An eco-compatible synthesis of medicinally important novel class of trispiroheterocyclic framework using 2,2,2-trifluoroethanol as a reusable medium

Article abstract of DOI:10.1016/j.jfluchem.2013.07.008

A highly practical and efficient regio- and stereoselective synthesis of novel trispiropyrrolidine/thiapyrrolizidine derivatives have been accomplished via multi-component reaction of 7,9-bis[(E)arylidene]-1,4-dioxa-spiro[4,5] decane-8-ones, sarcosine/1,3-thiazolane-4-carboxylic acid and substituted isatins using 2,2,2-trifluoroethanol as a solvent. This new protocol has the advantages of environmental friendliness, higher atom economy, shorter reaction time and convenient operation. The structure and relative stereochemistry of spiro product was established by single crystal X-ray analysis and spectroscopic techniques. Synthesized compounds have been screened for their 'in vitro' antifungal and antimycobacterial activity against Mycobacterium tuberculosis H37Rv.

Full text of DOI:10.1016/j.jfluchem.2013.07.008

Journal of Fluorine Chemistry 156 (2013) 283–289
Contents lists available at ScienceDirect
Journal of Fluorine Chemistry
journal homepage: www.elsevier.com/locate/fluor
An eco-compatible synthesis of medicinally important novel class of
trispiroheterocyclic framework using 2,2,2-trifluoroethanol as a
reusable medium
a
b
b
Anshu Dandia a, , Ruby Singh , Jyoti Joshi , Sukhbeer Kumari
*
a Department of Chemistry, University of Rajasthan, Jaipur, India
b Department of Chemistry, Malaviya National Institute of Technology, Jaipur, India
A R T I C L E I N F O
A B S T R A C T
Article history:
A highly practical and efficient regio- and stereoselective synthesis of novel trispiropyrrolidine/
thiapyrrolizidine derivatives have been accomplished via multi-component reaction of 7,9-bis[(E)ar-
ylidene]-1,4-dioxa-spiro[4,5]decane-8-ones, sarcosine/1,3-thiazolane-4-carboxylic acid and substituted
isatins using 2,2,2-trifluoroethanol as a solvent. This new protocol has the advantages of environmental
friendliness, higher atom economy, shorter reaction time and convenient operation. The structure and
relative stereochemistry of spiro product was established by single crystal X-ray analysis and
spectroscopic techniques. Synthesized compounds have been screened for their ‘in vitro’ antifungal and
antimycobacterial activity against Mycobacterium tuberculosis H37Rv.
Received 15 April 2013
Received in revised form 9 July 2013
Accepted 11 July 2013
Available online 19 July 2013
Keywords:
Multicomponent reaction
2,2,2-Trifluoroethanol
Trispiropyrrolidine/thiapyrrolizidine
derivatives
ß 2013 Elsevier B.V. All rights reserved.
Diastereoselectivity
Antimycobacterial activity
1. Introduction
Biologically active molecules created in nature act as the main
source of templates and motivation for the synthesis of
Environmental concern associated with chemical synthesis
has posed stringent and compelling demands for greener
processes [1]. Fluorinated solvents have attracted an increasing
interest in the context of green synthesis during recent years.
Fluorinated solvents were initially introduced as an alternative
green reaction media because of their unique chemical and
physical properties [2]. But, today they have marched far beyond
this border, showing their significant role in controlling the
reaction as powerful reaction media [3]. Reactions in fluorinated
solvents are generally selective and without effluents, allowing a
facile isolation of the product and a recovery of the solvent by
distillation [4].
Further, the multicomponent reactions offer significant advan-
tages over conventional linear-type synthesis and recognized as
cost-effective and comparatively fast routes generating less
chemical waste. Consequently, they are regarded as viable
synthetic routes both economical and environmental benefits of
chemical transformations [5].
compounds for the purpose of biological phenomena to study
and drug development [6]. Naturally occurring heterocyclic
compounds containing pyrrolidine ring serves as an important
structural unit in biologically active molecules [7]. On the other
hand spiro-oxindole framework is an important structural motif
present in numerous alkaloids and pharmacologically important
compounds [8]. In particular, spirooxindolopyrrolidine and their
derivatives have served as potential synthetic intermediates [9]
and act as antiviral, antitumoral, antibiotic agents, local aneas-
thetics, and inhibitors of human NK-1 receptor etc. [10].
Spirotryprostatine, rhynchophylline, elacomine and pteropodine
are some of the alkaloids containing spiropyrrolidinyloxindole
ring system (Fig. 1) [11]. Hence, there has been renewed interest in
the synthesis of such interesting compounds. In addition, 1,3-
dioxolane derivatives having important chemical utilities, with
interesting biophysical properties. Itraconazole containing 1,3-
dioxolane pharmacophore possesses potent antiangiogenic ac-
tivity both ‘in vitro’ and ‘in vivo’ [12].
