A novel and green protocol for two-carbon homologation: A direct amino acid/K2CO3-catalyzed four-component reaction of aldehydes, active methylenes, Hantzsch esters and alkyl halides

Article abstract of DOI:10.1016/j.tetlet.2005.11.128

A novel and green approach for the two-carbon homologation of aldehydes using amino acid catalysis has been developed and further extended to the generation of pharmaceutically active cyano-esters via four-component reactions in one-pot.

Full text of DOI:10.1016/j.tetlet.2005.11.128

Tetrahedron
Letters
Tetrahedron Letters 47 (2006) 651–656
A novel and green protocol for two-carbon homologation:
a direct amino acid/K CO -catalyzed four-component reaction
of aldehydes, active methylenes, Hantzsch esters and alkyl halides
2
3
*
Dhevalapally B. Ramachary, M. Kishor and K. Ramakumar
School of Chemistry, University of Hyderabad, Central University (P.O.), Hyderabad 500 046, India
Received 9 October 2005; revised 17 November 2005; accepted 24 November 2005
Abstract—A novel and green approach for the two-carbon homologation of aldehydes using amino acid catalysis has been devel-
oped and further extended to the generation of pharmaceutically active cyano-esters via four-component reactions in one-pot.
ꢀ
2005 Elsevier Ltd. All rights reserved.
Two-carbon homologation is a very important transfor-
mation in synthetic organic chemistry and numerous
1
methods are available although most involve redox
functional group transformations rather than carbon–
carbon bond formation. In this regard, the development
of two-carbon homologation through carbon–carbon
bond formation using organocatalytic tandem method-
2
ology can provide an expedient access to homologated
products from simple starting materials.
As part of our program to engineer direct organocat-
2
a–e
alytic tandem or multi-component reactions,
we
report the first organocatalytic, regioselective, tandem
Knoevenagel and hydrogenation (K/H), Knoevenagel/
hydrogenation/hydrolysis (K/H/H) and Knoevenagel/
hydrogenation/alkylation (K/H/A) reactions that pro-
duce highly substituted two-carbon homologated esters
5
, 8 and 9, respectively, from commercially available
aldehydes 1a–t, active methylenes 2a–h, Hantzsch 1,4-
dihydropyridine esters 3a–b, alkyl halides 7a–d and
amino acids 4a–b as shown in Scheme 1. Homologated
esters 5 and 9 are attractive intermediates in medicinal
chemistry, and analogues thereof have broad utility in
3
pharmaceutical chemistry (herbicidal, anti-diabetic,
analgesic, anti-inflammatory and anti-thrombotics) and
in organic synthesis. Hence, new methods for their syn-
theses have continued to attract considerable interest.
Keywords: Amino acids; Hantzsch ester; Multi-component reactions;
Organocatalysis; Two-carbon homologation.
*
Corresponding author. Tel.: +91 40 23134816; fax: +91 40
3012460; e-mail: ramsc@uohyd.ernet.in
Scheme 1. Direct organocatalytic K/H, K/H/H and K/H/A reactions
in one-pot.
2
0040-4039/$ - see front matter ꢀ 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2005.11.128

652
D. B. Ramachary et al. / Tetrahedron Letters 47 (2006) 651–656
This letter outlines that amino acid 4 or Hantzsch ester 3
catalyzes the tandem Knoevenagel condensation of
logated product 5-benzyl-1,3-dimethyl-pyrimidine-2,4,6-
trione 5aa as a single isomer, with 99% conversion
(Table 1, entry 1). The same reaction, catalyzed by
L-proline 4a in EtOH at 25 ꢁC under tandem conditions,
furnished the product 5aa with 98% conversion in less
time (Table 1, entry 7), perhaps due to the catalytic nat-
ure of the Hantzsch ester 3a in the tandem K/H reac-
tion. Interestingly, the tandem K/H reaction of 1a, 2a
and 3a without catalyst at 25 ꢁC for 5 h furnished the
expected product 5aa with 99% conversion (Table 1,
entry 10) and this is the best demonstration of the
catalytic nature of reagent 3a in tandem reactions. Inter-
estingly, there is a little solvent effect on the proline
catalyzed tandem K/H reaction of 1a, 2a and 3a as
shown in Table 1. The one-pot K/H reaction of 1a, 2a
2
c
aldehydes 1 with the active methylenes 2 to form Knoe-
4
venagel products 10, which then undergo regioselective
5
hydrogenation with the NADH mimic organic hydride
Hantzsch esters 3 to produce homologated esters 5 in
good to excellent yields. Esters 5 could be converted into
compounds 8 and 9 via hydrolysis and alkylation
reactions catalyzed by acid and base, respectively, in
good to excellent yields over the three-step sequence
(
Scheme 1).
