The Proton Magnetic Resonance Spectral Characteristics of Tricyclic Diterpenic Substances

Abstract

water and 10 ml. of 2 IV hydrochloric acid. The solution was stirred in the cold for 30 min. and then 1.06 g. of benzaldehyde was added. After 10 min. stirring at room temperature, solid began to appear in the mixture. The beige-colored solid was separated after 2 hr. yielding 2.15 g. (47.3%) of product melting at 107-111°with considerable bubbling. The product was purified by dissolving in cold ethanol and precipitating by the addition of water to yield a straw-colored solid, m.p. 109-111°d ec.

Reactivity of (3-Methylpentadienyl)iron(1+) Cation: Late-stage Introduction of a (3-Methyl-2Z,4-pentadien-1-yl) Side Chain

“…In particular, for 18 the singlet for Me-19 appears at  1.03 ppm while for 8 this singlet appears at  0.84 ppm. The upfield chemical shift for this signal of 8 is consistent with an axial ester group at C-9 14 . In addition, there is an nOE interaction observed between Me-19 and one of the H-12 protons of 18, while a NOESY interaction was observed between the Me-19 and the methyl ester of 8.…”

“…The filter bed was washed several times with ether, the combined ethereal extracts were washed with saturated NaHCO 3 , followed by water, dried (MgSO 4 ) and concentrated under reduced pressure. The residue was purified by column chromatography (SiO 2 , hexanes-ethyl acetate = 8:1 → 5:1 gradient) to afford (±)-11 (1.45 g, 44%) as a colorless oil, followed by a variable but minor amount of the cis-isomer (10 1,2,3,4,4a,7,8,8a-Octahydro-4a,5-dimethyl-2-methylene-1-naphthalenecarboxylic acid methyl ester (14). To a suspension of NaNH 2 (637 mg, 16.3 mmol) in dry toluene (41 mL) under N 2 , was added methyltriphenylphosphonium bromide (4.48 g, 12.5 mmol), and the mixture was heated at reflux for 3 h. During this time formation of the ylide was detected by change of the solution to a bright orange color.…”

Struktur von Fuerstion

“…die ausfiihrlichen Mcssungen von WENKERT und Mitarbcitern [5] a n zahlreichen Ditcr- (3,76), 303 (3,67), 260 (3,33), 299 (3,66), 317 (3,27), 237 (4,30), 286 (3,82), 396 (3,85) 255 (3,25), 289 (3,82) -220 (4.80), -294 (3.25). 280 (3,23), -300 (3,25), 220 (4,91), 278 (3,27), -300 212 (4,10), 261 (3,32), 337 (2,76) -255 (3,27), 315 (3,04), 404 298 (300), 345 (2,87), 520 (1,43) 320 (3,39), 335 (3,44) 328 (3,14) 315 ( ist zu schliessen, dass sich diese Isopropylgruppe an einem aromatischen Kcrn befindet.…”

The Total Synthesis of Salvinolone

“…The stereochemistry of the cis-fused AB rings in 6b was indicated by characteristic signals at 0.85 ppm. 6 Catalytic hydrogenation of 6 by 5% Pd-C afforded a mixture of 7a and 7b which was directly oxidized with CrO 3 -HOAc-H 2 O. 7 In this oxidation, the trans-fused 7a was converted into the monoketone 8 and the cis-fused 7b was converted into the diketone 9.…”