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1.  (2E)-3-(2-Chloro-7-methyl­quinolin-3-yl)-1-(6-chloro-2-methyl-4-phenyl­quinolin-3-yl)prop-2-en-1-one ethanol monosolvate 
In the title ethanol solvate, C29H20Cl2N2O·C2H5OH, the quinolinyl residues form a dihedral angle of 46.41 (4)° with each other, and each is inclined [Cp—C—C=O and C=C—C—Cp (p = pyridyl) torsion angles = 54.8 (2) and 144.44 (19)°, respectively] with respect to the almost planar bridging prop-2-en-1-one residue [O=C—C=C torsion angle = −4.1 (3)°]. The ethanol solvent mol­ecule is disordered over two positions of equal occupancy and is located close to a centre of inversion. These mol­ecules reside in cavities defined by the organic mol­ecules, which are connected into a three-dimensional architecture by C—H⋯Cl, C—H⋯O and C—H⋯N inter­actions, as well as π–π contacts [inter-centroid distances = 3.5853 (10) and 3.8268 (11) Å], each involving pyridyl rings.
PMCID: PMC3884470  PMID: 24427050
2.  (2E)-3-(2-Chloro­benzo[h]quinolin-3-yl)-1-(2-methyl-4-phenyl­quinolin-3-yl)prop-2-en-1-one 
In the title compound, C32H21ClN2O, an almost planar (r.m.s. deviation = 0.033 Å) prop-2-en-1-one bridge links quinolinyl and benzoquinolinyl residues; the latter are twisted out of the plane of the bridge [dihedral angles = 75.94 (5) and 20.20 (5)°, respectively]. In the crystal, a three-dimensional architecture arises as a result of C—H⋯O, C—H⋯π and π–π [centroid–centroid distances involving pyridine rings = 3.5806 (7)–3.7537 (7) Å] interactions.
PMCID: PMC3884436  PMID: 24427034
3.  (2E)-3-(6-Chloro-2-meth­oxy­quinolin-3-yl)-1-(2-methyl-4-phenyl­quinolin-3-yl)prop-2-en-1-one acetone monosolvate 
In the title solvate, C29H21ClN2O2·C3H6O, a prop-2-en-1-one bridge links two quinolinyl residues; the latter are almost perpendicular [dihedral angle = 78.27 (6)°]. The dihedral angle between the quinonyl ring system and its pendant phenyl group is 59.78 (8)°. A small twist in the bridging prop-2-en-1-one group is noted [O=C—C=C torsion angle = −10.6 (3)°]. In the crystal, a three-dimensional architecture arises as a result of C—H⋯O and π–π stacking [centroid–centroid distances = 3.5504 (12)–3.6623 (12) Å].
PMCID: PMC3793806  PMID: 24109393
4.  (2E)-3-(2-Chloro-8-methyl­quinolin-3-yl)-1-(2-methyl-4-phenyl­quinolin-3-yl)prop-2-en-1-one 
In the title compound, C29H21ClN2O, there is a twist in the bridging prop-2-en-1-one group [C=C—C=O torsion angle = 22.7 (2)°]. The quinolinyl residues form a dihedral angle of 86.92 (4)°, indicating an almost perpendicular relationship. In the crystal, supra­molecular layers in the bc plane are stabilized by C—H⋯π and π–π inter­actions [centroid–centroid distance = 3.4947 (7) Å].
PMCID: PMC3793805  PMID: 24109392
5.  (2E)-3-(6-Chloro-2-meth­oxy­quinolin-3-yl)-1-(2,4-di­methyl­quinolin-3-yl)prop-2-en-1-one 
The mol­ecule of the title compound, C24H19ClN2O2, is bent, with the dihedral angle between the terminal quinoline ring systems being 63.30 (5)°. The quinolinyl residues are connected by an almost planar prop-2-en-1-one bridge (r.m.s. deviation = 0.022 Å), with the dihedral angles between this plane and the appended quinolinyl residues being 75.86 (7) and 38.54 (7)°. The C atom of the meth­oxy group is close to coplanar with its attached ring [deviation = 0.116 (2) Å]. In the crystal, a three-dimensional architecture is constructed by meth­yl–carbonyl C—H⋯O inter­actions and π–π inter­actions between centrosymmetrically related quinolinyl residues [centroid-to-centroid separations 3.5341 (10) and 3.8719 (9) Å].
