Nigellamines A3, A4, A5, and C, new dolabellane-type diterpene alkaloids, with lipid metabolism-promoting activities from the Egyptian medicinal food black cumin

New dolabellane-type diterpene alkaloids, nigellamines A(3), A(4), A(5), and C, were isolated from the methanolic extract of an Egyptian medicinal food, black cumin (the seeds of Nigella sativa). Their absolute configurations were determined on the basis of chemical and physicochemical evidence. Nigellamines were found to lower triglyceride levels in primary cultured mouse hepatocytes, and in particular, the activity of nigellamine A(5) was equivalent to that of the hypolipidemic agent, clofibrate.     

Convergent syntheses of polycyclic ethers. Illustrations of the utility of acetal-linked intermediates

One of the most characteristic and spectacular class of compounds isolated from marine sources is the polycyclic ethers. Following the initial report of the structural determination of brevetoxin B, a variety of novel polycyclic ethers have begun to surface. These natural products include ciguatoxins, gambierol, gambieric acids, yessotoxins and gymnocins, each of which exhibit distinct biological properties such as cytotoxicity and neurotoxicity, as well as antiviral and antifungal activities. Because of these intriguing biological activities and their complex molecular architecture, the total synthesis of these compounds has been pursued by many laboratories over two decades. In particular, the development of novel convergent strategies to assemble the structural fragments is crucial for the successful construction of these nano-scale molecules. This Perspective will focus on a recent convergent methodology using an acetal-linkage as a key motif. Application of this methodology culminated in the total syntheses of gambierol and ciguatoxin CTX3C.     

NanoPARCEL: a method for controlling cellular behavior with external light

We developed a simple preparation procedure for the protein encapsulated nanoparticle and used the nanoparticle for spatiotemporal activity control of various proteins. We succeeded in the local protein activation within cells by light using the nanoparticle.     

Rhodium-catalyzed enantioselective synthesis, crystal structures, and photophysical properties of helically chiral 1,1'-bitriphenylenes

The highly enantioselective synthesis of helically chiral 1,1'-bitriphenylenes has been achieved via rhodium-catalyzed double [2 + 2 + 2] cycloaddition of biaryl-linked tetraynes with 1,4-diynes (up to 93% ee). Crystal structures and photophysical properties of these helically chiral 1,1'-bitriphenylenes have also been studied.     

A Convenient Synthesis of Juglone Via Neutral Salcomine Oxidation

1,5-Dihydroxynaphthalene and its derivatives can be oxidized by molecular oxygen in the presence of catalytic amounts of salcomine under neutral conditions to afford the corresponding 1,4-naphthoquinones as the major products.     

A Convenient Method of Benzylic Oxidation with Pyridinium Chlorochromate

Oxidation of indans and tetralin derivatives to their corresponding indanones and tetralones is of considerable value i n organic synthesis and many methods have been reported for accomplishing this conversion. Traditionally these oxidations are performed with chromic acid in acetic acid and the yields in general are moderate. Recently Eisenbraun4 has studied indetail the benzylic oxidation with the Jones reagent and compared the selectivity and yield of oxidation with other chromium(V1) reagents like bipyridinim chlorochrmate, (BiPCC). It was found that there was no improvement in yield and in the case of BiPCC a molar ratio 16% 1 (oxidant: substrate) was employed to get     

New aplysiatoxin derivatives from the Okinawan cyanobacterium Moorea producens

The marine cyanobacterium Moorea producens is a rich source of diverse compounds that possess a variety of biological activities. In the present study, eight new aplysiatoxin derivatives, namely 6, 8–13, and 15, along with aplysiatoxin (1), debromoaplysiatoxin (2), 3-methoxyaplysiatoxin (3), anhydroaplysiatoxin (4), anhydrodebromoaplysiatoxin (5), oscillatoxin B2 (7), and 30-methyloscillatoxin D (14) were isolated and identified from the Okinawan M. producens. In cytotoxicity and diatom growth inhibition tests, the fifteen compounds tested (1–15) showed moderate or no activity at a concentration of 10?μg/mL.     

Thermal analysis graphite intercalation compounds with dichlorides of some d-elements: A.S. Skoropanov,G.S. Petrov,A.A. Vecher,Yu.N. Novikov and M.E. Vol'pin,Thermochim. Acta, 90 (1985) 339-342

Kinetic and thermodynamic aspects of the axial base dissociation of solid Co(salen) (X-py) complexes, X = H (1), 3-Me (2), 4-Me (3), 3,4-Me₂ (4), 3,5-Me₂ (5), 3-NH₂ (6), 3-Cl (7), 3-CN (8), 4-CN (9), have been investigated by means of TG-DSC and isothermal weight-loss measurements. These adducts endothermically dissociate the axial base giving rise to the oxygen-active Co(salen) complex. The axial base dissociation reactions fit the contracting disc equation and the kinetic compensation effect is observed for all the adducts excepting Adducts 4–6. For the remaining adducts the kinetic and thermodynamic stabilities of the Co-(X-py) bond are found to increase linearly with increasing Hammett's substitution constants of X except for Adducts 3 and 9. These results are discussed in terms of the σ and π interactions between cobalt(II) and substituted pyridine. Factors dominating the kinetic bond stability are briefly discussed.