Piperidine In Acetonitrile Research Articles

Synthesis and antibacterial evaluation of 3-acetyl-2H-selenopyrano[2,3-b]quinolin-2-ones

Abstract In the present study, we have worked out a convenient route for the synthesis of new series of novel 3-acetyl-2H-selenopyrano[2,3-b]quinolin-2-ones (4a-f) by the cyclization of 3-formyl-2-selenoquinolines (3a-f) using ethyl acetoacetate in the presence of catalytic amount of piperidine in acetonitrile as a solvent. The structures of all the synthesized products were confirmed with their elemental analysis, IR, 1H NMR, 13C NMR and mass spectral analysis. All the newly synthesized compounds (4a-f) were screened for in vitro antibacterial activities of three (Staphylococcus aureus, Micrococcus roseus) and (Escherichia coli) by disk diffusion method using ampicillin as positive and Dimethylformamide (DMF) as negative control. The tested, compounds 4d and 4e were highly active against S. aureus and M. roseus (gram positive) and moderately active against E. coli (gram negative), compound 4c was slightly active against M. roseus and E. coli. Compound 4e was slightly active against S. aureus and M. roseus and compounds 4a and 4b were slightly active against M. roseus.

A novel one-pot three-component synthesis of benzofuran derivatives via Strecker reaction: Study of antioxidant activity

A three-component Strecker-type reactions was applied for the synthesis of benzofuran derivatives through the reaction of 1-(6-hydroxy-2-isopropenyl-1-benzofuran-yl)-1-ethanone (euparin), primary amines and trimethylsilyl cyanide (TMSCN) in the presence of catalytic amount of ZnO-nanorods (ZnO-NR) and piperidine in acetonitrile at room temperature. The method has proved to be synthetically simple, and effective with high atom economy and yield. The catalyst also revealed significant reusability. Moreover, the antioxidant activity and free radical scavenging capacity of the newly synthesized such as 4a, 4c, 6a and 6c was screened using free radical scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays and compared with hydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ). These compounds exhibit good DPPH radical scavenging and ferric reducing antioxidant power (FRAP) assays.

Synthesis, Spectral Analysis, In Vitro Microbiological Evaluation, and Molecular Docking Studies of Some Novel 1-(1-Aryl-1H-tetrazol-5-yl)-2-(piperidin-1-yl)ethanone Derivatives.

A new series of novel heterocyclic compounds containing both tetrazoles and piperidine nuclei together, namely, 1-(1-aryl-1H-tetrazol-5-yl)-2-(piperidin-1-yl)ethanone (22–28), were synthesized by the treatment of the respective 2-chloro-1-(1-aryl-1H-tetrazol-5-yl)ethanone (15–21) with piperidine in acetonitrile for 6 h. A series of novel tetrazole substituted piperidine derivatives were synthesized and evaluated for their antimicrobial activity using serial dilution method. The structures of the synthesized compounds were characterized by IR, 1H NMR, 13C NMR, mass spectral data, and elemental analysis. Evaluation of antimicrobial activity shows that several compounds exhibit good activity when compared with the reference drug candidates and thus could be promising new lead molecules.

ChemInform Abstract: Facile Synthesis of E-γ-Hydroxy α,β-Unsaturated Sulfones from Aldehydes.

Abstract Reaction of enolizable aldehydes with p-tolylsulfinylmethyl phenyl sulfone (1), in the presence of piperidine in acetonitrile at O°C, gave selectively E-γ-hydroxy-α,β-unsaturated phenyl sulfones in good yields.

