Abdul Rauf Raza

Evaluation of Silica-H2SO4 as an Efficient Heterogeneous Catalyst for the Synthesis of Chalcones

We report an efficient silica-H2SO4 mediated synthesis of a variety of chalcones that afforded the targeted compounds in very good yield compared to base catalyzed solvent free conditions as well as acid or base catalyzed refluxing conditions.

Steroids: A Diverse Class of Secondary Metabolites

Steroidsform a group of secondary metabolites having diversity in their structure and biological functions. These natural products, although often linked with the deleterious effect on health, have many medicinal applications and the research is still continued in search of these secondary metabolites as potential lead in drug design/discovery. The Aim of this review is to systematically compile the basic information related to this class of natural products.

Free Radical–Mediated Chemoselective Reduction of Enones

Abstract A novel methodology has been devised for the chemoselective reduction of enones involving the use of n Bu3SnH and azobisisobutyronitrile. The 1,4-reduction of variously substituted α,β-unsaturated cyclic and acyclic enones has been successfully carried out under free radical reaction conditions. The reaction has been determined to proceed via single-electron transfer. [Supplementary materials are available for this article. Go to the publishers online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.] GRAPHICAL ABSTRACT

Asymmetric Synthesis of 4,1-Benzoxazepine-2,5-Diones — Effect of the Halogen of (2S)-α-Haloacids

Novel chiral 4,1-benzoxazepine-2,5-diones have been unusually synthesized in a single step by exploiting the chiral pool methodology. Substituted anthranilic acids afford N-acylanthranilic acids and (3R)-3-alkyl-4,1-benzoxazepines-2,5-dione upon coupling with α-chloroacids or α-bromoacids, respectively.

5-Chloro-2-hy­droxy­benzoic acid

The asymmetric unit of the title compound, C7H5ClO3, contains two molecules; both feature an intramolecular O—H⋯O hydrogen bond, which generates an S(6) ring. In the crystal, both molecules form inversion dimers linked by pairs of O—H⋯O hydrogen bonds with R 2 2(8) ring motifs. The dimers are interlinked by C—H⋯O interactions.

N-(3-Chlorophenyl)-2-hydroxybenzamide

In the title compound, C13H10ClNO2, the dihedral angle between the aromatic rings is 20.02 (6)° and intramolecular N—H⋯O and C—H⋯O hydrogen bonds both generate S(6) rings. In the crystal, molecules are linked by O—H⋯O hydrogen bonds into C(6) chains propagating in [010].

2-Hy­droxy-N-(3-nitro­phen­yl)benzamide

In the crystal structure of title compound, C13H10N2O4, as expected, the nitro- and hydroxy-substituted benzene rings are planar with r. m. s. deviations of 0.0037 and 0.0014 Å, respectively, but are twisted slightly relative to each other, making a dihedral angle of 12.23 (7)°. The nitro group is only slightly twisted [by 2.71 (16)°] with respect to its parent ring. An intramolecular N—H⋯O hydrogen bond forms an S(6) ring motif. Intermolecular N—H⋯O and O—H⋯O hydrogen bonds build up sheets parallel to the ab plane. Futhermore, weak π–π interactions [centroid–centroid distances = 3.7150 (8) 3.7342 (6) and 3.9421 (8) Å] between the rings yield a three-dimensional network.

Stereoselective Synthesis of (3R)‐3‐Alkyl‐4,1‐Benzoxazepine‐2,5‐Diones

Novel 3-alkyl-4,1-benzoxazepine-2,5-diones were synthesized in good ee exploiting the chiral pool methodology, an economical way of asymmetric synthesis. Various anthranilic acids are coupled with different α-haloacids to afford N-acylated anthranilic acid intermediates which undergo cyclization to (3R)-3-alkyl-4,1-benzoxazepines-2,5-diones.

2-Hy­droxy-N-(4-methyl­phen­yl)benzamide

In the crystal structure of the title compound, C14H13NO2, the molecules are approximately planar, the r.m.s. deviation for all non-H atoms being 0.0435 Å; the dihedral angle between the two rings is 3.45 (12)°. The planarity is accounted for in terms of the presence of intramolecular N—H⋯O and C—H⋯O hydrogen bonding, each of which completes an S(6) ring motif. The molecules are stabilized in the form of supramolecular chains extending along the crystallographic c axis due to intermolecular O—H⋯O and C—H⋯O hydrogen bonding; each type leads to an R 2 1(6) ring motif.

Tetra­kis(μ-2-methyl­benzoato-κ2O:O′)bis­[(methanol-κO)copper(II)]

In the title compound, [Cu2(C8H7O2)4(CH3OH)2], the Cu—O bond distances are in the range 1.943 (2)–2.149 (2) Å within a sligthly distorted square-pyramidal coordination. The Cu⋯Cu separation is 2.5912 (4) Å. In the crystal, the molecules are linked into polymeric chains propagating in [001] by intermolecular O—H⋯O hydrogen bonds and C—H⋯π interactions.