602. Synthesis of 1,2,3,4-tetrahydro-7-hydroxy-4-isopropyl-1,6-dimethylnaphthalene. A degradation product of copaene

Abstract

By WESLEY COCKER and D. M. SAINSBURY , 4 raceinic form of 1,2,3,4-tetrahydro-'7-hydroxy-4-isopropyl-1,6-dinieth~lnaphthalene (I; R = H, R1 = I Pri) has been shown to be identical in gross structure with an optically active form derived from copaene (11).THE structure of copaene has recently been revisedOne of its derivatives was the phenol ( I ; R = H, R1 = Pri) which has now been shown to be identical in gross structure with a synthetic specimen of a compound of this structure.and shown to be (11).Condensation of methyl o-tolyl ether with isobutyryl chloride afforded 4-methosy-3rnethylisobutyrophenone (111), which on reaction with ethyl bromoacetate and zinc gave ethyl 3-hydroxy-3-(4'-methoxy-3'-methylphenyl) -4-methylpent anoate (IV) . This was dehydrated, giving ethyl 3-(4'-rnethoxy-3'-methylphenyl)-4-methylpent-2-enoate (V;It was therefore hydrolysed with methanolic potassium hydroxide giving a mixture from which the acid (V; R = H, R1 = Pri, irz = 0) and p-(4-methoxy-3-methylphenyl)-yy-dimethylbutyrolactone (VI) were isolated by acidification. The identity of the latter was confirmed by its infrared and n.m.r. spectra.

Synthetic studies on CP-225,917 and CP-263,114: concise synthesis of the bicyclic core using an intramolecular Mukaiyama aldol reactionElectronic supplementary information (ESI) available: crystal data for 13a. See http://www.rsc.org/suppdata/p1/b2/b202752f/

“…Coupling constants are measured in Hertz. The multiplicities in 13 C spectra were determined by DEPT experiments. Infra-red spectra were run on a Perkin-Elmer 1605 FT-IR machine from 4000-600 cm Ϫ1 .…”

Polyphosphoric Acid in Organic Synthesis

“…The transformation of the acid 10 to dihydronaphthalene 11 is accomplished in two steps: (i) cyclization with PPA and (ii) treatment of the resulting tetralone with methylmagnesium iodide. Oxidation of 11 with OsO 4 /NMMO.H 2 O in acetone gives a mixture of diols 12 (Cocker & Sainsbury, 1965) which is oxidized (Bowers etal., 1953) to yield a mixture of ketone 13 and lacinilene C methyl ether 14. Treatment of the mixture with dicyanodichlorobenzquinone (DDQ) provides the natural product 14 in 27% yield.…”