Shazia Kousar - Academia.edu (original) (raw)

Papers by Shazia Kousar

Pakistan journal of pharmaceutical sciences, 2016

Benzamides and tryptamine are biologically significant compounds, therefore, various benzamide an... more Benzamides and tryptamine are biologically significant compounds, therefore, various benzamide analogous of tryptamine have been efficiently synthesized using tryptamine and different benzoyl chlorides, in order to find new biologically active compounds. The resulting products were then characterized by melting point determination, calculation of Rf values and LC-MS techniques. At last, structure activity relationship (SAR) of the synthesized compounds was evaluated against two microbial strains; Bacillus subtilis and Aspergillus niger. All the five prepared products have shown high yield, sharp characterization and significant resistance against the growth of tested microorganism, providing a new range of tryptamine based benzamide derivatives having significant antimicrobial activities.

Journal of Pharmacovigilance

Tryptamine the important psychotropic drug having indole ring has wider biological and pharmaceut... more Tryptamine the important psychotropic drug having indole ring has wider biological and pharmaceutical significance. The focus is to see the relevant and recent achievements as neurotransmitter and neuromodulator, vasoconstrictor and vasodilator, antimicrobial and antibacterial, antioxidant and antifungal agents. Tryptamine and its natural and synthetic derivative have been reported for the variety of biological significance in the above mentioned area. This review covers all these aspects in a comprehensive way.

International Journal of Pharmaceutical Chemistry, Jul 1, 2013

Amines are ammonia derivatives in which alkyl or aryl groups are added by replacing one or more h... more Amines are ammonia derivatives in which alkyl or aryl groups are added by replacing one or more hydrogen atoms. These are divided into primary, secondary and tertiary amines according to the number of alkyl or aryl groups attached to the nitrogen atom 1,2. Some of the main examples of amines are amino acids, biogenic amines, trimethylamine and aniline. One of the hydrogen atoms in the ammonia is replaced by an alkyl or aryl group in primary amines. Examples include methylamine. Secondary amines have two alkyl or aryl substituents bound to nitrogen atom together with one hydrogen atom. Examples include dimethylamine. All the three hydrogen atoms in tertiary amines are replaced by organic substituents. Examples include N-methylpiperidine. Cyclic amines have either secondary or tertiary amines. The nitrogen atom is connected to an aromatic ring in aromatic amines as in anilines. The basicity of the amine is decreased, depending on the substituent's by the presence of nitrogen atom. Due to electron-donating effect of the amine group the reactivity of the aromatic ring increases strongly. Derivatives of amines are excellent inhibitor of the viral polymerases. Amines substituted with 3-piperidyl derivatives of rifamycin-SV are particularly active against viral infections. Murine sarcoma virus causes cell transformation by obstruction of viral polymerase derivatives. Inhibition of DNA-directed DNA polymerase was less as compared to the virion polymerase 3. Now-a-days a major problem faced by medical world is the evolution of microorganisms that have more opposition to already available antimicrobial agents. So medical science requires the development of antimicrobial agents with enhanced pharmacological and pharmacokinetics characteristics as well as with broad range activity. For this purpose in the

Pakistan journal of pharmaceutical sciences, 2016

Benzamides and tryptamine are biologically significant compounds, therefore, various benzamide an... more Benzamides and tryptamine are biologically significant compounds, therefore, various benzamide analogous of tryptamine have been efficiently synthesized using tryptamine and different benzoyl chlorides, in order to find new biologically active compounds. The resulting products were then characterized by melting point determination, calculation of Rf values and LC-MS techniques. At last, structure activity relationship (SAR) of the synthesized compounds was evaluated against two microbial strains; Bacillus subtilis and Aspergillus niger. All the five prepared products have shown high yield, sharp characterization and significant resistance against the growth of tested microorganism, providing a new range of tryptamine based benzamide derivatives having significant antimicrobial activities.

ACS National Meeting Book of Abstracts

RSC Adv., 2015

The present study describes the regioselective synthesis of novel 2,3,4,4a-tetrahydro-1H-carbazol... more The present study describes the regioselective synthesis of novel 2,3,4,4a-tetrahydro-1H-carbazoles (syn-2(a–q) and anti-3(a–b)) from l-menthone via Fischer indole synthesis.

