Efficient click chemistry towards novel 1H-1,2,3-triazole-tethered 4H-chromene-d-glucose conjugates: Design, synthesis and evaluation of in vitro antibacterial, MRSA and antifungal activities.

The series of 2-amino-7-propargyloxy-4H-chromene-3-carbonitriles 5a-t were synthesized from corresponding 2-amino-7-phydroxy-4H-chromene-3-carbonitriles 4a-t and propargyl bromide. Two procedures were used in these syntheses: KCO/acetone and NaH/DMF procedures with yields of 65-89% and 80-96%, respectively. 1H-1,2,3-Triazole-tethered 4H-chromene-d-glucose conjugates 7a-t were synthesized using click chemistry of propargyl ethers 5a-t and tetra-O-acetyl-β-d-glucopyranosyl azide. Cu@MOF-5 was the optimal catalyst for this chemistry. The yields of 1H-1,2,3-triazoles were 80-97.8%. All triazoles 7a-t were evaluated in vitro for anti-microorganism activities. Among tested compounds with MIC values of 1.56-6.25 μM, there were four compounds against B. subtilis, four compounds against S. aureus, and four compounds against S. epidermidis; five compounds against E. coli, four compounds against K. pneumoniae, five compounds against P. aeruginosa, and six compounds against S. typhimurium. Compounds 7c,7d,7f,7h, and 7r had MIC values of 1.56-6.25 μM for three clinical MRSA isolates. Some compounds had inhibitory activities against four fungi, including A. niger, A. flavus, C. albicans, and S. cerevisiae, with MIC values of 1.56-6.25 μM. Some 1H-1,2,3-triazoles had comparatively low toxicity against RAW 264.7 cells.