane nitrilesa
a Reaction conditions: 5,7-dimethyl-4,6,8-trioxo-2-aryl-5,7-diazaspiro[2.5]-octane-1,1-dicarbonitrile (2a–g) (1.0 mmol), arylboronic acid (1.2 mmol),
90 °C, 2 h.
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Fig. 1 (a) ORTEP diagram of compound 4a (CCDC 1952896).† (b)
ORTEP diagram of compound 5g (CCDC 1952797).†
Scheme 3 Diastereoselectivity of the reaction.
We also performed some control experiments to establish
the diastereoselectivity of the reaction using different nitrile
compounds (Scheme 2). We took 1k as our nitrile substrate
where an aromatic nitrile group resides along with both
cyclopropylic nitriles. Then the reaction with 2.4 equiv. of
phenylboronic acid resulted in the transformation of one
cyclopropylic nitrile along with the aromatic nitrile into the
corresponding keto functionality. We also found that both of
the nitrile groups of pimelonitrile (6) and malononitrile (10)
can be converted to ketones through this protocol and the
products 7 and 11 were obtained in 94% and 88% yields,
respectively. Interestingly, when the amount of phenylboronic
acid was reduced to half (1.2 equiv.), we obtained the same
products from 1k, 6 and 10 but the yields obtained were very
low and almost half of the starting material remained
unreacted. The yields obtained for the products 4x, 7 and 11
were 43%, 46% and 33% respectively (see ESI, Scheme S2†).
Additionally, phenyl acetonitrile can also be converted to 1,2-
diphenylethan-1-one with an excellent yield. Interestingly,
despite the efficacy of this protocol towards converting aro-
matic and aliphatic nitrile groups into the corresponding
ketones, one of the two geminal nitriles of the starting spiro-
cyclopropane always remained inactive during the reaction.
This confirms that the diastereoselectivity lies inherently in
the starting molecules which can be easily explained by con-
sidering the steric environment of the starting substrates
(Scheme 3). Since 2 is present as an enantiomeric mixture of
2aa and 2ab, during the reaction, four stereoisomers can be
obtained, at least theoretically. However, since the formation
of isomers 5aa and 5ab′ is sterically forbidden, they were not
obtained during the reaction which is confirmed by analyz-
ing NMR and X-ray data. Only 5aa′ and 5ab were found to be
the products which are essentially enantiomers with respect
to each other. Interestingly, 5aa and 5ab′, bearing an enantio-
meric relationship to each other, possess a diastereomeric
relationship with 5aa′ and 5ab respectively. Thus, it is quite
clear that this reaction is indeed a diastereoselective reaction
mixture. From (Scheme 3) and Scheme S1 (see the ESI)† it is
evident that the structure of these cyclopropanes (1 and 2)
plays a crucial role in this diastereoselective reaction, so we
applied our protocol on 2-phenylcyclopropane-1,1-dicarboni-
trile (12) and cyclopropane-1,1-dicarbonitrile (13) which are
free of any steric hindrance. On reaction with 2.4 equiv. of
phenylboronic acid, both of the nitrile groups of 12 and 13
were converted to ketones (14 and 15) with excellent yields
(Scheme 4). We also performed this reaction with 1.2 equiv.
of phenylboronic acid for cyclopropane 12 and 13, which led
to the same product but in
a lower yield (see ESI,
Scheme S2†). Furthermore, we investigated the suitability of
other organo-boron compounds like aryl boron pinacolate
and potassium aryl boron trifluoride salt in this protocol and
they showed very impressive results (Scheme 2). We also
obtained an optical image of the reaction mixture (Fig. 2)
which confirms the formation of micelles promoted by
DBSA. The formation of the micellar medium facilitates the
reaction to occur in the hydrophobic interior14 and elimin-
ates water from the core which essentially improves the
overall rate and yield of the reaction. Again, we performed
and affords only one diastereomer as an enantiomeric Scheme 4 Scope of the steric hindrance free cyclopropane nitriles.
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Fig. 3 Micellar size distribution as observed in the dynamic light scat-
tering experiment.
Scheme 2 Control experiments.
Fig. 4 Transmission electron microscopy image of the DBSA solution
showing an ∼0.7–1 nm sized micellar distribution (small dark spots).
Fig. 2 Optical micrograph of the micellar medium.
DLS and TEM studies to identify the size distribution pattern
and shape of micelles. The dynamic light scattering study
discloses that the hydrodynamic radius of the micelles lies in
in the 0.7–1 nm range (Fig. 3). The TEM image of a drop of
DBSA solution further confirms this fact as small dark spots
Scheme 5 Scale-up synthesis of 4a and 5a.
According to the previous literature8,15 and based on the
can be seen in the polymeric matrix arising from the micel- above results, it is clear that transmetallation and co-ordina-
lar aggregation (Fig. 4). tion of Pd(II) complex species with nitriles are the key steps of
To check the practical applicability of this protocol, we per- this reaction. Hence the plausible reaction mechanism can be
formed the gram-scale synthesis of 4a and 5a and they were the transfer of aryl group to the CuN bond forming intermedi-
obtained in 91% and 90% yields respectively (Scheme 5).
ate C. Protonolysis of C produces D and regenerates the palla-
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were recorded on a Köfler Block apparatus and are uncor-
rected. DBSA and organo-boron compounds were purchased
from
Sigma-Aldrich.
For
column
chromatography,
100–200 mesh silica gel was used. All the organic solvents
used in the reaction were appropriately dried and distilled
prior to use.
General procedure for the synthesis of the required pyrazo-
lone derivatives. Sodium acetate (574.0 mg, 7.0 mmol) was
added in a suspension of aromatic hydrazine hydrochloride
derivatives (7.0 mmol) in 8 mL of EtOH and 2 mL of water,
and the mixture was stirred at rt for 5 min. Then, to the
mixture, ethyl acetoacetate (911.0 mg, 7.0 mmol) or ethyl ben-
zoylacetate (1345.5 mg, 7.0 mmol) was added, and the resul-
tant mixture was heated to reflux for 3 h. After that, the
mixture was poured dropwise onto crushed ice (50 g) with vig-
orous stirring, and the resulting precipitate was then filtered
and crystallized from EtOH. The obtained pyrazolone deriva-
tives were then used for the synthesis of pyranopyrazoles
without further purification.16
Scheme 6 Plausible mechanism of the reaction.
General procedure for the synthesis of pyranopyrimidine-
diones and pyranopyrazoles. Triethylamine (2 drops) was
added to a mixture of aromatic aldehydes (4.0 mmol), malono-
nitrile (264 mg, 4.0 mmol), and 1,3-dimethylbarbituric acid
(624 mg, 4.0 mmol) or pyrazolones (4.0 mmol) in EtOH
(8 mL), and the reaction mixture was refluxed for 15 min. The
precipitate that was formed after cooling the reaction mixture
to room temperature was filtered, washed with water (3 ×
5 mL) and EtOH (2 × 5 mL), and finally crystallized from
EtOH. The crystallized pure pyranopyrimidine-diones and pyr-
anopyrazoles were then employed for the synthesis of spirocy-
clopropyl barbiturates and pyrazolones without further
purification.13
General method for the synthesis of spirocyclopropyl-
pyrazolones (1a–k) and barbiturates (2a–g). To a stirring sus-
pension of PIDA (483.2 mg, 1.5 mmol) in 7 mL of DCM, I2
(380.1 mg, 1.5 mmol) was added and stirred for 5 min at rt.
Then, pyranopyrimidine-diones (3.0 mmol) or pyranopyrazoles
(3.0 mmol) were added in this mixture, followed by the
addition of triethylamine (6.0 mmol), and the resulting
mixture was stirred for 30 min at rt. After completion of the
reaction (monitored by TLC), the solvent was evaporated from
the reaction mixture under reduced pressure and the resulting
crude mass was triturated with MeOH (8 mL). The solid pre-
dium catalyst. Hydrolysis of D yields ketones as the products
(Scheme 6).
