Bis-heterocyclic Compound Research Articles

An elegant approach for the synthesis of multisubstituted imidazole via FeCl3/SiO2 catalyzed activation of acetals: a photophysical study of an imidazole-carbazole hybrid.

A simple and solvent-free catalytic system was developed for the direct conversion of multisubstituted imidazoles through the reaction of acetals and benzils with ammonium acetate/amines as the source of nitrogen. The reaction occurred under mild and benign conditions using FeCl3/SiO2 as a heterogeneous catalyst without the requirement of any toxic organic solvents. The easy preparation and recyclability of the catalyst allows the reaction to be simple and highly efficient, resulting in very good yields of imidazoles. Novel imidazole-carbazole hybrid compounds were also synthesised by adopting the present methodology. Single crystal X-ray diffraction study indicated the presence of a CH⋯π supramolecular interaction that renders effective molecular packing in the solid state. The steady-state and spectro-dynamic behaviours of these hybrid molecules were investigated, and it was revealed that a solvent-dependent excimer-coupled ICT phenomenon guided excited state photophysics. Very unusual excimer lifetime was noticed in the solid state of this bis-heterocyclic compound owing to the stacking of molecules via CH⋯π interaction, as evident from the X-ray studies.

Ferrocenyl-bis-(1-(4-benzyl-5-morpholinooxazol-2-yl)-N-(4-(trifluoromethyl)benzyl)methanamine)

The new bis-heterocyclic compound ferrocenyl-bis-(1-(4-benzyl-5-morpholinooxazol-2-yl)-N-(4-(trifluoromethyl)benzyl)methanamine) (1) was synthesized in 73% overall yield in 1.5 hours via a pseudo-repetitive Ugi-Zhu five-component reaction, starting from 1,1′-ferrocenedicarboxaldehyde, 4-(trifluoromethyl)benzylamine, and 2-isocyano-1-morpholino-3-phenylpropan-1-one, in 1:2.1:2.2 proportions, respectively, using scandium(III) triflate as a Lewis-acid catalyst, microwaves as a heat source, and toluene as a solvent. The synthesized compound was characterized by 1D (1H, 13C, and 19F) and 2D (COSY, HSQC, and HMBC) NMR, HRMS, and FT-IR.

Theoretical investigation of the mechanism of forming a silicic bis-heterocyclic compound between dichlorosilylenesilylene [Cl2Si = Si:] and ethylene

The mechanism of the cycloaddition reaction between singlet state unsaturated silylene dichlorosilylenesilylene [Cl2Si = Si:] and ethylene, which generates a silicic bis-heterocyclic compound, has been investigated with the CCSD(T)// MP2/6-31G* method. The calculations show that the dominant reaction pathway consists of three steps. (I) The 3p unoccupied orbital of the Si atom in dichlorosilylenesilylene [Cl2Si = Si:] (R1) and the π-orbital of ethylene (R2) firstly form a π → p donor–acceptor bond, which makes the two reactants generate a three-membered cyclic intermediates (INT) through a barrier-free exothermic reaction of 127.7 kJ mol−1. (II) INT then isomerises to a four-membered cyclic silylene (P1) by the ring-expansion effect, which is via a transition state (TS1) with an energy barrier of 6.4 kJ mol−1. (III) sp3 hybridisation of the Si atom finally makes P1 react directly with ethylene to form a silicic bis-heterocyclic compound (P2) without any intermediates and transition states, and this step is also a barrier-free exothermic reaction of 138.6 kJ mol−1.

Ab initio study of the reaction between silylene germylidene (H2Si = Ge:) and ethene to form a bis-heterocyclic compound containing Si and Ge

The mechanism of the cycloaddition reaction between singlet state silylene germylidene (H2Si = Ge:) and ethene has been investigated with the CCSD(T)//MP2/6-31G* method; from the potential energy profile, we predict that the reaction has one dominant reaction pathway. This dominant pathway has the two reactants firstly forming a Si-heterocyclic four-membered ring germylene (INT1) through a [2 + 2] cycloaddition reaction. Due to the sp3 hybridisation of the Ge: atom in INT1, the latter further combines with ethene to form a bis-heterocyclic product containing Si and Ge (P2).

