Search

The development of a versatile new one pot, catalyst free, multicomponent-tandem strategy for assembly of spirooxindole-indazolones and spirooxindole-pyrazolines is described. The reported protocol includes several advantages like environmental friendliness, cost effectiveness, high atom economy, short reaction times and high yields. The reported method is the first green synthesis of spirooxindole-indazolones and spirooxindole-pyrazolines.

A new environmentally friendly methodology for the efficient synthesis of biologically significant triazole thiazolidinone hybrids in aqueous medium, using acetic acid as an organocatalyst in the presence of cetyltrimethylammonium bromide (CTAB) surfactant has been developed for the first time. The effect of several surfactants on the yield and completion time of the reaction was investigated and it was found that the use of CTAB at 60 °C gave the best results (79–96% in 20 min–35 min) for the synthesis of the target compounds.

An efficient triphenylphosphine-catalyzed synthesis of β-acetamido carbonyls via multicomponent reaction of aromatic aldehydes, enolizable ketones or β-keto esters, acid chlorides and acetonitrile at room temperature is described. The process is remarkably simple, environmentally benign, and uses Lewis base for the first time in such type of reaction.

A series of novel dihydropyrrolo[2,1-a]isoquinolines and dihydropyrrolo[1,2-a]quinolines have been synthesized from isoquinolines/quinolines, various substituted phenacyl bromides and substituted dialkylacetylenedicarboxylates via [3+2] cycloaddition reaction. The reaction proceeds in aqueous micellar medium with DBU as a catalyst. The present protocol offers a simple one pot sequential reaction affording products in excellent yields.

Multi-threshold complementary metal-oxide-semiconductor (MTCMOS) is often used to reduce the leakage current in idle circuit. Ground bounce noise produced during a transition mode (sleep-to-active) is an important challenge in MTCMOS. In this paper, various noise-aware combinational MTCMOS circuit was used to evaluate the ground bounce noise. An intermediate mode was applied in the sleep-to-active mode transition to reduce the charge stored on virtual lines to real ground. The dependence of ground bounce noise on voltage, transistor size and temperature was investigated with different MTCMOS circuit technique. The peak amplitude of ground bounce noise was reduced up to 78.82%. The leakage current of the circuit was decreased up to 99.73% and the active power of the circuit was reduced up to 62.32%. Simulation of multiplier with different MTCMOS circuit techniques was performed on 45 nm CMOS technology.

A microwave-induced technique has been developed for the synthesis of a series of novel spiro indoline-based heterocycles (7a–g) at atmospheric pressure in an open vessel using an environmentally benign procedure. This rapid method produces pure products in good yields within a few minutes in comparison to the conventional procedure developed for the synthesis of these heterocycles. The synthesized compounds have been screened in vitro for antifungal activity against two fungal strains (i.e., Aspergillus niger and Aspergillus flavus). All compounds have shown significant activity against these pathogens. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource: Full experimental and spectral details.]

In high speed ADC, comparator influences the overall performance of ADC directly. This paper describes a very high speed and high resolution preamplifier comparator. The comparator use a self biased differential amp to increase the output current sinking and sourcing capability. The threshold and width of the new comparator can be reduced to the millivolt (mV) range, the resolution and the dynamic characteristics are good. Based on UMC 0.18um CMOS process model, simulated results show the comparator can work under a 25dB gain, 55MHz speed and 210.10µW power .

Reversible logic is becoming one of the best emerging design approaches for future computation of reversible logic having its more application in low power application. This logic is applied in the quantum computers, optical computing, communication and nanotechnology. In reversible logic approach generates the garbage input/output. In this paper design of proposed reversible logic multiplexer with garbage input/output, that the low power, area design technique are using that is the Gate -Diffusion -Input (GDI cell) in this dynamic component of power is reduced, In GDI cell PMOS is not connected to supply voltage VDD and NMOS is not connected to the GND.GDI circuits provide some measure issues of enhanced hazard tolerance and low voltage operation of reversible logic circuits. In this paper propose a novel application of GDI (Gate-Diffusion Input) circuits to Reversible logic multiplexer with its Garbage input and output. The new proposed design technique will consume less power than the other traditional gate. In recent years ago reversible logic circuit is less power dissipation. This GDI cell technique reduces the power of the circuit, delay, PowerDelay Product (PDP) and it also reduced frequency. The device scaling is limited by the power dissipation are more optimize in terms of delay, power supply, frequency , duty cycle, frequency jitter bandwidth of the signal and also demonstrated the noise of the circuit. The proposed reversible logic design. the GDI is effective in low power, low leakage current and lower Delay, The transistor implementation of the proposed gates is done by using Virtuoso tool of cadence. Based on simulation results and analysis at 45 nm technology, some of the trade-offs are made in the design to improve the efficiency.