Conclusion
In summary, we have developed a protocol for palladium cata-
lyzed diastereoselective addition of arylboronic acids to
complex cyclopropyl dinitriles which is the first case of these
types of reactions involving such a complex scaffold. Moreover,
this reaction is unique compared to the rest of the reactions of
this category due to the use of catalytic DBSA in aqueous
media. Additionally, the advantages offered by this reaction
are: low catalyst loading, greener solvents, mild conditions and
shorter reaction time. The extension and development of this
protocol by inclusion of other suitable species instead of
boronic acid are in progress.
Experimental
Materials, methods and general synthetic procedures
1H-NMR and 13C-NMR spectral analyses were carried out using cipitate thus obtained was then filtered and washed with
300 MHz, 400 MHz, 500 MHz, 75 MHz, 100 MHz, and MeOH (3 × 5 mL) and finally crystallized from ethyl acetate to
125 MHz instruments where tetramethylsilane (TMS) was used obtain the pure products.13
as an internal standard. Infrared spectra were recorded in KBr
Procedure for the synthesis of 2-phenylcyclopropane-1,1-
pellets in the reflection mode on a FTIR spectrophotometer. dicarbonitrile (12). A 25 mL oven dried RB flask was charged
High resolution mass spectra were obtained using a mass with styrene (412.5 mg, 3 mmol) and malononitrile (238.0 mg,
spectrometer. Elemental analyses were performed using an 3.6 mmol). Then 6 mL of dry DCE was added to it and stirred.
autoanalyzer. Suitable single crystals of compounds 4a and 5g Next, PhI(OAc)2 (1063.0 mg, 3.3 mmol) and K2CO3 (456.1 mg,
were mounted on an X-ray diffractometer equipped with a 3.3 mmol) were added in the mixture and heated at 80 °C.
graphite monochromator. All the reactions were monitored by After completion of the reaction (monitored by TLC), the
thin layer chromatography carried out on aluminium-blocked mixture was cooled to room temperature and poured into
silica gel plates coated with silica gel GF254 under UV light and 25 mL brine and extracted with DCM (3 × 15 mL). The solvent
also by exposure to iodine vapor for detection. Melting points was removed under reduced pressure, and the residue was pur-
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ified by flash silica gel column chromatography (EtOAc–pet- then another 10 mL of distilled water was added to mark up
roleum ether = 1 : 10).17
the volume. Next, the mixture was heated at 90 °C in an open
Procedure for the synthesis of cyclopropane-1,1-dicarboni- atmosphere for 2 hours. After completion of the reaction
trile (13). In a 100 mL RB flask, malononitrile (1 g, 15.2 mmol) (monitored by TLC), the mixture was allowed to cool to room
and K2CO3 (5.5 g, 39.8 mmol) were dissolved in 40 mL anhy- temperature and then neutralized with 50 mL saturated
drous DCM. Then, 1,2-dibromoethane (3.85 g, 20.6 mmol) and NaHCO3 solution and extracted with 3 × 20 mL ethyl acetate.
crown ether 18-C-6 (0.7 g, 2.65 mmol) were added in this Then the combined organic layers were washed with saturated
mixture and stirred for 48 hours under a nitrogen atmosphere. brine and dried over anhydrous Na2SO4. After that, the solvent
After completion of the reaction, the reaction mixture was fil- was reduced under vacuum and the product was purified by
tered and concentrated under reduced pressure. Finally, it was column chromatography in 100–200 mesh silica gel using a
purified by flash silica gel column chromatography.18
mixture of ethyl acetate in petroleum ether as an eluent to
General procedure for the synthesis of 4a–o, 5a–h and 9. In afford 4a (91%) and 5a (90%) as pure products.
a 25 mL oven-dried RB flask, 3 mol% Pd(OAc)2 (6.74 mg) and
3 mol% 2,2′-bipyridine (4.68 mg) were taken. Then a solution
Characterization data for the products 4a–w and 5a–i
of 0.2 mmol 4-dodecylbenzenesulfonic acid (65.3 mg) in
1-Benzoyl-4-methyl-7-oxo-2,6-diphenyl-5,6-diazaspiro[2.4]hept-
1.5 mL of distilled water was added and stirred for 5 minutes. 4-ene-1-carbonitrile (4a). Off-white solid (389.2 mg, 96%); mp:
After that, 1.0 mmol of 1, 2 or 8 and 1.2 mmol arylboronic acid 184–186 °C; 1H NMR (300 MHz; CDCl3; Me4Si): δ 7.95–7.88 (m,
(3) were added in the RB flask sequentially under vigorous stir- 2H), 7.76–7.69 (m, 2H), 7.64 (t, J = 7.4 Hz, 1H), 7.50 (t, J = 7.6
ring and then another 1.5 mL of distilled water was added to Hz, 7H), 7.37 (t, J = 7.9 Hz, 2H), 7.20 (t, J = 7.4 Hz, 1H), 4.27 (s,
mark up the volume. Next, the mixture was heated at 90 °C in 1H), 2.00 (s, 3H); 13C{1H}NMR (75 MHz; CDCl3; Me4Si): δ
an open atmosphere for 2 hours. After completion of the reac- 183.2, 165.4, 153.1, 137.1, 134.6, 132.8, 129.1, 129.0, 128.9,
tion (monitored by TLC), the mixture was allowed to cool to 128.8, 128.6, 125.4, 118.5, 118.4, 118.3, 113.7, 46.2, 39.9, 36.6,
room temperature and then neutralized with 30 mL saturated 16.4; IR (KBr): 2961, 2230, 1718, 1550, 1487, 1328, 1257, 1161,
NaHCO3 solution and extracted with 3 × 15 mL ethyl acetate. 1110, 1015, 834 cm−1; anal. calcd for [C26H19N3O2]: C 77.02; H
Then the combined organic layers were washed with saturated 4.72; N 10.36; O 7.89. Found: C 77.05; H 4.74; N 10.34; O 7.90.
brine and dried over anhydrous Na2SO4. After that, the solvent
1-(4-(tert-Butyl)benzoyl)-4-methyl-7-oxo-2,6-diphenyl-5,6-dia-
was reduced under vacuum and the product was purified by zaspiro[2.4]hept-4-ene-1-carbonitrile (4b). White (452.3 mg,
column chromatography in 100–200 mesh silica gel using a 98%); mp: 168–170 °C; 1H NMR (300 MHz; CDCl3; Me4Si): δ
mixture of ethyl acetate in petroleum ether (1 : 19 to 3 : 17) as 7.85 (d, J = 8.6 Hz, 2H), 7.70 (d, J = 7.6 Hz, 2H), 7.50 (dd, J =
an eluent.
5.3, 3.4 Hz, 7H), 7.37 (t, J = 7.9 Hz, 2H), 7.20 (t, J = 7.4 Hz, 1H),
General procedure for the synthesis of 4p and 7. In a 25 mL 4.26 (s, 1H), 2.00 (s, 3H), 1.32 (s, 9H); 13C{1H}NMR (75 MHz;
oven-dried RB flask, 3 mol% Pd(OAc)2 (13.4 mg) and 3 mol% DMSO-d6; Me4Si): δ 183.3, 165.8, 158.8, 153.1, 137.3, 130.4,
2,2′-bipyridine (10.0 mg) were taken. Then a solution of 129.8, 129.27, 129.2, 129.1, 129.0, 128.7, 126.5, 125.7, 118.8,
0.4 mmol 4-dodecylbenzenesulfonic acid (130.6 mg) in 1.5 mL 114.3, 46.4, 36.6, 35.2, 30.7, 30.6, 16.4; IR (KBr): 2946, 2232,
of distilled water was added and stirred for 5 minutes. After 1721, 1558, 1481, 1323, 1247, 1149, 1101, 1010, 823 cm−1
;
that, 1.0 mmol of 1j or 6 and 2.4 mmol phenylboronic acid anal. calcd for [C30H27N3O2]: C 78.07; H 5.90; N 9.10; O 6.93.