Journal of Saudi Chemical Society, 2014

ABSTRACT The present study reports a convenient approach for the synthesis of thiophene sulfonami... more ABSTRACT The present study reports a convenient approach for the synthesis of thiophene sulfonamide derivatives (3a–3k) via Suzuki cross coupling reaction. This method of synthesis involved the reactions of various aryl boronic acids and esters with 5-bromthiophene-2-sulfonamide (2) under mild and suitable temperature conditions. The compounds synthesized in the present study were subjected to urease inhibition and hemolytic activities. The substitution pattern and the electronic effects of different functional groups (i.e., Cl, CH3, OCH3, F etc.) available on the aromatic ring are found to have significant effect on the overall results. The compound 5-Phenylthiophene-2-sulfonamide 3a showed the highest urease inhibition activity with IC50 value ∼ 30.8 μg/mL compared with the thiourea (used as standard) having IC50 value ∼ 43 μg/mL. Moreover, almost all of the compounds were examined for the hemolytic activity against triton X-100 with positive results obtained in most of the cases. In addition, the antibacterial activities of the derivatives of 5-arylthiophene-2-sulfonamide and 5-bromothiophene-2-acetamide were also investigated during the course of the study.

Proceedings of the National Academy of Sciences, 2007

Addition of a sterically demanding cyclic (alkyl)(amino)carbene (CAAC) to AuCl(SMe 2) followed by... more Addition of a sterically demanding cyclic (alkyl)(amino)carbene (CAAC) to AuCl(SMe 2) followed by treatment with [Et3Si(Tol)] ؉ [B(C6F5)4] ؊ in toluene affords the isolable [(CAAC)Au(2-toluene)] ؉ [B(C6F5)4] ؊ complex. This cationic Au(I) complex efficiently mediates the catalytic coupling of enamines and terminal alkynes to yield allenes and not propargyl amines as observed with other catalysts. Mono-, di-, and tri-substituted enamines can be used, as well as aryl-, alkyl-, and trimethylsilyl-substituted terminal alkynes. The reaction tolerates sterically hindered substrates and is diastereoselective. This general catalytic protocol directly couples two unsaturated carbon centers to form the three-carbon allenic core. The reaction most probably proceeds through an unprecedented ''carbene/vinylidene cross-coupling.'' catalysis ͉ enamines ͉ alkynes ͉ transition metal C arbon-carbon bond-forming reactions are at the heart of Author contributions: V.L. designed research; G.D.F. and S.K. performed research; B.D. contributed new reagents/analytic tools; and G.B. wrote the paper.

Molecules, 2013

In general, benzothiazole derivatives have attracted great interest due to thier pharmaceutical a... more In general, benzothiazole derivatives have attracted great interest due to thier pharmaceutical and biological importance. New 2-amino-6-arylbenzothiazoles were synthesized in moderate to excellent yields via Suzuki cross coupling reactions using various aryl boronic acids and aryl boronic acid pinacol esters and the antiurease and nitric oxide (NO) scavenging activity of the products were also examined. The most active compound concerning urease enzyme inhibition was 6-phenylbenzo[d]thiazole-2-amine 3e, with an IC 50 value of 26.35 µg/mL. Compound 3c, 6-(4-methoxyphenyl) benzo[d]thiazole-2-amine, exhibited the highest nitric oxide percentage scavenging at 100µg/mL.

Journal of Organometallic Chemistry, 2008

A series of mono-and dicarbene gold(I) complexes of types Au(CAAC)(Cl) [CAAC = cyclic (alkyl) (am... more A series of mono-and dicarbene gold(I) complexes of types Au(CAAC)(Cl) [CAAC = cyclic (alkyl) (amino)carbene] (1) and [Au(CAAC) 2 ] + [X]-(X = Cl, AuCl 2) (2) have been prepared through reaction of AuCl(SMe 2) with free carbenes a-e, and structurally characterized by single X-ray diffraction studies (1a, 1b, 2d, 2e). In addition two new free cyclic (alkyl)(amino)carbenes (c and e) have been synthesized.

