Oxidative coupling of 1-(2-methyl-4-phenylquinolin-3-yl)ethanone with ethanol and unexpected deacetylative synthesis of 3-hydroxy quinoline.

An efficient one pot method for the synthesis of anti-α,ß-epoxy ketones from 1-(2-methyl-4-phenylquinolin-3-yl)ethanone and ethanol has been developed by a modified Darzen reaction. The reaction occurs under oxidative conditions via a cascade sequence of bromination, aldol condensation followed by substitution. The reaction in the presence of NBS and a base however, in the absence of an oxidant, led to the formation of the corresponding 3-hydroxylated product via an unusual rearrangement.

Transition-Metal-Free C-3 Arylation of Quinoline-4-ones with Arylhydrazines.

A transition-metal-free C-3-arylation of quinolin-4-ones in the presence of base has been achieved by using arylhydrazines as aryl radical source and air as oxidant. The reaction proceeds smoothly at room temperature and does not require any prefunctionalization and N-protection of quinoline-4-ones. The utility of this methodology is further demonstrated in synthesis of quinoline-quinolone hybrid as well as 6-aryl-benzofuro[3,2-c]quinoline scaffold.

Synthesis and antimalarial activity of 3,3-spiroanellated 5,6-disubstituted 1,2,4-trioxanes.

Novel 3,3-spiroanellated 5-aryl, 6-arylvinyl-substituted 1,2,4-trioxanes 19-34 have been synthesized and appraised for their antimalarial activity against multidrug-resistant Plasmodium yoelii nigeriensis in Swiss mice by oral route at doses ranging from 96 mg/kg × 4 days to 24 mg/kg × 4 days. The most active compound of the series (compound 25) provided 100% protection at 24 mg/kg × 4 days, and other 1,2,4-trioxanes 22, 26, 27, and 30 also showed promising activity. In this model, ß-arteether provided 100 and 20% protection at 48 mg/kg × 4 days and 24 mg/kg × 4 days, respectively, by oral route. Compound 25 displayed a similar in vitro pharmacokinetic profile to that of reference drug ß-arteether. The activity results demonstrated the importance of an aryl moiety at the C-5 position on the 1,2,4-trioxane pharmacophore.

A review on cassane and norcassane diterpenes and their pharmacological studies.

The natural Cassane and norcassane diterpenes are biosynthetic rearrangement products of Pimarane precursor in the biosynthetic pathway of diterpenes. Their distribution is highly restricted to various genera of Fabaceae family (especially to Caesalpinia genus). A comprehensive account of the structural diversity (322 structures, 114 references) is given in this review along with biological activities of cassane and norcassane diterpenes up to September 2011.