(3a) were added in the RB flask sequentially under vigorous Found: C 78.05; H 5.91; N 9.07; O 6.91.
stirring and then another 3.5 mL of distilled water was added
1-(2-Naphthoyl)-4-methyl-7-oxo-2,6-diphenyl-5,6-diazaspiro
to mark up the volume. Next, the mixture was heated at 90 °C [2.4]hept-4-ene-1-carbonitrile (4c). Off-white (423.6 mg, 93%);
1
in an open atmosphere for 2 hours. After completion of the mp: 192–193 °C; H NMR (300 MHz; CDCl3; Me4Si): δ 8.44 (s,
reaction (monitored by TLC), the mixture was allowed to cool 1H), 7.95–7.84 (m, 4H), 7.72–7.49 (m, 9H), 7.31 (t, J = 7.9 Hz,
to room temperature and then neutralized with 30 mL satu- 2H), 7.15 (t, J = 7.4 Hz, 1H), 4.34 (s, 1H), 2.06 (s, 3H); 13C{1H}
rated NaHCO3 solution and extracted with 3 × 15 mL ethyl NMR (75 MHz; CDCl3; Me4Si): δ 184.3, 166.6, 154.3, 138.1,
acetate. Then the combined organic layers were washed with 136.9, 133.0, 132.12, 131.2, 130.6, 130.3, 130.2, 130.09, 130.0,
saturated brine and dried over anhydrous Na2SO4. After that, 129.6, 129.5, 128.5, 128.0, 126.4, 124.3, 119.5, 114.8, 47.4, 41.1,
the solvent was reduced under vacuum and the product was 37.8, 17.5; IR (KBr): 2964, 2223, 1711, 1564, 1489, 1321, 1240,
purified by column chromatography in 100–200 mesh silica 1154, 1108, 1012, 765 cm−1; anal. calcd for [C30H21N3O2]: C
gel using a mixture of ethyl acetate in petroleum ether as an 79.10; H 4.65; N 9.22; O 7.02. Found: C 79.11; H 4.63; N 9.23;
eluent.
Synthesis of 4a and 5a on a 5 mmol scale. In a 50 mL oven-
O 7.01.
1-Benzoyl-4-methyl-7-oxo-6-phenyl-2-(p-tolyl)-5,6-diazaspiro
dried RB flask, 3 mol% Pd(OAc)2 (33.6 mg) and 3 mol% 2,2′- [2.4]hept-4-ene-1-carbonitrile (4d). Yellow (385.9 mg, 92%);
bipyridine (23.4 mg) were taken. Then a solution of 1.0 mmol mp: 190–191 °C; 1H NMR (300 MHz; CDCl3; Me4Si): δ 7.91 (d, J
4-dodecylbenzenesulfonic acid (327.0 mg) in 5 mL of distilled = 7.2 Hz, 2H), 7.73 (d, J = 7.7 Hz, 2H), 7.63 (t, J = 7.4 Hz, 1H),
water was added and stirred for 5 minutes. After that, 7.49 (t, J = 7.6 Hz, 2H), 7.35 (dt, J = 23.9, 8.0 Hz, 6H), 7.20 (t, J =
5.0 mmol of 1a or 2a and 6.0 mmol arylboronic acid (3a) were 7.4 Hz, 1H), 4.23 (s, 1H), 2.44 (s, 3H), 2.02 (s, 3H); 13C{1H}NMR
added in the RB flask sequentially under vigorous stirring and (75 MHz; CDCl3; Me4Si): δ 183.6, 165.8, 153.6, 139.3, 137.5,
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134.9, 133.2, 129.9, 129.3, 129.2, 128.97, 128.9, 128.8, 125.7, 86%); mp: 192–193 °C; 1H NMR (300 MHz; CDCl3; Me4Si): δ
125.6, 118.7, 114.1, 46.6, 40.2, 37.0, 21.2, 16.8; IR (KBr): 2992, 7.90 (d, J = 7.2 Hz, 2H), 7.71 (d, J = 7.7 Hz, 2H), 7.64 (t, J = 7.4
2242, 1710, 1510, 1372, 1334, 1167, 1012, 812 cm−1; anal. calcd Hz, 1H), 7.49 (dd, J = 9.9, 5.5 Hz, 4H), 7.37 (t, J = 7.9 Hz, 2H),
for [C27H21N3O2]: C 77.31; H 5.05; N 10.02; O 7.63. Found: C 7.20 (t, J = 8.4 Hz, 3H), 4.21 (s, 1H), 2.03 (s, 3H); 13C{1H}NMR
77.29; H 5.03; N 10.03; O 7.65.
1-(4-(tert-Butyl)benzoyl)-4-methyl-7-oxo-6-phenyl-2-(p-tolyl)- 137.3, 134.9, 132.9, 131.3, 131.2, 129.2, 128.8, 125.7, 124.6,
5,6-diazaspiro[2.4]hept-4-ene-1-carbonitrile (4e). Yellow 118.6, 116.5, 116.2, 113.8, 46.4, 39.3, 36.9, 16.7; IR (KBr): 2968,
(75 MHz; CDCl3; Me4Si): δ 183.2, 165.5, 164.6, 161.3, 153.0,
(451.8 mg, 95%); mp: 185 °C; 1H NMR (300 MHz; CDCl3; 2231, 1712, 1559, 1495, 1331, 1254, 1168, 1113, 1009,
Me4Si): δ 7.83 (d, J = 8.6 Hz, 2H), 7.70 (d, J = 7.7 Hz, 2H), 7.49 834 cm−1; anal. calcd for [C26H18FN3O2]: C 73.75; H 4.28; F
(d, J = 8.6 Hz, 2H), 7.42–7.29 (m, 6H), 7.20 (t, J = 7.4 Hz, 1H), 4.49; N 9.92; O 7.56. Found: C 73.74; H 4.26; F 4.51; N 9.91; O
4.21 (s, 1H), 2.43 (s, 3H), 2.00 (s, 3H), 1.31 (s, 9H); 13C{1H} 7.58.
NMR (75 MHz; CDCl3; Me4Si): δ 183.2, 165.9, 158.9, 153.7,
1-(4-(tert-Butyl)benzoyl)-2-(4-fluorophenyl)-4-methyl-7-oxo-6-
139.2, 137.5, 130.7, 129.9, 129.3, 129.0, 128.9, 128.8, 128.7, phenyl-5,6-diazaspiro[2.4]hept-4-ene-1-carbonitrile (4j). Yellow
1
126.3, 125.8, 125.6, 118.8, 114.3, 46.6, 40.2, 37.2, 35.3, 30.8, (422.0 mg, 88%); mp: 184–185 °C; H NMR (300 MHz; CDCl3;
21.2, 16.8; IR (KBr): 2995, 2237, 1710, 1508, 1378, 1330, 1161, Me4Si): 7.80 (d, J = 8.5 Hz, 2H), 7.66 (d, J = 7.7 Hz, 2H),
1002, 821 cm−1; anal. calcd for [C31H29N3O2]: C 78.29; H 6.15; 7.51–7.44 (m, 4H), 7.34 (t, J = 7.9 Hz, 2H), 7.18 (t, J = 8.4 Hz,
N 8.84; O 6.73. Found: C 78.30; H 6.13; N 8.85; O 6.72.
3H), 4.17 (s, 1H), 1.99 (s, 3H), 1.28 (s, 9H); 13C{1H}NMR
1-Benzoyl-2-(4-bromophenyl)-4-methyl-7-oxo-6-phenyl-5,6-dia- (75 MHz; CDCl3; Me4Si): δ 182.8, 165.6, 164.6, 161.3, 159.1,
zaspiro[2.4]hept-4-ene-1-carbonitrile (4f). Yellow (435.9 mg, 153.1, 137.3, 131.4, 131.3, 130.4, 128.9, 128.8, 128.7, 126.3,
90%); mp: 162 °C; 1H NMR (300 MHz; CDCl3; Me4Si): δ 8.11 125.7, 124.8, 118.8, 116.5, 116.2, 114.0, 46.4, 39.3, 37.0, 35.3,
(td, J = 8.6, 6.4 Hz, 1H), 7.87–7.80 (m, 2H), 7.51–7.35 (m, 8H), 30.8, 16.7; IR (KBr): 2988, 2237, 1709, 1562, 1491, 1339, 1256,
7.21 (t, J = 7.4 Hz, 1H), 7.10–7.02 (m, 1H), 6.89–6.79 (m, 1H), 1165, 1109, 1015, 847 cm−1; anal. calcd for [C30H26FN3O2]: C
4.31 (s, 1H), 1.89 (s, 3H); 13C{1H}NMR (75 MHz; DMSO-d6; 75.14; H 5.47; F 3.96; N 8.76; O 6.67. Found: C 75.15; H 5.46; F
Me4Si): δ 183.5, 165.6, 152.7, 137.3, 135.4, 132.7, 132.1, 129.6, 3.98; N 8.75; O 6.66.