Ab initio study of the formation of bis-heterocyclic compound involving Si and Ge from dichlorosilylene germylidene (Cl2Si=Ge:) and ethene

The mechanism of the cycloaddition reaction between singlet state dichlorosilylene germylidene (Cl2Si=Ge:) and ethene has been investigated with CCSD(T)//MP2/6-31G* method, from the potential energy profile, we predict that the reaction has one dominant reaction pathway. The presented rule of the reaction is that the two reactants firstly form a Si-heterocyclic four-membered ring germylene through the [2+2] cycloaddition reaction. Due to the sp 3 hybridization of the Ge: atom in Si-heterocyclic four-membered ring germylene, the Si-heterocyclic four-membered ring germylene further combined with the ethene to form a bis-heterocyclic compound with Si and Ge.

Ab initio study of mechanism of forming bis-heterocyclic compound with Si and Ge between silylene germylene (H2Si=Ge:) and formaldehyde

The mechanism of the cycloaddition reaction between singlet state silylene germylene (H2Si=Ge:) and formaldehyde has been investigated with the CCSD(T)//MP2/cc-pvtz method, from the potential energy profile, it could be predicted that the reaction has one dominant reaction pathway. The reaction rules presented is that [2 + 2] cycloaddition reaction between two reactants firstly generates a Si-heterocyclic four-membered ring germylene. Because of the 4p unoccupied orbital of the Ge atom in (the) Si-heterocyclic four-membered ring germylene and the π orbital of formaldehyde forming a π → p donor–acceptor bond, the Si-heterocyclic four-membered ring germylene further combines with formaldehyde to form an intermediate. Because the Ge atom in intermediate happens sp 3 hybridization after transition state, then, intermediate isomerizes to a bis-heterocyclic compound with Si and Ge via a transition state.

Ab initio study of mechanism of forming a silicic bis-heterocyclic compound between (CH3)2Si=Si: and ethane

The mechanism of the cycloaddition reaction of forming a silicic bis-heterocyclic compound between singlet state (CH3)2Si=Si: and ethene has been investigated with the CCSD(T)//MP2/6-31G* method. From the potential energy profile, it can be predicted that the reaction has one dominant reaction pathway. The presented rule of this dominant reaction pathway that the 3p unoccupied orbital of Si: in (CH3)2Si=Si: and the π orbital of ethane forming a π → p donor-acceptor bond, resulting in the formation of a three-membered ring intermediate (INT1); Then, INT1 isomerizes to a four-membered ring silylene (P1), which driven by ring-enlargement effect; Due to sp 3 hybridization of Si: atom in the four-membered ring silylene (P1), P1 further combines with ethene to form a silicic bis-heterocyclic compound (P2).

An ab initio study of the mechanism of formation of a silicic bis-heterocyclic compound from silylenesilylene (H2Si=Si:) and ethene

The mechanism of the cycloaddition reaction of the formation of a silicic bis-heterocyclic compound between singlet state silylenesilylene (H2Si=Si:) and ethene wasi investigated by the CCSD(T)//MP2/6-31G* method. From the potential energy profile, it can be predicted that the reaction has one dominant reaction pathway. The presented rule of the dominant reaction pathway is that the [2+2] cycloaddition effect of the two reactants leads to the formation of a four-membered ring silylene (INT1). When the four-membered ring silylene (INT1) interacts with ethene, due to sp3 hybridization of the Si: atom in four-membered ring silylene (INT1), the four-membered ring silylene (INT1) further combines with ethene to form a silicic bis-heterocyclic compound (P2).

