Advancements in the Preparation of 4H‐Chromenes: An Overview

Abstract

Functionalized 4H‐chromenes represent one class of the most important structural scaffolds in both synthetic and medicinal chemistry. They often appear in an arrange of biological natural products, pharmaceutical agents and drug candidates. The significance has stimulated the development of efficient methodologies for the synthesis of such compounds. In this review, a comprehensive discussion on different synthetic approaches to 4H‐chromenes has been presented with an emphasis on reaction features and mechanisms. Three main categories are outlined: 1) nucleophilic addition to 2H‐chromene derivatives, 2) 4H‐chromene ring formation involved cycloaddition or cyclization reactions, and 3) miscellaneous reactions.

Producing p‐tolylmethanol derivatives through an eco‐friendly electro‐organic method: A highly efficient Grignard reaction utilizing a magnesium electrode

“…White solid; Yield = 91%; m.p: 76–77°C (m.p: 74–76°C), 33 1 H NMR (300 MHz, CDCl 3 ) ppm: 8.22 (ArH, 2H, J = 4.9 Hz, t), 7.00–7.58 (ArH, 2H, m), 7.31–7.36 (ArH, 2H, m), 7.03–7.09 (ArH, 2H, m), 5.93 (CH, 1H, s), 2.40 (OH, 1H, s). Anal Calcd for C 13 H 10 FNO 3 : C, 63.16; H, 4.08; N, 5.67; O, 19.42%.…”

“…White solid; Yield = 91%; m.p: 76-77 C (m.p: 74-76 C), 33 Note: Reaction conditions: A mixture of 1 mmol of benzaldehyde 1, 1 mmol of bromobenzene 2, and NaBr 3 was combined in 20 mL of 1,4-dioxane and subjected to electrolysis using a 7 cm 2 magnesium cathode and a 7 cm 2 graphite anode. The experimental setup employed an undivided cell configuration, and a steady electric current was applied.…”

Isocyanide-based multicomponent reactions for the synthesis of benzopyran derivatives with biological scaffolds

“…15). 127 Daemonorops draco is an evergreen climbing palm that is used for resin production, medicinal purposes, and the preparation of ingredients. 128 Uvaria afzelii is a small tree or shrub with antimicrobial properties, harvested from Scheme 17 3-CR of OH-acids, an activated alkyne, and isocyanides for the synthesis of a chromene-based structure.…”

ZnO-ZnS Heterostructure as a Potent Photocatalyst in the Preparation of Some Substituted Chromenes and Remarkable Antigastrointestinal Cancer Activity

“…Chromenes play a pivotal role as key components in various biologically active materials because of their hybrid heterocyclic structure. − These compounds offer a diverse range of biological activities, including antimicrobial and anticancer effects. Moreover, the use of chromenes as drugs in the gastrointestinal field is an area of ongoing research because of their anti-inflammatory and antioxidant properties.…”