129.0, 128.6, 128.5, 125.6, 122.7, 118.6, 114.0, 16.5; IR (KBr):
1-Benzoyl-4-methyl-2-(4-nitrophenyl)-7-oxo-6-phenyl-5,6-dia-
2952, 2237, 1712, 1560, 1497, 1324, 1256, 1162, 1116, 1001, zaspiro[2.4]hept-4-ene-1-carbonitrile (4k). Yellow (364.8 mg,
840 cm−1; anal. calcd for [C26H18BrN3O2]: C 64.47; H 3.75; Br 81%); mp: 201–202 °C; 1H NMR (300 MHz; CDCl3; Me4Si): δ
16.50; N 8.68; O 6.61. Found: C 64.48; H 3.73; Br 16.51; N 8.67; 8.27 (d, J = 8.5 Hz, 2H), 7.78 (d, J = 7.5 Hz, 2H), 7.58 (dt, J =
O 6.63.
19.0, 9.4 Hz, 5H), 7.41 (t, J = 7.6 Hz, 2H), 7.27 (t, J = 7.8 Hz,
2-(4-Bromophenyl)-1-(4-(tert-butyl)benzoyl)-4-methyl-7-oxo-6- 2H), 7.11 (t, J = 7.3 Hz, 1H), 4.17 (s, 1H), 1.92 (s, 3H); 13C{1H}
phenyl-5,6-diazaspiro[2.4]hept-4-ene-1-carbonitrile (4g). Yellow NMR (75 MHz; CDCl3; Me4Si): δ 182.7, 165.0, 152.1, 148.3,
1
(502.6 mg, 93%); mp: 158–159 °C; H NMR (300 MHz; CDCl3; 137.1, 136.0, 135.2, 132.6, 130.6, 129.3, 128.79, 128.7, 125.9,
Me4Si): δ 7.81 (d, J = 8.6 Hz, 2H), 7.66 (t, J = 8.6 Hz, 4H), 7.49 124.39, 124.3, 118.69, 118.6, 113.4, 46.2, 38.8, 36.4, 16.7; IR
(d, J = 8.6 Hz, 2H), 7.37 (dd, J = 14.4, 8.0 Hz, 4H), 7.20 (t, J = 7.4 (KBr): 2968, 2231, 1712, 1559, 1495, 1345, 1250, 1168, 1113,
Hz, 1H), 4.16 (s, 1H), 2.03 (s, 3H), 1.31 (s, 9H); 13C{1H}NMR 1009, 834 cm−1; anal. calcd for [C26H18N4O4]: C 69.33; H 4.03;
(75 MHz; CDCl3; Me4Si): δ 182.8, 165.6, 159.3, 153.1, 137.4, N 12.44; O 14.21. Found: C 69.34; H 4.01; N 12.46; O 14.20.
132.6, 132.5, 131.2, 130.5, 129.0, 128.98, 128.9, 128.1, 126.4,
125.8, 123.7, 118.9, 114.0, 46.4, 39.5, 37.0, 35.4, 30.9, 16.9; IR 5,6-diazaspiro[2.4]hept-4-ene-1-carbonitrile
(KBr): 2958, 2232, 1716, 1559, 1495, 1331, 1254, 1168, 1113, (419.9 mg, 93%); mp: 146–147 °C; H NMR (300 MHz; CDCl3;
1009, 844 cm−1; anal. calcd for [C30H26BrN3O2]: C 66.67; H Me4Si): δ 7.90–7.84 (m, 2H), 7.68 (d, J = 7.7 Hz, 2H), 7.61 (t, J =
4.85; Br 14.78; N 7.78; O 5.92. Found: C 66.65; H 4.86; Br 7.4 Hz, 1H), 7.48 (d, J = 7.9 Hz, 2H), 7.42–7.29 (m, 6H), 7.18 (t,
1-Benzoyl-4-methyl-2-(4-(methylthio)phenyl)-7-oxo-6-phenyl-
(4l). Yellow
1
14.77; N 7.77; O 5.94.
J = 7.4 Hz, 1H), 4.17 (s, 1H), 2.52 (s, 3H), 2.01 (s, 3H); 13C{1H}
1-(4-(tert-Butyl)benzoyl)-2-(4-methoxyphenyl)-4-methyl-7-oxo- NMR (75 MHz; CDCl3; Me4Si): δ 183.1, 165.3, 153.0, 140.3,
6-phenyl-5,6-diazaspiro[2.4]hept-4-ene-1-carbonitrile (4h). Yellow 137.0, 134.6, 132.7, 129.4, 128.9, 128.5, 126.1, 125.3, 124.6,
(447.3 mg, 91%); mp: 155 °C; 1H NMR (300 MHz; CDCl3; 118.4, 113.6, 46.2, 39.5, 36.6, 16.5, 14.8; IR (KBr): 2962, 2229,
Me4Si): δ 7.84 (d, J = 8.5 Hz, 2H), 7.70 (d, J = 7.8 Hz, 2H), 1708, 1551, 1331, 1254, 1178, 1123, 1012, 843 cm−1; anal. calcd
7.52–7.33 (m, 6H), 7.20 (t, J = 7.4 Hz, 1H), 7.01 (d, J = 8.7 Hz, for [C27H21N3O2S]: C 71.82; H 4.69; N 9.31; O 7.09; S 7.10.
2H), 4.19 (s, 1H), 3.88 (s, 3H), 2.02 (s, 3H), 1.31 (s, 9H); 13C{1H} Found: C 71.84; H 4.67; N 9.30; O 7.08; S 7.11.
NMR (75 MHz; CDCl3; Me4Si): δ 183.9, 166.6, 160.9, 159.7,
1-(4-(tert-Butyl)benzoyl)-2-(4-(tert-butyl)phenyl)-4-methyl-7-
154.4, 138.2, 131.4, 129.5, 127.0, 126.3, 121.4, 119.6, 115.3, oxo-6-phenyl-5,6-diazaspiro[2.4]hept-4-ene-1-carbonitrile (4m).
1
115.0, 56.0, 47.4, 40.7, 38.0, 36.0, 31.5, 17.5; IR (KBr): 2955, Yellow (502.1 mg, 97%); mp: 175–176 °C; H NMR (500 MHz;
2230, 1712, 1651, 1552, 1492, 1329, 1251, 1166, 1111, 1011, CDCl3; Me4Si): δ 7.83–7.81 (m, 2H), 7.70–7.68 (m, 2H),
768 cm−1 anal. calcd for [C31H29N3O3]: C 75.74; H 5.95; N 8.55; 7.49–7.46 (m, 4H), 7.42 (d, J = 8.0 Hz, 2H), 7.35–7.32 (m, 2H),
O 9.76. Found: C 75.75; H 5.93; N 8.54; O 9.79.