We were pleased to find that the one-pot reaction of
benzaldehyde 1a, N,N-dimethylbarbituric acid 2a and
Hantzsch ester 3a with a catalytic amount of L-proline
4
a in EtOH at 25 ꢁC for 2–14 h furnished the homo-
and 3a in H O without catalyst furnished the expected
2
a
Table 1. Optimization of the direct organocatalytic tandem Knoevenagel and hydrogenation reactions of 1a, 2a and 3a
b
Entry
Catalyst
Solvent
Ester 3a (equiv)
Time (h)
Conversion (%)
1
2
3
4
5
6
7
8
4a
4a
4a
4a
4a
4a
4a
4a
4b
—
—
—
EtOH
MeOH
DMF
1.06
1.06
1.06
1.06
1.06
1.06
1.00
1.00
1.00
1.00
—
2–14
4–6
3–6
4–6
3–6
2–14
2
2
3
5
48
99
82
99
90
98
99
98
97
99
99
—
99
DMSO
CHCl
CH CN
EtOH
CH CN
EtOH
3
3
3
c
9
10
11
12
CH
CH
3
CN
CN
d
3
H
2
O
1.00
0.25–2
a
Experimental conditions: Method A: A mixture of 1a (0.3 mmol), 2a (0.3 mmol) and catalyst 4 (20 mol %) was stirred at room temperature for 2–4 h
then 3a was added and stirring continued at the same temperature: Method B: All reactants 1a, 2a, 3a and catalyst 4 were mixed at the same time
and stirred at room temperature.
Determined by H NMR spectroscopy.
Product 5aa was isolated as a 1:1 mixture of keto and enol forms.
b
c
1
d
Knoevenagel product did not form.
Scheme 2. Dual role of Hantzsch ester 3a as a catalyst and reagent in the tandem Knoevenagel/hydrogenation reactions.

D. B. Ramachary et al. / Tetrahedron Letters 47 (2006) 651–656
653
homologated product 5aa with very good conversion
and these are the optimal reaction conditions for the
construction of C–C and C–H bonds under green reac-
tion conditions (Table 1, entry 12). The simple amino
acid, glycine also catalyzed the tandem K/H reaction
to furnish homologated product 5aa with 99% conver-
sion as a 1:1 ratio of keto/enol forms (Table 1, entry
Table 3. Chemically diverse libraries of two-carbon homologated
esters 5
9
). The best conditions for the tandem K/H reaction
of 1a, 2a and 3a in CH CN, EtOH or H O at 25 ꢁC to
3
2
furnish 5aa with excellent conversions required the pres-
ence of the amino acid (entries 7 and 8), but not in the
cases of entries 10 and 12.
Following these promising results, we proceeded to
investigate the scope and limitations of the tandem K/H
reaction with a range of aldehydes 1a–t, active methyl-
enes 2a–h and Hantzsch esters 3a–b with and without
catalyst (Scheme 2, Tables 2 and 3). Unfortunately, tan-
dem K/H reaction of 1a, 2a and 4-phenyl Hantzsch
ester 3b with and without proline catalysis did not fur-
nish the expected tandem product 5aa and furnished
only the Knoevenagel product, 5-benzylidene-1,3-dimethyl-
pyrimidine-2,4,6-trione (results not shown). Tandem
K/H reactions of 4-fluorobenzaldehyde 1d, MeldrumÕs
acid 2b and Hantzsch ester 3a in CH CN at 25 ꢁC for
3
5
h and benzaldehyde 1a, ethyl cyanoacetate 2e and
Hantzsch ester 3a in EtOH at 25 ꢁC for 5 h furnished
the tandem products 5-(4-fluoro-benzyl)-2,2-dimethyl-
[
1,3]dioxane-4,6-dione 5db and ethyl benzyl-cyano-acet-
ate 5ae with 75% conversions, respectively. However,
the same reactions under proline catalysis furnished
the expected products 5db and 5ae with 99% conversion
and in shorter times (Scheme 2). The regioselective
one-pot K/H reaction of benzaldehyde 1a and Hantzsch
ester 3a with a variety of active methylene compounds
2
a–h was screened in H O at 25 ꢁC without catalysis,
2
which furnished the expected homologated products
5
aa–ah in very good to poor yields as shown in Table
2
. After testing the autocatalytic nature of the Hantzsch
ester 3a and H O promoted reactions in one-pot K/H
2
reactions with different aldehydes 1 and active methyl-
Table 2. Tandem Knoevenagel/hydrogenation reactions of 1a, 2 and
a
2
3a in H O
b
Entry
Active methylene 2
Time (h)
Conversion (%)
enes 2 as shown in Scheme 2 and Table 2, we generated
a library of homologated esters 5 under proline
catalysis.