PMCID: PMC3793769  PMID: 24109356
6.  (2E)-3-(2-Chloro-8-methyl­quinolin-3-yl)-1-(2,4-di­methyl­quinolin-3-yl)prop-2-en-1-one 
In the mol­ecule of the title compound, C24H19ClN2O, the terminal quinolinyl residues are close to perpendicular to each other [dihedral angle 83.72 (4)°]. The quinolinyl residues are connected by and inclined to the prop-2-en-1-one bridge, with the Car—Car—C—C (ar = aromatic) torsion angles being 71.01 (17) and 20.6 (2)°. The crystal structure features phen­yl–carbonyl C—H⋯O inter­actions and π–π inter­actions between centrosymmetrically related quinolinyl residues [3.5341 (10) and 3.8719 (9) Å], which together lead to a three-dimensional architecture.
PMCID: PMC3793770  PMID: 24109357
7.  β-Keto esters from ketones and ethyl chloroformate: a rapid, general, efficient synthesis of pyrazolones and their antimicrobial, in silico and in vitro cytotoxicity studies 
Pyrazolones are traditionally synthesized by the reaction of β-keto esters with hydrazine and its derivatives. There are methods to synthesize β-keto esters from esters and aldehydes, but these methods have main limitation in varying the substituents. Often, there are a number of methods such as acylation of enolates in which a chelating effect has been employed to lock the enolate anion using lithium and magnesium salts; however, these methods suffer from inconsistent yields in the case of aliphatic acylation. There are methods to synthesize β-keto esters from ketones like caboxylation of ketone enolates using carbon dioxide and carbon monoxide sources in the presence of palladium or transition metal catalysts. Currently, the most general and simple method to synthesize β-keto ester is the reaction of dimethyl or ethyl carbonate with ketone in the presence of strong bases which also requires long reaction time, use of excessive amount of reagent and inconsistent yield. These factors lead us to develop a simple method to synthesize β-keto esters by changing the base and reagent.
A series of β-keto esters were synthesized from ketones and ethyl chloroformate in the presence of base which in turn are converted to pyrazolones and then subjected to cytotoxicity studies towards various cancer cell lines and antimicrobial activity studies towards various bacterial and fungal strains.
The β-keto esters from ethyl chloroformate was successfully attempted, and the developed method is simple, fast and applicable to the ketones having the alkyl halogens, protecting groups like Boc and Cbz that were tolerated and proved to be useful in the synthesis of fused bicyclic and tricyclic pyrazolones efficiently using cyclic ketones. Since this method is successful for different ketones, it can be useful for the synthesis of pharmaceutically important pyrazolones also. The synthesized pyrazolones were subjected to antimicrobial, docking and cytotoxicity assay against ACHN (human renal cell carcinoma), Panc-1 (human pancreatic adenocarcinoma) and HCT-116 (human colon cancer) cell line, and lead molecules have been identified. Some of the compounds are found to have promising activity against different bacterial and fungal strains tested.
PMCID: PMC3726461  PMID: 23870758
β-keto esters; Ethyl chloroformate; Pyrazolones; Efficient synthesis; Anti-bacterial activity; Fungicidal activity; Cytotoxicity studies
8.  Flavonoid from Carica papaya inhibits NS2B-NS3 protease and prevents Dengue 2 viral assembly 
Bioinformation  2013;9(18):889-895.
Dengue virus belongs to the virus family Flaviviridae. Dengue hemorrhagic disease caused by dengue virus is a public health problem worldwide. The viral non structural 2B and 3 (NS2B-NS3) protease complex is crucial for virus replication and hence, it is considered to be a good anti-viral target. Leaf extracts from Carica papaya is generally prescribed for patients with dengue fever, but there are no scientific evidences for its anti-dengue activity; hence we intended to investigate the anti-viral activity of compounds present in the leaves of Carica papaya against dengue 2 virus (DENV-2). We analysed the anti-dengue activities of the extracts from Carica papaya by using bioinformatics tools. Interestingly, we find the flavonoid quercetin with highest binding energy against NS2B-NS3 protease which is evident by the formation of six hydrogen bonds with the amino acid residues at the binding site of the receptor. Our results suggest that the flavonoids from Carica papaya have significant anti-dengue activities.
ADME - Absorption, distribution, metabolism and excretion, BBB - Blood brain barrier, CYP - Cytochrome P450, DENV - – Dengue virus, DHF - Dengue hemorrhagic fever, DSS - Dengue shock syndrome, GCMS - – Gas chromatography- Mass spectrometry, MOLCAD - Molecular Computer Aided Design, NS - Non structural, PDB - Protein data bank, PMF - Potential Mean Force.
