Synthesis of chromones, annulated with oxygen-containing heterocycles with two hetero atoms at C(7)-C(8) bond

The present review represented the advanced synthetic strategies for chromones annulated at the C(7)-C(8) bond with five-membered, six-membered, and seven-membered oxygen-containing heterocycles with two heteroatoms, such as 6H-[1,3]dioxolo[4,5-h]chromen-6-one, 2,3-dihydro-7H-[1,4]dioxino[2,3-h]chromen-7-one, 3,4-dihydro-2H,8H-[1,4]dioxepino[2,3-h]chromen-8-one, 2,3-dihydro-1H,7H-chromeno[7,8-b][1,4]oxazin-7-one, 4H,12H-pyrano[2,3-a]phenoxazine-4-one and 9,10-dihydro-4H,8H-chromeno[8,7-e][1,3]oxazin-4-one. The biological activity of naturally occurring and modified synthetic fused hetarenochromones has been also highlighted

Synthesis of linear hetarenochromones based on 7-hydroxy-6-formyl(acetyl)chromones

Fused chromones are attracting increasing attention as novel therapeutic agents due to their wide distribution in nature, effective bioactivities and low toxicity. 6-Carbonyl-7-hydroxychromones proved to be versatile synthons for the synthesis of linear hetarenochromones by annulation of heterocycle to the chromone core. The present review is focused on the syntheses of furo[3,2-g]chromones, pyrano[3,2-g]chromones and some of their N-containing analogues, namely chromeno[6,7-d]isoxazoles, pyrano[3’,2’:6,7]chromeno[4,3-b]pyridine-5,11-diones and pyrano[3’,2’:6,7]chromeno[4,3-c]pyridine-5,11-diones based on the 7-hydroxy-6-formylchromones or 7-hydroxy-6-acetylchromones and shows the current state of research to date. The methods for the synthesis of the starting 7-hydroxy-6-formylchromones and 7-hydroxy-6-acetylchromones have been also mentioned. The biological activity of naturally occurring and modified synthetic linear hetarenochromones has been also represented

Isoflavonoids Modified with Azole Heterocycles with Three Heteroatoms

Heterocycle modified chromones are attracting increasing attention as novel potential therapeutic agents due to their effective bioactivities and low toxicity. This review describes all strategies and versatile synthons that have been developed for the synthesis of isoflavone heterocyclic analogs containing isolated 5-member heterocyclic rings with three identical or different heteroatoms. Their biological activity is also presented

Chromones Modified with 7-Membered Heterocycles: Synthesis and Biological Activity

The present mini-review for the first time summarizes and systematizes all the data available in the literature on the synthesis and properties of сhromones modified with 7-membered heterocycles throughout the chemical space around the chromone framework. Most of the 2-, 6-, 7- and 8-hetarylsubstituted сhromones are represented in the patent literature and were obtained by nucleophilic substitution in the chromone core with a cyclic amine moiety. Methods for the synthesis of heterocyclic analogs of isoflavones are mainly based on 3-formylchromone, its derivatives, chromonylchalcones and by means of multicomponent reactions. The biological activity of сhromones substituted with 7-membered heterocycles are also surveyed

Hetarenocoumarins based on 7-hydroxy-3-(benzothiazol-2-yl)coumarin

The syntheses of angular hetarenocoumarins, namely chromeno[8,7-e][1,3]oxazin-2-ones and furo[2,3-h]chromen-2-one, have been accomplished starting from 7-hydroxy-3-(benzothiazol-2-yl)-coumarin using aminomethylation and formylation reactions

6-Oxyindan-1-ones with amino acid fragments

New indan-1-one derivatives (8 examples) with amino acid fragments were synthesized through the N-acylation of the amino acids by 2-(3-oxo-2,3-dihydro-1H-inden-5-yloxy)acetic acid using the method of activated N-hydroxysuccinimide esters. To obtain corresponding methyl esters (2 examples) two ways were possible: the N-acylation of the amino acid methyl esters by 2-(3-oxo-2,3-dihydro-1-inden-5-yloxy)acetic acid through the activated imidazole derivatives or methylation of the carboxylic function of preformed N-{[(1-oxoindan-6-yl)oxy]acetyl}amino acids

The synthesis of angular heteroarenochromones based on 7-hydroxy-8-carbonylchromones

The present review highlights advanced strategies to the synthesis of the chromones annulated with O- and N-containing heterocycles at C(7)-C(8) bond. Due to the prevalence of such motives in different kinds of natural flavonoids and some alkaloids, fused chromones have attracted a great deal of attention so far. On the other hand a wide range of biological activities is displayed by the compounds of this type both among naturally occurring flavonoids and their synthetic analogues. 8-Carbonyl-7-hydroxychromones proved to be versatile synthones for the synthesis of angular hetarenochromones via approach of annulation of a heterocycle to the chromone core. It also addresses the question of the biological activity of naturally occurring and fused synthetic hetarenochromones