Novel spiro-oxindole derivatives were synthesised by one-pot multicomponent reaction using isatins, urea and 1,3-dicarbonyls. β-Cyclodextrin, an oligosaccharide, catalysed the reaction and can be reused for further reaction after recovery. This developed synthetic route is environmentally benign in which water is used as solvent to produce excellent yields of products. The synthesised compounds were evaluated for their antimicrobial activities against two bacteria and two fungi. All the synthesised spiro-oxindoles exhibit significant antimicrobial activity.

An efficient and convenient protocol of broad scope for the synthesis of quinoxaline by cyclization-oxidation of phenacyl bromide with equimolar amount of phenylenediamine at room temperature catalyzed by thiamine in the form of N-heterocyclic carbene (NHC). High efficiency, inexpensiveness, and non-toxicity are the interesting features of the catalyst, which make it eco-friendly and highly attractive.

An efficient and general method has been described for the synthesis of imidazo[2,1-b]-1,3,4-thiadiazole by the reaction of 2-aminothiadiazoles with phenacyl bromides in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO). The method is suitable for the synthesis of functionalized imidazothiadiazoles.

The incidence of invasive fungal infections caused by opportunistic pathogens, often characterized by high mortality rates, has been increasing over the past two decades. Patients that become severely immunocompromised because of underlying diseases such as leukemia or, recently, acquired immunodeficiency syndrome or patients who undergo cancer chemotherapy or organ transplantation are particularly susceptible to opportunistic fungal infections. A matter of concern in the treatment of fungal infections is the limited number of efficacious antifungal drugs. Many of the currently available drugs are toxic, produce recurrence because they are fungistatic and not fungicides or lead to the development of resistance due in part to the prolonged periods of administration of the available antifungal drugs. There is, therefore, a clear need for the discovery of new structures with antifungal properties, which could lead to the development of new drugs for the management of fungal infections and treatment of systemic mycoses. Up to only 30 years ago the choice of systemically available antimycotics was between two drugs, amphotericin B and flucytosine, neither of which was satisfactory. Then a series of inhibitors of the biosynthesis of ergosterol, the major sterol of the fungal cell membrane, were found to have excellent antifungal activity, improved safety, and some were also active after oral or parenteral application. Starting with miconazole and ketoconazole, and improving through fluconazole and itraconazole, the imidazole and triazole inhibitors of lanosterol l4α-ademethylation have been the most successful. Although the use of a new generation of triazoles, the available polyenes in lipid formulations, the use of echinocandins or the combination therapy have been introduced as alternatives in the last 10 years, the number of available preparations to treat systemic fungal infections is still limited and more alternatives are needed, particularly with improved efficacy against emerging pathogens with limited susceptibility to the available preparations. We find out that the imidazole derivatives have shown potent antifungal activity associated with good antimycobacterial activity. In addition, aryl phenyl ether group is a widely used in pesticide and drug molecular design. With the reference to above information and help of bioisoterism, we have synthesized a series of compounds in which the imidazole moiety is directly linked at position 4 and aryl phenyl ether at the position 3 of pyrazole ring to improve antifungal activity.