Developing efficient synthetic methods for the synthesis of
oxindoles derivatized at C3 with spiroheterocycles are particu-
larly important in organic synthesis [13]. Among the different
synthetic strategies, 1,3-dipolar cycloaddition reactions of
azomethine ylides [14] play a key role in the construction of
* Corresponding author. Tel.: +91 1412525845; fax: +91 1412702306.
E-mail addresses: dranshudandia@yahoo.co.in, dandiaanshu1957@gmail.com
(A. Dandia).
0022-1139/$ – see front matter ß 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jfluchem.2013.07.008

284
A. Dandia et al. / Journal of Fluorine Chemistry 156 (2013) 283–289
Me
Table 1
O
Preparation of 6a in different solvents for optimization of reaction conditions.a
O
H
O
N
HN
Yieldb (%)
H
Entry
Solvent
Temp (8C)
Time (h)
N
H
N
H
1
2
3
4
5
6
Ethanol
Methanol
Acetonitrile
1,4-Dioxane
THF
Reflux
Reflux
Reflux
Reflux
Reflux
Reflux
8 h
78
75
69
71
68
93
H
6 h
O
OMe
5 h
O
O
O
6 h
N
H
7 h
SpirotryprostatinA
TFE
30 min
Pteropodine
Me
a
Reaction conditions: 1 mmol of 3a, 4 and 5.
NH
b
Isolated yields.
Me
Me
OMe
CO2Me
N
2. Results and discussion
2.1. Preparation of trispiroheterocyclic framework
O
H
H
N
H
HO
O
N
H
Elacomine
Rhynchophylline
The required dipolarophiles 7,9-bis[(E)arylidene]-1,4-dioxa-
spiro[4,5]decane-8-ones 3a–e were prepared by green approach
using water and mild base K2CO3 under microwaves by the
reaction of spiro[4,5]decan-8-one 1 with various substituted
benzaldehydes 2 in shorter reaction time and in excellent yield
as compared to conventional method [19]. The geometry of the
olefinic double bond was found to be E as evidenced by 1H NMR
Fig. 1. Spiropyrrolidinyloxindole alkaloid natural products.
spirooxindoles [15]. Although each of the recent methods of
these cycloaddition reactions had their own merits, but some
methods are weakened by at least one limitation, such as low
yield, complicated workup procedure, technical intricacy and no
recovery of catalyst and solvent. Therefore, the development of a
simple and efficient method for synthesis of novel spirooxindole
derivatives via 1,3-dipolar cycloaddition reactions addressing
the management of the above mentioned drawbacks would be an
interesting challenge.
In continuation of our endeavor toward environmentally
benign synthesis of biologically active spiro heterocycles [16]
and dispiropyrrolidines [17], we report herein synthesis of novel
trispiropyrrolidines via, a facile catalyst-free, three-component
1,3-dipolar cycloaddition reaction of 7,9-bis[(E)arylidene]-1,4-
dioxa-spiro[4,5]decane-8-ones 3, isatin 4 and sarcosine 5 using
2,2,2-trifluoroethanol as a recoverable greener solvent for the first
time (Scheme 1). Although the synthesis of spiroheterocyclic
compounds by the 1,3-dipolar cycloaddition of azomethine ylides
and arylidene derivatives are known [18], but to the best of our
knowledge, there is no report for the design and synthesis of novel
trispiropyrrolidine derivatives using isatin, sarcosine and bis
arylidene substituted spiro[4,5]decan-8-one so far.
spectra wherein the olefinic protons appeared at
d 7.64–7.67 (s,
2H) and is found to be identical with those of authentic samples
prepared by reported method.
The choice of an appropriate reaction medium is of crucial
importance for successful synthesis. Initially, the three component
reaction of bis arylidene-1,4-dioxa-spiro[4,5]decane 3a, isatin 4a,
and sarcosine 5 as a simple model substrate was investigated to
establish the feasibility of the strategy and to optimize the reaction
conditions (Scheme 1). Different solvents such as ethanol,
methanol, acetonitrile, 1,4-dioxane, tetrahydrofuran (THF) and
2,2,2-trifluoroethanol were explored. The results are summarized
in Table 1. As evident from Table 1, the best results were obtained
using 2,2,2-trifluoroethanol to yield product 6a as a single
regioisomer in high yield in shorter reaction time. (Table 1, entry
6). Reaction in other solvents did not give satisfactory yield of the
product even after longer reaction time (Table 1, entries 1–5). The
azomethine ylide generated ‘in situ’ by the reaction of sarcosine 5
with isatin 4a reacted readily with the dipolarophile 3a to give
corresponding cycloadduct 6a as single regioisomer (Scheme 1).