7.17 (m, 1H), 4.19 (s, 1H), 1.97 (s, 3H), 1.35 (s, 9H), 1.29 (s,
1-Benzoyl-2-(4-fluorophenyl)-4-methyl-7-oxo-6-phenyl-5,6-dia- 9H); 13C{1H}NMR (100 MHz; CDCl3; Me4Si): δ 183.3, 166.1,
zaspiro[2.4]hept-4-ene-1-carbonitrile (4i). White (364.1 mg, 159.1, 153.8, 152.7, 137.7, 130.9, 129.2, 129.07, 129.04, 129.0,
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126.4, 126.3, 126.0, 125.7, 119.0, 114.5, 46.7, 40.3, 37.3, 35.4, 96%); mp: 195–196 °C; 1H NMR (300 MHz; CDCl3; Me4Si): δ
34.9, 31.3, 31.0, 16.9; IR (KBr): 2957, 2229, 1715, 1535, 1490, 7.92–7.85 (m, 2H), 7.76 (dd, J = 8.7, 1.0 Hz, 2H), 7.53–7.46 (m,
1331, 1251, 1172, 1107, 1013, 835 cm−1; anal. calcd for 5H), 7.41–7.34 (m, 2H), 7.24–7.17 (m, 1H), 6.99–6.92 (m, 2H),
[C34H35N3O2]: C 78.89; H 6.82; N 8.12; O 6.18. Found: C 78.91; 4.26 (s, 1H), 3.85 (s, 3H), 1.99 (s, 3H); 13C{1H}NMR (75 MHz;
H 6.83; N 8.10; O 6.17.
CDCl3; Me4Si): δ 181.82, 165.87, 164.98, 153.61, 137.60, 131.45,
1-Benzoyl-4-methyl-7-oxo-2-phenyl-6-(p-tolyl)-5,6-diazaspiro 129.55, 129.34, 129.29, 129.07, 128.97, 126.17, 125.69, 118.75,
[2.4]hept-4-ene-1-carbonitrile (4n). Yellow (381.7 mg, 91%); 114.66, 114.41, 77.52, 77.09, 76.67, 55.69, 46.57, 40.35, 36.99,
mp: 183–184 °C; 1H NMR (300 MHz; CDCl3; Me4Si): δ 7.78 (d, J 16.87; IR (KBr): 2970, 2232, 1726, 1542, 1480, 1328, 1248, 1162,
= 7.2 Hz, 2H), 7.46 (d, J = 8.1 Hz, 3H), 7.37 (s, 7H), 7.03 (d, J = 1117, 1027, 831 cm−1; anal. calcd for [C27H21N3O3]: C 74.47; H
8.1 Hz, 2H), 4.13 (s, 1H), 2.21 (s, 3H), 1.87 (s, 3H); 13C{1H}NMR 4.86; N 9.65; O 11.02. Found: C 74.49; H 4.84; N 9.63; O 11.05.
(75 MHz; CDCl3; Me4Si): δ 183.5, 165.4, 153.2, 135.4, 134.9,
1-(4-Chlorobenzoyl)-4-methyl-7-oxo-2,6-diphenyl-5,6-diazas-
134.8, 133.0, 129.4, 129.3, 129.1, 129.0, 128.8, 118.7, 113.9, piro[2.4]hept-4-ene-1-carbonitrile (4s). White solid (400.2 mg,
46.4, 40.0, 36.7, 20.8, 16.6; IR (KBr): 2998, 2245, 1713, 1511, 91%); mp: 177–178 °C; 1H NMR (300 MHz; CDCl3; Me4Si): δ
1374, 1329, 1165, 1007, 819 cm−1; anal. calcd for [C27H21N3O2]: 7.88–7.81 (m, 2H), 7.74 (dd, J = 8.7, 1.1 Hz, 2H), 7.50 (s, 6H),
C 77.31; H 5.05; N 10.02; O 7.63. Found: C 77.33; H 5.04; N 7.47 (s, 1H), 7.39 (t, J = 7.9 Hz, 2H), 7.22 (t, J = 7.4 Hz, 1H),
10.01; O 7.64.
4.25 (s, 1H), 1.98 (s, 3H); 13C{1H}NMR (75 MHz; CDCl3; Me4Si):
1-(4-(tert-Butyl)benzoyl)-7-oxo-2,4,6-triphenyl-5,6-diazaspiro δ 182.61, 165.70, 153.47, 141.78, 137.43, 131.53, 130.21,
[2.4]hept-4-ene-1-carbonitrile (4o). Yellow (507.9 mg, 97%); 129.78, 129.47, 129.37, 129.03, 128.69, 125.88, 118.71, 113.87,
mp: 178–180 °C; 1H NMR (300 MHz; CDCl3; Me4Si): δ 8.04 (d, J 77.48, 77.05, 76.63, 46.61, 40.34, 36.72, 16.82; IR (KBr): 2972,
= 7.8 Hz, 2H), 7.53 (d, J = 8.6 Hz, 2H), 7.47–7.29 (m, 11H), 7.22 2235, 1729, 1537, 1469, 1320, 1253, 1168, 1121, 1022,
(t, J = 3.7 Hz, 1H), 7.15 (t, J = 7.7 Hz, 2H), 6.88 (d, J = 7.3 Hz, 835 cm−1; anal. calcd for [C26H18ClN3O2]: C 70.99; H 4.12; Cl
2H), 4.75 (s, 1H), 1.30 (s, 9H); 13C{1H}NMR (125 MHz; CDCl3; 8.06; N 9.55; O 7.27. Found: C 70.97; H 4.14; Cl 8.08; N 9.54; O
Me4Si): δ 183.1, 163.7, 159.8, 154.4, 138.1, 130.7, 130.5, 129.6, 7.26.
129.4, 129.2, 129.1, 129.0, 128.5, 128.0, 127.8, 126.2, 125.9,
1-(4-Bromobenzoyl)-4-methyl-7-oxo-2,6-diphenyl-5,6-diazas-
119.0, 112.6, 44.8, 40.4, 37.2, 35.6, 31.1; IR (KBr): 2989, 2242, piro[2.4]hept-4-ene-1-carbonitrile (4t). Yellow solid (426.2 mg,
1711, 1512, 1364, 1322, 1164, 1005, 809 cm−1; anal. calcd for 88%); mp: 160–162 °C; 1H NMR (300 MHz; CDCl3; Me4Si): δ
[C35H29N3O2]: C 80.28; H 5.58; N 8.02; O 6.11. Found: C 80.31; 7.80–7.70 (m, 4H), 7.65 (d, J = 8.7 Hz, 2H), 7.50 (s, 5H), 7.39 (t,
H 5.59; N 8.01; O 6.10.
1-(4-Ethylbenzoyl)-4-methyl-7-oxo-2,6-diphenyl-5,6-diazas- 3H); 13C{1H}NMR (75 MHz; CDCl3; Me4Si): δ 182.98, 165.80,
piro[2.4]hept-4-ene-1-carbonitrile (4p). White solid 153.57, 137.53, 132.88, 132.04, 130.77, 130.32, 129.57, 129.48,
J = 7.9 Hz, 2H), 7.23 (t, J = 7.4 Hz, 1H), 4.25 (s, 1H), 1.98 (s,
1
(420.1 mg, 97%); mp: 180–181 °C; H NMR (300 MHz; CDCl3; 129.15, 128.78, 126.00, 118.83, 113.96, 77.58, 77.16, 76.74,
Me4Si): δ 7.90 (d, J = 8.3 Hz, 2H), 7.51–7.40 (m, 5H), 7.34 (d, J = 46.72, 40.44, 36.80, 16.93; IR (KBr): 2974, 2231, 1726, 1535,
8.3 Hz, 2H), 4.34 (s, 1H), 3.36 (s, 3H), 3.19 (s, 3H), 2.73 (q, J = 1470, 1321, 1251, 1166, 1126, 1032, 834 cm−1; anal. calcd for
7.6 Hz, 2H), 1.26 (t, J = 7.6 Hz, 3H); 13C{1H}NMR (75 MHz; [C26H18BrN3O2]: C 64.47; H 3.75; Br 16.50; N 8.68; O 6.61.
CDCl3; Me4Si): δ 183.65, 166.39, 154.11, 152.95, 138.07, 131.44, Found: C 64.46; H 3.76; Br 16.51; N 8.68; O 6.60.
