A Novel Synthesis of 4‐Pyridazineacetic Acids via Ring Expansion of N‐Cyanomethylated 3‐Pyrazoline‐4‐acetic Acids

A novel synthetic route to 4‐pyridazineacetic acids 10 – 12 has been achieved by the ring‐expansion reaction of N‐cyanomethylated 3‐pyrazoline‐4‐acetic acids 7 – 9 . 1H‐Pyrazole‐4‐acetic acids 1 – 3 were reacted with iodoacetonitrile in the presence of triethylamine in refluxing acetonitrile to give the corresponding C‐cyanomethylated 1H‐pyrazole‐4‐acetic acids 4 – 6 as major products together with N‐cyanomethylated 3‐pyrazoline‐4‐acetic acids 7 and 8 as minor products. On the other hand, reactions of 1 and 3 with chloroacetonitrile in the presence of triethylamine in refluxing chloroform afforded the corresponding N‐cyanomethylated 3‐pyrazoline‐4‐acetic acids 7 and 9 as major products. Thermal treatment of 7 – 9 with sodium hydride in N,N‐dimethylformamide caused ring expansion to yield the corresponding 4‐pyridazineacetic acids 10 – 12 .     

Three new cycloartane glycosides from Thalictrum thunbergii D.C.

Three new cycloartane glycosides possessing a five-membered ring, which is constructed by a C–C bond, at the side chain have been isolated from the aerial parts of Thalictrum thunbergii D.C. Their structures were determined by the use of 2D NMR techniques and chemical evidence.     

Syntheses of thiopyrone and pyrone derivatives by photocyclization reaction of 3‐aryl‐2‐( Benzothien‐3‐yl)propenoic acids

Naphtho[1,2‐b][1]benzothiophene‐6‐carboxylic acids, 6H‐benzo[b]naphtho[2,3‐d]thiopyran‐6‐ones and 6H‐benzo[b]naphtho[2,3‐d]pyran‐6‐ones were synthesized in one step by the photocyclization reaction of 3‐aryl‐2‐([1]benzothien‐3‐yl)propenoic acids. The photocyclization reaction did not occur when the 3‐aryl group contained the electron‐withdrawing nitro group. The assignment of the ¹H and ¹³C nmr spectra of 6H‐benzo[b]naphtho[2,3‐d]thiopyran‐6‐one and 6H‐benzo[b]naphtho[2,3‐d]pyran‐6‐one by two‐dimensional nmr methods is described. The difference between the chemical shift values of H12 for these two compounds is attributed to different molecular geometries.     

Refractive indices of a molten ternary nitrate system from 218 to 400°C

Refractive indices of a certain molten nitrate mixture measured goniometrically with visible light at nine wavelengths, varied linearly with temperature at a given wavelength. Dispersion phenomenon was also observed at a fixed temperature. Electronic polarizability was determined using the refractive index extrapolated to infinite wavelength and the semiclassical Clausius-Mossotti equation.     

Homo-cholestane glycosides from Solanum aethiopicum

The first naturally occurring steroidal glycosides, named aethiosides A, B and C, possessing a homo-cholestane skeleton with an aromatized ring E, were isolated from Solanum aethiopicum. They are presumably regarded to be derived from polyhydroxycholesterol by the conjugation of acetyl CoA or malonyl CoA.     

Reaction of 2,3-diphenylpyrazine 1-oxides with acetic anhydride

Some 2,3-diphenylpyrazine 1-oxides were heated with acetic anhydride to give the corresponding 2,3-di-acetoxy-2,3-dihydro-5,6-diphenylpyrazines. By X-ray diffraction analysis, the configuration of two acetoxyl groups was determined to be trans.     

Mössbauer spectroscopic study of phthalocyanineiron/II/ in NaY zeolite

Phthalocyanineiron/II/ in NaY zeolite was synthesized via various processes from an iron carbonyl compound into NaY zeolite in gaseous phase. Mössbauer spectra of the final product /phthalocyanineiron/II// and the precursor species /iron oxide and [phthalocyaninato/2-/]bis/pyridine/iron/II// in NaY zeolite were measured to characterize the chemical and physical states of the iron species.     

New highly oxidized fusicoccane diterpenoids from the liverwort subsp.

Four novel fusicoccane diterpenoids, fusicoplagins A, B, C, and D, have been isolated from the liverwort subsp. and the structures determined by spectroscopic methods, chemical transformations, and X-ray crystallographic analysis.