X
CH3
HN
N
O
O
O
Ar
O
X
H
O
O
O
O
N
H
6a-h
Ar
Ar-CHO
Ar
Ar
4
TFE
2
(X= H, F, Br, Cl)
30-40 min
X
MW, K2CO3, H2O
O
O
O
O
COOH
N
H
CH3
3a-e
3b = 2-Cl-C H
1
HN
5
N
3a = 4-F-C H ;
6
4
6
4
O
;3d = 4-OMe-C H
4
O
3c = 4-Cl-C H
6
4
6
O
Ar
3e = 4-Br-C H
6
4
H
O
Ar
7a-h
Scheme 1. Synthesis of trispiro-oxindole derivatives (6a–h).

A. Dandia et al. / Journal of Fluorine Chemistry 156 (2013) 283–289
285
Table 2
Table 3
Synthetic results of 1-N-methyl-spiro[2,30]oxindole-spiro[3,900]-700-arylmethyli-
dene-1,4-dioxa-spiro[400,500]decan-4-aryl-pyrrolidine-800,20-diones (6a–h).
Synthetic results of spiro[4,30]oxindole-spiro[5,900]-700-arylmethylidene-1,4-dioxa-
spiro[400,500]decan-6-aryl-thiapyrrolizidine-800,20-diones (9a–c).
Products
Ar
X
Yield (%)
Mp (8C)
Rf (Hexane:ethyl
acetate 8:2)
Products
Ar
X
Yield (%)
Mp (8C)
Rf (Hexane:ethyl
acetate 8:2)
6a
6b
6c
6d
6e
6f
4-F-C6H4
H
H
Cl
H
H
H
Br
F
93
93
94
92
89
90
92
94
222–224
218–220
204–206
221–223
228–230
250–252
234–236
245–247
0.64
0.57
0.54
0.65
0.63
0.68
0.56
0.64
9a
9b
9c
4-F-C6H4
H
H
H
91
90
89
235–237
255–257
240–242
0.35
0.38
0.36
2-Cl-C6H4
2-Cl-C6H4
4-Cl-C6H4
4-OMe-C6H4
4-Br-C6H4
4-Cl-C6H4
4-F-C6H4
4-Me-C6H4
4-OMe-C6H4
X
6g
6h
S
HN
O
N
O
O
Ar
Ar
S
X
O
TFE
30-40min
Ar
O
O
No trace of other regioisomer 7 was detected. The regio- and
stereochemical outcome of the cycloaddition reaction was
determined by spectroscopic and X-ray analysis of 6a (Fig. 2).
Only one C55C of 3 is involved in the cycloaddition reaction,
ascribable to steric hindrance encountered for the second
cycloaddition resulting in chemoselectivity.
COOH
N
H
N
H
H
O
O
O
Ar
3
8
4
9
Scheme 2. Synthesis of trispiro-oxindole-thiapyrrolizidines (9a–c).
Encouraged by this success, the optimized reaction condition
was extended to other bis arylidene-1,4-dioxa-spiro[4,5]decane-8-
ones 3b–e and isatins to explore its scope and generality. It can be
seen from Table 2 that all the substrates reacted in 2,2,2-
trifluoroethanol smoothly and efficiently affording 6a–h in good
to excellent yields. A single product was isolated in all cases and no
trace of the other isomer was formed even after prolonged reaction
time. The 1H NMR spectra of all the products confirmed the
formation of single regio- and stereoisomer.
Encouraged by diverse medicinally importance of pyrrolothia-
zole derivatives [20] a novel class of trispirothiapyrrolizidines 9
were also synthesized under the optimized reaction conditions
(Scheme 2) replacing sarcosine by thiaproline 8. The results are
summarized in Table 3.
198.43 ppm, respectively, and three spiro carbons appeared at
105.44, 76.21 and 64.32 ppm. Furthermore, the presence of
molecular ion peak at m/z 541.55 (M++1) in the mass spectrum
confirmed the formation of the cycloadduct 6a. The stereochem-
istry of the product 6a was established by single X-ray analysis
as shown in Fig. 2.
A plausible mechanism for the formation of the cycloadducts
is proposed in Scheme 3. It is known that due to the Bronsted
acidity (pKa = 12.4) and strong ionizing power of 2,2,2-trifluor-
oethanol play unique behavior in organic transformations [21]. In
the present cycloaddition reaction of isatin 4 with sarcosine 5
leads to the ‘in situ’ formation of an azomethine ylide 10.
Subsequent 1,3-dipolar cycloaddition reaction of dipolarophile 3
and 10 afford trispiropyrrolidine derivative 6. The hydrogen
atom of TFE being electron-deficient and could form hydrogen
bonds with carbonyl groups of both isatin and dipolarophile 3
thereby catalyses reaction. Further, the polar transition state of
the reaction could be stabilized well by high ionizing solvent TFE.
This catalysis presumably expedites the reaction in TFE relative
to other solvents.
d
The 1H NMR spectrum of 6a revealed one sharp singlet at
1.91 due to the N-methyl protons. The –NCH2 protons and
benzylic proton of pyrrolidine ring appeared at 3.28 (m, 1H),
d
d
3.70 (t, 1H, J = 9.3 Hz), 5.01 (t, 1H, J = 9.3 Hz) which explained the
regiochemistry of the cycloadduct. In contrast, if the other
regioisomer had been formed, the benzylic proton would have
appeared as a singlet instead of triplet in the 1H NMR spectrum.