130.05, 129.86, 129.81, 129.71, 129.52, 129.45, 129.41, 126.23,
1-(4-Acetylbenzoyl)-4-methyl-7-oxo-2,6-diphenyl-5,6-diazas-
119.34, 117.30, 114.77, 78.01, 77.58, 77.16, 47.08, 40.82, 37.55, piro[2.4]hept-4-ene-1-carbonitrile (4u). Yellow gummy liquid
1
29.62, 17.36, 15.45; IR (KBr): 2967, 2226, 1722, 1547, 1482, (402.7 mg, 90%); H NMR (300 MHz; CDCl3; Me4Si): δ 7.99 (q,
1318, 1251, 1159, 1113, 1021, 830 cm−1; anal. calcd for J = 8.6 Hz, 4H), 7.74–7.68 (m, 2H), 7.48 (s, 5H), 7.34 (dd, J =
[C28H23N3O2]: C 77.58; H 5.35; N 9.69; O 7.38. Found: C 77.60; 10.7, 5.2 Hz, 2H), 7.18 (t, J = 7.4 Hz, 1H), 4.24 (s, 1H), 2.59 (s,
H 5.33; N 9.70; O 7.39.
3H), 1.97 (s, 3H); 13C{1H}NMR (75 MHz; CDCl3; Me4Si): δ
4-Methyl-1-(3-methylbenzoyl)-7-oxo-2,6-diphenyl-5,6-diazas- 196.92, 183.36, 165.71, 153.47, 141.36, 137.43, 136.16, 129.52,
piro[2.4]hept-4-ene-1-carbonitrile (4q). White gummy liquid 129.47, 129.39, 129.15, 129.03, 129.01, 128.63, 125.87, 118.68,
(377.5 mg, 90%); 1H NMR (300 MHz; CDCl3; Me4Si): δ 7.71 113.75, 77.51, 77.09, 76.66, 46.70, 40.39, 36.85, 26.91, 16.80; IR
(dd, J = 8.4, 7.2 Hz, 3H), 7.61 (d, J = 7.6 Hz, 1H), 7.52–7.44 (m, (KBr): 2975, 2239, 1721, 1585, 1486, 1310, 1245, 1150, 1121,
5H), 7.41 (d, J = 7.6 Hz, 1H), 7.38–7.30 (m, 3H), 7.22–7.15 (m, 1026, 841 cm−1; anal. calcd for [C28H21N3O3]: C 75.15; H 4.73;
1H), 4.23 (s, 1H), 2.36 (s, 3H), 1.98 (s, 3H); 13C{1H}NMR N 9.39; O 10.73. Found: C 75.17; H 4.75; N 9.37; O 10.71.
(75 MHz; CDCl3; Me4Si): δ 183.74, 165.90, 153.60, 139.41,
137.50, 135.91, 133.12, 129.56, 129.53, 129.38, 129.31, 129.10, 5,6-diazaspiro[2.4]hept-4-ene-1-carbonitrile
4-Methyl-7-oxo-2,6-diphenyl-1-(3-(trifluoromethyl)benzoyl)-
(4v). Yellow
128.96, 126.07, 125.77, 118.84, 114.12, 77.50, 77.07, 76.65, gummy liquid (407.2 mg, 86%); 1H NMR (300 MHz; CDCl3;
46.61, 40.29, 37.03, 21.36, 16.83; IR (KBr): 2972, 2230, 1725, Me4Si): δ 8.20 (s, 1H), 7.96 (d, J = 7.9 Hz, 1H), 7.86 (d, J = 7.9
1545, 1487, 1312, 1247, 1153, 1117, 1024, 837 cm−1; anal. calcd Hz, 1H), 7.72–7.67 (m, 2H), 7.62 (t, J = 7.9 Hz, 1H), 7.49 (s, 5H),
for [C27H21N3O2]: C 77.31; H 5.05; N 10.02; O 7.63. Found: C 7.36 (dd, J = 10.7, 5.2 Hz, 2H), 7.19 (t, J = 7.4 Hz, 1H), 4.25 (s,
77.333; H 5.07; N 10.01; O 7.61.
1H), 1.98 (s, 3H); 13C{1H}NMR (75 MHz; CDCl3; Me4Si): δ
1-(4-Methoxybenzoyl)-4-methyl-7-oxo-2,6-diphenyl-5,6-diazas- 165.67, 153.43, 137.30, 133.70, 131.60, 130.05, 129.58, 129.45,
piro[2.4]hept-4-ene-1-carbonitrile (4r). White solid (418.0 mg, 129.42, 129.01, 128.49, 125.97, 118.80, 113.59, 77.47, 77.05,
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76.62, 46.67, 40.34, 36.63, 16.76; IR (KBr): 2980, 2247, 1725, 28.9; IR (KBr): 3417, 2943, 2234, 1675, 1421, 1257, 1117, 839,
1587, 1490, 1319, 1254, 1159, 1120, 1030, 844 cm−1; anal. calcd 741, 495 cm−1; anal. calcd for [C26H24BrN3O4]: C 59.78; H 4.63;
for [C27H18F3N3O2]: C 68.50; H 3.83; F 12.04; N 8.88; O 6.76. Br 15.30; N 8.04; O 12.25. Found: C 59.79; H 4.61; Br 15.31; N
Found: C 68.48; H 3.84; F 12.06; N 8.89; O 6.75.
8.05; O 12.24.
1-(2,4-Difluorobenzoyl)-4-methyl-7-oxo-2,6-diphenyl-5,6-dia-
1-(4-(tert-Butyl)benzoyl)-2-(4-fluorophenyl)-5,7-dimethyl-4,6,8-
zaspiro[2.4]hept-4-ene-1-carbonitrile (4w).
White solid trioxo-5,7-diazaspiro[2.5]octane-1-carbonitrile
(5e).
Yellow
1
1
(346.6 mg, 72%); mp: 171–172 °C; H NMR (300 MHz; CDCl3; (406.1 mg, 88%); mp: 210–212 °C; H NMR (300 MHz; CDCl3;
Me4Si): 8.18–8.08 (m, 1H), 7.86 (dd, J = 8.7, 1.0 Hz, 2H), Me4Si): δ 7.91 (d, J = 8.6 Hz, 2H), 7.58–7.47 (m, 4H), 7.13 (t, J =
7.50–7.38 (m, 7H), 7.23 (t, J = 7.4 Hz, 1H), 7.12–7.04 (m, 1H), 8.6 Hz, 2H), 4.31 (s, 1H), 3.38 (s, 3H), 3.19 (s, 3H), 1.36 (s, 9H);
6.92–6.82 (m, 1H), 4.33 (s, 1H), 1.91 (s, 3H); 13C{1H}NMR 13C{1H}NMR (75 MHz; CDCl3; Me4Si): δ 183.3, 164.3, 163.4,
(75 MHz; CDCl3; Me4Si): δ 180.1, 166.5, 154.1, 137.6, 134.2, 160.3, 159.1, 150.2, 130.8, 130.7, 130.4, 128.6, 126.2, 124.4,
129.39, 129.3, 129.2, 190.0, 125.6, 113.6, 113.3, 105.2, 104.8, 116.08, 115.7, 112.7, 43.2, 42.0, 40.8, 35.3, 30.7, 29.1; IR (KBr):
46.5, 40.9, 29.7, 16.5; IR (KBr): 2981, 2235, 1730, 1532, 1471, 3427, 2940, 2230, 1671, 1425, 1252, 1113, 1012, 835, 743,
1325, 1255, 1161, 1132, 1037, 843 cm−1; anal. calcd for 487 cm−1; anal. calcd for [C26H24FN3O4]: C 67.67; H 5.24; F
[C26H17F2N3O2]: C 70.74; H 3.88; F 8.61; N 9.52; O 7.25. Found: 4.12; N 9.11; O 13.87. Found: C 67.69; H 5.22; F 4.12; N 9.10; O
C 70.75; H 3.86; F 8.63; N 9.51; O 7.26.
1-Benzoyl-5,7-dimethyl-4,6,8-trioxo-2-phenyl-5,7-diazaspiro
13.88.