1
2
3
2a
2b
2c
2d
2e
2f
0.25–2
1–16
3–25
5–40
3–54
2–25
48
99
85
40
—
40
60
<25
99
c
4
5
c
The results in Table 36,7 demonstrate the broad scope of
this reductive methodology covering a structurally di-
verse group of activated aldehydes 1a–t and methylenes
2a–h with many of the yields obtained being very good,
or indeed better, than previously published homologa-
tion reactions starting from the corresponding alde-
hydes. Although diethyl malonate 2d did not react
efficiently using this methodology, we have found that
2d did not undergo Knoevenagel condensation either.
6
7
c
2g
2h
8
0.5–4
a
A mixture of 1a (0.5 mmol) and 2 (0.5 mmol) was stirred at room
temperature for 0.25–5 h then 3a was added and stirring continued at
the same temperature.
Determined by H NMR spectroscopy.
Knoevenagel product formation was very poor.
b
c
1

654
D. B. Ramachary et al. / Tetrahedron Letters 47 (2006) 651–656
Tandem K/H reaction of E-cinnamaldehyde 1m, Mel-
drumÕs acid 2b and Hantzsch ester 3a furnished the
regioselectively hydrogenated ester 5mb and completely
hydrogenated ester 5nb in a 2.5:1 ratio in 99% yield
Table 4. Generation of chemically diverse libraries of analgesic and
anti-inflammatory cyano-esters 9 via proline/K CO -catalyzed tandem
Knoevenagel/hydrogenation/alkylation reactions
2
3
a
(
Table 3; Scheme 3). Homologated esters 2-benzyl-in-
dan-1,3-dione 5ac and 5-(4-cyano-benzyl)-2,2-dimethyl-
1,3]dioxane-4,6-dione 5rb are important intermediates
[
3
a
3c
for herbicidal and anti-thrombotic chemicals; tan-
dem ester 5-anthracen-9-ylmethyl-2,2-dimethyl-[1,3]dio-
xane-4,6-dione 5lb is a very useful intermediate to pre-
3
d
pare dienophile scavengers, emphasizing the value of
this approach. Tandem K/H ester 5-benzyl-2,2-di-
methyl-[1,3]dioxane-4,6-dione 5ab was converted into
the two-carbon homologated ester ethyl 3-phenyl-propi-
onate 8a via a tandem K/H/H sequence in good yield
with HCO H/Et N in one-pot as shown in Scheme 4.
2
3
Based on the results of the proline-catalyzed three-and
four-component K/H and K/H/H reactions with vari-
ous aldehydes 1a–t and active methylenes 2a–h, we also
engineered a novel proline/K CO -catalyzed four-com-
2
3
ponent K/H/A reaction of aldehydes 1, ethyl cyanoacet-
ate 2e, Hantzsch ester 3a and alkyl halides 7a–d in
one-pot (Table 4). Highly substituted cyano-esters 9
containing a quaternary carbon were constructed in
good yields with various substituents as shown in Table
a
A mixture of 1b–c (0.5 mmol), 2e (0.5 mmol), 3a (0.5 mmol) and
cataylyst 4a (20 mol %) was stirred at room temperature for 3–24 h
then R-I or R-Br 7a–d (2.5 mmol) and K CO (0.4 g) were added and
2 3
stirring continued at the same temperature.
Yield refers to the column purfied product.
