Palladium-mediated synthesis of 5-substituted 4-alkynylthieno[2,3-c]pyran-7-ones

Thienochromene derivatives inhibit pSTAT1 and pSTAT5 signaling induced by cytokines

Furanocoumarins, particularly furo[3,2-c]coumarins, are found in many natural products. However, coumarins annulated to a thiophene ring have received scarce attention to date in the literature. Therefore, we synthesized 4-oxo-4H-thieno[3,2-c]chromene derivatives and tested in vitro their anti-inflammatory activity. Anti-inflammatory potential of the synthesized compounds (1, 2, 6-8, 9a-e and 10a-c) has been evaluated by measuring various pSTAT (signal transducer and activator of transcription) inhibition within the JAK (Janus-activated family kinase)/STAT signaling pathway. Ethyl 7-hydroxy-4-oxo-4H-thieno[3,2-c]chromene-2-carboxylate (7) showed best inhibition properties on pSTAT5 in GM-CSF (Granulocyte-macrophage colony-stimulating factor)-triggered PBMC assay, with IC₅₀ value of 5.0 µM.

Pd/C-mediated synthesis of α-pyrone fused with a five-membered nitrogen heteroaryl ring: a new route to pyrano[4,3-c]pyrazol-4(1H)-ones

Pd/C-mediated alkynylation of 5-iodo-pyrazole-4-carboxylic acid, involving the first regioselective construction of α-pyrone ring on a pyrazol moiety via tandem coupling–cyclization process, has been developed to afford pyrano[4,3-c]pyrazol-4(1H)-one in a single pot.

Facile synthesis of substituted thiophenes via Pd/C-mediated sonogashira coupling in water

The first successful Pd/C-mediated Sonogashira coupling of iodothiophene with terminal alkynes in water is described here. Pd/C-CuI-PPh(3) was found to be an efficient catalyst system for this coupling reaction. Using this economic and reliable process a variety of acetylenic thiophenes with a wide range of functional groups were prepared in good yields. Synthetic applications and in vitro anticancer properties of some of the compounds synthesized are described.