1-(4-(tert-Butyl)benzoyl)-5,7-dimethyl-2-(4-nitrophenyl)-4,6,8-
[2.5]octane-1-carbonitrile (5a). Yellow (364.1 mg, 94%); mp: trioxo-5,7-diazaspiro[2.5]octane-1-carbonitrile (5f). Yellow
1
220–222 °C; H NMR (400 MHz; CDCl3; Me4Si): δ 7.97 (d, J = (400.5 mg, 82%); mp: 216 °C; 1H NMR (300 MHz; CDCl3;
7.6 Hz, 2H), 7.64 (t, J = 7.2 Hz, 1H), 7.52–7.40 (m, 7H), 4.31 (s, Me4Si): δ 8.32–8.26 (m, 2H), 7.90–7.83 (m, 2H), 7.66 (d, J = 8.3
1H), 3.34 (s, 3H), 3.16 (s, 3H); 13C{1H}NMR (100 MHz; CDCl3; Hz, 2H), 7.56–7.51 (m, 2H), 4.40 (s, 1H), 3.38 (s, 3H), 3.14 (s,
Me4Si): δ 184.2, 163.8, 160.5, 150.4, 135.0, 133.4, 129.3, 129.1, 3H), 1.34 (s, 9H); 13C{1H}NMR (75 MHz; CDCl3; Me4Si): δ
129.0, 128.8, 128.7, 112.8, 44.5, 42.3, 40.8, 29.4; IR (KBr): 3412, 182.7, 162.9, 160.3, 159.6, 150.1, 147.9, 136.2, 130.2, 130.0,
2951, 2231, 1680, 1429, 1262, 1120, 842, 747, 497 cm−1; anal. 128.7, 126.4, 123.9, 112.3, 94.1, 41.9, 41.6, 40.8, 35.4, 30.8,
calcd for [C22H17N3O4]: C 68.21; H 4.42; N 10.85; O 16.52. 29.3; IR (KBr): 3412, 2941, 2237, 1671, 1535, 1419, 1346, 1251,
Found: C 68.20; H 4.41; N 10.87; O 16.51.
1112, 831, 739, 492 cm−1; anal. calcd for [C26H24N4O6]: C
1-(2-Naphthoyl)-5,7-dimethyl-4,6,8-trioxo-2-phenyl-5,7-dia- 63.93; H 4.95; N 11.47; O 19.65. Found: C 63.91; H 4.94; N
zaspiro[2.5]octane-1-carbonitrile (5b). Yellow (402.4 mg, 11.48; O 19.67.
92%); mp: 210–212 °C; 1H NMR (300 MHz; CDCl3; Me4Si): δ
2-([1,1′-Biphenyl]-4-yl)-1-(4-(tert-butyl)benzoyl)-5,7-dimethyl-
8.54 (s, 1H), 8.00–7.87 (m, 4H), 7.68–7.52 (m, 4H), 7.49–7.42 4,6,8-trioxo-5,7-diazaspiro[2.5]octane-1-carbonitrile (5g).
1
(m, 1H), 4.41 (s, 1H), 3.38 (s, 3H), 3.14 (s, 3H); 13C{1H}NMR Yellow (498.8 mg, 96%); mp: 194–196 °C; H NMR (300 MHz;
(125 MHz; CDCl3; Me4Si): δ 184.3, 163.9, 160.6, 150.5, 136.3, CDCl3; Me4Si): δ 7.94 (d, J = 8.5 Hz, 2H), 7.60 (ddd, J = 30.2,
132.4, 131.2, 130.8, 130.0, 129.7, 129.5, 129.1, 129.0, 128.9, 13.2, 8.5 Hz, 9H), 7.46 (t, J = 7.3 Hz, 2H), 4.38 (s, 1H), 3.38 (s,
128.0, 127.5, 127.1, 123.7, 112.9, 44.6, 42.4, 41.1, 29.46, 29.4; 3H), 3.22 (s, 3H), 1.34 (s, 9H); 13C{1H}NMR (75 MHz; CDCl3;
IR (KBr): 3425, 2957, 2242, 1699, 1431, 1265, 1125, 842, 745, Me4Si): δ 183.7, 163.7, 160.5, 159.0, 150.3, 141.7, 140.0, 130.6,
486 cm−1; anal. calcd for [C26H19N3O4]: C 71.39; H 4.38; N 129.3, 128.7, 127.6, 127.4, 127.1, 126.2, 112.9, 44.1, 42.1, 40.9,
9.61; O 14.63. Found: C 71.40; H 4.37; N 9.63; O 14.62.
1-(4-(tert-Butyl)benzoyl)-5,7-dimethyl-4,6,8-trioxo-2-(p-tolyl)-
35.3, 30.8, 29.28, 29.2; IR (KBr): 3421, 2951, 2235, 1689, 1433,
1268, 1123, 848, 749, 491 cm−1; anal. calcd for [C32H29N3O4]: C
5,7-diazaspiro[2.5]octane-1-carbonitrile (5c). Yellow (443.8 mg, 73.97; H 5.63; N 8.09; O 12.32. Found: C 73.99; H 5.64; N 8.08;
97%); mp: 164–166 °C; 1H NMR (300 MHz; CDCl3; Me4Si): δ O 12.31.
7.94 (d, J = 8.6 Hz, 2H), 7.54 (d, J = 8.6 Hz, 2H), 7.41 (d, J = 7.9
1-(4-(tert-Butyl)benzoyl)-5,7-dimethyl-2-(3-nitrophenyl)-4,6,8-
Hz, 2H), 7.26 (d, J = 8.0 Hz, 2H), 4.33 (s, 1H), 3.37 (s, 3H), 3.22 trioxo-5,7-diazaspiro[2.5]octane-1-carbonitrile (5h). Yellow
1
(s, 3H), 2.40 (s, 3H), 1.36 (s, 9H); 13C{1H}NMR (75 MHz; CDCl3; (420.1 mg, 86%); mp: 200–202 °C; H NMR (300 MHz; CDCl3;
Me4Si): δ 183.8, 163.8, 160.5, 159.0, 150.4, 138.9, 130.7, 129.6, Me4Si): δ 8.17–8.12 (m, 2H), 7.88 (d, J = 7.5 Hz, 1H), 7.79 (d, J =
128.8, 126.2, 125.6, 112.9, 44.5, 40.9, 35.3, 30.9, 29.3, 29.2, 8.4 Hz, 2H), 7.57 (t, J = 7.8 Hz, 1H), 7.44 (d, J = 8.7 Hz, 2H),
21.2; IR (KBr): 3420, 2970, 2231, 1680, 1429, 1376, 1258, 1122, 4.31 (s, 1H), 3.26 (s, 3H), 3.05 (s, 3H), 1.25 (s, 9H); 13C{1H}
848, 741, 492 cm−1; anal. calcd for [C27H27N3O4]: C 70.88; H NMR (75 MHz; CDCl3; Me4Si): δ 182.7, 162.9, 160.4, 159.5,
5.95; N 9.18; O 13.99. Found: C 70.89; H 5.93; N 9.17; O 14.00.
2-(4-Bromophenyl)-1-(4-(tert-butyl)benzoyl)-5,7-dimethyl-4,6,8-
150.1, 148.1, 134.7, 131.2, 130.2, 129.9, 128.6, 126.3, 124.3,
123.6, 112.3, 41.8, 41.3, 40.7, 35.3, 30.7, 29.2; IR (KBr): 3410,
trioxo-5,7-diazaspiro[2.5]octane-1-carbonitrile
(5d).
Yellow 2940, 2238, 1675, 1540, 1422, 1344, 1249, 1132, 836, 732,
1
(470.1 mg, 90%); mp: 204–206 °C; H NMR (300 MHz; CDCl3; 484 cm−1; anal. calcd for [C26H24N4O6]: C 63.93; H 4.95; N
Me4Si): δ 7.90 (d, J = 8.6 Hz, 2H), 7.56 (t, J = 8.2 Hz, 4H), 7.38 11.47; O 19.65. Found: C 63.91; H 4.94; N 11.48; O 19.67.
