S,4 -Camphanic Acid

Figure 6.14 Examples of the application of normal-phase, radio-HPLC to the analysis of de novo biosynthetic pathways in bark beetles (Scolytidae). Derivatization of 14C-labeled ipsenol from Ips paraconfusus (A, B) and 14C-labeled ipsdienol from Ips pini (C, D) leads to expected retention time shifts of radioactivity for each compound and derivative. Derivatization of /. paraconfusus ipsenol with (2/= )-(+)-a-methoxy-a-(trifluoromethyl) phenylacetic acid (MTPA) leads to the formation of only one diastereomer [(4S)-(-)-ipsenoyl-(2 P )-2 -methoxy-2 -phenyl-2 - (trifluoromethyl) phenylacetate] indicating the de novo biosynthesis of highly pure (4S)-(-)-ipsenol (B) Derivatization of I. pini ipsdienol with (1 S)-(-)-camphanic acid leads to the formation of both diastereomers [(4R)- -)- and (4S)-(+)-ipsdienyl-(TS)-camphanates] indicating the de novo biosynthesis of approximately 90 percent-(4/ )-(-)-ipsdienol (D). Figures adapted from Seybold et al. (1995b).

The resolution of D,L-2-deoxy-2,2-difluoro-myo-inositol (l,4,5)-triphosphate with S(-)-camphanic acid chloride has been described." The D-enantiomer is a good analogue of Ins(l,4,5)P3 and a substrate for Ins(l,4,5)P3-5-phosphatase and 3-kinase. 

When distilled with phosphorus pentoxide, camphor yields cymene, and with iodine, carvacrol. Both of these bodies are para-derivatives of benzene. On oxidation with nitric acid camphor yields many acids, of which the chief are camphoric acid, CjgHjgO, camphanic acid, CjoHj O, and camphoronic acid, CgHj Og. The constitution of these acids has an important bearing on that of camphor. Many formulae have been suggested for camphor during the past few years, but that of Bredt is now universally accepted, and has received complete confirmation by Komppa s synthesis of camphoric acid. This synthesis confirms the formula for camphoric acid as—... 

The encouraging result of the trans-epoxy acylates with the chiral spiro compounds was appUed to the optically active system (Scheme 15). Asymmetric reduction of the enone 31 by Corey s method [72] afforded the allyl alcohol (-)-34 (90% ee). Epoxidation of (-)-34 by the stereoselective Sharpless epoxidation [73] afforded the cts-epoxy alcohol, cfs-(-)-35, as the sole product. The Mitsunobu reaction [74] of czs-(-)-35 with benzoic acid gave the trans-epoxy benzoate, trans- -)-36, (90% ee) in 89% yield. Treatment of trans-(-)-36 with BF3-Et20 afforded the optically active spiro compound (+)-37 in 89% yield with retention of the optical purity (90% ee). This means that the rearrangement occurs stereospecifically. The optically pure epoxy camphanate (-)-38 could be obtained after one recrystallization of the crude (-)-38 (90% de), which was obtained by the Mitsimobu reaction of cfs-(-)-35 with D-camphanic acid. The optically pure spiro compoimd (+)-39 (100% de) was obtained from the optically pure (-)-38 in 89% yield. 

Separation and Assay. Procedures for the separation, purification, and assay of carotenoids and retinoids by h.p.l.c., g.c., and g.c.-m.s. are given in an extensive article." Another, general, review includes information on the h.p.l.c. separation of retinoids.A particularly useful method has been developed for resolution and analysis of some carotenoid optical isomers.For example, (3R,3 R)-, (3S,3 S)-, and (3/ ,3 5)-astaxanthin were converted into the diastereomeric (-)-camphanic acid diesters, which were separated by h.p.l.c. This procedure has been used to analyse the isomeric composition of a natural astaxanthin sample. An h.p.l.c. procedure for separation of a-, P-, and y-carotenes (173)—(175) and lycopene (176) has been described." Several papers describe methods for the h.p.l.c. separation and purification of various retinal and retinol isomers and derivatives.A procedure for the preparative t.l.c. of oxidation products of retinyl acetate has been described,and a competitive protein-binding radioassay for retinoic has been reported. 

Trimethyl-3-oxo-2-oxa-bicyclo[2.2.1]heptane-l-carboxylic acid [(-)-1 -(1 S,4R)-camphanic acid]... 

Phenolic oxidation of the diphenolic amide 285 using potassium ferric (III) cyanide afforded (-l-)-iV-formyldibromonarwedine (286), which was reduced successively with lithium tri-s-butylborohydride (L-Selectride) and with LiAlH4 to afford ( )-261. Resolution of ( )-261 using rf-camphoric acid provided (-)- and (-l-)-galanthamines (261) through the camphanate derivatives 287 and 288 165) (Scheme 30). 

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