6
,7
b
4
and this process is the first example of the utility of the
proline/K CO combination in catalysis. One-pot
2
3
cyano-esters 9 have direct applications in pharmaceuti-
cal chemistry.
highly substituted homologated esters in a regioselective
fashion, which are useful in pharmaceutical chemistry.
For the first time in organocatalysis, the reagent has
acted as a catalyst in tandem reactions and this is a very
good example of autocatalysis. Further work is in pro-
gress to utilize an asymmetric version of this tandem
process.
3
b
In summary, we have developed the first examples of
amino acid-catalyzed direct tandem K/H, K/H/H and
K/H/A reactions. This experimentally simple and envi-
ronmentally friendly approach can be used to construct
Scheme 3. Direct organocatalytic tandem Knoevenagel/hydrogenation of 1m, 2b and 3a.
Scheme 4. Direct organocatalytic two-carbon homologation reaction in one-pot.

D. B. Ramachary et al. / Tetrahedron Letters 47 (2006) 651–656
655
Acknowledgements
Fonseca, M. T.; List, B. Angew. Chem., Int. Ed. 2005, 44,
08; (d) Ouellet, S. G.; Tuttle, J. B.; MacMillan, D. W. C. J.
1
Am. Chem. Soc. 2005, 127, 32.
We thank DST (New Delhi) for funding this project. We
thank UGC (New Delhi) for recognizing our University
of Hyderabad as a ÔUniversity with potential for excel-
lenceÕ (UPE) and also recognizing our School of Chem-
istry as a Center for Advanced Studies in Chemistry and
for providing instrumental facilities. M.K. and K.R.K.
thank CSIR (New Delhi) for their research fellowships.
6
. General experimental procedures for the two-carbon
homologation reactions: Amino acid-catalyzed Knoevena-
gel/hydrogenation reactions in one-pot: To 0.3 mmol of
aldehyde 1 and 0.3 mmol of active methylene compound 2
was added 1.0 mL of solvent, and then the amino acid
catalyst 4 (0.06 mmol) was added and the reaction mixture
was stirred at 25 ꢁC for 0.25–5 h. Hantzsch ester 3a
(
0.3 mmol) was added and stirring continued for the time
indicated in Tables 1, 2 or 3. The crude reaction mixture
was directly loaded onto a silica gel column with or without
aqueous work-up and pure one-pot products 5 were
obtained by column chromatography (silica gel, mixture
of hexane/ethyl acetate). Amino acid-catalyzed tandem
Knoevenagel/hydrogenation reactions: To 0.3 mmol of
aldehyde 1, 0.3 mmol of active methylene compound 2
and 0.3 mmol of Hantzsch ester 3a was added 1.0 mL of
solvent, and then the amino acid catalyst 4 (0.06 mmol) was
added and the reaction mixture was stirred at 25 ꢁC for the
time indicated in Tables 1, 2 or 3. The crude reaction
mixture was purified as before. Amino acid-catalyzed
Knoevenagel/hydrogenation/hydrolysis reactions in one-
pot: To 0.5 mmol of aldehyde 1, 0.5 mmol of active
methylene compound 2 and 0.5 mmol of Hantzsch ester
Supplementary data
Experimental procedures and analytical data for all
new compounds. Supplementary data associated with
this article can be found, in the online version, at doi:
1
0.1016/j.tetlet.2005.11.128.
References and notes
1
. Representative examples: (a) Garden, S. J.; Guimaraes, C.
R. W.; Correa, M. B.; Fernandes de Oliveira, C. A.; Pinto,
A. C.; Bicca de Alencastro, R. J. Org. Chem. 2003, 68, 8815;
b) Reid, M.; Rowe, D. J.; Taylor, R. J. K. Chem. Commun.
003, 18, 2284; (c) Lee, H. W.; Kim, B. Y.; Ahn, J. B.; Son,
H. J.; Lee, J. W.; Ahn, S. K.; Hong, C. Heterocycles 2002,
7, 2163; (d) Jorgensen, M.; Iversen, E. H.; Madsen, R. J.
(
2
3
a was added 1.0 mL of EtOH followed by the amino acid
catalyst 4 (0.1 mmol) and the reaction mixture was stirred
at 25 ꢁC for the time indicated in Table 3. To the crude
reaction mixture was added 0.5 mL of HCO H, 1.8 mL of
2
5
Org. Chem. 2001, 66, 4625; (e) Satyamurthi, N.; Singh, J.;
Indrapal Singh, A. Synthesis 2000, 3, 375; (f) Hara, S.;
Kishimura, K.; Suzuki, A.; Dhillon, R. S. J. Org. Chem.
