Marwa S. Salem

Synthesis, Antibacterial, and Antiviral Evaluation of New Heterocycles Containing the Pyridine Moiety

A facile one‐pot four‐component reaction was utilized to construct 2‐oxo‐1,2‐dihydropyridine‐3‐carbonitrile as a scaffold for the synthesis of many fused heterocyclic systems, namely, furopyridine, pyridothiadiazepinthione, and pyridotriazine, as well as non‐fused heterocyclic systems such as phthalazin‐2(1H)‐ylnicotinonitrile, pyridin‐2‐yl‐1H‐pyrazole, and pyrazol‐1‐ylnicotino‐nitrile,1‐(3‐cyanopyridin‐2‐yl)‐1H‐pyrazole. The new compounds were evaluated as antimicrobial and antiviral agents.

Synthetic Utility of Enaminonitrile Moiety in Heterocyclic Synthesis: Synthesis of Some New Thienopyrimidines

The hitherto unknown 3-amino-5-bromo-4, 6-dimethylthieno [2, 3-b] pyridine-2-carbonitrile ( 4 ) was condensed with p-anisaldehyde affording the Schiff base ( 5 ). Acylation of the thienopyridine derivative ( 4 ) using freshly distilled acetic anhydride gave a mixture of mono and diacetyl derivatives ( 6 ) and ( 7 ). Condensation of ( 4 ) with triethylorthoformate yielded the ethoxymethyleneamino derivative ( 8 ), which was treated with hydrazine hydrate to give the hydrazide derivative ( 9 ), which in turn was converted to a triazolopyrimidine derivative ( 10 ) upon treatment with freshly distilled acetic anhydride. Thiation of ( 4 ) with carbon disulfide afforded the pyrimidine dithione derivative ( 11 ), which was alkylated with ethyl iodide to give the di-s-ethylpyrimidine derivative ( 12 ).On the other hand, treatment of ( 4 ) with formamide yielded the aminopyrimidine derivative ( 13 ), whereas its treatment by formic acid produced the thienopyrimidinone derivative (1 4 ). Chlorination of (1 4 ) with a mixture of phosphorus pentachloride and phosphorus oxychloride gave the chloropyrimidine derivative ( 15 ), which in turn afforded the hydrazide derivative ( 9 ) upon treatment with hydrazine hydrate. Hydrazinolysis of ethyl-3-amino-5-bromo-4,6-dimethylthieno[2,3-b]pyridine-2-carboxylate ( 17 ) gave the hydrazino derivative ( 18 ), which in turn was converted to 8-bromo-7,9-dimethyl-3-formylaminopyrido[3′,2′:4,5]thieno[3,2-d]pyrimidin-4(3H)-one ( 19 ) and 8-bromo-3-diacetylamino-2,7,9-trimethylpyrido[3′,2′:4,5]thieno[3,2-d]pyrimidin-4(3H)-one ( 20 ) upon treatment with formic acid and freshly distilled acetic anhydride, respectively.

Novel Pyrazolo[3,4-b]pyridine Derivatives: Synthesis, Characterization, Antimicrobial and Antiproliferative Profile.

Three novel series of pyridine derivatives, namely Schiffs bases, 4-thiazolidinones and azetidin-2-ones bearing pyrazolo[3,4-b]pyridine moiety, have been synthesized. The chemical structures of the synthesized compounds were characterized. The compounds were tested for their antimicrobial activity using the agar well diffusion and broth macrodilution methods. The compounds were also evaluated for their antiproliferative activity using the sulforhodamine B (SRB) assay. The majority of the tested compounds exhibited slight to high antimicrobial activity against the test microorganisms with minimum inhibitory concentrations (MICs) of 0.12-62.5 µg/mL when compared to that of 3 standard antimicrobial agents (Ampicillin, 0.007-0.03 µg/mL; Gentamicin; 0.015-0.24 µg/mL; and Amphotericin B, 0.03-0.98 µg/mL). Compound (7b) was found to be nearly as active as the standard antimicrobial drug Amphotericin B against Fusarium oxysporum fungal strain with MIC of 0.98 µg/mL. Some of the test compounds showed remarkable cytotoxic activities against Hep G2 (hepatocellular carcinoma) cells (IC50=0.0158-71.3 µM) in comparison to the standard anticancer drug doxorubicin (IC50=0.008 µM). Among the compounds tested, (5), (6a), (6b), (7b), and (10) exhibited antiproliferative potency (IC50=0.0001-0.0211 µM) that was found to be better than that of doxorubicin (IC50=0.099 µM) against MCF7 (breast adenocarcinoma) cells. In particular, (7b) displayed the highest significant antiproliferative efficacy against both Hep G2 and MCF7 cell lines showing IC50 values of 0.0158 µM and 0.0001 µM, respectively. Our findings suggest that the synthesized compounds may be promising candidates as novel antimicrobial and antiproliferative agents.