The Effects of Ring Substituents and Leaving Groups on the Kinetics of SNAr Reactions of 1‐Halogeno‐ and 1‐Phenoxy‐nitrobenzenes with Aliphatic Amines in Acetonitrile

AbstractRate constants are reported for the reactions of a series of 1‐chloro‐, 1‐fluoro‐ and 1‐phenoxy‐nitrobenzenes activated by CF3 or CN groups or by ring‐nitrogen with n‐butylamine, pyrrolidine or piperidine in acetonitrile. The results are compared with results reported previously for more strongly ring‐activated compounds. Decreasing ring activation leads to lower values of k1 for nucleophilic attack although this may be mediated by reduced steric congestion around the reaction centre. Specific steric effects, leading to rate‐retardation, is noted for the ortho‐CF3 group. The 1‐phenoxy compounds are subject to base catalysis and values of kAm/k–1 are reduced relative to more strongly activated compounds. This is likely to reflect increases in values of k–1 coupled with decreases in values of kAm as the proton transfer from zwitterionic intermediates to catalysing amine becomes less thermodynamically favourable. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Effects of ortho‐ and para‐Ring Activation on the Kinetics of SNAr Reactions of 1‐Chloro‐2‐nitro‐ and 1‐Phenoxy‐2‐nitrobenzenes with Aliphatic Amines in Acetonitrile

AbstractRate constants are reported for reaction of 4‐substituted 1‐chloro‐2,6‐dinitrobenzenes 1, 6‐substituted 1‐chloro‐2,4‐dinitrobenzenes 2, and some of the corresponding 1‐phenoxy derivatives, 3 and 4, with n‐butylamine, pyrrolidine and piperidine in acetonitrile as solvent. Values of k1, the rate constant for nucleophilic attack at the 1‐position, increase with increasing ring‐activation but may be reduced by steric repulsion at the reaction centre which increases in the order Cl < OPh, and n‐butylamine < pyrrolidine ≈ piperidine. ortho‐Substituents may also have adverse steric effects, and those of the trifluoromethyl group are particularly serious. X‐ray crystal structures of phenyl 2,4‐dinitro‐6‐trifluoromethylphenyl ether and phenyl 2,6‐dinitro‐4‐trifluoromethylphenyl ether are reported. Base catalysis in the 1‐phenoxy derivatives is attributed to rate‐limiting proton transfer from the zwitterionic intermediates 6 to base. Values of rate constants for this process decrease with increasing steric congestion at the reaction centre and in the order n‐butylamine > pyrrolidine > piperidine. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

Syntheses, reactivity, and crystal structures of molybdenum complexes with pyridine-2-thionate (pyS)-containing ligands: crystal structures of [Mo(eta(3)-C(3)H(5))(CO)(2)](2)(mu-eta(1),eta(2)-pyS)(2), exo-[Mo(eta(3)-C(3)H(5))(CO)(eta(2)-pyS)(eta(2)-dppe)], [Mo(CO)(3)(eta(1)-SC(5)H(4)NH)(eta(2)-dppm)], and [Mo(CO)(eta(2)-pyS)(2)(eta(2)-dppm)

