Muhammad Zareef

Synthesis and antimalarial activity of novel chiral and achiral benzenesulfonamides bearing 1, 3, 4-oxadiazole moieties

A series of new benzenesulfonamides, most of which are chiral, incorporating 1, 3, 4-oxadiazole and amino acid moieties have been synthesized. Some of these compounds were screened for antimalarial activity and also evaluated for their ability to inhibit hem polymerization. The electrophoretic analysis indicated that one compound was effective in inhibiting the degradation of hemoglobin. The synthesized compounds were tested in mice infected with Plasmodium berghei. These derivatives have the potential for the development of novel antimalarial lead compounds.

Synthesis, Anti-HIV, and Antifungal Activity of New Benzensulfonamides Bearing the 2,5-Disubstituted-1,3,4-Oxadiazole Moiety

A series of novel chiral and achiral N-[1-(1,3,4-oxadiazol-2ylthio)alkyl]-4-methyl/chloro/methoxybenzenesulfonamides 5a–l were prepared by the reaction of 4-(4-methyl, chloro, methoxyphenylsulfonamido)alkyl carboxylic acid hydrazides 4a–l with CS2 and KOH. Another series of new secondary benzenesulfonamides 10a–j and bis-benzenesulfonamides 11a–j have been synthesized by a new approach using Et3N and dimethylaminopyridine. All synthesized compounds were characterized by physical, microanalytical, and spectral data. Some of the synthesized compounds were screened in vitro for their anti–HIV and antifungal activities.

N′-(2-Fluoro­benzo­yl)benzohydrazide

In the crystal structure of the title compound, C14H11FN2O2, the molecule is centrosymmetric. The F atom is disordered over four positions, on the two ortho positions of each ring, with occupancies of 0.287:0.213 (5). In the crystal structure, molecules are linked by intermolecular N—H⋯O and C—H⋯O hydrogen bonds.

Carbonic anhydrase inhibitors. Inhibition of human tumor-associated isozymes IX and cytosolic isozymes I and II with some 1,3,4-oxadiazole-thiols

A series of chiral 1,3,4-oxadiazole-5-thiols incorporating 2-substituted-benzenesulfonamide moieties has been prepared from amino acids, via the ester and carbohydrazide intermediate, followed by cyclization with carbon disulfide. Some of these compounds have been investigated for the inhibition of three physiologically relevant carbonic anhydrase (CA, EC 4.2.1.1) isoforms, the human cytosolic hCA I and II, and the human, transmembrane, tumor-associated isozyme hCA IX. All these compounds showed weak (millimolar) affinity for the three isozymes, except two carbohydrazides and two heterocyclic thiols which selectively inhibited the tumor-associated isozyme with inhibition constants around 10 μM. Such compounds constitute interesting lead molecules for the possible design of CA IX-selective inhibitors.

A novel synthesis and antimicrobial activity of 1-[(Substituted-phenyl) sulfonyl]pyrrolidin-2-ones

Novel cyclization of 4-(substituted-phenylsulfonamido)butanoic acids to their corresponding 1-[(substituted-phenyl)sulfonyl]pyrrolidin-2-ones was successfully achieved by using polyphosphate ester (PPE). The reaction time was considerably reduced with corresponding increase in the yields, when polyphosphate ester (PPE) was used in combination with 4-(N,N-dimethylamino)pyridine (DMAP). All the synthesized compounds were screened for their antimicrobial activity. Minimum Inhibitory Concentration (MIC) values of synthesized compounds were also determined, and were found to be in the range of 0.09–1.0 mg.

2-[4-Benzyl-5-(2-fur­yl)-4H-1,2,4-triazol-3-ylsulfan­yl]acetamide

In the title compound, C15H14N4O2S, the phenyl ring is inclined at 70.25 (6)° with respect to the approximately planar furyl–triazolsulfanyl–acetamide unit. In the crystal structure, molecules related by inversion centers form dimers via intermolecular N—H⋯O hydrogen bonds between acetamide groups, resulting in eight-membered rings with an R 2 2(8) motif. In addition, the other H atom of the acetamide group is involved in an intermolecular hydrogen bond with an N atom of the triazole ring, resulting in chains extended along the c axis. The overall effect is the formation of a hydrogen-bonded two-dimensional framework perpendicular to the a axis.

4-Methyl-N-[1-(5-thioxo-4,5-dihydro-1,3,4-oxadiazol-2-­yl)prop­yl]benzene­sulfonamide

The structure of (I) is composed of two conformers of (I) in unequal proportions; the major component is shown in Fig. 1. The oxadiazole ring is essentially planar and is inclined at 17.6 (1) with respect to the benzene ring. The N2 C2 and S1 C1 double bonds (Table 1) agree with the corresponding distances in three structures containing similar systems reported in the Cambridge Structural Database [2006 Release (Allen, 2002); refcodes: AVULIM (Öztürk et al., 2004), AVULUY (Du et al., 2004) and YITMUJ (Ziyaev et al., 1992)]. The structure is stabilized by a network of strong hydrogen bonds of the type N—H O, involving both H atoms bonded to N atoms and the O atoms bonded to S2 (Table 2). However, it is interesting to note that N3 and N30, in the major and minor conformers, are hydrogen bonded to O3 and N2, respectively, and may be responsible for the disorder, resulting in two conformations for (I).

N-{[1-(5-Benzyl­sulfanyl)-1,3,4-oxadiazol-2-yl]eth­yl}-4-chloro­benzene­sulfonamide

The crystal structure of the title compound, C17H16ClN3O3S2, contains hydrogen-bonded chains lying along the b axis. In the molecule, the benzene rings lie almost parallel to each other and the heterocyclic oxadiazole ring is oriented nearly perpendicular to the benzene rings.

A New Method of Reducing 2-Mercapto-Substituted 1,3,4-Oxadizoles: Synthesis of Acylhydrazine Derivatives

A new method has been developed for the synthesis of acylhydrazines 5a-g by the reduction of unsymmetrical 1,3,4-oxadiazoles 4a-g by using sodium borohydride/acetic acid combination. Later on, acylhydrazines 5a-g were converted to their corresponding sulfonamide derivatives 6a-d.

Ethyl 2-(5-phenyl-1,3,4-oxadiazol-2-ylsulfan­yl)acetate

The title molecule, C12H12N2O3S, is composed of two individually planar units, viz. 5-phenyl-1,3,4-oxadiazol-2-yl-sulfanyl and ethyl acetate, which are oriented at almost right angles [80.07 (8)°] with respect to each other. The structure is stabilized by weak intermolecular C—H⋯O and C—H⋯N hydrogen bonds. The phenyl and oxadiazole rings show π–π stacking interactions [centroid–centroid distance = 3.846 (2) Å] and there is also a short π-interaction between the carbonyl O atom and the oxadiazole ring [the distance from this O atom to the centroid of the oxadiazole ring is 3.156 (2) Å].