Theoretical Study of the Mechanism of Cycloaddition Reaction between Silylene Silylene (H2SiSi:) and Acetone

AbstractThe mechanism of the cycloaddition reaction between singlet silylene silylene (H2SiSi:) and acetone has been investigated with the CCSD (T)//MP2/6‐31G∗︁ method. According to the potential energy profile, it can be predicted that the reaction has two competitive dominant reaction channels. The present rule of this reaction is that the [2+2] cycloaddition reaction of the two π‐bonds in silylene silylene (H2SiSi:) and acetone leads to the formation of a four‐membered ring silylene (E3). Because of the unsaturated property of Si: atom in E3, it further reacts with acetone to form a silicic bis‐heterocyclic compound (P7). Simultaneously, the ring strain of the four‐membered ring silylene (E3) makes it isomerize to a twisted four‐membered ring product (P4).

Ab initio study of mechanism of forming bis-heterocyclic compound with Si and Ge between dimethylsilylene germylidene (Me2Si=Ge:) and ethene

The mechanism of the cycloaddition reaction between singlet dimethylsilylene germylidene (Me2Si=Ge:) and ethene has been investigated with the CCSD(T)//MP2/6-31G* method. From the potential energy profile, it could be predicted that the reaction has one dominant reaction pathway. The reaction rules presented is that the two reactants firstly form a Si-heterocyclic four-membered ring germylene through the [2+2] cycloaddition reaction. Due to the sp3 hybridization of the Ge: atom in Si-heterocyclic four-membered ring germylene, the Si-heterocyclic four-membered ring germylene further combined with ethene to form a bis-heterocyclic product with Si and Ge (P2).

Ab Initio Study of Mechanism of Forming Germanic Bis-Heterocyclic Compound between Dimethyl-Germylene Carbene (Me2Ge=C:) and Acetone

The mechanism of the cycloaddition reaction of forming germanic bis-heterocyclic compound between singlet dimethylgermylene carbene and acetone has been investigated with CCSD(T)//B3LYP/6- method. From the potential energy profile, it can be predicted that, this reaction has one dominant channel. The presented rule of this dominant channel is that the two reactants firstly form a four-membered ring carbene (RC4) through the [2+2] cycloaddition reaction. Due to hybridization of carbene C atom in RC4, RC4 further combines with acetone to form a reactant complexe (RC5). Due to the further hybridization of carbene C atom in RC4, RC5 isomerizes to a germanic bisheterocyclic compound (P6) via the transition state (TS5).

Ab initio study of the mechanism of the formation of a bisheterocyclic compound containing Si and Ge by reaction of germylene silylene (H2Ge=Si:) and ethene

The mechanism of the cycloaddition reaction between singlet state germylene silylene (H2Ge=Si:) and ethene was investigated by the CCSD(T)//MP2/6-31G

Ab initioStudy on Mechanism of Forming a Silicic Bis-Heterocyclic Compound Between Dimethylmethylenesilylene and Ethene

The mechanism of the cycloaddition reaction of forming a silicic bis-heterocyclic compound between singlet dimethylmethylenesilylene (Me2C=Si:) and ethene has been investigated with the CCSD(T)//MP2/6-31G* method. From the potential energy profile, it can be predicted that, this reaction has one dominant channel. The presented rule of this dominant channel: the 3p unoccupied orbital of Si in dimethylmethylenesilylene and the π orbital of ethene forming the π→p donor-acceptor bond, resulting in the formation of three-membered ring intermediate (INT1); INT1 then isomerizes to a four-membered ring silylene (P2), which is driven by ring-enlargement effect; due to sp3 hybridization of Si atom in P2, P2 further combines with ethene to form a silicic bis-heterocyclic compound.

