New pentacyclic cyclol-type naphthohydroquinone from the roots of Pentas bussei

Traditional antimalarial phytotherapy remedies used by the Kwale community of the Kenyan Coast

“…Mdobe (D) Herb RB Hot water decoction Oxygen heterocycles (Bukuru et al, , 2003 Root decoction used for venereal diseases by the Digo (Beentje, 1994;Kokwaro, 1993) Rubiaceae Pentas longiflora Oliv. (CM 126) Mdobe dombe (D) Herb RB Decoction, hot water extract Antiplasmodial activity (Wanyoike et al, 2004), quinoid cpds (El-Hady et al, 2002) Root decoction in milk used for malaria (Kokwaro, 1993) Rubiaceae (Kusamba et al, 1993) Whole plant used for cerebral malaria (Chhabra and Mahunnah, 1994) Rutaceae Toddalia asiatica (L.) Lam.…”

Efficient and novel one-pot synthesis of polycycles bearing cyclols by FeCl3-promoted [2 + 2] cycloaddition: application to cannabicyclol, cannabicyclovarin, and ranhuadujuanine A

“…4 Recently, several biologically active compounds with a cannabinoid moiety were isolated from different sources. 11 Given the importance of these biological and pharmacological activities, several synthetic methods have been developed for the preparation of cyclol moieties that utilize intramolecular photochemical [2 + 2] cycloadditions. 6 Furthermore, the inhibitory effect of 4 (IC 50 = 83 μM) has been reported to be comparable to that of the potent anti-inflammatory indomethacin (IC 50 = 250 μM) with respect to compound 48/80-induced histamine release from rat peritoneal mast cells.…”

“…10 Other polycycles, eriobrucinol (10) and compound 11, have been isolated from Pentas bussei. 11 Given the importance of these biological and pharmacological activities, several synthetic methods have been developed for the preparation of cyclol moieties that utilize intramolecular photochemical [2 + 2] cycloadditions. 12 However, the reported photochemical intramolecular [2 + 2] cycloadditions sometimes provide polycycles bearing a cyclol moiety as mixtures of diastereomers.…”

Recent applications of the hetero Diels–Alder reaction in the total synthesis of natural products

“…146,147 The extract obtained from Mallotus philippensis showed antibacterial potency. Polycycles having citrans are wide spread in nature 67,148,149 and show a broad range of biological and pharmacological potencies. 69,70 In this approach compound 113 was provided in satisfactory yield via treatment of 2,4,6-trihydroxyacetophenone with prenyl bromide reaction of 113 with 1.2 equiv.…”

“…Aphadilactones A-D (146)(147)(148)(149), a new family of diterpenoid dimers, were initially isolated from the leaves of Aphanamixis grandifolia, an arbor tree that grows chiey in the tropical and subtropical areas of Asia, by Liu and his colleagues. 170 The total synthesis involves a catalytic asymmetric HDA cycloaddition reaction to construct the dihydropyran ring, along with simultaneous assemblage of the lactone and furan moieties via a cascade acid-catalyzed acetal cleavage/oxidation/cyclization process, and an IMHDA cycloaddition reaction to obtain the desired target products.…”