Mili Sarkar

Studies on β-Enaminonitriles: A one-pot Regiospecific Synthesis of Polysubstituted 3,4-Dihydro-2(1H)-Pyridones

Abstract Reaction of α, β-unsaturated acid chlorides with primary enaminonitriles in presence of triethylamine affords, under very mild conditions, a simple and highly efficient regiospecific synthesis of polysubstituted 3,4-dihydro-2(1H)-pyridones.

Onset of Chaos for Different Non Linear Systems by Varying System Parameters

Chaos is one of the most important behaviors exhibited by non linear dynamical system and refers to the predictable although seemingly random, motion of trajectories of a dynamical system. Chaotic systems display chaotic behaviors only for specific range of values of their parameters. In this paper, the generation of chaos in two chaotic systems, namely, Lorenz System and Rӧssler’s model was shown using SIMULINK with few specific initial conditions and parameter values. The state space trajectories act as strange attractors and this shows the emergence of chaos for chosen set of control parameter values.

A short and expeditious regiospecific synthesis of novel pyrazoles

α-Cyano-β-enaminones, obtained by regioselective acylation of β-aminocrotononitrile, are smoothly and regiospecifically converted into substituted pyrazoles in good to excellent yields.

Design of 1-bit Full Adder using β-driven threshold element

In this paper, we have designed a β driven 1-bit full-adder circuit. Circuits based on threshold elements have raised extensive interest in recent years. It uses a CMOS(complementary metal oxide semiconductor field effect transistor) pair with variable β. Transformation of a regular analytic representation of the threshold function in a ratio form is the concept behind the design of the β driven circuit. Addition is the most fundamental arithmetic operation hence full adders are one of the most basic building blocks for computing circuits. The major advantage of this β-driven threshold logic based full adder circuit design is that the Full Adder is its simplicity and lower transistor count. The circuit is done using PSpice.

DC analysis of a MOS based NDR circuit

The DC analysis of a Metal Oxide Semiconductor Field Effect Transistor based negative differential resistor (NDR) is investigated. V-I characteristic of NDR is obtained by adjusting the parameters of NMOS transistors. Here the NDR circuit exhibits lambda type V-I characteristic. The circuit is easy to fabricate as all the components used here are NMOS. To study the characteristic curve of the NDR circuit CADENCE software is used. The circuit is designed based on the standard 0.18um technology. Analytical DC analysis is verified by MATLAB.

Synthesis of substituted isoxazolones and isoxazoles from cyanoenaminones

α-Cyano-β-enaminones, obtained by regioselective acylation of β-aminocrotononitrile, are smoothly and regiospecifically converted into substituted 5-isoxazolones, which on alkaline hydrolysis afford 4-acyl-3-substituted-5-hydroxyisoxazoles in good to excellent yields.

Design of Minnick counter using MOS-based threshold logic

Minnick counter is a special kind of electronic circuit that is employed to determine the number of ones in a binary input sequence. Here we have proposed a circuit which can determine the number of ones in a binary sequence. If we look close to the circuit then we may find that this circuit can also be used as a Full Adder circuit with a little alteration. The 3 bit Minnick Counter circuit can act like an one bit Full Adder. Therefore we can serve two major purposes that we often encounter while designing most of the circuits for the mathematical calculations in the computers and in arithmetic and logical circuits. This is designed using CMOS based threshold logic and also verified using SPICE simulator.

Design of 1-bit full adder using NMOS based negative differential resistance

In this paper a new implementation technique of 1-bit full adder using Negative Differential Resistance (NDR) circuit composed of N-MOSFETs is presented. The design is based on Monostable to Bistable transition logic element (MOBILE) theory. In this circuit peak current level of the load and driver NDR is modulated by controlling the gate voltage of n-MOS device connected in parallel to the NDR element according to the logic input thus producing different output for different input. The major advantage of this NDR based full adder circuit is its power efficiency and simplicity. High speed of operation can also be obtained using NDR element. In the circuit, the current magnitudes are in the order of a few microamperes leading to lower power consumption which in turn ensures lower heat dissipation, which facilitates higher stability and reliability. The circuit is designed based on the standard 0.18μm technology. The circuit simulation is done using software, CADENCE and MATLAB.

The synthesis of novel ethyl 4-(substituted amino)isothiazolo[5,4-b]-pyridine-5-carboxylates

The preparation of ethyl 4-(substituted amino)isothiazolo[5,4-b]pyridine-5-carboxylates via nucleophilic displacement of 4-chloroisothiazolo[5,4-b]pyridines by amino compounds is reported.