Et
3
N and stirring continued at 120 ꢁC for 12 h. The crude
reaction mixture was worked up with aqueous NaHCO
and NH Cl solutions and the aqueous layer was extracted
with dichloromethane (2 · 20 mL). The combined organic
2 4
layers were dried (Na SO ), filtered and concentrated. Pure
3
4
1
990, 55, 6356; (g) Brown, H. C.; Midland, M. M.; Levy, A.
B. J. Am. Chem. Soc. 1972, 94, 3662; (h) Toth, G.; Koever,
K. E. Synth. Commun. 1995, 25, 3067.
products 8 were obtained by column chromatography
silica gel, mixture of hexane/ethyl acetate). Amino acid/
CO -catalyzed Knoevenagel/hydrogenation/alkylation
2
. (a) Ramachary, D. B.; Chowdari, N. S.; Barbas, C. F., III
Angew. Chem., Int. Ed. 2003, 42, 4233; (b) Ramachary, D.
B.; Anebouselvy, K.; Chowdari, N. S.; Barbas, C. F., III J.
Org. Chem. 2004, 69, 5838; (c) Ramachary, D. B.; Barbas,
C. F., III Chem. Eur. J 2004, 10, 5323; (d) Ramachary,
D. B.; Barbas, C. F., III Org. Lett. 2005, 7, 1577; (e)
Ramachary, D. B.; Ramakumar, K.; Kishor, M. Tetra-
hedron Lett. 2005, 46, 7037; (f) List, B.; Castello, C. Synlett
(
K
2
3
reactions in one-pot: To 0.5 mmol of aldehyde 1, 0.5 mmol
of active methylene compound 2 and 0.5 mmol of Hantzsch
ester 3a was added 1.0 mL of solvent followed by the
proline catalyst 4a (0.1 mmol) and the reaction mixture was
stirred at 25 ꢁC for 3–24 h. Then R-I or R-Br 7 (2.5 mmol)
and K CO (0.4 g) were added and stirring continued at the
same temperature for 7–24 h. The crude reaction mixture
was worked up with aqueous NH Cl solution and the
aqueous layer was extracted with dichloromethane
2
3
2
001, 11, 1687; (g) Edin, M.; Backvall, J. E.; Cordova, A.
Tetrahedron Lett. 2004, 45, 7697; (h) Halland, N.; Aburel, P.
S.; Jorgensen, K. A. Angew. Chem., Int. Ed. 2004, 43, 1272.
. (a) Hosokawa, A.; Ikeda, O.; Minami, N.; Kyomura, N.
Eur. Pat. Appl., 1993, 33 pp. CODEN: EPXXDW EP
4
3
(
(
2 · 20 mL). The combined organic layers were dried
Na SO ), filtered and concentrated. Pure products 9 were
2
4
5
62361 A1 19930929, CAN 120:244386 (patent written in
obtained by column chromatography (silica gel, mixture of
hexane/ethyl acetate).
English); (b) Pitta da Rocha, I.; Boucherle, A.; Luu Duc, C.
Eur. J. Med. Chem. 1974, 9, 462; (c) Al-Obeidi, F.; Lebl,
M.; Ostrem, J. A.; Safar, P.; Stierandova, A.; Strop, P.;
Walser, A. U.S. Patent, 2004, 32 pp. CODEN: USXXAM
US 6759384 B1 20040706, CAN 141:106734; (d) Lei, X.;
Porco, J. A., Jr. Org. Lett. 2004, 6, 795.
. The amino acids proline 4a and glycine 4b and Hantzsch
ester 3a catalyzed the Knoevenagel condensation of alde-
hydes 1a–t with active methylenes 2a–h to furnish in situ
Knoevenagel products 10 in very good yields (see Eq. 1).
