Synthesis and properties of 4-(3-amino-2-benzofuranyl)-coumarins

Abstract

The healing properties of many plants have been long known and their present use is continuing to increase since an advantage of plant preparations is their low toxicity and the possibility of using them for long periods without the risk of side-reactions. The major groups of therapeutically active plants are alkaloids, steroid glycosides, saponins, flavonoids, coumarins, organic acids, and vitamins.Derivatives of oxygen heterocycles are among the most common classes of natural products [1]. Compounds containing two or more oxygen heterocycles are encountered in nature much less frequently. Some of the most important such compounds are furocoumarins [2], linear and angular furochromones, coumestans, rotenoids [3], and coumarin and flavonoid derivatives containing a pyran ring fused to ring A or B [4,5].Coumarin derivatives containing a benzofuran ring possess anti-inflammatory, hypotensive, and analgesic action [6-9]. Thus, in a continuation of a study of the synthesis and properties of coumarin heteroanalogs, we investigated the preparation and reactivity of substituted 4-(3-amino-2-benzofuranyl)-coumarins. Special interest was found in the synthesis of condensed derivatives of pyridino[3,4-c]coumarins since such alkaloids have been isolated from Schumanniophyton problematicum [10]. Many alkaloids are known to be very valuable pharmaceutical products or serve as starting materials for the synthesis of such products.The alkylation of salicylonitrile by 4-bromomethylcoumarin in acetone in the presence of potassium carbonate at room temperature leads to 4-(2-cyanophenoxymethoxy)coumarins, which are converted upon heating in ethanol at reflux in the presence of potassium carbonate into 4-(3-amino-2-benzofuranyl)coumarins [9].

Synthesis and antimicrobial evaluation of the novel heteroannulated furo[3′,2′:6,7]chromeno[2,3‐b]pyridines: Part 1

“…[ 13–15 ] Biological activity is well known for furo[3,2‐g]chromenes such as antimicrobial, [ 16 ] anticancer, [ 17 ] antitumor, [ 18 ] anti‐HIV, [ 19 ] analgesic, and anti‐inflammatory activities. [ 20–22 ] The ring‐opening ring closure (RORC) reactions of chromone‐3‐carbonitrile are well known. [ 23–26 ] Khellin‐6‐carbonitrile (4,9‐dimethoxy‐5‐oxo‐5 H ‐furo[3,2‐ g ]chromene‐6‐carbonitrile) [ 27 ] may represent a good precursor for building of novel heterocyclic systems fused furo[3,2‐g]chromenes due to the unique position of carbonitrile functional group in khellin‐6‐carbonitrile which is typically similar to chromone‐3‐carbonitrile.…”

Synthesis of benzofuro[3,2-b]furo[2,3-d]pyridin-4(5H)-ones, derivatives of a novel heterocyclic system

“…A number of analogous heterocyclic systems with the benzo[d]-annelated pyridine ring, such as benzofuro [3,2c]isoquinolines [4][5][6], inhibit hepatitis C viral infection [7] and are used to treat erectile dysfunction [8], inflammation and cardiovascular diseases [9]. At the same time, heteroannelated benzofuropyridines are much less studied and the reported compounds are restricted to a few quinolino [10,11] and coumarino derivatives [12,13] with anti-inflammatory and antimicrobial activities. Their analogues with a fused furan ring are hitherto unknown.…”

“…Most of the benzo and heteroannelated benzofuropyridines described in the literature have been synthesized starting with salicylonitriles [4][5][6][11][12][13] under the conditions of the Pictet-Spengler reaction. One approach used in this paper, provides a convenient way to obtain benzofuro [3,2-b]…”

Chemical Reactivity of 4,9‐Dimethoxy‐5‐oxo‐5H‐furo[3,2‐g]chromene‐6‐Carboxaldehyde Toward Some Nucleophilic Reagents

“…The photodynamic properties of khellin in its photoreaction with DNA have been studied . Generally, furochromones are known to have anti‐inflammatory and analgesic , antitumor , and antimicrobial activities . Benzofurans showed a wide range of biological activities including aromatase inhibitory effect , anti‐HIV , anticancer potency , antimicrobial , antitumor and antiviral , analgesic, and anticonvulsant activities .…”