This cycloaddition is regioselective with the electron rich
The –NH proton of the oxindole showed a broad singlet at
10.63 and aromatic protons appeared as a multiplet in the region
6.73–7.97 ppm. In 13C NMR spectrum of 6a, the oxindole and
cyclohexane carbonyl carbons resonated at 176.46 and
d
carbon of the dipole adding to the b-carbon of the a,b-unsaturated
moiety of 3 and stereoselective affording only one diastereomer
exclusively, despite the presence of three stereo centers in the
product. The formation of one diastereomer shown in Scheme 1
d
Fig. 2. ORTEP diagram of compound 6a.

286
A. Dandia et al. / Journal of Fluorine Chemistry 156 (2013) 283–289
X
H
N
H
N
O
N
CH3
CH3
N
O
H
X
N
N
X
X
H
O
O
O
H
Ar
4
N
H
O
OCH2CF3
COOH
O
O
H
O
Ar
N
H
H3C
O
10
O
H
Ar
3
Ar
5
OCH2CF3
6
T.S.
Scheme 3. Plausible mechanism for synthesis of spiro derivatives.
Table 4
Table 5
Results of antifungal screening of synthesized compounds (Minimum inhibitory
Results of antimycobacterial screening of synthesized compounds (against M.
tuberculosis H37Rv strain minimum inhibitory concentrations (MICs, g/mL).
concentrations (MICs,
m
g/mL).
m
Compound
C. albicans
A. niger
A. clavatus
Compound
MIC (mg/mL)
MTCC 227
MTCC 282
MTCC 1323
6a
25
50
6a
100
100
500
1000
1000
250
1000
1000
1000
25
500
1000
1000
250
6b
6b
6c
3.25
6c
500
6d
50
250
50
6d
1000
1000
1000
250
100
6e
6e
1000
1000
1000
12.5
250
6f
6f
6g
250
6g
6h
3.25
6h
9a
25
250
250
9a
100
25
9b
9b
250
500
250
250
100
500
9c
9c
250
ISONIAZID
0.20
NYSTATIN
GRESEOFULVIN
100
100
500
100
100
of drugs to test upon standard bacterial strains. MIC of compounds
was determined against M. tuberculosis H37Rv strain by using
Lowenstein-Jensen medium (conventional method) as described
by Rattan [23].
Among tested compounds 6a (4-F phenyl), 6b (2-Cl phenyl),
and 6h (4-F phenyl and 5-F indole) from trispiropyrrolidine series
and compound 9a (4-F phenyl) from trispirothiapyrrolizidine
series displayed significant inhibition compared to other com-
with the carbonyl linked to the cyclohexane ring system and the
amide carbonyl are in trans-relationship with respect to C2–C3
bond of the pyrrolidine ring system, this is presumably ascribable
to the preferred spatial arrangement of the dipolarophile and the
azomethine ylide in the cycloaddition step as shown in Scheme 3
for the formation of 6 and 9, which would minimize the repulsion
between the carbonyl groups.
All compounds are stable solids whose structures are fully
supported by IR, 1H and 13C NMR spectroscopy, mass spectrom-
etry and elemental analysis. To support the results obtained
from spectroscopic techniques, the X-ray crystal of one of the
product 6a was prepared and its structure was confirmed [22].
The ORTEP diagram of 6a shows that the cyclohexanone ring
adopts a chair conformation and pyrrolidine ring, adopts an
envelope-shape conformation and the two carbonyls linked to
cyclohexane and isatin are in trans relationship.
pounds at MIC = 100
exhibited highest inhibition at MIC = 25
Compounds 6h showed excellent potency at MIC = 25
MIC = 12.5 g/mL against A. niger and A. clavatus, respectively,
m
g/mL against C. albicans. Compound 9a
g/mL against A. niger.
g/mL and
m
m
m
which were more potent than griseofulvin and nystatin standard
antifungal agents. Amongst all synthesized compounds fluoro
derivatives exerted significant activity. This attributed to smaller
size of fluorine atom, which may give stability to compound and
reduce ring strain.
Antimycobacterial activity: As shown in Table 5, compounds 6c
and 6h displayedsignificantanti-tubercularactivitiesagainsttheM.
2.2. Biological evaluation
tuberculosis H37Rv strain (MIC = 3.25
mg/mL). On the other hand,
rest of compounds showed moderate and very poor MIC values
The synthesized compounds were subjected to antifungal
screening against three fungal strains (Table 4). In addition, the
potency of the synthesized compounds was also checked for their
antimycobacterial efficacy against M. tuberculosis H37Rv strain
(Table 5).