7
. All new compounds were characterized on the basis of IR,
1
13
H and C NMR and LRMS data. Spectral data for
selected compounds: 5db: IR (neat): 1786, 1739 (OAC@O),
ꢀ1 1
; H NMR (400 MHz, CDCl ) d 7.29 (2H, m,
3
1
602 cm
Ar-H), 6.96 (2H, t, J = 8.8 Hz, Ar-H); 3.75 (1H, t, J =
.8 Hz, CH), 3.45 (2H, d, J = 4.8 Hz, CH ), 1.73 (3H, s,
CH ), 1.53 (3H, s, CH ); C NMR (100 MHz, CDCl3,
4
4
2
1
3
3
3
DEPT-135) d 165.1 (C, 2·OAC@O), 161.9 (C, d, J =
2
44.3 Hz, C-F), 132.7 (C, d, J = 3.4 Hz), 131.5 (2·CH, d,
J = 7.9 Hz), 115.3 (2·CH, J = 21.1 Hz), 105.2 (C, O–C–O),
4
8.1 (CH), 31.2 (CH ), 28.3 (CH ), 27.2 (CH ); HRMS: m/z
2
3
3
+
calcd for C13
H
13FO (M ): 252.0798; found: 252.0790.
4
ꢀ
1
9
bec: IR (neat): 2229 (C„N), 1734 (OAC@O), 1608 cm ;
1
H NMR (400 MHz, CDCl
2H, m, Ar-H); 5.85 (1H, m, olefinic-H), 5.26 (2H, m,
olefinic-H), 4.21 (2H, q, J = 7.2 Hz, OCH CH ), 3.37 (2H,
AB q, J = 14.0 Hz, Ph-CH ), 2.82 (1H, dd, J = 14.0,
7.6 Hz), 2.56 (1H, dd, J = 14.0, 7.6 Hz), 1.22 (3H, t,
3
) d 7.40 (2H, m, Ar-H), 7.25
ð1Þ
(
5
. (a) Adolfsson, H. Angew. Chem., Int. Ed. 2005, 44, 3340; (b)
Yang, J. W.; Hechavarria Fonseca, M. T.; List, B. Angew.
Chem., Int. Ed. 2004, 43, 6660; (c) Yang, J. W.; Hechavarria
2
3
2

656
D. B. Ramachary et al. / Tetrahedron Letters 47 (2006) 651–656
1
3
J = 7.2 Hz, OCH
DEPT-135) d 167.8 (C, OAC@O), 134.9 (C), 132.2 (C),
31.4 (CH), 130.5 (CH), 129.8 (CH), 129.1 (CH), 126.9
2
CH
3
); C NMR (100 MHz, CDCl
3
,
2 2
Ph-CH ), 3.40 (1H, d, J = 14.4 Hz, Ph-CH ), 2.95 (1H, dd,
J = 14.8, 2.0 Hz), 2.76 (1H, dd,J = 14.8, 2.0 Hz), 2.25 (1H,
1
t, J = 2.8 Hz, CH C„CAH), 1.22 (3H, t, J = 7.2 Hz,
2
1
3
(
CH), 121.1 (CH
2
), 118.1 (C, C„N), 62.9 (CH
), 50.2 (C), 41.0 (CH ), 38.4 (CH ), 13.9 (CH
); HRMS: m/z calcd for
2
,
,
2 3 3
OCH CH ); C NMR (100 MHz, CDCl , DEPT-135) d
OCH
OCH
2
CH
3
2
2
3
166.9 (C, OAC@O), 134.9 (C), 131.8 (CH), 131.6 (C), 129.8
(CH), 129.4 (CH), 127.0 (CH), 117.5 (C, C„N), 76.9 (C,
CH C„C-H), 73.3 (CH, CH C„CAH), 63.4 (CH2,
2
CH
3
C
15
H
16NO
2
ClNa
(
2
M+Na): 300.0700; found: 300.0757. 9bed: IR (neat):
2
2
ꢀ1 1
251 (C„N), 1745 (OAC@O) cm ; H NMR (400 MHz,
) d 7.43 (2H, m, Ar-H), 7.27 (2H, m, Ar-H); 4.27
2H, q, J = 7.2 Hz, OCH CH ), 3.52 (1H, d, J = 14.4 Hz,
OCH
2
CH
3
), 49.4 (C), 37.7 (CH
2
), 26.6 (CH
2
), 13.8 (CH
3
,
CDCl
3
OCH
2 3
CH ); HRMS: m/z calcd for
C
15
H14NO
2
ClNa
(
(M+Na): 298.0600; found: 298.0603.
2
3