The chemistry of the Western Australian rutaceae—VI

Constituents of the Cultivated Mulberry Tree

“…Irradiation on the proton doublet at ö 3.02 changed the proton quartet at ô 2.52 into a doublet (J = 7.5 Hz), and irradiation on the proton multiplet at b 2.28 changed the proton quartet at ö 2.52 into a doublet U = 9.6 Hz). The chemical shifts and the splitting patterns of these signals are similar to those of the corresponding protons of compounds, such as cannabicy-do1 (VIII) [11,12,15] and hydroxyeriobrucinol (IX) [14], which have the ,,cy-do1" (VII) unit in the formula. Moreo- The 1H NMR spectrum of II in pyridine-d5 showed the meta-coupled doublet (J = 2 Hz) at ö 6.38 (C6-H) and ö 6.47 (C8-H) which indicated that the A ring was unsubstituted at the 6-and the 8-positions [8].…”

“…The mass spectrum exhibited, together with a molecular ion peak at m/z 422, strong peaks at m/z 407 (M-CH3), 404 (M-H2O), and 153 (IV) [9]. Moreover, the base peak, m/z 339 (C,9H,506), appeared most significantly, which corresponded to the oxonium ion (V) expected for flavanone derivatives containing a pyran ring fused to the aromatic nucleus [10][11][12][13][14]. The combined evidence thus pointed strongly to the partial structure (VI) plus a C5 unit.…”

New Cannabinoid-Like Chromane and Chromene Derivatives from Rhododendron anthopogonoides

“…The 13 C-NMR spectrum exhibited the presence of 18 carbon signals comprising a carboxy, a benzene ring, four methyls, two methylenes, three aliphatic methines, and two quaternary carbons including an oxygen-bearing quaternary carbon. The presence of a cyclol [4][5][6] unit, characterized by a dihydropyran, a cyclopentane and a cyclobutan ring, was deduced from the 1 H-1 H correlation spectroscopy (COSY) and heteronuclear multiple bond connectivity (HMBC) spectra. The HMBC correlations of H 3 -16 with C-4a, C-5, and C-6; H-8 with C-4a, C-6, C-7, and C-8a; and H-4 with C-2, C-4a, C-5, and C-8a, indicated that a methyl group, a carboxy group, and a chelated hydroxy group were located at C-5, C-6, and C-7, respectively.…”

Synthesis of (±)-eriobrucinol and regioisomeric monoterpenoid coumarins, using intramolecular cycloadditions

“…For synthesis of eriobrucinol (8) and its regioisomers (13) and ( 16), we required the chromens (12), (15), and (18). Chromenylation of 5,7-dihydroxycoumarin, using citral and pyridine, has been described by us in another context; the formation of only two major isomers, (12) and ( 15 (10) observed, and methyl resonances attributable to a single cyclol product had appeared. Isolation through preparative layer chromatography (p.1.c.)…”