Chemistry - A European Journal, 2009

Carbon-carbon and carbon-nitrogen bond formations are at the heart of modern organic chemistry. T... more Carbon-carbon and carbon-nitrogen bond formations are at the heart of modern organic chemistry. The development of novel coupling strategies that facilitate the rapid and efficient construction of complex molecules remains a preeminent goal in synthetic chemistry. For a long time, allenes have been considered as chemical curiosities.[1] Nowadays, these cumulenes are not only used as building blocks for the synthesis of complex molecules,[2] but because of the intriguing biological properties of many allenic natural products, the C=C=C skeleton is often introduced in pharmacologically active classes of compounds.[3] Consequently, despite a number of synthetic routes known, new efficient preparative methods are highly desirable. Of special interest are catalytic processes, which directly build the three-carbon allene core by coupling two different fragments, thus allowing for convergent synthesis. The first of such processes was discovered in 1979, namely the Crabbé homologation[4] (Figure 1a). This is a CuBr mediated three-component reaction between a terminal alkyne, formaldehyde, and diisopropylamine. The most important drawback of this process is that ketones and even aldehydes cannot be used in place of formaldehyde, and thus only mono-substituted allenes can be produced. In 2000, Barrett reported a few examples of allene cross metathesis,[5] which allow one of the terminal carbon units of a preformed allene to be exchanged to yield a new symmetrically substituted 1,2-diene, although extensive polymerization side reactions occur (Figure 1b). More recently, we have shown that cationic Au(I) complex A 1 efficiently mediates the catalytic coupling of enamines and terminal alkynes to yield allenes[6] (and not propargyl amines as observed with other catalysts),[7] along with the corresponding imines (Figure 1c). For this process all types of terminal alkynes can be used, as well as mono-, di-, and trisubstituted enamines; however the latter have to be tertiary derivatives, and one of the Nsubstituents an alkyl group with a hydrogen atom next to nitrogen, in order to deliver a hydrogen. The tertiary enamines are formally hydroamination adducts of alkynes with secondary amines.[8] Therefore, we reasoned that if the gold complex A 1 were also able to catalyze the addition of secondary amines to alkynes,[9] it would be possible in one-pot reactions to form allenes from two alkynes and a secondary amine; formally, the only restriction would be the use of a terminal alkyne for the second step (Figure 1d).

ACS National Meeting Book of Abstracts

Pakistan journal of pharmaceutical sciences, 2016

Benzamides and tryptamine are biologically significant compounds, therefore, various benzamide an... more Benzamides and tryptamine are biologically significant compounds, therefore, various benzamide analogous of tryptamine have been efficiently synthesized using tryptamine and different benzoyl chlorides, in order to find new biologically active compounds. The resulting products were then characterized by melting point determination, calculation of Rf values and LC-MS techniques. At last, structure activity relationship (SAR) of the synthesized compounds was evaluated against two microbial strains; Bacillus subtilis and Aspergillus niger. All the five prepared products have shown high yield, sharp characterization and significant resistance against the growth of tested microorganism, providing a new range of tryptamine based benzamide derivatives having significant antimicrobial activities.

Journal of Pharmacovigilance

Tryptamine the important psychotropic drug having indole ring has wider biological and pharmaceut... more Tryptamine the important psychotropic drug having indole ring has wider biological and pharmaceutical significance. The focus is to see the relevant and recent achievements as neurotransmitter and neuromodulator, vasoconstrictor and vasodilator, antimicrobial and antibacterial, antioxidant and antifungal agents. Tryptamine and its natural and synthetic derivative have been reported for the variety of biological significance in the above mentioned area. This review covers all these aspects in a comprehensive way.