Ab initioStudy of Mechanism of Forming Germanic Bis-Heterocyclic Compound Between Dichloro-Germylene Carbene (Cl2Ge = C:) and Formaldehyde

The mechanism of the cycloaddition reaction of forming germanic bis-heterocyclic compound between singlet dichloro-germylene carbene and formaldehyde has been investigated with CCSD(T)//MP2/6–31G* method, from the potential energy profile, we predict that the reaction has two competitive dominant reaction pathways. The presented rule of this reaction: the 2p unoccupied orbital of the C atom in dichloro-germylene carbene insert the π orbital of formaldehyde from oxygen side, resulting in the formation of intermediate. In the intermediate and between two reactants, because of the two bonding π orbital in dichloro-germylene carbene and formaldehyde have occurred [2+2] cycloaddition reaction, forming two four-membered ring compounds in which Ge and O are in the opposite orientation and in the syn-position, respectively. Because of the unsaturated property of C atom from carbene in the two four-membered ring compounds, they further reacts with formaldehyde, resulting in the generation of two germanic bis-heterocyclic compounds.

Chemopreventive potential of 3-[2,6-bis(4-fluorophenyl)-3-methylpiperidin-4-ylideneamino]-2-thioxoimidazolidin-4-one on 7,12-dimethylbenz[a]anthracene (DMBA) induced hamster buccal pouch carcinogenesis

In the present work, a new bis heterocyclic compound comprising both the piperidone and thiohydantoin nuclei namely 3-[2,6-bis(4-fluorophenyl)-3-methylpiperidin-4-ylideneamino]-2-thioxoimidazolidin-4-one was synthesised and characterised with the help of mp, elemental analysis, FT-IR, MS and one-dimensional NMR (1H and 13C) spectra. The inhibitory effect of 3-[2,6-bis(4-fluorophenyl)-3-methylpiperidin-4-ylideneamino]-2-thioxoimidazolidin-4-one on 7,12-dimethylbenz[a]anthracene (DMBA) induced buccal pouch carcinogenesis was investigated in Syrian male hamsters. All the hamsters that were painted with DMBA on their buccal pouches for 14 weeks developed squamous cell carcinoma. Administration of 3-[2,6-bis(4-fluorophenyl)-3-methylpiperidin-4-ylideneamino]-2-thioxoimidazolidin-4-one effectively suppressed the oral carcinogenesis initiated with the DMBA as revealed by a reduced incidence of neoplasms. Lipid peroxidation, glutathione (GSH) content and the activities of glutathione peroxidase (GPx), glutathione S-transferase (GST) were used to biomonitor the chemopreventive potential of 3-[2,6-bis(4-fluorophenyl)-3-methylpiperidin-4-ylideneamino]-2-thioxoimidazolidin-4-one. Lipid peroxidation was found to be significantly decreased, whereas GSH, GPx, GST and GGT were elevated in the oral mucosa of tumour bearing animals. Our data suggest that 3-[2,6-bis(4-fluorophenyl)-3-methylpiperidin-4-ylideneamino]-2-thioxoimidazolidin-4-one may exert its chemopreventive effects in the oral mucosa by modulation of lipid peroxidation, antioxidants and detoxification systems.

Density Functional Theory Study of Mechanism of Cycloaddition Reaction Between Dimethyl-Silylene Carbene and Acetone

The mechanism of the cycloaddition reaction between singlet dimethyl-silylene carbene and acetone has been investigated with density functional theory, From the potential energy profile, it can be predicted that the reaction has two competitive dominant reaction pathways. The presented rule of this reaction: the [2+2] cycloaddition effect between the π orbital of dimethyl-silylene carbene and the π orbital of π-bonded compounds leads to the formation of a twisty four-membered ring intermediate and a planar four-membered ring product; The unsaturated property of C atom from carbene in the planar four-membered ring product, resulting in the generation of CH3-transfer product and silicic bis-heterocyclic compound.