Antifungal activity was screened against three fungal strains
viz. Candida albicans MTCC 227, Aspergillus niger MTCC 282
and Aspergillus clavatus MTCC 1323. All MTCC cultures were
collected from Institute of Microbial Technology, Chandigarh and
tested against above mentioned known drugs. Mueller Hinton
broth was used as nutrient medium to grow and dilute the drug
suspension for the test. Inoculum size for test strain was adjusted
to 108 CFU (Colony Forming Unit) per milliliter by comparing the
turbidity. DMSO was used as diluents to get desired concentration
compared to the reference compound isoniazid (MIC = 0.20 mg/mL).
3. Conclusion
In conclusion, an efficient protocol for the synthesis of novel
trispiro pyrrolidinyl/thiapyrrolizidinyl derivatives through 1,3-
dipolar cycloaddition reaction was introduced here using TFE as
promoter. The simple experimental and product isolation proce-
dure combined with ease of recovery and reuse of this novel
reaction medium is expected to contribute to the development of
green and waste free chemical process. Novel synthesized
compounds were screened for their anti-fungal and anti-tubercu-
lar activities, and the MIC values obtained were compared against
those of standard drugs.

A. Dandia et al. / Journal of Fluorine Chemistry 156 (2013) 283–289
287
4. Experimental
3.28 (m, 1H), 3.40–3.56 (m, 4H, OCH2)2, 3.71 (t, 1H, J = 9.0 Hz), 4.96
(t, 1H, J = 9.0 Hz), 6.76–7.90 (m, 12H, Ar–H and 55CH–Ar), 10.79 (s,
1H, NH); 13C NMR (75 MHz)
d 34.44, 35.81, 37.55, 48.36, 57.62,
4.1. General
61.00, 63.26, 64.05 (spiro C), 77.18 (spiro C), 105.41 (spiro C), 109.01,
114.13, 114.39, 114.88, 115.16, 120.88, 126.89, 128.76, 130.92,
131.41, 132.06, 132.16, 133.34, 136.03, 142.90, 176.27 (C55O),
198.98(C55O). MS(m/z):610[M+H]+. Anal. Calcd. forC33H30Cl3N2O4:
C, 63.42; H, 4.84; N, 4.48. Found: C, 63.60; H, 4.89; N, 4.45.
Analytical grade solvents and commercially available reagents
were used without further purification. The melting points of all
compounds were determined on
a Toshniwal apparatus in
capillary and uncorrected. The purity of compounds was checked
on thin layers of silica Gel-G coated glass plates and hexane:ethyl
acetate (8:2) as eluent. IR spectra were recorded on a Shimadzu FT
IR-8400S spectrophotometer using KBr pellets. 1H and 13C NMR
spectra were recorded in dimethyl sulfoxide (DMSO-d6) and
chloroform (CDCl3) as a solvent on a Bruker Avance spectropho-
tometer at 300 and 75 MHz, respectively. Chemical shifts are
expressed in parts per million (ppm) using tetramethylsilane
(TMS) as an internal standard. The following abbreviations were
used to explain the multiplicities: s = singlet, d = doublet, t = trip-
let, q = quartet, m = multiplet. The Mass spectra of representative
compounds were obtained using JEOL SX-102 spectrometer at
70 eV. Elemental analyses were carried out on a Carlo-Erba 1108
CHN Elemental analyzer. X-ray intensity data were collected on
Bruker Kappa Apex II diffractometer.
4.2.4. Compound (6d)
IR (KBr, n d1.27 (d,
): 3284, 1710, 1685 cmꢀ1; 1H NMR (300 MHz):
1H, J = 14.7 Hz), 1.91 (s, 3H, N–CH3), 2.07–2.14 (m, 2H), 2.49 (m, 1H),
3.35 (m, 1H), 3.39–3.50 (m, 4H, OCH2)2, 3.73 (t, 1H, J = 7.9 Hz), 4.97
(t, 1H, J = 7.9 Hz), 6.73–7.85 (m, 13H, Ar–H and 55CH–Ar), 10.79 (s,
1H, NH); 13C NMR (75 MHz)
d 34.45, 35.56, 37.43, 47.67, 57.19,
61.36, 63.98, 65.18 (spiro C), 76.97 (spiro C), 105.34 (spiro C), 109.21,
115.35, 115.54, 116.26, 116.67, 122.16, 125.17, 127.53, 130.27,
132.76, 133.16, 133.37, 135.87, 138.21, 139.76, 143.32, 176.83
(C55O), 197.91 (C55O). MS (m/z): 576 [M+H]+. Anal. Calcd. for
C32H28Cl2N2O4: C, 66.79; H, 4.90; N, 4.87. Found: C, 66.63; H, 4.87; N,
4.84.
