Synthesis and biological evaluation of novel 1,5-benzothiazepin-4(5H)-ones as potent antiangiogenic and antioxidant agents
, Pages: 133-144
Channegowda V. Deepu, Goravanahalli M. Raghavendra, Nanjappagowda D. Rekha, K. Mantelingu, Kanchugarakoppal S. Rangappa and Doddamedur G. Bhadregowda PDF (230 K)
Abstract: Novel 1,5-benzothiazepin-4-(5H)-one derivatives (8a-8g) have been synthesized by intramolecular cyclization of 6 using propyl phosphonic anhydride (T3P) as a cyclodehydrating agent. The anti-angiogenic and anti-oxidant properties of the new derivatives were then evaluated. Compounds 8b, 8d, 8e, 8f and 8g exhibited very good inhibition of capillary proliferation, thus proving their anti-angiogenic properties. In addition, the in vitro antioxidant activities of these compounds were evaluated using diphenyl picryl hydrazine (DPPH), OH-, metal ion-chelating and NO (nitric oxide) assays, and the results compared with butylated hydroxytoluene (BHT), a well known anti-oxidant. Compounds 8a-8g showed excellent free-radical scavenging activities in the metal ion-chelating assay, and compounds 8f and 8g showed nitric oxide radical scavenging properties at a concentration of 20-100 µg/mL, and are thus more potent than BHT.
Keywords: Anti-Angiogenic, Anti-oxidants, 1,5-Benzothiazepin-4(5H)-ones, T3P
The DFT study on racemisation of atropisomeric biaryls
, Pages: 145-152
Katarzyna Kapłon, Oleg M. Demchuk and K. M. Pietrusiewicz PDF (230 K)
Abstract: The process of racemisation of atropisomeric biaryls was modelled by means of DFT calculations at an advanced B3LYP/6-31G* theoretical level. Thus, the detailed protocol of determination of the racemisation rate presented herein provides a practical prediction tool for elucidation of the configurational stability of atropisomers.
Keywords: Biaryls, Activation energy, Racemisation half-time, Atropisomeric compound, Rotation barrier, Racemisation path, DFT
4Å molecular sieves catalyzed ring-opening of epoxides to 1,2-diacetates with acetic anhydride
, Pages: 153-158
Masumeh Gilanizadeh and Behzad Zeynizadeh PDF (230 K)
Abstract: This study was aimed at highly stereoselective ring-opening of epoxides with acetic anhydride in the presence of molecular sieves 4Å as an efficient reagent. Yields of the 1,2-diacetates are uniformly good to excellent and the reagent may be recycled without the requirement for purification. High yields, short reaction times, ease of preparation and simple work-up procedure (filtration) are advantages of this method.
Keywords: Acetic anhydride, 1,2-Diacetate, Epoxide, Molecular sieves, Ring-opening
ZrOCl2.8H2O as a green and efficient catalyst for the expeditious synthesis of substituted 3-arylpyrimido[4,5-c]pyridazines in water
, Pages: 159-168
Mehdi Rimaz, Hossein Mousavi, Paria Keshavarz and Behzad Khalili PDF (230 K)
Abstract: A new and simple synthetic methodology for the preparation of 3-arylpyrimido[4,5-c]pyridazine-5,7(6H,8H)-diones and 3-aryl-5-oxo-7-thioxo-7,8-dihydropyrimido[4,5-c]pyridazin-5(6H)-ones by a one-pot three component reaction of barbituric acid or thiobarbituric acid with arylglyoxals in the presence of catalytic amount of ZrOCl2∙8H2O as green Lewis acid and hydrazine hydrate at ambient temperature in water was reported. All of these pyrimidopyridazines derivatives have one clustered water molecule in their molecular structure. The use of ZrOCl2∙8H2O catalyst is feasible because of its easy availability, convenient handling, high stability, simple recovery, reusability, good activity and eco-friendly.
Keywords: ZrOCl2.8H2O, Arylglyoxal, Hydrazine, Pyrimidopyridazine, Clustered water
An adapted route to efficient synthesis of 1,8-dioxooctahydro-xanthene derivatives using InCl3 and (HPO3)n as recyclable catalysts
, Pages: 169-180
Bahador Karami Shahin Nejati and Khalil Eskandari PDF (230 K)
Abstract: Indium (III) chloride (InCl3) and metaphosphoric acid ((HPO3)n) were found to be efficient and recyclable catalysts for the synthesis of 1,8-dioxooctahydroxanthene derivatives as biologically important molecules in high turnover numbers and rates. Several substituted xanthenes can be prepared in high yield and purity by direct reaction of cyclic β-diketones and aldehyde derivatives in the presence of a catalytic amount of InCl3 and (HPO3)n as Lewis acids and at ambient temperature under solvent-free conditions. This newly reported procedure profit some advantages such as short reaction times, high yields of products, cheap, easy to use, facile practical conditions, and wholesome with green chemistry without using harmful solvents.
Keywords: Indium trichloride, Metaphosphoric acid, Recyclable catalyst, Cyclic β-diketone, Solvent-free
® 2015 GrowingScience.Com