Constitution and absolute configuration of meta,meta-bridged, strained biphenyls from Myrica nagi; X-ray analysis of 16-bromomyricanol

Abstract

Chemical and spectroscopic studies lead to the [7,0] metacyclophane structures (2) and (3) for myricanol and myricanone, phenolic extractives from Myrica nagi. X-Ray analysis of the meta-bridged biphenyl, 16-bromomyricanol (nitromethane solvate), by the heavy-atom method, confirmed these assignments, and gave the absolute configuration of myricanol. The compound crystallises in the monoclinic space group P2, with Z = 2 in a unit cell of dimensions a = 6.02 * 0.01. b = 17.34 f 0.02, c = 11 a 2 2 f 0.02 8, and p = 98.4" f 0.2"; the structure was refined to R 0.057 for 1075 independent reflections. C.d. measurements suggest t h a t myricanol prefers t h e same conformation in solution as in the crystalline state. The biphenyl nucleus in 16-bromomyricanot is detormed by metameta-bridging. Similar strain in myricanone (3) is relieved by rearrangement with Lewis acids to the onho,rneta-bridged ketone (1 3). The natural phenols may be biogenetically related to diarylheptanoids.THE stem bark of Mypica nagi (Myricaceae) (reputed to be a fish poison) has been stated 2 to contain the rotenoid (I) among its phenolic constituents, with a t r a n s -~/ c ring fusion of unspecified absolute configuration, and a previously all assigned a C ~S -B / C junction (6aSJ12aS) with ring E attachment, if present,, isoprenoid (or degraded isoprenoid) in character. We have attempted reisolation of the claimed rotenoid, without success. t r 11 10 hexadienyl substituent in ring E. Both reported The phenolic fractions from M . nagi have instead features would be unique among natural rote no id^,^ yielded two unusual meta-bridged biphenyls, myricanol, t Professor Seshadri has informed us that the rotenoid assigne v. K*shnamoodhy, N. R. Krisnaswamy, and T. R. seshadri, ment should now be withdrawn.

Diarylheptanoid Sulfates and Related Compounds from Myrica rubra Bark

“…1,2 In previous phytochemical studies, some diarylheptanoids including myricanol (5) 3 and myricanone (6) 3 were isolated from the bark of M. rubra. 4,5 Their biological activities such as melanogenesis inhibitory effects, 5 antiandrogenic activity, 6 and inhibitory effects against NO production in lipopolysaccharide-activated peritoneal macrophages 7 were also reported.…”

Isolation of Macrocyclic Metacyclophanes From the Attempted Synthesis of [7.0]Metacyclophanes of the Myricanone Series by Thorpe-Ziegler - Intramolecular Cyclization of Diaryls Substituted by ω-Cyanoalkyl Chains

“…We next chose to synthesize a rather simple diaryl bearing on each ring a cyanopropyl chain, as a potential precursor for trideoxyasadaninene (3). The diaryldicarbaldehyde 16 was generated from the aryl iodide 15 by an Ullmann reaction (Scheme 3).…”

“…(2) (Figure 2) by Whiting and his co-workers [3] in 1970 from the stem bark of Myrica nagi, used in folk medicine, approximately 25 different diarylheptanoids of this type have been reported. Related natural products such as porson, [4] trideoxyasadaninene (3), [5] garugarin, [6] etc, have also been identified from other plant sources.…”

A Review on Ethnomedicinal, Phytochemical and Pharmacological Aspects of Myrica esculenta

“…The ethanol extract of bark at dose of 75 mg/kg given by oral route was found to exhibit remarkable antiasthmatic activity through several mechanisms which include: antianaphylactic activity in guinea pigs induced by egg albumin, spasmolytic activity Tannin, ascorbic acid Fruits [13,21,55] Gallic acid Bark [56,57] , fruits [58] , leaves [59] Catechin, cholorogenic acid, p-coumaric acid, caffeic acid, trans-cinnamic acid, ellagic acid Fruit [58] Ethyl-β-D-glucopyranoside; 3-hydroxybenzaldehyde, isovanillin, 4-(hydroxymethyl) phenol, 4-methoxybenzoic acid Leaves [59] Castalagin, epigallocatechin-3-O-gallate; epigallocatechin-(4β→8)-epigallocatechin-3-O-gallate; 3-O-galloylepigallocatechin-(4β→8)-epigallocatechin-3-O-gallate Bark [56] Flavonoids: Myricetin Bark [60,61] , fruits [19] , leaves [62] Quercetin Leaves [63] Flavonoid Glycosides: Myricitrin (myricetin 3-O-rhamnoside) Bark [61] , leaves [59,62] Flavone 4'-hydroxy-3',5,5'-trimethoxy-7-O-β-D-glucopyranosy) (1→4)-α-Lrhamnopyranoside; flavone 3',4'-dihydroxy-6-methoxy-7-O-α-L-rhamnopyranoside Leaves [63] myricetin [61] Steroids: β-sitosterol Bark [12,64] , leaves [59,63] Taraxerol Bark [12,64] Stigmasterol Bark [57] β-rosasterol, daucosterol Leaves [59] β-sitosterol-β-D-glucopyranoside Leaves [63] Ionones: Corchoionoside C; (6S,9R)-roseoside Leaves [62] Diarylhetanoids: Myricanol Bark [65,56,66] , leaves [59,62] Myricanone Bark [56,66] , leaves …”