Oxygen as moderator in the zinc-mediated reduction of aromatic nitro to azoxy compounds

A simple and useful protocol for the reduction of nitro arenes to their corresponding azoxy derivatives by employing zinc and NH₄Cl in a mixture of [bmim][BF₄] and water is described. The selective reduction of nitro to azoxy is attributed to the hitherto unknown moderating effect of oxygen on zinc metal.     

Application of Response Surface Method for Studying the Role of Dissolved Oxygen and Agitation Speed on Gamma-Linolenic Acid Production

To study the effect of agitation speed (rpm) and dissolved oxygen concentration (DO) on the production of gamma linolenic acid by Mucor sp. RRL001, a central composite design experiment was performed in a 5-L stirred tank bioreactor. The design consisted of a total of 10 runs consisting of runs at five levels for each factor and was divided in two blocks. The ANOVA analysis and Pareto chart of effects suggested agitation speed (p = 0.0142) linear effect and DO concentration (p = 0.0342) quadratic effects were significant factors with significant contribution to the response. The validation run based on the optimum production zone in response surface plot resulted in the maximum 350.3 mg l⁻¹ GLA yield as compared with model predicted value of 340.7 mg l⁻¹. The study suggests that agitation rate is having more pronounced effect on GLA yield than dissolved oxygen concentration by ensuring enhanced mass transfer and by preventing wall growth at elevated agitation speed. Also, it shows that higher GLA yields can be obtained in a simple medium at moderate oxygen saturation and that the Mucor sp. RRL001 is resistant to high agitation linked shear stress and suitable for GLA production at higher scale.     

Hybrid synchronization of hyperchaotic Lu system

In this paper, we study the hybrid synchronization between two identical hyperchaotic Lu systems. Hybrid synchronization of hyperchaotic Lu system is achieved through synchronization of two pairs of states and anti-synchronization of the other two pairs of states. Active controls are designed to achieve hybrid synchronization between drive and response systems using the sum and difference of relevant variables of the chaotic systems. Numerical simulations are presented to evaluate the analysis and effectiveness of the controllers.     

Regio- and diastereoselective reduction of nonenolizable alpha-diketones to acyloins mediated by indium metal

[reaction: see text] Alpha-diketones are efficiently reduced with indium metal in methanol-water in the presence of NH(4)Cl, LiCl, or NaCl to give regio- and diastereoselectively the corresponding acyloins in good to excellent yield. The cleavage of the acyloins under Pb(OAc)(4)/MeOH-PhH condition provides a convenient and regioselective access to highly functionalized cyclopentane carboxaldehydes, potential building blocks in organic syntheses.     

A rapid and stereoselective route to the trans-hydrindane ring system

A short and stereoselective route to the trans-hydrindane derivative, a potential building block for the synthesis of steroidal and related molecules, was achieved by the operation of indium, tin, and ruthenium based reagents, starting from a tetrabromo norbornyl derivative.     

Biotechnological Approaches for Production of Artemisinin,an Anti-Malarial Drug from Artemisia annua L.

Artemisinin is an anti-malarial sesquiterpene lactone derived from Artemisia annua L. (Asteraceae family). One of the most widely used modes of treatment for malaria is an artemisinin-based combination therapy. Artemisinin and its associated compounds have a variety of pharmacological qualities that have helped achieve economic prominence in recent years. So far, research on the biosynthesis of this bioactive metabolite has revealed that it is produced in glandular trichomes and that the genes responsible for its production must be overexpressed in order to meet demand. Using biotechnological applications such as tissue culture, genetic engineering, and bioreactor-based approaches would aid in the upregulation of artemisinin yield, which is needed for the future. The current review focuses on the tissue culture aspects of propagation of A. annua and production of artemisinin from A. annua L. cell and organ cultures. The review also focuses on elicitation strategies in cell and organ cultures, as well as artemisinin biosynthesis and metabolic engineering of biosynthetic genes in Artemisia and plant model systems.