PMCID: PMC3842573  PMID: 24307765
Dengue virus; Carica papaya; Quercetin; ADMET; NS2B-NS3 protease
9.  10a-Hy­droxy-9-(4-meth­oxy­phen­yl)-3,4,5,6,7,8a,9,10a-octa­hydro-1H-xanthene-1,8(2H)-dione 
In the title compound, C20H22O5, the tetra­hydro­pyran, cyclo­hexene and cyclo­hexane rings of the xanthene ring system adopt half-chair, half-boat and chair conformations, respectively. The mean plane of the four roughly planar atoms of the tetra­hydro­pyran ring (r.m.s. deviation = 0.111 Å) forms a dihedral angle of 82.91 (4)° with the meth­oxy­benzene group. In the crystal, mol­ecules are linked via O—H⋯O and C—H⋯O hydrogen bonds into sheets lying parallel to the ac plane. The crystal is further consolidated by weak C—H⋯π inter­actions.
PMCID: PMC3414299  PMID: 22904832
10.  Diethyl 2,6-dihy­droxy-4-(3-nitro­phen­yl)-2,6-bis­(trifluoro­meth­yl)piperidine-3,5-dicarboxyl­ate 
In the title compound, C19H20F6N2O8, the eth­oxy and ethyl groups are disordered over two sets of sites, with occupancy ratios of 0.212 (18):0.788 (18) and 0.746 (6):0.254 (6), respectively. The piperidine ring adopts a chair conformation. In the mol­ecule, intra­molecular O—H⋯O hydrogen bonds form two S(6) ring motifs. In the crystal, mol­ecules are linked via O—H⋯O and C—H⋯O hydrogen bonds, forming dimers.
PMCID: PMC3275076  PMID: 22347021
11.  Diisobutyl 4-(3-eth­oxy-4-hy­droxy­phen­yl)-2,6-dimethyl-1,4-dihydro­pyridine-3,5-dicarboxyl­ate 
The asymmetric unit of the title compound, C25H35NO6, contains two independent mol­ecules. In each mol­ecule, the 1,4-dihydro­pyridine ring adopts a flattened boat conformation. The dihedral angles between the 1,4-dihydro­pyridine and benzene rings are 87.55 (7) and 87.23 (7)°. In one of these mol­ecules, one of the isobutyl groups is disordered over two sets of sites, with an occupancy ratio of 0.890 (2):0.110 (2). In the crystal, mol­ecules are linked through N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds forming two-dimensional networks parallel to the ab plane. The crystal structure is further stabilized by weak C—H⋯π inter­actions.
PMCID: PMC3274982  PMID: 22346927
12.  3-Ethyl-4-methyl-1H-pyrazol-2-ium-5-olate 
The title compound, C6H10N2O, is a zwitterionic pyrazole derivative. The crystal packing is predominantly governed by a three-center iminium–amine N+—H⋯O−⋯H—N inter­action, leading to an undulating sheet-like structure lying parallel to (100).
PMCID: PMC3213569  PMID: 22091146
13.  9-(4-Hy­droxy­phen­yl)-3,3,6,6-tetra­methyl-4,5,6,9-tetra­hydro-3H-xanthene-1,8(2H,7H)-dione 
In the title compound, C23H26O4, the two cyclo­hexene rings adopt envelope conformations whereas the pyran ring adopts a boat conformation. In the crystal, pairs of inter­molecular O—H⋯O hydrogen bonds link the mol­ecules into inversion dimers.
PMCID: PMC3212272  PMID: 22090929
14.  4-{[5-(4-Chloro­phen­yl)-1-(4-fluoro­phen­yl)-1H-pyrazol-3-yl]carbon­yl}-N-ethyl­piperazine-1-carboxamide 
The asymmetric unit of the title compound, C23H23ClFN5O2, contains two crystallographically independent mol­ecules. In one mol­ecule, the pyrazole ring makes dihedral angles of 43.93 (7) and 35.82 (7)°, respectively, with the fluoro- and chloro-substituted benzene rings, while the corresponding angles in the other mol­ecule are 52.26 (8) and 36.85 (7)°. The piperazine rings adopt chair conformations. In the crystal, adjacent mol­ecules are connected via inter­molecular N—H⋯O, C—H⋯F, C—H⋯N and C—H⋯O hydrogen bonds, forming a two-dimensional network parallel to the bc plane. The crystal structure is further stabilized by a weak π–π inter­action with a centroid–centroid distance of 3.6610 (8) Å and by C—H⋯π inter­actions.
