Synthesis of novel quinoxaline-alkynyl derivatives and their anti-Mycobacterium tuberculosis activity.

The study report on the synthesis of a series of novel quinoxaline-alkynyl derivatives that were evaluated for their activity against Mycobacterium tuberculosis (Mtb) HR strain. A total of 19 compounds bearing an alcohol, aldehyde, mesylate and ester groups on the alkynly group, and also containing a chloro and nitro groups at the 6-position, were prepared. Seven compounds (3c, 4a-b, 5a, 5c, 6c and 6i), were found to have MIC < 10 µM, while five compounds (3b, 6a, 6b, 6d and 6h) had MIC in the range 10-20 µM.

Double Sonogashira reactions on dihalogenated aminopyridines for the assembly of an array of 7-azaindoles bearing triazole and quinoxaline substituents at C-5: Inhibitory bioactivity against Giardia duodenalis trophozoites.

The synthesis of 2,3,5-trisubstituted 7-azaindoles as well as 2,5-disubstituted 7-azaindoles from 3,5-dihalogenated 2-aminopyridines is outlined. Using a double Sonogashira coupling reaction on 2-amino-3,5-diiodopyridine followed by the Cacchi reaction the synthesis of 2,3,5-trisubstituted 7-azaindoles was accomplished. In addition, using two sequential Sonogashira coupling reactions on 2-amino-5-bromo-3-iodopyridine and a potassium t-butoxide mediated ring closure reaction resulted in the assembly of 2,5-disubstituted 7-azaindoles.

The acid-catalysed synthesis of 7-azaindoles from 3-alkynyl-2-aminopyridines and their antimicrobial activity.

The synthesis of 7-azaindoles from 3-alkynyl-2-aminopyridines using acidic conditions, namely, a mixture of trifluoroacetic acid (TFA) and trifluoroacetic anhydride (TFAA), is described. This methodology resulted in the synthesis of fifteen 7-azaindoles, with most containing substituents at the 2- and 5-positions. The majority of these were tested for antimicrobial activity against a range of bacteria and yeasts.

The synthesis of 2- and 3-aryl indoles and 1,3,4,5-tetrahydropyrano[4,3-b]indoles and their antibacterial and antifungal activity.

A series of 2- and 3-aryl substituted indoles and two 1,3,4,5-tetrahydropyrano[4,3-b]indoles were synthesized from indole and 5-methoxyindole. The 2-aryl indoles were synthesized from the 1-(phenylsulfonyl)indole derivatives using magnesiation followed by iodination. The 2-iodinated compounds were then subjected to Suzuki-Miyaura reactions.