Theoretical study of mechanism of cycloaddition reaction between dimethyl-silylene carbene [(CH3)2SiC:] and formaldehyde

The mechanism of the cycloaddition reaction between singlet dimethyl-silylene carbene and formaldehyde has been investigated with MP2/6-31G* method, including geometry optimization and vibrational analysis for the involved stationary points on the potential energy surface. The energies of the different conformations are calculated by zero-point energy and CCSD (T)//MP2/6-31G* method. From the potential energy profile, it can be predicted that the reaction has two competitive dominant reaction pathways. The main products of first dominant reaction pathway are a planar four-membered ring product (P4) and its H-transfer product (P4.2). The main product of second dominant reaction pathway is a silicic bis-heterocyclic compound (P5). © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011

Ab initio study of mechanism of forming germanic bis-heterocyclic compound between germylene carbene (H2GeC:) and acetone

Abstract The mechanism of the cycloaddition reaction of forming germanic bis-heterocyclic compound between singlet germylene carbene and acetone has been investigated with MP2/6-31G* method, including geometry optimization and vibrational analysis for the involved stationary points on the potential energy surface. The energies of the different conformations are calculated by CCSD (T)//MP2/6-31G* method. From the potential energy profile, it can be predicted that the dominant reaction pathway of the cycloadditional reaction of forming germanic bis-heterocyclic compound consists of three steps: (1) the two reactants firstly form an intermediate INT4 through a barrier-free exothermic reaction of 181.4 kJ/mol; (2) INT4 further reacts with acetone (R2) to form an intermediate (INT5), which is also a barrier-free exothermic reaction of 148.9 kJ/mol; (3) INT5 then isomerizes to a germanic bis-heterocyclic product P5 via a transition state TS5 with an energy barrier of 53.3 kJ/mol.

Synthesis, crystal structure and fungicidal activity of 1-(4-chlorophenyl)-2-(5-((3,5-dimethyl-1H-pyrazol-1-yl)methyl)-4-phenyl-4H-1,2,4-triazol-3-ylthio)ethanone

A novel bis-heterocyclic compound was synthesized and characterized. The crystal structure of the title compound (C22H20ClN5OS, Mr = 437.94) has been determined by single-crystal X-ray diffraction. The crystal is of triclinic, space group P-1 with a = 8.646 (2), b = 9.148 (3), c = 14.540 (4) A, α = 94.422 (4), β = 98.500 (4), γ = 102.823 (4)°, V = 1101.8 (5) A3, Z = 2, F(000) = 312, Dc = 1.320 g/cm3, μ = 0.2900 mm−1, the final R1 = 0.041000 and wR2 = 0.1160 for 2675 observed reflections with I > 2σ(I). A total of 5623 reflections were collected, of which 3866 were independent (Rint = 0.019000). The fungicidal activity of title compound was determined, the results showed the title compound displayed moderate fungicidal activity against G. zeae Petch, Phytophthora infestans (Mont.) de Bary, Botryosphaeria berengeriana f. sp. piricola (Nose) koganezawa et Sakuma, Fusarium oxysporum f.sp. cucumerinum, and Cercospora arachidicola.

Theoretical study on the mechanism of cycloaddition reaction between silylene carbene and formaldehyde

The mechanism of the cycloaddition reaction between singlet silylene carbene and formaldehyde has been investigated with MP2/6-31G∗ method, including geometry optimization and vibrational analysis for the involved stationary points on the potential energy surface. The energies of the different conformations are calculated by CCSD(T)//MP2/6-31G∗ method. From the potential energy profile, it can be predicted that the two competitive dominant reaction pathways of the cycloadditional reaction between singlet silylene carbene and formaldehyde are reaction 4 and reaction 5. Reaction 4 consists of three steps: the two reactants (R1, R2) firstly form a twist four- membered ring intermediate INT4 through a barrier-free exothermic reaction, this intermediate INT4 then isomerizes to a four-membered ring compound P4 via a transition state TS4. subsequently, the compound P4 isomerizes to product P4.2 via a transition state TS4.2, which results from the hydrogen transfer. The process of reaction 5 is as following: on the basis of P4 formed from the reaction 4 between R1 and R2, P4 further reacts with formaldehyde (R2) to form the intermediate INT5 through a barrier-free exothermic reaction, then INT5 isomerizes to a silicic bis-heterocyclic compound P5 via a transition state TS5.