Rasheed Ahmad Khera

Biological transformations of steroidal compounds: A review

Microbial transformation is an important tool for structural modification of organic compounds, especially natural products with complex structures like steroids. It can be used to synthesize chemical structures that are difficult to obtain by ordinary methods and as a model of mammalian metabolism due to similarity between mammalian and microbial enzyme systems. During recent years research has been focused on the structural modifications of bioactive steroids by using various microorganisms, in order to obtain biologically potent compounds with diverse structures. Steroidal compounds are responsible for important biological functions in the cells and manifest a variety of activities. This article covers the microbial transformation of sterols, steroidal hormones and some new types of steroids known as bufadienolides. Emphasis has placed on reporting metabolites that may be of general interest and on the practical aspects of work in the field of microbial transformations. The review covers the literature from 1994 to 2011.

Electrochemical behavior of 1-ferrocenyl-3-phenyl-2-propen-1-one on glassy carbon electrode and evaluation of its interaction parameters with DNA

The electrochemical behavior of 1-ferrocenyl-3-phenyl-2-propen-1-one (ferrocenylone) and its interaction with DNA was studied by a glassy carbon electrode using cyclic voltammetry (CV) technique. The results from CV were supported by UV-Visible spectroscopy performed under the similar conditions. The positive peak potential shift in CV and the bathochromic shift in the UV-Vis absorption spectra suggested an intercalative mode of binding. The binding constant (K = 1.39 ± 0.02 × 104 mol-1 L) and the binding site size (0.53 bp) were obtained from voltammetric data which leads to a standard Gibbs free energy change (ΔGo= -RT lnK) of -23.64 kJ mol-1 and hence indicated the spontaneity of the binding interaction. The values of binding constants obtained from UV-Vis absorption and CV measurements, 1.26 ± 0.01 × 104 and 1.39 ± 0.02 × 104 mol-1 L respectively, were in close agreement.

Biotransformations of diterpenoids and triterpenoids: a review

During the past few years, research has focused on the microbial transformation of a huge variety of organic compounds to obtain compounds of therapeutic and/or industrial interest. Microbial transformation is a useful tool for organic chemists looking for new compounds, as a consequence of the variety of reactions for natural products. Terpenoids are a large family of natural products exhibiting a wide range of biological activities such as antibiotics, anti-inflammatory, anti-HIV and anti-tumor effects; hypotensive agents; sweeteners; insecticides; anti-feedants; phytotoxic agents; perfumery intermediates; and plant growth hormones. This article describes the biotransformation products of diterpenoids and triterpenoids in a variety of biological media. Emphasis is placed on reporting the metabolites that may be of special interest as well as the practical aspects of this work in the field of microbial transformations. This review covers the literature from 1991 to 2012.

4-Chloro-N-(2-chloro-phen-yl)benzamide.

In the molecular structure of the title compound, C13H9Cl2NO, the amide N—C=O plane makes dihedral angles of 31.53 (8) and 36.23 (8)°, respectively, with the 4-chloro- and 2-chlorophenyl rings. The dihedral angle between the two benzene rings is 6.25 (8)°. The molecules are stacked in columns along the b axis through intermolecular N—H⋯O hydrogen bonds. The columns are further connected by weak C—H⋯O hydrogen bonds. The compound is not isomorphous with the fluoro analogue.

4-Chloro-N-(3-methoxy-phen-yl)-benz-amide.

The title benzamide derivative, C14H12ClNO2, crystallizes with two independent molecules in the asymmetric unit. Both are close to being planar, with dihedral angles between the two benzene rings of 11.92 (6) and 12.80 (7)°. In the crystal structure, N—H⋯O hydrogen bonds link molecules into chains along a. These interactions are augmented by C—H⋯O hydrogen bonds to form two-dimensional layers in the ac plane. Additional C—H⋯O interactions result in a three-dimensional network consisting of undulating rows along c. The crystal studied was an inversion twin with a 0.59 (3):0.41 (3) domain ratio.

N-Butyl-4-chloro-benzamide.

In the title benzamide derivative, C11H14ClNO, the chlorobenzene and butylamine groups are each planar, with mean deviations from the planes of 0.013 and 0.030 Å, respectively, and a dihedral angle of 2.54 (9)° between the two planes. In the crystal structure, N—H⋯O hydrogen bonds link molecules in rows along a. Short intermolecular Cl⋯Cl interactions [3.4225 (5) Å] link these rows into sheets in the ac plane. Additional weak C—H⋯O and C—H⋯π interactions generate a three-dimensional network.

4-Chloro-N-(2-methoxy­phen­yl)benzamide

The title compound, C14H12ClNO2, was prepared by refluxing 4-chlorobenzoyl chloride with o-anisidine in CHCl3. The methoxyphenyl–amide segment of the molecule is almost planar, with a dihedral angle of 5.10 (7)° between the benzene ring and the C—N—C(O)—C fragment. A weak intramolecular N—H⋯O contact forms an S(5) ring and contributes to the planarity of this portion of the molecule. The two benzene rings are inclined at an angle of 26.74 (7)°. In the crystal structure, intermolecular Cl⋯O interactions of 3.1874 (9) Å generate centrosymmetric dimers. These are further linked by C—H⋯O and C—H⋯π interactions, forming inversion related sheets parallel to [001].

4,4,6-Trimethyl-1-(3-methyl­phen­yl)-3,4-dihydro­pyrimidine-2(1H)-thione

The asymmetric unit of the title compound, C14H18N2S, contains two independent and conformationally similar molecules, which form cyclic dimers via intermolecular hydrogen bonds of the type N—H⋯S [graph set R 2 2(8)]. The structure is isomorphous with that of one of the polymorphs of 4,4,6-trimethyl-1-phenyl-3,4-dihydropyrimidine-2(1H)-thione [Yamin et al. (2005 ▶). Acta Cryst. E61, o55–o57].

2-Methyl-N-o-tolyl-benzamide.

In the title compound, C(15)H(15)NO, the C-N-C(O)-C amide unit is planar (r.m.s. deviation = 0.003 Å) and subtends dihedral angles of 44.71 (5) and 43.33 (5)° with the two o-tolyl rings. These aromatic rings are inclined at 4.94 (7)° to one another. The ortho-methyl groups of the two tolyl rings are anti to one another. In the crystal structure, N-H⋯O hydrogen bonds augmented by C-H⋯π inter-actions link the mol-ecules in a head-to-head fashion into chains along a. Independent chains pack in a herringbone pattern along c.

N-(4-Chloro­phen­yl)-3,4,5-trimethoxy­benzamide

In the title compound, C16H16ClNO4, the dihedral angle between the two aromatic rings is 67.33 (8)°. The crystal packing shows strong intermolecular N—H⋯O hydrogen bonds that link the molecules to form chains along [01].