HFIP-driven Schmidt-type reaction enables chromone-3-carbonitriles and its applications

Chromone-3-carbonitrile has been extensively studied in a panel of high-value transformations. However, existing protocols for the synthesis of this scaffold are often constrained by the structure of the starting materials and harsh conditions. To address these issues, we present a novel strategy that HFIP (hexafluoroisopropanol)-driven strategy, enables chromone-3-carbonitriles synthesis without undesirable side reactions. This protocol features readily available feedstocks, mild conditions, catalytic amount of acid and good to excellent yields. The utility of this chemistry is further demonstrated by amenable modifications of chromone-pyrimidines and imidazoles. Moreover, the analogous transformation of aldehydes is successfully constructed to achieve useful compounds such as 2-hydroxybenzonitriles, heterocyclic nitriles, and α, β-unsaturated nitriles. The HFIP-driven strategy offers an interesting access to different types of nitriles in a sustainably manner.

Regioselective synthesis of substituted thiazoles via cascade reactions from 3-chlorochromones and thioamides

An efficient and regioselective strategy to synthesize substituted thiazoles via a cascade reaction in an environmentally benign medium was developed.

One Pot and Metal-Free Approach to 3-(2-Hydroxybenzoyl)-1-aza-anthraquinones

Herein, a direct strategy to synthesize 3-(2-hydroxybenzoyl)-1-aza-anthraquinones with excellent efficiency, mild conditions, and benign functional group compatibility was reported. A variety of 3-formylchromone compounds were employed as compatible substrates and this protocol gave the 3-(2-hydroxybenzoyl)-1-aza-anthraquinone derivatives in good to excellent yields without inert gas and expensive transition metal catalysts. Some compounds displayed good anti-proliferative activities.

Silver-mediated synthesis of novel 3-CF3/CN/phosphonate-substituted pyrazoles as pyrrolomycin analogues from 3-formylchromones and diazo compounds

Herein, a simple and regioselective synthesis of (2-hydroxyphenyl)(3-(trifluoromethyl/cyano/phosphonate)-1H-pyrazol-5-yl)methanones as pyrrolomycin analogues was reported.

One-pot transition-metal-free cascade synthesis of thieno[2,3-c]coumarins from chromones

A one-pot transition-metal-free, base-mediated synthesis of a novel series of functionalized thieno[2,3-c]coumarins has been developed through a cascade reaction from chromones.