Coumarin isolation

Two possible structures, A and B, were initially considered for a naturally occurring coumarin isolated from Murraya paniculata. Its nOe difference and H-NMR spectra are presented. The relevant H chemical shift values are given around structure A. On the basis of the nOe data, identify the correct structure of the coumarin. 

Negi N, Ochi A, Kurosawa M, Ushijima K, Kitaguchi Y, Kusakabe E, Okasho F, Kimachi T, Teshima N, Ju-Ichi M, Abou-Douh AM, Ito C and Furukawa H. 2005. Two new dimeric coumarins isolated from Murraya exotica. Chem Pharm Bull (Tokyo) 53(9) 1180—1182. 

Kang SY, Lee KY, Sung SH, Park MJ, Kim YC, Coumarins isolated from Angelica gigas inhibit acetylcholinesterase Structure-activity relationships, f Nat Prod 64 683-685,2001. 

Pengsuparp, T. Serb, M. Hughes, S. H. Soejarto, D. D. Pezzuto, J. M. Specific inhibition of human immunodeficiency vims t)fpe 1 reverse transcriptase mediated by soulattrolide, a coumarin isolated from the latex of Calophyllum teysmannii. J. Nat. Prod., 1996, 59 839-842. 

Among the coumarins isolated from species of Artemisia (Asteraceae), esculetin (6,7-dihydroxycoumarin) and its dimethyl-ether scoparone were known to be antiproliferative on vascular smooth muscle cells. This activity was further found in some very simple mono-substituted coumarins, which were even more potent than esculetin, although less effective. In an attempt to verify its mechanism of action, esculetin was tested for interactions with PTK and PKC. The induction of membrane PTK activity by either foetal calf serum or platelet-derived growth factor (PDGF) was moderately reduced by esculetin, whereas no effect was observed against PKC [56]. 

Examples of other antimicrobial coumarins from the Anthemideae tribe also included the coumarin derivatives isolated from the seeds of Centaurea nigra L. [243] and one coumarin isolated from Leontopodium alpinum, which selectively inhibited the growth of Streptococcus pyogenes and Streptococcus pneumoniae [36]. 

A total of twenty coumarins isolated from the leaves, stem-bark, roots and fraits of this plant have been discnssed. Okorie (81), Reisch and... 

Umbelliferone is one of about 1000 coumarins isolated from plants, primarily the families of Angiosperms Fabaceae,... 

Several reviews have been published dealing with natural products-derived antiviral compounds [11,12,16-23]. Presently, there are only two plant-derived compounds under clinical development [2]. (+)-Calanolide A (12) is a C22 coumarin isolated from the Malaysian rainforest tree, Calophyllum langigerum by the U.S. National Cancer Institute [2]. It shows a potent HIV-RT inhibitory activity [2]. In vitro studies of 12 demonstrated activity against HIV-1 including AZT and other nonnucleoside RT inhibitors-resistant strains. It also shows synergistic anti-HIV activity in combination with nucleoside RT inhibitors 7, 8 and 9 [2]. To overcome the difficulty of supply of 12, its total chemical synthesis was accomplished [2]. In June 1997, clinical development of 12 was started as a potential drug for treatment of AIDS. A single -center 7-month U.S. phase la clinical trial of 12 was started to assess its safety and... 

Coumarins isolated from fragrant angelica administered orally to rats in single doses of 25,50, or 100 mg/kg increased the duration of hypnosis induced by pentobarbital sodium. The 100 mg/kg dose also prolonged the latent period and shortened the duration of hypnosis induced by barbital sodium (Liu et al. 2006). 

Although predictions on the course of chemical progress can be widely off the mark, the main outlines of coumarin chemistry seem to be broadly established if one takes as a criterion, the new coumarin structures reported in the past decade. With the exception of a series of 3-substituted 4-hydroxy-5-methylcoumarins, probably biosynthesized from acetate and largely confined to the tribe Vernonieae (Compositae), most of the structures of new coumarins reported in this period are predictable variants of established structural patterns. Methods of coumarin isolation and structure determination are straightforward by modern standards. The literature contains a sizable data base of spectroscopic parameters making structure determination a fairly routine procedure. 

Rosselli S, Maggio A, Bellone G, Formisano C, Basile A, Cicala C, Alfieri A, Mascolo N, Bruno M (2007) Antibacterial and anticoagulant activities of coumarins isolated from the flowers of Magydaris tomentosa. Planta Med 73 116... 

Unfortunately, many natural coumarins have been assigned trivial names, mostly botanically derived. Although these can facilitate discussion, to a considerable extent they serve to confuse, especially since many of the endings (e,g, -ol, -one) are not at all consistent with structure. Thus umbelliferone (2) is a phenol while osthol (143) is the methyl ether of osthenol (142). Structurally closely related coumarins can have markedly different names aculeatin (249) is the epoxide of toddaculin (248), both of which occur in Toddalia aculeata, while conversely almost identical trivial names can be given to structurally quite dissimilar coumarins, e. g. ferudenol (339) and ferulenol (481). Not infrequently, the same coumarin isolated by different workers from different plant sources is given two or even three trivial names and even enantiomers are known with distinct trivial names, e.g. marmesin (103) and nodakenetin (104). 

Chatterjee, A., and S. Sen Gupta The Constitution of Archangelin, a New Coumarin Isolated from the Root of Angelica archangelica Linn. (Umbelliferae). Tetrahedron Letters, 1964, 1961. 

Structure of Sabandinin and Other Coumarins Isolated from the Roots of... 

Hata, K., M. Kozawa, Y. Ikeshiro, and K.-Y. Yen New Coumarins Isolated from the Root of Peucedanum formosanum Hayata and Peucedanum japonicum Thunb. Yakugaku Zasshi 88, 513 (1968) Chem. Abs. 69, 96521 (1968). 

Sang, K., I. Yosioka, and I. Kitagawa Stereostructures of Decursin, Decursidin and a New Coumarin Isolated from Angelica decursiva. Chem. and Pharm. Bull. (Japan) 21, 2095 (1973). 

Following this approach, pterophyUin 2 (33), a natural furo[3,2-c]coumarin isolated from the bark of the evergreen tree Ekebergia pterophylla [82], could be obtained in one-step from 3-diazo-5-methyI-2,4-chromenedione and 2-methyI-l-buten-3-yne (Scheme 14) [78]. The linear isomer 34, easily separable by column chromatography, was also formed in the reaction. 

K.H. Kang, C.S. Kong, Y. Seo, M.M. Kim, S.K. Kim, Anti-inflammatory effect of coumarins isolated from Cotydalis heterocarpa in HT-29 human colon carcinoma cells. Food Chem. Toxicol. 47 (2009) 2129-2134. 

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