Nopinone

Nabilone (37) is a synthetic 9-ketocannabinoid with antiemetic properties. One of the best of the various published routes to nabilone starts with the enolacetate of nopinone (33), which on short heating with lead tetraacetate undergoes allylic substitution to give Treatment with p-toluene-... 

A terpene yielding isofenchyl alcohol on hydration, which Wallach considers to be one of the fenchenes, was artificially prepared by converting nopinone into a hydroxy ester by means of bromoacetic ester and zinc-dust. The hydroxy ester is dehydrated by potassium bisulphate, and so yields an unsaturated ester, which on saponification yields an acid from which the terpene results by distillation. This fenchene has the following characters —... 

Following this procedure, optically active sapphyrin 58 can be obtained using the enantio-merically pure aldehyde (1./ )-(+ )-nopinone.19... 

The asymmetric Michael addition of chiral nonracemic ketone enolates has most frequently been used as part of the Robinson annulation methodology in the synthesis of natural products171-172. The enolates are then derived from carbocyclic chiral ketones such as (+)-nopinone, (-)-dihydrocarvone, or (-)-3-methylsabinaketone. 

The ligands derive their chirality from the ring bearing the phosphorus atom, synthesized from (+)-camphor (R=H) or (+)-nopinone (R=CH3) (Scheme 29.9). 

In addition to the characteristic CH stretching VCD, a number of molecules that are strocturally similar to 3-methylcyclohexanone exhibit characteristic ROA features in the skeletal region below 700 cm. Figure 6 (11). In particular, a bisignate couplet near 500 cm is observed in six-membered ring compounds with a carbonyl substituent [(-F)-pulegone(73), (-F)-camphor (74), (-t-)-3-brom-ocamphor (74), (+)-nopinone (75)] and a broad low frequency couplet is observed in ketones with a 3-methyl substituent (75). The ROA of 3-methylcyclohexanone exhibits a third characteristic couplet near 400 cm. In all cases the sense of the observed couplets correlates with the absolute configuration of the most stable chair conformation. 

The ciT-substituted cyclobutane ester 502 is of interest as intermediate for the synthesis of carbocyclic 503 (equation 218). Ring opening of the bicyclic (-l-)-Nopinone 501... 

This is supported by studies of the aerosol composition in forested areas. For example, Kavouras et al. (1998) identified cis- and tram-pinonic acids as well as pinonaldehyde and nopinone in particles in a forest in Portugal. The diurnal variations of the pinonic acids and formic acid were similar, peaking in the afternoon as expected if they were formed by the reaction of O, with a-pinene. On the other hand, the concentrations of pinonaldehyde, expected from the oxidation of a-pinene by OH, O, and NO, and nopinone, from the oxidation of j3-pinene, were the smallest in the after-... 

Another almost identical example is the pyrolysis of 6,6-dimethylbicyclo[3.1, l]heptan-2-one (nopinone, 18), whose corresponding diradical also enjoys stabilization by an adjacent carbonyl group. Thus, at 570 °C, 18 is converted substantially to the secondary ene products cis-2-methyl-3-isopropenylcyclopentanone (19) and /ra .s-2-methyl-3-isopropenylcyclopentanone (20), along with a small amount of the hydrogen transfer product 4-isopropenylcyclohexanone (21).100... 

Similarly, (ft)-( + )-6,6-dimcthylbicyclo[3.1, l]heptan-2-one [(R)-( + )-nopinone, 59] undergoes boron trifluoride promoted cyclobutane cleavage to give in 68% yield (4/ )-l-acetoxy-4-(2-acetoxy-2-propyl)cyclohex-l-ene (60).168,169... 

New examples of application appear regularly. In the following one [248] phenylsulfenylation of nopinone (4) was followed by oxidation to the sulfoxide. Pummerer rearrangement of the latter led directly to the a-phenylthio substituted a-unsaturated ketone (6) (overall yield 94%), starting material for further elaboration of natural sesquiterpene synthesis via 4,4-disubstituted nopinones (7). 

Nussim and Mazur (65) have observed that under mild basic conditions, the steroid derivatives 145, 147, and 149 yield specifically the rearranged ketones 146, 148, and 150 respectively, and Paukstelis and Macharia (56) found that treatment of 151 with sodium methoxide gave nopinone 152. Compounds J42, 145. 147. and I49 correspond to conformation J38 whereas that of 151 is similar to 139. 

Nopinone, see 6,6-Dimethylbicyclo[3.1.1]heptan-2-one, 3169 Norspermidine, see 3,3 -Iminobispropylamine, 2583a N5 tetraazidoborate, see Pentazonium tetraazidoborate, 0153b... 

The internal volume of the capsule (190-200 A3) cannot be empty, and the inclusion of a suitable guest (often the solvent) is a necessary condition for the dimerization. Various organic molecules (for example, (lR)-(+)-nopinone, (lR)-(+)-cam-phor, [32b,c]) have been included in the cavity [35], and the upfield shifts of their 1 H NMR signals provide an independent proof of the formation of dimeric capsules,... 

BicycIo[3,l,l]heptanes.—An 0-/3-D-glycoside of (-)-cis-chrysanthenol (208) has been isolated from Dicoria canescens302 and nopinone from the essential oil of Piper nigrum.96... 

Both (+)-nootkatone (566) and its (+)-4-isomer (565) have been synthesized from (+)-nopinone (564) (Scheme 69). ° On the other hand, Hiyama et have used a completely different approach for the synthesis of nootkatone (566) (Scheme 70) which involves as a key step the acid-induced cyclopentenone annulation. In an alternative route to eremophilane and valencane sesquiterpenes, NM et have used a stereoselective intramolecular Diels-Alder... 

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