Synthesis and structure of azole-fused indeno[2,1-c]quinolines and their anti-mycobacterial properties †

Prompted by our discovery of a new class of conformationally-locked indeno[2,1-c]quinolines as anti-mycobacterials, compounds 2a and 3a

A Minute Amount of S‑Puckered Sugars Is Sufficient for (6-4) Photoproduct Formation at the Dinucleotide Level

The di-2′-α-fluoro analogue of thymidylyl­(3′,5′)­thymidine, synthesized to probe the effect of a minimum amount of S conformer on the photoreactivity of dinucleotides, is endowed with only 3% and 8% of S sugar conformation at its 5′- and 3′-end, respectively. This analogue gives rise to the (6-4) photoproduct as efficiently as the dithymine dinucleotide (74% and 66% at the 5′- and 3′-end, respectively) under 254 nm. Our results suggest that the 5′-N, 3′-S conformer gives rise to the (6-4) photoproduct

C2′‑F Stereoconfiguration As a Puckering Switch for Base Stacking at the Dinucleotide Level

Fluorine configuration at C2′ of the bis­(2′-fluorothymidine) dinucleotide is demonstrated to drive intramolecular base stacking. 2′-β F-Configuration drastically reduces stacking compared to the 2′-α series. Hence, base stacking emerges as being tunable by the C2′-F stereoconfiguration through dramatic puckering variations scrutinized by NMR and natural bond orbital analysis. Accordingly, 2′-β F-isomer photoreactivity is significantly reduced compared to that of the 2′-α F-isomer