The doubly bridged pyridine-2-thionate (pyS) dimolybdenum complex [Mo(eta(3)-C(3)H(5))(CO)(2)](2)(mu-eta(1),eta(2)-pyS)(2) (1) is accessible by the reaction of [Mo(eta(3)-C(3)H(5))(CO)(2)(CH(3)CN)(2)Br] with pySK in methanol at room temperature. Complex 1 reacts with piperidine in acetonitrile to give the complex [Mo(eta(3)-C(3)H(5))(CO)(2)(eta(2)-pyS)(C(5)H(10)NH)] (2). Treatment of 1 with 1,10-phenanthroline (phen) results in the formation of complex [Mo(eta(3)-C(3)H(5))(CO)(2)(eta(1)-pyS)(phen)] (3), in which the pyS ligand is coordinated to Mo through the sulfur atom. Four conformational isomers, endo,exo-complexes [Mo(eta(3)-C(3)H(5))(CO)(eta(2)-pyS)(eta(2)-diphos)] (diphos = dppm, 4a-4d; dppe, 5a-5d), are accessible by the reactions of 1 with dppm and dppe in refluxing acetonitrile. Homonuclear shift-correlated 2-D (31)P((1)H)-(31)P((1)H) NMR experiments of the mixtures 4a-4d have been employed to elucidate the four stereoisomers. The reaction of 4 and pySK or [Mo(CO)(3)(eta(1)-SC(5)H(4)NH)(eta(2)-dppm)] (6) and O(2) affords allyl-displaced seven-coordinate bis(pyridine-2-thionate) complex [Mo(CO)(eta(2)-pyS)(2)(eta(2)-dppm)] (7). All of the complexes are identified by spectroscopic methods, and complexes 1, 5d, 6, and 7 are determined by single-crystal X-ray diffraction. Complexes 1 and 5d crystallize in the orthorhombic space groups Pbcn and Pbca with Z = 4 and 8, respectively, whereas 6 belongs to the monoclinic space group C2/c with Z = 8 and 7 belongs to the triclinic space group Ponemacr; with Z = 2. The cell dimensions are as follows: for 1, a = 8.3128(1) A, b = 16.1704(2) A, c = 16.6140(2) A; for 5d, a = 17.8309(10) A, b = 17.3324(10) A, c = 20.3716(11) A; for 6, a = 18.618(4) A, b = 16.062(2) A, c = 27.456(6) A, beta = 96.31(3) degrees; for 7, a = 9.1660(2) A, b = 12.0854(3) A, c = 15.9478(4) A, alpha = 78.4811(10) degrees, beta = 80.3894(10) degrees, gamma = 68.7089(11) degrees.

Facile synthesis of E-γ-hydroxy-α,β-unsaturated sulfones from aldehydes

Reaction of enolizable aldehydes with p-tolylsulfinylmethyl phenyl sulfone (1), in the presence of piperidine in acetonitrile at O°C, gave selectively E-γ-hydroxy-α,β-unsaturated phenyl sulfones in good yields.

A practical route to (E)-γ-hydroxy-αβ-unsaturated phenyl sulfones

Reaction of enolizable aldehydes with p-tolylsulfinylmethyl phenyl sulfone (1) in the presence of piperidine in acetonitrile gave selectively E-γ-hydroxy-αβ-unsaturated phenyl sulfones (2) in good yields. Reaction from enantiomerically pure sulfoxide 1 gave unsaturated sulfones 2 in moderate optical yields (ee= 10-50%).

ChemInform Abstract: Synthesis of Optically Active 4‐Hydroxyalk‐2‐enenitriles. Reaction of Optically Active 2‐(p‐Chlorophenylsulfinyl)acetonitrile with Aldehydes in the Presence of Piperidine in Acetonitrile.

AbstractThe optically active α‐cyanosulfoxides (I) are coupled with the aldehydes (II) to yield the chiral hydroxynitriles (V) directly.

Synthesis of optically active 4-hydroxyalk-2-enenitriles; Reaction of optically active 2-(p-chlorophenylsulfinyl)acetonitrile with aldehydes in the presence of piperidine in acetonitrile

Reaction of optically active 2-(p-chlorophenylsulfinyl)acetonitrile ((R)- 1a ) with aldehydes, in the presence of piperidine in acetonitrile at r.t., gave optically active 4-hydroxyalk-2-enenitriles in good optical and chemical yields. The absolute configuration of (−)-4-hydroxypent-2-enenitrile, predominantly obtained by the reaction of (R)- 1a with propanal, was determined to be R.

Derivatives of eis-NPCl2(NSOCl)2 and (NPCl2)2NSOCl, Part IX [1] Substitution Reactions of cis-NPCl2(NSOCl)2 with Piperidine

Aminolysis of cis-NPCl2(NSOCl)2 by piperidine in acetonitrile at room temperature proceeds via a non-geminal substitution pattern. During the first substitution step the reactivity of a SOCl-centre appears to be greater than that of a PCl2-centre. The second and third substitution step successively take place at the PCl2- and remaining SOCl-centre. The different isomeric forms of the mono-, bis-, tris-, and tetrakis(piperidino) derivatives are characterized by means of 31P NMR data. Application of 13C NMR leads in two cases to a structure assignment.