4-Hydroxy-2-quinolones: syntheses, reactions and fused heterocycles.

The interesting pharmaceutical and biological activities of 4-hydroxy-2-quinolones make them valuable in drug research and development. Hence, many publications have recently dealt with their synthetic analogous and the synthesis of their heteroannelated derivatives. Consequently, we have found that it is of importance to shed new light on these interesting heterocycles. This focused review article discusses the recent synthetic approaches and the applications of this class of compounds in the synthesis of related four-membered to seven-membered heterocycles, most of them showing unique biological activities.

Life span extension of Caenorhabditis elegans by novel pyridoperimidine derivative.

Zwitterions formed from the addition of triphenylphosphine to dialky acetylene-dicarboxylates attack the nucleus of both 1H-perimidine (1) and 1H-benzo[d]imidazole (9) to form novel pyrido[1,2,3-cd]perimidine and imidazo[4,5,1-ij]quinoline derivatives in moderate yields (64-72%). The biological activity of the products has been studied. Compound 3a was found to extend life span of wild type Caenorhabditis elegans under standard laboratory conditions. Both heat stress and induced chemical stress resistance of wild type C. elegans were improved in a reverse dose-dependent manner due to 3a treatment. In addition, treatment of worms with compound 3a significantly attenuated the formation of advanced glycation end products in a reverse dose-dependent manner.

A surprising new route to 4-nitro-3-phenylisoxazole.

A one-pot synthesis of 4-nitro-3-phenylisoxazole has been carried out by treatment of cinnamyl alcohol dissolved in acetic acid with sodium nitrite; in addition, 4-phenyl-3-furoxanmethanol was obtained in 40% yield.

Microwave assisted synthesis of triazoloquinazolinones and benzimidazoquinazolinones.

BACKGROUND: Benzimidazoquinazolinones and related quinazolines are classes of heterocycles that are of considerable interest because of the diverse range of their biological properties. Although numerous classes of quinazolines have been conventionally synthesized, their syntheses have been suffered due to the multiple steps that sometimes have described in their preparation and also their chemical transformations that have been taken hours or even days to be completed. However, microwave energy can offer numerous benefits for performing synthesis of organic compounds including reduced pollution, increased reaction rates, yield enhancements, and cleaner chemistries. RESULTS: Synthesis of a series of triazoloquinazolinones and benzimidazoquinazolinones has been achieved under microwave irradiation. The products were obtained in nearly quantitative yields within few minutes during the reaction of aromatic aldehydes with 5-amino-1(H)-1,2,4-triazole (or 2-aminobenzimidazole) and dimedone in DMF. CONCLUSION: Microwave irradiation can be used as a facile and general method for the construction of a wide variety of triazoloquinazolinones and benzimidazoquinazolinones. The reaction involves a three component condensation (with potential for combinatorial work) being carried out with almost productive yields by microwave irradiation and considerably shortened reaction time.

Novel reaction products from thiobarbituric Acid of biological interest.

The reactions of 1, 2-dihydro-2-thioxo-4, 6(1H, 5H)pyrimidinedione (1) with some pi-deficients have led to the formation of unexpected heterocyclic products such as anilinomethylenethioxopyrimidinedione, 2, 2'-bis(pyrimidinecarbothioamide), allylthioxopyrimidinecarbothioamide, indenopyranopyrimidine and benzofuropyrimidine derivatives. A possible mechanism for the formation of these products is discussed, and the biological activity is determined.