4.2.5. Compound (6e)
4.2. General procedure for the synthesis of trispiro-pyrrolidine/
IR (KBr, n d1.31 (d,
): 3275, 1705, 1690 cmꢀ1 1H NMR (300 MHz):
;
thiapyrrolizidines 6 and 9
1H, J = 15 Hz), 1.91 (s, 3H, N–CH3), 2.09–2.23 (m, 2H), 3.07 (m, 1H),
3.40 (m, 1H), 3.40–3.56 (m, 4H, OCH2)2, 3.77 (s, 3H, OCH3), 3.79 (s,
3H, OCH3), 3.86 (t, 1H, J = 9.1 Hz), 4.92 (t, 1H, J = 9.1 Hz), 6.78–7.92
An equimolar mixture of appropriate 7,9-bis[(E)arylidene]-1,4-
dioxa-spiro[4,5]decane-8-ones 3a–e (1 mmol) isatin 4 and sarco-
sine 5/thiaproline 8 (1 mmol) in 2,2,2-trifluoroethanol (2–3 mL)
was refluxed for the appropriate time (30–40 min). After comple-
tion of the reaction as indicated by (TLC), the solid precipitates
were filtered and washed with TFE to furnish pure trispiropyrro-
lidine/thiapyrrolizidine derivatives. The TFE was distilled off (to
recover for the next run). All the synthesized compounds were well
characterized by 1H NMR, 13C NMR, Mass and single crystal X-ray
analysis.
(m, 13H, Ar–H and55CH–Ar), 10.65 (s, 1H, NH); 13C NMR (75 MHz):
d
34.91, 35.52, 37.48, 47.61, 54.12, 55.32, 57.72, 61.32, 63.21, 64.39
(spiro C), 76.21 (spiro C), 105.36 (spiro C), 109.21, 115.29, 122.62,
127.65, 128.01, 129.23, 129.42, 130.11, 130.54, 132.31, 132.12,
134.81, 135.34, 135.86, 137.22, 140.35,177.24(C55O), 198.18(C55O).
MS (m/z): 567 [M+H]+. Anal. Calcd. for C34H34N2O6 C, 72.07; H, 6.05;
N, 4.94. Found: C, 72.22; H, 6.02; N, 4.98.
4.2.6. Compound (6f)
IR (KBr, n ; d 1.77
): 3285, 1709, 1688 cmꢀ1 1H NMR (300 MHz)
4.2.1. Compound (6a)
(d, 1H, J = 14.7 Hz), 2.08 (s, 3H, N–CH3), 2.42–2.57 (m, 2H), 3.03 (m,
1H), 3.45 (t, 1H, J = 8.6 Hz), 3.55–3.63 (m, 4H, OCH2)2, 3.76 (t, 1H,
J = 8.7 Hz), 4.78 (t, 1H, J = 8.7 Hz), 6.74–7.53 (m, 13H, Ar–H and
IR (KBr, n d 1.28
): 3245, 1710, 1680 cmꢀ1; 1H NMR (300 MHz,):
(d, 1H, J = 15 Hz), 1.91 (s, 3H, N–CH3), 2.03–2.14 (m, 2H), 3.03 (m,
1H), 3.28 (m, 1H), 3.42–3.56 (m, 4H, (OCH2)2), 3.70 (t, 1H,
J = 9.3 Hz), 5.01(t, 1H, J = 9.3 Hz), 6.73–7.97 (m, 13H, Ar–H and
55CH–Ar), 10.63 (s, 1H, N–H); 13C NMR (75 MHz)
37.43, 45.36, 56.30, 59.40, 63.34, 64.32 (spiro C), 76.21 (spiro C),
105.44 (spiro C), 109.00, 121.51, 125.35, 126.51, 126.98, 128.49,
129.13, 129.55, 130.42, 130.63, 131.53, 132.86, 134.08, 134.58,
135.28, 137.26, 175.46 (C55O), 198.43 (C55O); MS (m/z): 543
[M+H]+. Anal. Calcd. for C32H28F2N2O4: C, 70.84; H, 5.20; N, 5.16.
Found: C, 70.68; H, 5.12; N, 5.10.
55CH–Ar), 10.49 (s, 1H, NH); 13C NMR (75 MHz):
d 35.95, 46.26,
52.34, 55.17, 57.87, 60.66, 61.45, 65.73 (spiro C), 79.21 (spiro C),
105.29 (spiro C), 110.25, 115.67, 122.01, 122.75, 127.54, 128.18,
128.49, 128.63, 129.28, 130.58, 131.53, 132.97, 135.07, 135.16,
136.2, 140.1, 177.86 (C55O), 198.67 (C55O); MS (m/z): 665 [M+H]+.
