Anionic sigmatropic-electrocyclic-Chugaev cascades: accessing 12-aryl-5-(methylthiocarbonylthio)tetracenes and a related anthra[2,3-b]thiophene

1,4-Diols resulting from the double addition of ArCCLi (Ar = Ph, substituted phenyl, 2-thienyl) to ortho-C6H4(CHO)2 undergo cascades to tetracenes on simple admixture of LiHDMS, CS2 and MeI. Acene formation proceeds by [3,3]-sigmatropic rearrangement of xanthate anions followed by 6π electrocyclisations. The reactions are terminated by E2 or anionic Chugaev-type eliminations. Structural packing motifs and electronic properties are reported for the tetracenes

New furocarbazole alkaloids from Lonicera quinquelocularis

Two new furocarbazole alkaloids, 3-formyl-6,7-dimethoxy-furo[1,2]carbazole (1) and methyl-6,7-dimethoxy-furo[1,2]carbazole-3-carboxylate (2), along with two known carbazole alkaloids, 3-formyl-2-hydroxy-7-methoxycarbazole (3) and methyl 2,7-dimethoxycarbazole-3-carboxylate (4) were isolated from the ethyl acetate soluble fraction of Lonicera quinquelocularis. Their structures were established on the basis of spectroscopic analysis

Nano-biotechnology: a new approach to treat and prevent malaria

Malaria, the exterminator of similar to 1.5 to 2.7 million human lives yearly, is a notorious disease known throughout the world. The eradication of this disease is difficult and a challenge to scientists. Vector elimination and effective chemotherapy for the patients are key tactics to be used in the fight against malaria. However, drug resistance and environmental and social concerns are the main hurdles in this fight against malaria. Overcoming these limitations is the major challenge for the 21st-century malarial researchers. Adapting the principles of nano-biotechnology to both vector control and patient therapy is the only solution to the problem. Several compounds such as lipids, proteins, nucleic acid and metallic nanoparticles (NPs) have been successfully used for the control of this lethal malaria disease. Other useful natural reagents such as microbes and their products, carbohydrates, vitamins, plant extracts and biodegradable polymers, are also used to control this disease. Among these particles, the plant-based particles such as leaf, root, stem, latex, and seed give the best antagonistic response against malaria. In the present review, we describe certain efforts related to the control, prevention and treatment of malaria. We hope that this review will open new doors for malarial research

New Cholinesterase Inhibitory Constituents from <i>Lonicera quinquelocularis</i>

<div><p>A phytochemical investigation on the ethyl acetate soluble fraction of <i>Lonicera quinquelocularis</i> (whole plant) led to the first time isolation of one new phthalate; <i>bis(7-acetoxy-2-ethyl-5-methylheptyl) phthalate</i> (<b>3</b>) and two new benzoates; <i>neopentyl-4-ethoxy-3, 5-bis (3-methyl-2-butenyl benzoate</i> (<b>4</b>) <i>and neopentyl-4-hydroxy-3, 5-bis (3-methyl-2-butenyl benzoate</i> (<b>5</b>) along with two known compounds <i>bis (2-ethylhexyl phthalate</i> (<b>1</b>) and <i>dioctyl phthalate</i> (<b>2</b>). Their structures were established on the basis of spectroscopic analysis and by comparison with available data in the literature. All the compounds (<b>1–5</b>) were tested for their acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities in dose dependent manner. The IC₅₀ (50% inhibitory effect) values of compounds <b>3</b> and <b>5</b> against AChE were 1.65 and 3.43 µM while the values obtained against BChE were 5.98 and 9.84 µM respectively. Compounds <b>2</b> and <b>4</b> showed weak inhibition profile.</p></div

¹H and ¹³C NMR data (CDCl₃) and ¹H/¹³C correlations of compounds <b>4</b> and <b>5</b> (δ in ppm, <i>J</i> in Hz).

<p>¹H and ¹³C NMR data (CDCl₃) and ¹H/¹³C correlations of compounds <b>4</b> and <b>5</b> (δ in ppm, <i>J</i> in Hz).</p

Structures of compounds 1–5 from <i>L. quinquelocularis</i>.

<p>Structures of compounds 1–5 from <i>L. quinquelocularis</i>.</p

New furocarbazole alkaloids from <i>Lonicera quinquelocularis</i>

<div><p>Two new furocarbazole alkaloids, 3-formyl-6,7-dimethoxy-furo[1,2]carbazole (<b>1</b>) and methyl-6,7-dimethoxy-furo[1,2]carbazole-3-carboxylate (<b>2</b>), along with two known carbazole alkaloids, 3-formyl-2-hydroxy-7-methoxycarbazole (<b>3</b>) and methyl 2,7-dimethoxycarbazole-3-carboxylate (<b>4</b>) were isolated from the ethyl acetate soluble fraction of <i>Lonicera quinquelocularis</i>. Their structures were established on the basis of spectroscopic analysis.</p></div

Important HMBC correlations in 4 (H→C).

<p>Important HMBC correlations in 4 (H→C).</p

HMBC (H–C) correlations in compound 3.

<p>HMBC (H–C) correlations in compound 3.</p