Band 23, Heft 4

The genus Ajuga , a member of the Lamiaceae family, is comprised of more than 300 species of annual and perennial herbaceous flowering plants mainly distributed throughout the temperate regions of Asia, Europe, Australia, North America and Africa. These plants are used as folk medicines effective for rheumatic fevers, dysentery, malaria, hypertension, diabetes and gastrointestinal disorders, as well as anthelmintic, astringent, febrifuge diuretic, antifungal and anti-inflammatory agents. A variety of constituents has been isolated from these plants. This review summarizes the phytochemical progress of the genus Ajuga and lists the compounds isolated up to 2014.

Annulated 1,8-naphthyridines were synthesized by one-pot reaction of aromatic aldehyde, malononitrile dimer and enehydrazinoketone.

A visible-light catalyzed direct and regioselective (phenylsulfonyl)difluoromethylation of imidazo[1,2- a ]pyridines and benzo[ d ]-imidazo [2,1- b ]thiazoles with readily available PhSO 2 CF 2 I under mild conditions was developed. This synthetic methodology enables the introduction of a CF 2 SO 2 Ph group in an efficient and regioselective reaction through C-H bond functionalization with a broad substrate scope in good to excellent yields.

New hybrid compounds, thienopyrimidinyl-1 H -pyrazolo[3,4- b ]pyridine derivatives, were efficiently synthesized by the three-component reaction of 3-phenyl-1-(thienopyrimidin-4-yl)-1 H -pyrazol-5-amine, benzoylacetonitrile and an aromatic aldehyde in the presence of FeCl 3 on basic alumina.

The regioselective 1,4-conjugate aza-Michael addition of dienones with benzotriazole catalyzed by potassium acetate is described. A series of 3-(benzotriazol-1-yl)-1,5-diarylpent-4-en-1-ones were efficiently synthesized under mild conditions. This protocol has advantages of transition-metal free catalyst, high yield and high regioselectivity.

A novel, simple, one-pot synthesis of 2,4-diaryl-9 H -pyrido[2,3- b ]indoles is described. Heating a mixture of chalcone, oxindole and ammonium acetate in the presence of potassium tert -butoxide under solvent-free conditions afforded the title compounds in good to excellent yields.

Triethylamine-promoted domino cyclodimerization reaction of 3-phenacylideneoxindolines with amino ester hydrochlorides in acetonitrile afforded substituted dispiro[indoline-3,1′-cyclopentane-3′,3″-indolines] in good yields. The relative configuration of the major diastereoisomers was determined by the X-ray diffraction analysis of three single crystal structures.

3,4-Dihydro-2 H -chromeno[4,3- b ]pyridine-2,5(1 H )-dione derivatives were efficiently prepared by the reaction of 4-hydroxycoumarin, ammonia, aromatic aldehyde and Meldrum’s acid in refluxing 1-propanol.

Electrophilic heterocyclization of 2-alkenyllthioquinolin-3-carbaldehydes or 2-alkenylselenoquinolin-3-carbaldehydes 2 , 3 under the action of iodine or bromine non-regioselectively leads to the formation of fused quinolinium trihalogenides 4 , 5 . Type of the chalcogen atom does not affect regiochemistry of halogenation.

The rearrangement reaction of 1-alkyl-2-(benzoylmethyl)pyridinium iodides 3a–d, 6 in the presence of various nucleophiles leads to 2-alkylaminobenzophenone derivatives 4a–c . Best results were achieved with alkylammonium sulfites as recyclization reagents.

Substituted quinolines containing a 1,2,4-triazole moiety were synthesized using reported methods. The molecular docking studies support the experimental results that these compounds are active against A. fumigatus and C. albicans where N -myristoyl transferase (NMT) and dihydrofolate reductase (DHFR), respectively, are the target enzymes. The analogues that contain methoxy and chloro substituents exhibit the best antifungal activity.

In the development of antimicrobial agents, we designed and synthesized novel tetrazole derivatives. The structures of compounds 6a–f and 7a–f were characterized by IR, 1 H NMR, 13 C NMR, MS and elemental analysis. These compounds were tested for their antimicrobial activity against a series of strains Staphylococcus aureus, Bacillus subtilis, Escherichia coli , and Pseudomonas aeruginosa and for antifungal activity against the strains Candida albicans, Candida glabrata , and Candida tropicalis . Compounds 6e , 6f , 7a , and 7f exhibit potent antimicrobial activities compared to the reference drugs streptomycin and miconazole. Tetrazole derivatives 7a–f also inhibit biofilm formation and compound 7f exhibits best anti-biofilm activity with a biofilm inhibitory concentration (BIC) as low as 0.9 μ m .