A luminescent inorganic-organic hybrid, Cd(C16H10N2O8S)(H2O)], for the selective and recyclable detection of chromates and dichromates in aqueous solution

A new inorganic-organic hybrid compound Cd(H2L)(H2O)], 1, {where, H2L2- = 4,4 `-sulfonylbis(phenylene)bis(oxamate)} has been prepared under solvothermal conditions. The compound has a three-dimensional structure. The compound exhibits strong luminescence behavior, and was used for the detection of chromate and dichromate anions in aqueous media at low concentrations. The compound exhibited high selectivity and recyclability for the detection of low concentrations (ppm levels) of chromate and dichromate ions. Compound 1 was also found to be an effective catalyst for the Knoevenagel condensation involving aromatic aldehyde and malononitrile under green solvent-free conditions with high yield and recyclability

Asymmetric Synthesis of Nodulones C & D by Chemoenzymatic Approach gives Insight into their Biosynthesis

The first asymmetric total synthesis of fungal secondary metabolites, (R)-nodulone C (4) and trans-nodulone D (5) has been reported through the chemoenzymatic approach. The strategy utilizes NADPH-dependent naphthol reductases of Magnaporthe grisea for the reduction of putative biosynthetic substrates, synthesized non-enzymatically in multiple steps. A dihydronaphthalenone 32 and cis-nodulone D (30) has also been synthesized chemoenzymatically. The work implies for similar steps during the biosynthesis of nodulones and their analogs with the involvement of tetrahydroxynaphthalene reductase related enzyme(s)

Highly Efficient One-Pot Multienzyme Cascades for the Stereoselective Synthesis of Natural Naphthalenones

Herein, a biocatalytic cascade containing an ene-reductase (NostocER) and naphthol reductase (tetrahydroxynaphthalene or trihydroxynaphthalene reductase) of Magnaporthe grisea and NADPH is developed. The optimized multienzyme cascade is applied for the one-pot reduction of plumbagin to obtain biologically active cis-(3R,4R)-isoshinanolone, with drcis:trans 98:2 and >99% ee in 96% yield. Furthermore, naturally occurring (+)-isosclerone, (+)-shinanolone, (−)-shinanolone, and (S)-4-hydroxy-3,4-dihydronaphthalen-1­(2H)-one were also synthesized with excellent stereoselectivity and high yields (71–89%) using the enzymatic cascades. The investigation of NostocER–T4HNR-cascade reduction of menadione, plumbagin, and 5-methoxymenadione revealed specificity of tetrahydroxynaphthalene reductase toward these substrates. In addition, the kinetic studies showed a high catalytic efficiency of NostocER and T4HNR toward plumbagin and dihydroplumbagin, respectively, compared to other enzymes