Natural and Synthetic 2,2-Dimethylpyranocoumarins with Antibacterial Activity

Abstract

A new efficient synthetic approach to the natural coumarins 5-hydroxyseselin (5), 5-methoxyseselin (3), and (+/-) cis-grandmarin (9) is described as well as the synthesis of some new derivatives in the 5-methoxyseselin series (10-15). The natural coumarins 7-hydroxyalloxanthyletin (6), alloxanthoxyletin (8), and dipetalolactone (7) have also been obtained as secondary products. The type of fusion of the pyrano ring in all cases has been established by 2D NMR spectroscopy. The compounds have been studied for their in vitro antibacterial activity, which has been compared with that of some previously synthesized seselin derivatives. The most active compounds were 3, 7, 8, 11, and 14. Some structure-activity relationships are discussed.

Isolation and characterisation of silver(I) complexes of substituted coumarin-4-carboxylates which are effective against Pseudomonas aeruginosa biofilms

“…Coumarin and its derivatives have shown a diverse array of biological activities including antimicrobial [17], chemotherapeutic [18,19], anticoagulant [20] and antiinflammatory [21]. A number of both naturally occurring and synthetic coumarins including aminocoumarins [22,23], hydroxycoumarins [24,25], pyranocoumarins [26], and furanocoumarins [27] have been reported to have significant antimicrobial activity against a wide range of microbes. Following on from our previous work on a series of Ag(I) complexes of coumarin-3-carboxylates, which have proven antimicrobial activity and potential as effective biocides in hygienic coatings, a novel series of Ag(I) complexes of coumarin-4-carboxylates has been synthesised and screened for their antibacterial activity.…”

The characterisation of coumarins from selected structural classes by electrospray ionisation quadrupole time‐of‐flight tandem mass spectrometry

“…2 and Fig. 5 shows a typical ESI-QTOF-MS/MS spectrum of protonated seselin (7). Minor signals were observed at m/z 187.0469 (C 11 H 7 O 3 + ) and 159.0439 (C 10 H 7 O 2 + ).…”

“…Pyranocoumarins contain a six-membered ring and can exist in either linear or angular forms. An example of a pyranocoumarin is seselin (7), in which the oxygen at the 7-position is part of a fused six-membered heterocyclic ring system. Another major group is the coumarins that are substituted in the pyrone ring in either position 3 or position 4, such as 3,6-dimethyl-4-hydroxycoumarin (3), also investigated in this paper.…”

“…A number of studies have been carried out on the antibacterial activity of some of these groups. [7] The antimicrobial activities of 43 naturally occurring and synthetic coumarins have recently been studied using a microtitre assay, [8] showing that nearly one-half of the tested coumarins displayed antimicrobial activity. This latter study showed that nearly one-half of the tested coumarins displayed antimicrobial activity.…”

Isolation, characterisation and antibacterial activity studies of coumarins from Rhododendron lepidotum Wall. ex G. Don, Ericaceae

“…In 1945, Goth conducted the first antibacterial activity studies of coumarins and found that dicoumarol inhibited the growth of several bacterial strains (Goth, 1945). Melliou et al (2005) found that pyranocoumarin derivatives have a broad spectrum of activity. Dadak & Hodak (1966) suggested that the coumarins with antibacterial activity act selectively against gram positive bacteria.…”