A series of [4-(aryloxy)phenyl]cyclopropyl methanones were synthesized by reaction of different benzyl alcohols with 4-chloro-4′-fluorobutyrophenone in DMF in the presence of NaH/TBAB. The methanones were further reduced to respective methanols. The antitubercular activity of these compounds was evaluated in vitro against Mycobacterium tuberculosis H37Rv. Compounds 19, 21, 35, 36 and 37 have shown minimum inhibitory concentration (MIC) of 3.12 μg/mL, while compounds 14, 25 and 18 have shown MIC of 1.56 μg/mL and 0.78 μg/mL respectively. One of the compounds, cyclopropyl-4-[4-(2-piperidin-1-yl-ethoxy)benzyloxy]phenyl}methanol (36) showed 98% killing of intracellular bacilli in mouse bone marrow derived macrophages and was active against MDR, XDR and rifampicin clinical isolates resistant strains with MIC 12.5 μg/mL. Compound 36 was orally active in vivo in mice against M. tuberculosis H37Rv with an increase in MST by 6 days with 1 log reduction in the bacillary density in lungs as compared to control on 30th day after infection.

A simple, green, and efficient protocol is reported for the preparation of aryl-7,8-dihydro[1,2,4]triazolo[4,3- a ]-pyrimidine-6-carbonitriles through one-pot multi component reaction using substituted aromatic aldehydes, malononitrile, and 3-amino[1,2,4]triazole. The reaction is catalyzed by boric acid in aqueous micellar condition. Present protocol incorporates environmentally non-hazardous reaction condition, easy work-up, and use of recyclable catalytic system with associated benefits like excellent yield (84–96%) and shorter reaction time (20 min). Proposed methodology offers rapid access to substituted aryl-7,8-dihydro[1,2,4]triazolo[4,3- a ]pyrimidine-6-carbonitriles with high atom-economy and catalytic efficiency.

A study of the normal modes of vibration and their dispersion in polyguanylic acid along the chain axis (tetrad form) based on Urey–Bradley force field and Raman and Fourier transform infrared is reported. It has been greatly assisted by the vibrational analysis of guanine tetrad and spectral information for telomeric DNA d(G 12 ). Spectral relationship for polyG, telomeric DNA d(G 12 ) and characteristic features of dispersion curves such as regions of high density-of-states, repulsion and character mixing are discussed. Predictive value of heat capacity as a function of temperature is reported.

A study of the normal modes of vibration and their dispersion in polyurydilic acid (polyU) is reported using Wilson's GF Matrix method as modified by Higgs. This is done for the `bare' as well as for the helix `loaded' with uracil. Confusion that has prevailed regarding the assignments of the observed modes at 810 and 572 cm −1 is cleared and it is shown that the so called bare helix (polyU-U) has a different minimum energy state and hence spectrally different. Dispersion of the normal modes in the two helices shows marked differences which are characteristic of the extent of electrical/mechanical coupling along the chain and between the chain and the base. Values predicted for the heat capacity as a function of temperature for polyU is also reported.

Novel dihydropyrrolo[2,1-a]isoquinolines (IV) and dihydropyrrolo[1,2-a]quinolines (VI) are synthesized from isoquinoline or quinoline, phenacyl bromides, and dialkyl acetylenedicarboxylates in micellar medium (water/CTAB) under DBU catalysis.

A simple, efficient, and ecofriendly one-pot method has been reported for the synthesis of polyhydroquinolines in excellent yield using nucleophilic heterocyclic carbene as catalyst. The generalized approach is the Hantzsch four-component reaction of aromatic aldehyde, ethyl acetoacetate, cyclic 1,3-diketone, and ammonium acetate.

The process is remarkably simple, environmentally benign, and uses Lewis base for the first time in such type of reaction.

Biginelly type reaction of aminotriazole, aromatic aldehyde, and malononitrile under aqueous micellar conditions provides the title compounds in high yields and short reaction times.

A facile, environmentally benign and economic synthesis of spiro compounds (V) (7 examples) incorporating two biologically important heterocycles is described.

The theory of cooperative transition has been applied to explain the stability and melting behavior in a DNA tetraplex, which is a model for telomeres. The transition profile and heat capacity curves are best explained in terms of two variable parameters, namely nucleation and propagation parameters. The effect of strand concentration and consequent change in enthalpy is reflected in the sharpness of transition and change in nucleation parameter. The same is true for greater stabilization in the presence of K+ ions, compared with the Na+ ion. It is ascribed to dipole and dipole-induced interactions.