PMCID: PMC3151813  PMID: 21837133
15.  (E)-3-[4-(Dimethyl­amino)­phen­yl]-1-(2-methyl-4-phenyl­quinolin-3-yl)prop-2-en-1-one 0.7-hydrate 
In the title compound, C27H24N2O·0.7H2O, the quinoline ring system is approximately planar, with a maximum deviation of 0.011 (1) Å, and forms dihedral angles of 74.70 (4) and 80.14 (4)° with the phenyl and benzene rings, respectively. In the crystal, the mol­ecules are linked to the water mol­ecules via inter­molecular O—H⋯N hydrogen bonds and further stabilized by C—H⋯π inter­actions involving the centroid of the benzene ring of the quinoline group. This benzene ring is observed to form a π–π inter­action with an adjacent pyridine ring [centroid–centroid distance = 3.7120 (6) Å].
PMCID: PMC3120557  PMID: 21754884
16.  (E)-1-(2-Methyl-4-phenyl­quinolin-3-yl)-3-phenyl­prop-2-en-1-one 
In the title compound, C25H19NO, the quinoline ring system is approximately planar, with a maximum deviation of 0.32 (1) Å, and forms dihedral angles of 80.74 (3) and 81.71 (4)° with the two phenyl rings. In the crystal. mol­ecules are stacked along the b axis by way of a C—H⋯π inter­action and a weak π–π inter­action between the pyridine and phenyl rings with a centroid–centroid distance of 3.6924 (5) Å.
PMCID: PMC3100028  PMID: 21754059
17.  1,3-Dimethyl-4-phenyl­sulfanyl-1H-pyrazol-5-ol 
In the title compound, C11H12N2OS, the pyrazole ring makes a dihedral angle of 85.40 (8)° with the phenyl ring. In the crystal, inter­molecular N—H⋯O and C—H⋯O hydrogen bonds link mol­ecules into a two-dimensional network parallel to the bc plane.
PMCID: PMC3052103  PMID: 21522387
18.  (2E)-1-(6-Chloro-2-methyl-4-phenyl­quinolin-3-yl)-3-(4-chloro­phen­yl)prop-2-en-1-one 
Two independent mol­ecules comprise the asymmetric unit of the title chalcone, C25H17Cl2NO, and while each has an E configuration about the ethyl­ene double bond, they differ in the relative orientations of the carbonyl and ethyl­ene double bonds within the prop-2-en-1-one residues, i.e. anti and syn. For each mol­ecule, the benzene [dihedral angles = 71.04 (9) and 73.34 (12)°] and prop-2-en-1-one [C—C—C—O = 91.2 (2) and −119.1 (3)°] substituents are twisted out of the plane of the quinoline moiety to which they are attached. The crystal structure is stabilized by C—H⋯π and π–π [Cg(quinoline)⋯Cg(quinoline) = 3.7809 (12) and 3.8446 (11) Å] inter­actions.
PMCID: PMC3052117  PMID: 21522380
19.  (E)-4-(1,3-Benzodioxol-5-yl)but-3-en-2-one 
In the title compound, C11H10O3, the benzodioxole ring adopts a flattened [puckering parameters: q 2 = 0.107 (2) Å, ϕ2 = 160 (1)°] envelope conformation with the methylene C atom as the flap. The crystal packing features chains, parallel to the c axis, composed of dimers connected by weak C—H–O hydrogen bonds and extending in layers in the bc plane.
PMCID: PMC3052036  PMID: 21522344
20.  3-Isobutyl-4-phenyl­sulfan­yl-1H-pyrazol-5-ol 
The asymmetric unit of the title compound, C13H16N2OS, contains two independent mol­ecules (A and B). The pyrazole ring [maximum deviations = 0.0049 (17) Å in mol­ecule A and 0.0112 (19) Å in mol­ecule B] makes a dihedral angle of 70.23 (11) and 73.18 (12)° with the phenyl ring in mol­ecules A and B, respectively. The isobutyl group in mol­ecule B is disordered over two sets of sites with a ratio of refined occupancies of 0.858 (5):0.142 (5). In the crystal, mol­ecules A and B are linked via a pair of inter­molecular N—H⋯O hydrogen bonds, generating an R 2 2(8) ring motif. These ring motifs are further linked into two-dimensional arrays parallel to the bc plane by inter­molecular N—H⋯O and weak C—H⋯S hydrogen bonds. The crystal is further stablized by weak π–π inter­actions [centroid–centroid distances = 3.5698 (13) and 3.5287 (12) Å].