International Journal of Pharmaceutical Chemistry, Jul 1, 2013

Amines are ammonia derivatives in which alkyl or aryl groups are added by replacing one or more h... more Amines are ammonia derivatives in which alkyl or aryl groups are added by replacing one or more hydrogen atoms. These are divided into primary, secondary and tertiary amines according to the number of alkyl or aryl groups attached to the nitrogen atom 1,2. Some of the main examples of amines are amino acids, biogenic amines, trimethylamine and aniline. One of the hydrogen atoms in the ammonia is replaced by an alkyl or aryl group in primary amines. Examples include methylamine. Secondary amines have two alkyl or aryl substituents bound to nitrogen atom together with one hydrogen atom. Examples include dimethylamine. All the three hydrogen atoms in tertiary amines are replaced by organic substituents. Examples include N-methylpiperidine. Cyclic amines have either secondary or tertiary amines. The nitrogen atom is connected to an aromatic ring in aromatic amines as in anilines. The basicity of the amine is decreased, depending on the substituent's by the presence of nitrogen atom. Due to electron-donating effect of the amine group the reactivity of the aromatic ring increases strongly. Derivatives of amines are excellent inhibitor of the viral polymerases. Amines substituted with 3-piperidyl derivatives of rifamycin-SV are particularly active against viral infections. Murine sarcoma virus causes cell transformation by obstruction of viral polymerase derivatives. Inhibition of DNA-directed DNA polymerase was less as compared to the virion polymerase 3. Now-a-days a major problem faced by medical world is the evolution of microorganisms that have more opposition to already available antimicrobial agents. So medical science requires the development of antimicrobial agents with enhanced pharmacological and pharmacokinetics characteristics as well as with broad range activity. For this purpose in the

Pakistan journal of pharmaceutical sciences, 2016

Benzamides and tryptamine are biologically significant compounds, therefore, various benzamide an... more Benzamides and tryptamine are biologically significant compounds, therefore, various benzamide analogous of tryptamine have been efficiently synthesized using tryptamine and different benzoyl chlorides, in order to find new biologically active compounds. The resulting products were then characterized by melting point determination, calculation of Rf values and LC-MS techniques. At last, structure activity relationship (SAR) of the synthesized compounds was evaluated against two microbial strains; Bacillus subtilis and Aspergillus niger. All the five prepared products have shown high yield, sharp characterization and significant resistance against the growth of tested microorganism, providing a new range of tryptamine based benzamide derivatives having significant antimicrobial activities.

ACS National Meeting Book of Abstracts

RSC Adv., 2015

The present study describes the regioselective synthesis of novel 2,3,4,4a-tetrahydro-1H-carbazol... more The present study describes the regioselective synthesis of novel 2,3,4,4a-tetrahydro-1H-carbazoles (syn-2(a–q) and anti-3(a–b)) from l-menthone via Fischer indole synthesis.

Journal of Saudi Chemical Society, 2014

ABSTRACT The present study reports a convenient approach for the synthesis of thiophene sulfonami... more ABSTRACT The present study reports a convenient approach for the synthesis of thiophene sulfonamide derivatives (3a–3k) via Suzuki cross coupling reaction. This method of synthesis involved the reactions of various aryl boronic acids and esters with 5-bromthiophene-2-sulfonamide (2) under mild and suitable temperature conditions. The compounds synthesized in the present study were subjected to urease inhibition and hemolytic activities. The substitution pattern and the electronic effects of different functional groups (i.e., Cl, CH3, OCH3, F etc.) available on the aromatic ring are found to have significant effect on the overall results. The compound 5-Phenylthiophene-2-sulfonamide 3a showed the highest urease inhibition activity with IC50 value ∼ 30.8 μg/mL compared with the thiourea (used as standard) having IC50 value ∼ 43 μg/mL. Moreover, almost all of the compounds were examined for the hemolytic activity against triton X-100 with positive results obtained in most of the cases. In addition, the antibacterial activities of the derivatives of 5-arylthiophene-2-sulfonamide and 5-bromothiophene-2-acetamide were also investigated during the course of the study.

Proceedings of the National Academy of Sciences, 2007

Addition of a sterically demanding cyclic (alkyl)(amino)carbene (CAAC) to AuCl(SMe 2) followed by... more Addition of a sterically demanding cyclic (alkyl)(amino)carbene (CAAC) to AuCl(SMe 2) followed by treatment with [Et3Si(Tol)] ؉ [B(C6F5)4] ؊ in toluene affords the isolable [(CAAC)Au(2-toluene)] ؉ [B(C6F5)4] ؊ complex. This cationic Au(I) complex efficiently mediates the catalytic coupling of enamines and terminal alkynes to yield allenes and not propargyl amines as observed with other catalysts. Mono-, di-, and tri-substituted enamines can be used, as well as aryl-, alkyl-, and trimethylsilyl-substituted terminal alkynes. The reaction tolerates sterically hindered substrates and is diastereoselective. This general catalytic protocol directly couples two unsaturated carbon centers to form the three-carbon allenic core. The reaction most probably proceeds through an unprecedented ''carbene/vinylidene cross-coupling.'' catalysis ͉ enamines ͉ alkynes ͉ transition metal C arbon-carbon bond-forming reactions are at the heart of Author contributions: V.L. designed research; G.D.F. and S.K. performed research; B.D. contributed new reagents/analytic tools; and G.B. wrote the paper.