The Zimm and Bragg theory for helix-to-coil transitions has been suitably amended and applied to explain the two-step transition in the DNA triplex. The experimental measurements reported elsewhere have been successfully interpre- ted. The order-order and order-disorder transitions associated with the melting of the DNA triple helix, with and without netropsin binding, were characterized by the nucleation parameter, enthalpy change, sharpness of transition, and heat capacity. The destabilization of the triplex and stabilization of the duplex on netropsin binding are reflected in these characteristic parameters.

Zimm and Bragg theory for helix to coil transition has been suitably amended and applied to explain the two step transition in DNA triplex. The experimental measurements reported by G. E. Plum et al. and Y. W. Park et al. have been interpreted. The order-order and order-disorder transitions associated with the melting of DNA triple helix, with and without netropsin binding, have been characterized by the nucleation parameter, enthalpy change, sharpness of transition, and heat capacity. The destabilization of the triplex and stabilization of duplex on netropsin binding are reflected in these characteristic parameters.

A simple, efficient, and ecofriendly one-pot method has been reported for the synthesis of polyhydroquinolines in excellent yield using nucleophilic heterocyclic carbene as catalyst. The generalized approach is the Hantzsch four-component reaction of aromatic aldehyde, ethyl acetoacetate, cyclic 1,3-diketone, and ammonium acetate.

An efficient sequential one pot three component reaction involving anilines, DEAD/DMAD and glyoxal in aqueous media is reported. The protocol is environmentally benign and provides a new synthetic route to access polyfunctionalised pyrrole derivatives in high yield. The reaction proceeded via supramolecular catalysis.

In this paper, we bring in the incomparable features of modification in symmetrical Triple-gate (TG) MOSFET. The modified structure of Triple gate (TG) MOSFET reduces short-channel effects (SCEs) in comparison of the Double-gate (DG) MOSFET model. The threshold voltage, the drain-induced barrier lowering (DIBL) and surface potential are calculated. We will also discuss a model for the trans-conductance, drain current and drain conductance. The proposed Triple-gate (TG) structure province increase in the trans-conductance and drain current and reduces the short-channel effects (SCEs), electric field and drain conductance and in comparison of the Double-gate (DG) MOSFET.

The Reversible logic has emerged as more compatible and appropriate logic approaches and more prominent technology having its applications in the reversible operation based Low Power CMOS, Quantum Computing, Garbage inputs/outputs, Cryptography, Communication, nanotechnology, Optical Computing and Computer graphics. The Reversible logic circuit is very concise approach for the design of low power; low loss of information of computational structures that are very essential with the construction of arithmetic circuits used low power digital. This paper presents two new optimized reversible logic based gates circuits is one of the best design ability to this reversible half adder and half subtract or. The results with to the proposed design show that the circuits are more optimized in terms of delay, power supply (0.7V) and frequency. In this paper using design adder to 2:1 multiplexer and 3-transistor XOR gate. The power dissipation, power-delay and propagation delay produced using the new design are analyzed and compared with those of other design simulations. The results show that the proposed Reversible gate has ability to design both lower power consumption and a lower Power-Delay Product (PDP) value for PRT-l (1.912×10-19 joule), frequency response 50.6 MHz', duty cycle (44.29 %) periodic jitter (40.0 ns), frequency jitter (1.214 ns) and PRT-2 (5.160×10-19 joule) frequency response 50.0 MHz's, duty cycle (44.29 %). The transistor implementation of the proposed gates is done by using Virtuoso tool of cadence. Based on simulation results and analysis at 45 nm technology, some of the trade-offs are made in the design to improve the efficiency.

Reversible logic has emerged as one of the most important approaches and more prominent technology having its applications in Low Power CMOS, Quantum Computing, Garbage inputs/outputs, Cryptography, Communication, nanotechnology, Optical Computing and Computer graphics. This paper presents a novel reversible multiplexer gate is proposed and the design of differential reversible multiplexer using the proposed reversible gate is discussed. The results of the proposed design show that the circuits are more optimized in terms of delay, power supply (0.7V) and voltage gain (0.76V). The power dissipation, power-delay and propagation delay produced using the new design are analyzed and compared with those of other design simulations. The results show that the proposed Reversible multiplexer has both lower power consumption and a lower Power-Delay Product (PDP) value (2.384 ×10-25 joule), frequency response 50.0 MHz's. The transistor implementation of the proposed gates is done by using Virtuoso tool of cadence. Based on simulation results and analysis at 45 nm technology, some of the trade-offs are made in the design to improve the efficiency.

