A new entry to pyrazolo[4,3‐e][1,4]diazepines. Facile synthesis of pyrazolo [4,3‐e][1,4]diazepin‐5,8‐diones, 5,6,8‐triones and pyrazolo[4,3‐e]pyrrolo‐[1,2‐a][1,4]diazepin‐5,10‐diones

A facile approach to pyrazolo[4,3‐e][1,4]diazepin‐5,8‐diones and pyrazolo[4,3‐e]pyrrolo[1,2‐a][1,4]‐diazepin‐5,10‐diones is reported. Strategy involved the utility of α‐amino acid as a three‐atom segment in the construction of diazepine skeleton on the preformed pyrazole ring.     

Electron paramagnetic resonance and optical absorption spectral studies on covellite mineral

A covellite mineral sample from Coquimbo region, Chile is used in the present study. An electron paramagnetic resonance (EPR) study on powdered sample confirms the presence of Mn(II) and Cu(II). Optical absorption spectrum indicates that Fe(II) and Cu(II) impurities are present in octahedral structure. Bands in the near-infrared from 7,000 to 5,000 cm(-1) result from the overtones of the first fundamental OH-stretching modes.     

Sc(OTf)<Subscript>3</Subscript> catalyzed synthesis of novel 6-phenyl-6<Emphasis Type="Italic">H</Emphasis>-chromeno[4,3-b]quinolines and evaluation of their cytotoxicity

Novel 6-phenyl-6H-chromeno[4,3-b]quinoline derivatives have been prepared by reaction of 4-chloro-2-phenyl-2H-chromene-3-carbaldehyde with various aromatic amines using 5 mol % of Sc(OTf)3 in acetonitile. This is the first example of one-pot synthesis of 6-phenyl-6H-chromeno[4,3-b]quinoline from 4-chloro-2-phenyl-2H-chromene-3-carbaldehyde at ambient temperature. Preliminary evaluation of cytotoxic activity of these chromeno[4,3-b]quinoline derivatives has been carried out. Some products exhibited anti cancer activity against two carcinoma cell lines A549 and B-16.     

2‐Arylethenyl‐2′‐arylethynyl sulfones: A potential source for some spiroheterocycles

The double Michael addition of dimethyl malonate to 2‐arylethenyl‐2′‐arylethynyl sulfones (3) resulted in 3,5‐diaryl‐5,6‐dihydro‐4,4‐dimethoxycarbonyl‐1‐thiin‐1,1‐dioxides (4) . The latter on cyclocondensation with urea / thiourea / hydrazine hydrate / hydroxylamine hydrochloride gave spiroheterocycles.