SYNTHESIS AND ELECTROLUMINESCENT PROPERTY OF ALUMINUM AND α-PYRIDOIN COMPLEX

A novel light-emitting aluminum complex (PAl) containing the dihydroxy derivative of trans-1,2-dipyridylethene, α-pyridoin, was synthesized and its electroluminescent (EL) properties characterized. The chemical structure of the complex was elucidated by FT-IR, UV-Vis and XPS. The complex showed thermal stability up to 350°C under nitrogen flow by TGA. The photoluminescence (PL) was measured from PAl cast film on quartz plate. Electroluminescent device having the structure of ITO/TPD/PAl/Al was fabricated by vacuum deposition, where N,N-bis(3-methylphenyl)-N,N′-diphenylbenzidine (TPD) was used as a hole transporting layer. The device emitted blue-green light of around 480 nm. The maximum luminance of 38 cd/m2 and current density of 0.09 mA/cm2 were observed at 34 V.

Crystal structures of ecdysteroids: the role of solvent molecules in hydrogen bonding and isostructurality

Three crystal forms of the steroid 20-hydroxyecdysone were identified by single-crystal X-ray diffraction analysis: a solvent-free modification, a methanol solvate hydrate and a trihydrate. The structure of a closely related steroid, polypodine B (the 5,20-dihydroxy derivative of ecdysone), was determined in its monohydrate form. Since the unit-cell volume of unsolvated 20-hydroxyecdysone was found to be considerably smaller than that of ecdysone [Huber & Hoppe (1965). Chem. Ber. 98, 2403–2424], a new structure determination of ecdysone was performed, which confirmed the unexpected difference between the unit-cell volumes. The crystals of ecdysone and 20-hydroxyecdysone are isostructural, while the mixed solvate of 20-hydroxyecdysone is homostructural with the hydrate of polypodine B. A detailed analysis of the hydrogen-bond networks in these closely related crystal pairs highlights their packing similarities, demonstrates the role of solvent molecules, and explains the unexpectedly small cell volume of 20-hydroxyecdysone.

Initial Transformations in the Biodegradation of Benzothiazoles by Rhodococcus Isolates

ABSTRACT Benzothiazole-2-sulfonate (BTSO3) is one of the side products occurring in 2-mercaptobenzothiazole (MBT) production wastewater. We are the first to isolate an axenic culture capable of BTSO3 degradation. The isolate was identified as aRhodococcus erythropolis strain and also degraded 2-hydroxybenzothiazole (OBT) and benzothiazole (BT), but not MBT, which was found to inhibit the biodegradation of OBT, BT, and BTSO3. In anaerobic resting cell assays, BTSO3 was transformed into OBT in stoichiometric amounts. Under aerobic conditions, OBT was observed as an intermediate in BT breakdown and an unknown compound transiently accumulated in several assays. This product was identified as a dihydroxybenzothiazole. Benzothiazole degradation pathways seem to converge into OBT, which is then transformed further into the dihydroxy derivative.

Antiproliferative Activity of Derivatives of trans-Bis(salicylaldoximato)copper(II) in vitro. Some in vivo Properties of the Parent Compound

Several derivatives and analogs of the recently reported antiproliferative and antitumor agent trans-bis(salicylaldoximato) copper(II) (CuSAO2) have been prepared and tested for antiproliferative activity against L1210 leukemia cells in vitro. The salicylaldimine analog of CuSAO2 had a very strong antiproliferative activity, the 2-day IC50 value being lower than 3 μg/ml- The 2,3-dihydroxybenzaldoxime analog was equally active with CuSAO2, while the corresponding 2,5-dihydroxy derivative had a slightly lower activity. The 2,3,4-trihydroxybenzaldoxime derivative had a much lower activity than had the dihydroxybenzaldoxime derivatives. The zinc(II) analog of CuSAO2 had only a low antiproliferative activity. The ligand of CuSAO2, salicylaldoxime, resembles pyridoxal oxime, a vitamin B6 antagonist and a powerful inhibitor of pyridoxal kinase. An attempt to reduce the toxicity of CuSAO2 in vivo with pyridoxal hydrochloride led to increased toxicity.

Synthesis of Pyranobenzopyranopyridines and Benzodipyran Derivatives

6-Formyl-7-hydroxy-5-methoxy-2-methylchromone on bromination yields the 8-bromo derivative or the 8-bromo-6-formyl-5,7-dihydroxy derivative depending on the reaction condition. Cyclization of both leads to the corresponding 3-acetyl-, 3-benzoyl-, 3-carboxamido-, 3-carbethoxybenzodipyran derivatives.The 3-acetylbenzodipyran derivative when treated with ethyl acetoacetate or ethyl cyanoacetate in the presence of ammonium acetate yields the corresponding dihydropyranobenzopyranopyridine dione or the dihydropyranobenzopyranopyridine trione.The reaction of the 3-acetyl derivative with cyanoacetamide in the presence of ammonium acetate affords the substituted pyranobenzopyranopyridine dione.The 3-acetyl derivative undergoes self condensation to form the substituted benzopyranobenzopyran derivative.