Synthesis and antimicrobial evaluation of novel 1,3-thiazoles and unsymmetrical azines

Abstract1,3-Thiazol derivatives have been synthesized via reaction of 1-(1-(5,6-dimethoxy-2-oxobenzo[d]thiazol-3(2H)-yl)propan-2-ylidene)-4-substituted thiosemicarbazide with different halides, namely, ethyl bromoacetate, ethyl-2-bromopropionate, phenacyl bromide, p-bromophenacyl bromide and/or substituted hydrazonoyl halides. The new compounds were evaluated as antimicrobial agents.

Antioxidant Activity of Novel Fused Heterocyclic Compounds Derived from Tetrahydropyrimidine Derivative

6-(Benzo[d][1,3]dioxol-5-yl)-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonitrile has been utilized for synthesis of the fused heterocyclic compounds namely thiazolopyrimidines, tetrazolopyrimidine, pyrimidoquinazoline, pyrimidothiazolopyrimidine, pyrimidothiazolotriazine and pyrrolothiazolopyrimidine derivatives. The newly synthesized compounds were characterized by IR, (1)H-NMR, (13)C-NMR, and mass spectral data. Antioxidant activities of all synthesized compounds were investigated.

Design methodology and power conditioning circuit of vibration based MEMS converters for wireless sensor networks

This paper proposes a new design methodology for the MEMS energy converter to optimize its performance parameters in order to maximize its output power range and to validate charge transfer operation between the converter and the power conditioning circuit using the common circuit simulator SPICE. We developed a circuit model for the converter. An efficient transfer of charge between the reservoir and the converter has been found

Comparison of radiation hardening techniques for standard CMOS technologies

This paper is mainly concerned with the comparison of two well-known hardness techniques on the circuit level rather than on the technology level (low-cost standard CMOS technology is assumed). The inverter has been taken as a case study. The implementation technology is CMOS 0.6/spl mu/ from AMS.

Determining the Required Pulses for Controlling the Operation of Electrostatic MEMS Converters

The main objective of this paper is to determine the required controlling pulses which control the charging and the discharging operations of the electrostatic MEMS converter. These converters found in the energy scavenging system for wireless sensor nodes. To achieve this objective, a SPICE model for the converter is implemented in order to describe its behavior. Thus the required controlling pulses are determined by simulating the interaction between the converter model and the energy scavenging system

Synthesis and anticancer activity of novel quinazolinone and benzamide derivatives

In trying to develop new anticancer agents, a series of quinazolinone and benzamide derivatives were synthesized via reaction of 6-iodo-2-phenyl-4H-benzoxazin-4-one with nitrogen nucleophiles, namely, formamide, ammonium acetate, hydrazine hydrate, hydroxylamine hydrochloride, substituted aromatic amines, benzyl amine, and/or thiocarbonohydrazide. All compounds were fully characterized by means of IR, MS, and 1H-NMR spectra. Some of the synthesized compounds were evaluated in vitro for their anti-proliferative activity against HePG-2 and MCF-7 cell lines. 2-(Benzoylamino)-N-(4-hydroxyphenyl)-5-iodobenzamide and tetrazino[1,6-c]quinazoline-3(4H)-thione derivative were the most potent against the two cancer cells comparable to that of doxorubicin. Most of the synthesized compounds also exhibited good cytotoxic activity.

Synthesis, antileishmanial and cytotoxicity activities of fused and nonfused tetrahydroquinoline derivatives

Developing novel antileishmanial, and cytotoxic drugs has been a significant area in modern pharmaceutical research. A series of novel triazolo[4,3-a]quinoline, triazino[4,3-a]quinoline, thiadiazepino[5,6-b]quinoline and pyrazolquinoline have been synthesized from the reaction of 2-hydrazinyltetrahydroquinoline-3-carbonitrile with formamide, formic acid, ethyl chloroacetate, carbon disulphide in an alcoholic solution of potassium hydroxide acetyl acetone and/or ethyl cyanoacetate, respectively. These compounds were evaluated for their in vitro studies against L. major leishmanial. The brine shrimp bioassay was also conducted to study their in vitro cytotoxic properties which displayed potent cytotoxic activity against Vincristine. The newly synthesized compounds were all characterized through IR, 1H-NMR, and MS.