Anal. Calcd. for C32H28Br2N2O4: C, 57.85; H, 4.25; N, 4.22. Found: C,
57.69; H, 4.20; N, 4.19.
d 34.14, 36.85,
4.2.7. Compound (6g)
IR (KBr, n d 1.29
): 3288, 1706, 1680 cmꢀ1; 1H NMR (300 MHz):
4.2.2. Compound (6b)
(d, 1H, J = 14.6 Hz), 1.97 (s, 3H, N–CH3), 2.37–2.44 (m, 2H), 2.89 (m,
1H), 3.39 (m, 1H), 3.49–3.55 (m, 4H, OCH2)2, 3.79 (t, 1H, J = 7.7 Hz),
5.08 (t, 1H, J = 7.7 Hz), 6.73–7.85 (m, 12H, Ar–H and 55CH–Ar),
IR (KBr, n d1.59 (d,
): 3280, 1707, 1684 cmꢀ1; 1H NMR (300 MHz):
1H, J = 15 Hz), 1.93 (s, 3H, N–CH3), 2.42–2.61(m, 2H), 2.97 (m, 1H),
3.30 (m, 1H), 3.46–3.61 (m, 5H, (OCH2)2 and 1H), 4.75 (t, 1H,
J = 9.4 Hz), 6.68–7.46 (m, 13H, Ar–H and 55CH–Ar), 10.60 (s, 1H, N–
H); 13C NMR (75 MHz)
63.32, 64.28 (spiro C), 77.07 (spiro C), 105.51 (spiro C), 109.18,
114.61, 114.89, 115.38, 115.67, 121.19, 125.17, 127.23, 129.14,
131.24, 131.90, 132.02, 132.32, 133.67, 135.73, 142.99, 176.33
(C55O), 198.80 (C55O). MS (m/z): 576 [M+H]+. Anal. Calcd. for
10.88 (s, 1H, NH); 13C NMR (75 MHz):
d 34.78, 35.71, 37.91, 47.64,
58.15, 61.23, 63.52, 64.56 (spiro C), 79.17 (spiro C), 105.47 (spiro
C), 112.37, 115.35, 120.48, 122.56, 127.52, 130.7, 131.89, 132.08,
132.61, 133.6, 134.46, 135.76, 135.47, 137.34, 139.34, 143.94,
178.21 (C55O), 198.65 (C55O); MS (m/z): 655 [M+H]+. Anal. Calcd.
for C32H27BrCl2N2O4: C, 58.73; H, 4.16; N, 4.28. Found: C, 58.60; H,
4.14; N, 4.21.
d 34.58, 35.70, 37.63, 47.93, 57.06, 61.39,
C32H28Cl2N2O4: C, 66.79; H, 4.90; N, 4.87. Found: C, 66.62; H, 4.88; N,
4.84.
4.2.8. Compound (6h)
IR (KBr, n d 1.45
): 3286, 1714, 1684 cmꢀ1; 1H NMR (300 MHz):
4.2.3. Compound (6c)
IR (KBr,
1H, J = 15 Hz), 1.93 (s, 3H, N–CH3), 2.09–2.22 (m, 2H), 3.03 (m, 1H),
(d, 1H, CH, J = 14.6 Hz), 2.11 (s, 3H, N–CH3), 2.43–2.54 (m, 2H), 2.96
(m, 1H), 3.45 (m, 1H), 3.55–3.64 (m, 4H, OCH2)2, 3.81 (t, 1H,
J = 8.7 Hz), 5.02 (t, 1H, J = 8.7 Hz), 6.76–7.89 (m, 12H, Ar–H and
n d1.29 (d,
): 3270, 1717, 1682 cmꢀ1; 1H NMR (300 MHz):

288
A. Dandia et al. / Journal of Fluorine Chemistry 156 (2013) 283–289
55CH–Ar), 10.89 (s, 1H, NH); 13C NMR (75 MHz,):
d 34.56 35.89,
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37.67, 46.08, 54.78, 57.94, 60.52, 66.31 (spiro C), 78.56 (spiro C),
105.67 (spiro C), 121.79, 122.56, 127.34, 128.60, 129.32, 130.65,
130.36, 131.19, 132.40,133.12, 134.39, 135.21, 135.25, 136.23,
140.45, 142.82, 177.60 (C55O), 198.51 (C55O), MS (m/z): 561
[M+H]+. Anal. Calcd. for C32H27F3N2O4: C, 68.56; H, 4.85; N, 5.00.
Found: C, 68.45; H, 4.80; N, 5.04.
4.2.9. Compound (9a)
(b) H. Alinezhad, M. Tajbakhsh, M. Zare, J. Fluorine Chem. 132 (2011) 995–1000.
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2005;
IR (KBr, n d 1.86 (d,
): 3275, 1710, 1678 cmꢀ1; 1H NMR (300 MHz)
1H, J = 13.8 Hz,), 2.61–2.81 (m, 3H), 2.89 (dd, 2H), 3.11 (m, 1H), 3.55
(dd, 1H, J = 7.2 Hz), 3.66–3.74 (m, 4H, OCH2)2, 4.31 (d, 1H,
J = 10.5 Hz), 4.51 (m, 1H), 6.31–7.59 (m, 12H, Ar–H and 55CH–Ar),
10.63 (s, 1H, NH); 13C NMR (75 MHz)
52.10, 53.01, 63.33, 64.84, 66.60 (spiro C), 76.77 (spiro C), 105.96
(spiro C), 109.59, 114.98, 115.26, 116.23, 121.11, 124.23, 129.74,
129.97, 131.38, 132.30, 132.41, 132.60, 132.70, 133.33, 133.52,
133.92, 142.75, 177.93 (C55O), 197.61 (C55O). MS (m/z) 587 [M+H]+.
