Synthesis of biologically active heterocyclic compounds from allenic and acetylenic nitriles and related compounds

Cyclic and polycyclic compounds containing moieties such as imidazole, pyrazole, isoxazole, thiazoline, oxazine, indole, benzothiazole and benzoxazole benzimidazole are prized molecules because of the various pharmaceutical properties that they display. This led Prof. Landor and co-workers to engage in the synthesis of several of them such as alkylimidazolenes, oxazolines, thiazolines, pyrimidopyrimidines, pyridylpyrazoles, benzoxazines, quinolines, pyrimidobenzimidazoles and pyrimidobenzothiazolones. This review covers the synthesis of biologically active heterocyclic compounds by the Michael addition and the double Michael addition of various amines and diamines on allenic nitriles, acetylenic nitriles, hydroxyacetylenic nitriles, acetylenic acids and acetylenic aldehydes. The heterocycles were obtained in one step reaction and in most cases, did not give side products. A brief discussion on the biological activities of some heterocycles is also provided.

Chemical diversity and bioactivity of marine sponges of the genus Oceanapia: A review

: The marine sponges of the genus Oceanapia sp. is comprised of more than 50 species and are distributed in the seas around the tropical and subtropical regions. They are mainly found in the northern Indian oceans, Japan, and the south pacific coast. They are highly colored and known to be a rich source of various secondary metabolites, particularly, alkaloids. Several other secondary metabolites were also reported from this genus which include terpenes, sphingolipids, ceramides, cerebrosides, acetylenic acids, and thiocyanatins, etc. Many of these compounds isolated from this genus exhibited various biological properties including anticancer, antimicrobial, anti-HIV, ichthyotoxicity and nematocidal activities. Although several secondary metabolites have been reported from this genus, a dedicated review of the chemicals and biological activities of this genus is so far lacking. Keeping this in mind this review describes the various chemical entities isolated from the sponges of the genus Oceanapia detailing their chemical structures along with their reported biological properties.

SYNTHETIC ACETYLENE CARBOXYLIC ACIDS

The article presents some methods for the synthesis of acetylene mono, dicarbonoaliphatic, aromatic, heterocyclic acids. Among them, some possess antifungal and biological properties. By the interaction of acids or acid chlorides with the corresponding alcohols, esters can be obtained. Their biological properties, as well as some chemical transformations, were studied. Many synthetic acetylenic acids and their derivatives were synthesized mainly by the Grignard reaction and other methods in order to study their physiological activity. Some of them have gained application as a stabilizer of corrosion methods and others.

Synthesis of Acetylenic Amides with Propyllactam Moieties by In Situ DBU or DBN Ring-Opening Rearrangement in the Presence of Acetylenic Esters

DBN (1,5-diazabicyclo[4.3.0]non-5-ene) and DBU (1,8-diaza­bicyclo[5.4.0]undec-7-ene) react with methyl esters of acetylenic acids and excess water (the reactant molar ratio 1:1, in aqueous MeCN, at 20–25 °C, for 48 h) to afford acetylenic amides with pyrrolidone and caprolactam moieties in 89–100% yields. The synthesis involves amines formed in situ from the cyclic amidines, which further react with acetylenic esters.