Molecules, 2013

In general, benzothiazole derivatives have attracted great interest due to thier pharmaceutical a... more In general, benzothiazole derivatives have attracted great interest due to thier pharmaceutical and biological importance. New 2-amino-6-arylbenzothiazoles were synthesized in moderate to excellent yields via Suzuki cross coupling reactions using various aryl boronic acids and aryl boronic acid pinacol esters and the antiurease and nitric oxide (NO) scavenging activity of the products were also examined. The most active compound concerning urease enzyme inhibition was 6-phenylbenzo[d]thiazole-2-amine 3e, with an IC 50 value of 26.35 µg/mL. Compound 3c, 6-(4-methoxyphenyl) benzo[d]thiazole-2-amine, exhibited the highest nitric oxide percentage scavenging at 100µg/mL.

Journal of Organometallic Chemistry, 2008

A series of mono-and dicarbene gold(I) complexes of types Au(CAAC)(Cl) [CAAC = cyclic (alkyl) (am... more A series of mono-and dicarbene gold(I) complexes of types Au(CAAC)(Cl) [CAAC = cyclic (alkyl) (amino)carbene] (1) and [Au(CAAC) 2 ] + [X]-(X = Cl, AuCl 2) (2) have been prepared through reaction of AuCl(SMe 2) with free carbenes a-e, and structurally characterized by single X-ray diffraction studies (1a, 1b, 2d, 2e). In addition two new free cyclic (alkyl)(amino)carbenes (c and e) have been synthesized.

Chemistry - A European Journal, 2009

Carbon-carbon and carbon-nitrogen bond formations are at the heart of modern organic chemistry. T... more Carbon-carbon and carbon-nitrogen bond formations are at the heart of modern organic chemistry. The development of novel coupling strategies that facilitate the rapid and efficient construction of complex molecules remains a preeminent goal in synthetic chemistry. For a long time, allenes have been considered as chemical curiosities.[1] Nowadays, these cumulenes are not only used as building blocks for the synthesis of complex molecules,[2] but because of the intriguing biological properties of many allenic natural products, the C=C=C skeleton is often introduced in pharmacologically active classes of compounds.[3] Consequently, despite a number of synthetic routes known, new efficient preparative methods are highly desirable. Of special interest are catalytic processes, which directly build the three-carbon allene core by coupling two different fragments, thus allowing for convergent synthesis. The first of such processes was discovered in 1979, namely the Crabbé homologation[4] (Figure 1a). This is a CuBr mediated three-component reaction between a terminal alkyne, formaldehyde, and diisopropylamine. The most important drawback of this process is that ketones and even aldehydes cannot be used in place of formaldehyde, and thus only mono-substituted allenes can be produced. In 2000, Barrett reported a few examples of allene cross metathesis,[5] which allow one of the terminal carbon units of a preformed allene to be exchanged to yield a new symmetrically substituted 1,2-diene, although extensive polymerization side reactions occur (Figure 1b). More recently, we have shown that cationic Au(I) complex A 1 efficiently mediates the catalytic coupling of enamines and terminal alkynes to yield allenes[6] (and not propargyl amines as observed with other catalysts),[7] along with the corresponding imines (Figure 1c). For this process all types of terminal alkynes can be used, as well as mono-, di-, and trisubstituted enamines; however the latter have to be tertiary derivatives, and one of the Nsubstituents an alkyl group with a hydrogen atom next to nitrogen, in order to deliver a hydrogen. The tertiary enamines are formally hydroamination adducts of alkynes with secondary amines.[8] Therefore, we reasoned that if the gold complex A 1 were also able to catalyze the addition of secondary amines to alkynes,[9] it would be possible in one-pot reactions to form allenes from two alkynes and a secondary amine; formally, the only restriction would be the use of a terminal alkyne for the second step (Figure 1d).

ACS National Meeting Book of Abstracts