An efficient and general method is described for the synthesis of imidazothiadiazoles (III) (12 examples) via DABCO-catalyzed reaction of 2-aminothiadiazoles with phenacyl bromides.

The intention of this paper is to reduce leakage power and leakage current of 3T DRAM while maintaining the competitive performance. A new high performance 3T DRAM using FINFET on new logic approach is presented in this paper. Fin-type field-effect transistors (FinFETs) are capable substitutes for bulk CMOS at the nano-scale. FinFETs are double-gate devices. The two gates of a FinFET can either be shorted for higher recital or independently restricted for lower leakage or reduced transistor count. Many advanced processors now have on chip instructions and data memory using DRAMs. The major contribution of power dissipation in DRAM cell is off-state leakage current. Thus, improving the power efficiency of a DRAM cell is critical to the overall system power dissipation. We investigate the use FinFET CMOS technology provides low leakage and high performance operation by utilizing high speed, low Vt transistors for logic cells and low leakage, high Vt of transistor and show that it is particularly effective in sub threshold circuits and can eliminate performance variations with Low power. A 6ns access time and frequency 0.16 GHz provide 45nm CMOS process technology with 0.7V power supply is employed to carry out 3T DRAM cell using FinFET.

In this paper power dissipation analysis for 3T DRAM cell and 4T DRAM cell design have been carried out for the Nanoscale technology. Many advanced processors now have on chip instructions and data memory using DRAMs. The major contribution of power dissipation in DRAM cell is off-state leakage current. Thus, improving the power efficiency of a DRAM cell is critical to the overall system power dissipation. This paper investigates the effectiveness of 3T DRAM cell and 4T DRAM cell circuit design techniques and power dissipation analysis. 3T DRAM cell is designed with the semantic design technique for the analysis of power dissipation using CADENCE Tool. In this paper, we have taken two circuits of dynamic random access memory (DRAM). Read and write operation for single bit storage of 3T DRAM and 4T DRAM circuit is shown by simulating it on CADENCE tool.

Oxa-aza-phenanthrene and anthracene derivatives which contain a bridgehead nitrogen are synthesized in an aqueous micellar system. The synthetic route is easy and yield is excellent. In this proposed method, solvent, base and surfactant are optimized and the best result was obtained by DBU in water with surfactant CTAB. All synthesized molecules are new. This method is an efficient, viable and sequential one pot synthetic route for the construction of desired product.

Oxa-aza-phenanthrene and anthracene derivatives which contain a bridgehead nitrogen are synthesized in an aqueous micellar system. The synthetic route is easy and yield is excellent. In this proposed method, solvent, base and surfactant are optimized and the best result was obtained by DBU in water with surfactant CTAB. All synthesized molecules are new. This method is an efficient, viable and sequential one pot synthetic route for the construction of desired product.

Diethyl sodiomalonate reacts readily with 8,8′-bisbromomethyl-1,1′-binaphthyl to form a nine-membered carbocyclic ring: this behaviour is similar to the reactions of diethyl sodiomalonate with 2,2′-bisbromomethylbiphenyl to form a seven-membered ring, and with o-xylylene dibromide to form a five-membered ring. The preparation of diethyl 8,9-dihydro-7H-cyclonona[1,2,3-de:4,5,6-d′e′]dinaphthalene-8,8-dicarboxylate, in the racemic and in the optically active state, and of derived substances, is described.

Determination of the absolute configuration of 1,1′-binaphthyls by the use of Cotton effects associated with the short wave band of the electronic absorption spectra is discussed and applied to examples with substituents in the 8- and 8′-positions. Racemisation parameters are determined for 1,1′-binaphthyl-8,8′-diacetic acid in 0·1N-aqueous sodium hydroxide solution.