(d, J = 8.1 Hz, 2H), 4.28 (s, 1H), 3.38 (s, 3H), 3.18 (s, 3H), 1.35
1-(4-Ethylbenzoyl)-5,7-dimethyl-4,6,8-trioxo-2-phenyl-5,7-dia-
(s, 9H); 13C{1H}NMR (75 MHz; CDCl3; Me4Si): δ 182.9, 163.1, zaspiro[2.5]octane-1-carbonitrile (5i). White solid (398.7 mg,
160.0, 158.9, 149.9, 131.7, 131.6, 130.2, 130.1, 130.0, 128.49, 96%); mp: 189–190 °C; 1H NMR (300 MHz; CDCl3; Me4Si): δ
128.4, 127.5, 126.0, 122.9, 112.3, 42.8, 41.6, 40.5, 35.0, 30.5, 7.90 (d, J = 8.3 Hz, 2H), 7.51–7.40 (m, 5H), 7.34 (d, J = 8.3 Hz,
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2H), 4.34 (s, 1H), 3.36 (s, 3H), 3.19 (s, 3H), 2.73 (q, J = 7.6 Hz, for [C23H18O2]: C 84.64; H 5.56; O 9.80. Found: C 84.65; H
2H), 1.26 (t, J = 7.6 Hz, 3H); 13C{1H}NMR (75 MHz; CDCl3; 5.57; O 9.79.
Me4Si): δ 183.73, 163.81, 160.55, 152.45, 150.48, 131.02,
Cyclopropane-1,1-diylbis(phenylmethanone) (15). White
129.10, 129.06, 128.97, 128.88, 128.79, 112.91, 77.49, 77.07, (220.3 mg, 88%); mp: 69–70 °C; 1H NMR (300 MHz; CDCl3;
76.64, 44.39, 42.16, 40.97, 29.41, 29.34, 29.14, 15.01; IR (KBr): Me4Si): δ 7.79–7.72 (m, 4H), 7.36 (dd, J = 5.0, 3.7 Hz, 2H), 7.27
3427, 2971, 2235, 1689, 1439, 1379, 1268, 1127, 851, 761, (ddd, J = 8.1, 3.4, 1.1 Hz, 4H), 1.79 (s, 4H); 13C{1H}NMR
495 cm−1; anal. calcd for [C24H21N3O4]: C 69.39; H 5.10; N (75 MHz; CDCl3; Me4Si): δ 197.49, 137.64, 132.88, 128.53,
10.11; O 15.40. Found: C 69.41; H 5.11; N 10.09; O 15.41.
128.45, 40.71, 16.63; anal. calcd for [C17H14O2]: C 81.58; H
5.64; O 12.78. Found: C 81.56; H 5.65; O 12.79.
Characterization data for the products 4x, 7, 9, 11, 14 and 15
1-Benzoyl-2-(4-benzoylphenyl)-4-methyl-7-oxo-6-phenyl-5,6-
Conflicts of interest
diazaspiro[2.4]hept-4-ene-1-carbonitrile (4x). Off-white solid
1
(458.6 mg, 90%); mp: 196–198 °C; H NMR (300 MHz; CDCl3; There are no conflicts to declare.
Me4Si): δ 7.88–7.72 (m, 6H), 7.58 (ddt, J = 11.2, 7.4, 2.3 Hz,
6H), 7.49–7.37 (m, 4H), 7.31–7.23 (m, 2H), 7.11 (ddd, J = 8.5,
2.2, 1.1 Hz, 1H), 4.20 (s, 1H), 1.96 (s, 3H); 13C{1H}NMR
(75 MHz; CDCl3; Me4Si): δ 195.7, 183.2, 165.4, 152.9, 138.4,
Acknowledgements
137.3, 136.9, 135.2, 133.2, 132.98, 132.9, 130.8, 130.0, 129.6, We acknowledge the financial support from the Centre of
129.4, 129.0, 128.9, 128.5, 125.9, 118.8, 113.8, 46.4, 39.7, 36.7, CAS-V (Synthesis and functional materials) (support offered by
16.9; IR (KBr): 2972, 2244, 1731, 1708, 1581, 1489, 1306, 1240, the UGC, New Delhi) of the Department of Chemistry,
1147, 1117, 1021, 835 cm−1; anal. calcd for [C33H23N3O3]: C University of Calcutta. D. D. thanks the CSIR, New Delhi, India
77.78; H 4.55; N 8.25; O 9.42. Found: C 77.79; H 4.54; N 8.24; for his Senior Research Fellowship (File No: 09/028(0993)/
O 9.44.
2017-EMR-I). Crystallography was performed at the DST-FIST,
1,7-Diphenylheptane-1,7-dione (7). White (263.5 mg, 94%); India-funded Single Crystal Diffractometer Facility at the
mp: 94–96 °C; 1H NMR (400 MHz; CDCl3; Me4Si): δ 7.96–7.93 Department of Chemistry, University of Calcutta. We are also
(m, 4H), 7.56–7.52 (m, 2H), 7.46–7.42 (m, 4H), 2.98 (t, J = 7.6 pleased to acknowledge Prof. D. K. Maiti, University of
Hz, 4H), 1.80 (p, J = 7.6 Hz, 4H), 1.52–1.46 (m, 2H); 13C{1H} Calcutta for extending his help by offering the instrumentation
NMR (100 MHz; CDCl3; Me4Si): δ 200.3, 137.1, 133.0, 128.6, facility.
128.1, 38.4, 29.0, 24.1; IR (KBr): 3050, 1790, 1785, 1580, 1447,
986, 835 cm−1; anal. calcd for [C17H16O2]: C 80.94; H 6.37; O
12.70. Found: C 80.93; H 6.39; O 12.69.
Notes and references
1,2-Diphenylethan-1-one (9). White (188.4 mg, 96%); mp:
1
58–60 °C; H NMR (300 MHz; CDCl3; Me4Si): δ 8.10–8.03 (m,
2H), 7.63–7.56 (m, 1H), 7.54–7.46 (m, 2H), 7.43–7.25 (m, 5H),
4.33 (s, 2H); 13C{1H}NMR (75 MHz; CDCl3; Me4Si): δ 197.2,
136.2, 134.2, 132.8, 129.2, 129.17, 129.1, 128.7, 128.4, 128.3,
128.2, 128.1, 127.6, 127.5, 126.5, 45.1; IR (KBr): 3090, 1792,
1496, 992, 842 cm−1; anal. calcd for [C14H12O]: C 85.68; H 6.16;
O 8.15. Found: C 85.69; H 6.14; O 8.16.
1,3-Diphenylpropane-1,3-dione (or 3-hydroxy-1,3-diphenyl-
prop-2-en-1-one) (11). White (197.2 mg, 88%); mp: 76–77 °C;
1H NMR (300 MHz; CDCl3; Me4Si): δ 8.07–7.99 (m, 4H),
7.63–7.48 (m, 6H), 6.90 (s, 1H); 13C{1H}NMR (75 MHz; CDCl3;
Me4Si): δ 185.80, 135.56, 132.51, 128.73, 127.21, 93.19, 77.52,
77.10, 76.68; IR (KBr): 3065, 1602, 1296, 1004 cm−1; anal. calcd
for [C15H12O2]: C 80.34; H 5.39; O 14.27. Found: C 80.33; H
5.38; O 14.27.
(2-Phenylcyclopropane-1,1-diyl)bis(phenylmethanone) (14).
White (297.0 mg, 91%); mp: 96–97 °C; 1H NMR (300 MHz;
CDCl3; Me4Si): δ 7.83–7.76 (m, 2H), 7.66–7.58 (m, 2H), 7.34
(dddd, J = 10.9, 6.0, 2.9, 1.3 Hz, 5H), 7.25–7.05 (m, 6H), 4.03 (t,
J = 8.5 Hz, 1H), 2.88 (dd, J = 8.0, 4.7 Hz, 1H), 1.76 (dd, J = 9.0,
4.7 Hz, 1H); 13C{1H}NMR (75 MHz; CDCl3; Me4Si): δ 197.00,
194.45, 137.88, 137.69, 134.10, 132.95, 132.74, 128.58, 128.56,
128.49, 128.26, 128.10, 127.11, 49.90, 32.40, 19.74; anal. calcd
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