PMCID: PMC3051470  PMID: 21523124
21.  4-Methyl-5-phenyl-1H-pyrazol-3(2H)-one 
The asymmetric unit of the title compound, C10H10N2O, contains two crystallographically independent mol­ecules with similar geometries, which exist in the keto form. The C=O bond lengths are 1.2878 (12) Å in mol­ecule A and 1.2890 (12) Å in mol­ecule B, indicating that the compound undergoes enol-to-keto tautomerism during the crystallization process. In mol­ecule A, the pyrazole ring is approximately planar [maximum deviation = 0.007 (1) Å] and forms a dihedral angle of 36.67 (6)° with the attached phenyl ring. In mol­ecule B, the dihedral angle formed between the pyrazole ring [maximum deviation = 0.017 (1) Å] and the phenyl ring is 41.19 (6)°. In the crystal, inter­molecular N—H⋯O hydrogen bonds link neighbouring mol­ecules into dimers generating R 2 2(8) ring motifs. These dimers are linked into ribbons along [101] via inter­molecular N—H⋯O hydrogen bonds, forming R 4 2(10) ring motifs.
PMCID: PMC3050219  PMID: 21522659
22.  4a-Hy­droxy-9-(2-meth­oxy­phen­yl)-4,4a,5,6,7,8,9,9a-octa­hydro-3H-xanthene-1,8(2H)-dione 
In the title compound, C20H22O5, an S(6) ring motif is formed by an intra­molecular C—H⋯O hydrogen bond, which contributes to the stabilization of the mol­ecule. In the xanthene system, the cyclo­hexane ring adopts a chair conformation, the cyclo­hexene ring adopts a half-boat conformation and the tetra­hydro­pyran ring adopts a half-chair conformation. The mean plane of the four essentially planar atoms of the tetra­hydro­pyran ring [r.m.s deviation = 0.092 (1) Å] forms a dihedral angle of 64.13 (6)° with the mean plane of the meth­oxy­phenyl group. In the crystal, inter­molecular O—H⋯O and weak C—H⋯O hydrogen bonds link mol­ecules into chains along the a axis, which are further stabilized by C—H⋯π inter­actions.
PMCID: PMC3050262  PMID: 21522746
23.  (2E)-3-(4-Eth­oxy­phen­yl)-1-(2-methyl-4-phenyl­quinolin-3-yl)prop-2-en-1-one monohydrate 
The title hydrate, C27H23NO2·H2O, features an almost planar quinoline residue (r.m.s. deviation = 0.015 Å) with the benzene [dihedral angle = 63.80 (7) °] and chalcone [C—C—C—O torsion angle = −103.38 (18)°] substituents twisted significantly out of its plane. The configuration about the C=C bond [1.340 (2) Å] is E. In the crystal, mol­ecules related by the 21 symmetry operation are linked along the b axis via water mol­ecules that form O—H⋯Oc and O—H⋯Nq hydrogen bonds (c = carbonyl and q = quinoline). A C—H⋯O inter­action also occurs.
PMCID: PMC3011764  PMID: 21589564
24.  3-(2,5-Dimethyl­furan-3-yl)-1H-pyrazol-5-ol–ethyl 3-(propan-2-yl­idene)carbazate (1/1). Corrigendum 
Corrigendum to Acta Cryst. (2010), E66, o3020–o3021.
The address of three of the authors in the paper by Shahani et al. [Acta Cryst. (2010), E66, o3020–o3021] is corrected.
PMCID: PMC3011539  PMID: 21589200
25.  3-(2,5-Dimethyl­furan-3-yl)-1H-pyrazol-5-ol–ethyl 3-(propan-2-yl­idene)carbazate (1/1) 
In the title 1:1 adduct, C6H12N2O2·C9H10N2O2, the maximum deviations from the 1H-pyrazole-5-ol and furan rings are 0.014 (1) and 0.003 (1) Å, respectively. The dihedral angle formed between the 1H-pyrazol-5-ol and 2,5-dimethyl­furan rings is 21.07 (5)°. In the crystal, pairs of inter­molecular O—H⋯N hydrogen bonds form inversion dimers of the 3-(2,5-dimethyl­furan-3-yl)-1H-pyrazol-5-ol species, generating R 2 2(8) ring motifs. Mol­ecules are further linked by inter­molecular N—H⋯O, N—H⋯N and C—H⋯O hydrogen bonds to form ribbons along the [010] direction containing bifurcated R 1 2(5) and R 2 1(7) ring motifs. Further stablization of the packing is provided by weak π–π [centroid–centroid distance = 3.5686 (15) Å] and C—H⋯π inter­actions.
PMCID: PMC3009126  PMID: 21589178

Results 1-25 (71)