ChemInform Abstract: Synthesis of Novel Polycyclic Ring Systems Containing Two Pyrano[2,3‐c]pyrazol‐4‐(1H)one Moieties.

Abstract

Two Pyrano[2,3-c]pyrazol-4-(1H)one Moieties. -The synthesis of the hitherto unknown polyheterocycles (IV) and (VI) is reported. -(ELLER*, G. A.; WIMMER, V.; HOLZER, W.; Chem.

Heterocyclic analogs of xanthiones: 5,6‐fused 3‐methyl‐1‐phenylpyrano[2,3‐c]pyrazol‐4(1H) thiones—synthesis and NMR (1H, 13C, 15N) data

“…In the course of a program devoted to the synthesis of new heterocyclic scaffolds for bioactive compounds,1–10 we recently presented the synthesis of various [5,6]pyrano[2,3‐ c ]pyrazol‐4(1 H )‐ones of type 4 via reaction of 2‐pyrazolin‐5‐ones 1 with o ‐haloheteroarenecarbonyl chlorides 2 and the subsequent ring closure of the resulting 4‐heteroaroylpyrazol‐5‐ols 3 (Scheme ). Following this approach, we have obtained type 4 compounds carrying—among others—a pyridine (all positional isomers),1 quinoline,1 thiophene (all positional isomers),2, 3 benzo[b]thiophene,2 and thieno[2,3‐ b ]thiophene system3 as the variable heteroaromatic moiety (‘Het’) condensed to the central γ‐pyranone ring.…”