Anal. Calcd. for C33H28F2N2O4S: C, 67.56; H, 4.81; N, 4.78; Found: C,
67.70; H, 4.85; N, 4.82.
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d 31.13, 35.85, 37.46, 45.03,
4.2.10. Compound (9b)
IR (KBr, n d 1.84 (d,
): 3285, 1720, 1685 cmꢀ1; 1H NMR (300 MHz)
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1H, J = 13.7 Hz,), 2.15 (s, 3H, CH3), 2.19(s, 3H, CH3),2.64–2.85(m, 3H),
2.86(dd, 2H), 3.08(m, 1H), 3.52 (dd, 1H, J = 7.4 Hz), 3.62–3.71(m, 4H,
OCH2)2, 4.28 (d, 1H, J = 10.5 Hz), 4.52 (m, 1H), 6.28–7.52 (m, 12H, Ar–
H and55CH–Ar), 10.62 (s, 1H, NH); 13C NMR (75 MHz)
d 19.16, 19.41,
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30.85, 34.79, 37.06, 47.68, 51.90, 52.08, 63.84, 64.21, 66.94 (spiro C),
76.14 (spiro C), 105.67 (spiro C), 109.08, 114.20, 120.42, 124.12,
127.16, 128.73, 129.31, 129.39, 129.84, 130.57, 131.05, 132.33,
134.31, 136.74, 141.09, 157.97, 158.21, 176.87 (C55O), 197.47 (C55O).
MS(m/z):579[M+H]+.Anal. Calcd.forC35H34N2O4S: C, 72.64;H,5.92;
N, 4.84. Found: C, 72.78; H, 5.96; N, 4.88.
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4.2.11. Compound (9c)
IR (KBr, n d 1.87 (d,
): 3290, 1715, 1686 cmꢀ1; 1H NMR (300 MHz)
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(dd, 1H, J = 7.2 Hz), 3.68–3.76 (m, 4H, OCH2)2, 3.81(s, 3H, OCH3), 3.82
(s, 3H, OCH3), 4.26 (d, 1H, J = 10.5 Hz), 4.48 (m, 1H), 6.32–7.64 (m,
12H, Ar–H and55CH–Ar), 10.57 (s, 1H, NH): 13C NMR (75 MHz) 30.86,
35.38, 37.36, 47.66, 51.82, 52.24, 55.04, 55.31, 62.79, 64.26, 66.17
(spiro C), 76.09 (spiro C), 105.71 (spiro C), 109.05, 114.12 120.56,
124.09, 127.04, 128.67, 129.17, 130.94, 131.55, 132.25, 134.18,
137.08, 142.38, 158.18, 159.66, 159.93, 177.50 (C55O), 197.23 (C55O).
MS (m/z): 611 [M+H]+. Anal. Calcd. for C35H34N2O6S: C, 68.83; H,
5.61; N, 4.59. Found: C, 68.70; H, 5.65; N, 4.54.
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Acknowledgements
Financial assistance from the C.S.I.R. New Delhi is gratefully
acknowledged. We are thankful to the Central Drug Research
Institute (CDRI), Lucknow for the spectral analyses and elemental
analyses. We are also thankful to STIC Cochin for single crystal X-
ray analysis.
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Appendix A. Supplementary data
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[22] Crystallographic data (excluding structure factors) for trispiroderivative 6a in this
letter have been deposited with the Cambridge Crystallographic Data Centre as
supplementary publication numbers CCDC 874668. Copy of the data can be
obtained, free of charge, on application to CCDC, 12 Union Road, Cambridge
CB2 1EZ, UK [fax: +44 (0)1223-336033 or deposit@ccdc.cam.ac.uk].
A 2 mg/mL stock solution was prepared for each synthesized drug. DMSO (1%)
was used as diluent/vehicle to obtain the desired concentration of drug to test
upon standard fungal strains. In a primary screening, 500, 250, and 125 mg/mL
concentrations of the synthesized drugs were used. The active synthesized drugs
identified in this primary screening were then diluted to obtain 100, 50, 25, 12.5,
6.250, 3.125 and 1.5625 mg/mL concentrations, and further tested in a second set
of dilutions against all microorganisms. The standard strain MTB H37Rv was
retested with each new batch of medium. The minimum inhibitory concentration
(MIC) was defined as the minimum concentration of compound required to
inhibit 99% of bacterial growth. Vehicle and reference agents were used in every
test as the negative and positive controls, and the assays were performed in
duplicate.
[23] The H37Rv clinical isolate was obtained from the Institute of Microbial Technol-
ogy, Surat, India. L.J. was used as nutrient medium to grow and dilute the testing
drug suspensions. The inoculum size for the strain test was adjusted to 1 mg/mL.