Reaction of malonates with camphoranile synthesis of 4‐hydroxy‐2‐pyridones attached to the bornane ring system

Abstract

The reaction of camphoraniles 3a,b with "magic malonates" (bis-2,4,6-trichlorophenylmalonates) 4a,b leads to 4-hydroxy-2(1H)-pyridones attached to bornane ring system 6a-c in good yields. Less satisfactory yields were obtained with the diethyl malonate 5b. The reaction of an excess of diethyl malonate 5 itself with 3b yields the pyrono derivative 7, which can readily be degraded via the acetyl derivative 8 to the basic structure 9.

Facile eco-friendly synthesis of novel chromeno[4,3-b]pyridine-2,5-diones and evaluation of their antimicrobial and antioxidant properties

“…Similarly, alternative synthesis of these fused systems reported by Kafka et al using camphoranils with excess of dimethylmalonate suffer from poor yields. 23 Owing to the necessity for an improved methodology for the synthesis of these fused scaffolds and prevalence of impressive biological properties of both pyridine-2ones and coumarins, we were interested in developing a mild synthetic protocol for the synthesis of the fused chromeno[4,3-b]pyridine-2,5-dione scaffolds.…”