Tetrahedron Letters N0.40, pp. 4255-4256, 1968. Pergsmon Press. Printed in Great Britain.

SYNTHESIS UF RUBROSTEROHB,

A METABOLITE OF INSECT-MOULTIlVG SUBSTANCES FROM ACHYRANT EES RUBELOFUSCA

H. Hikino, Y. Hikino, and T. Takenot

Pharmaceutical Inetitute, School of Medicine, Tohoku Univereity, Sendai, Japan.

(Received in Japan 15 June 1968; received in UIC for publication 5 July 1968)

Rubmatemne (I)l) Is the novel steroid which has been isolated first from Aohyrenthee rubro-

fusca vight2) end later from 4. fauriei L&eilld et Vaniot ') (Amaranthaoeae). Since these

plenta aleo contain the Insect-moulting eubstencen, 2-4) ecdyatemne end inokoetemne, rubmstemne

lr considered to be most probably a metabolite of these steroids in the plants. M interest bio-

logically is that rubmeterone chows little insect-monltlng hormone activity, while it still ex-

hibits high stimulating effect on protein synthesis in mouee. A eyntheeie oonfixaing both q true-

ture and absolute configuration is now presented.

2g-&etoxy-3~,14a-dihydm~-3g-pregn-7-ene-6,2G-dione (II), derived fmm ecdystemne ') which

has already been eyntheeieed, 6, was hydrolyzed to give the known methyl ketone (111)7) which on

pertrifluoroaoetio acid oxidation afforded the acetate (IV), m.p. 226-+?2G*, Y_ 3420 (hydmxyl),

1727, 1242 (aoetoql), and 1645 cm" (cyclohexenone)? Eydrolyeie of the acetate (IV) with potae-

slum carbonate In aqueous methanol yielded the tetra-ol (V), m.p. 268-27W, V,, 3340 (hydmxyl)

and 1648 cm" (cyclohexenone). When the corresponding acetonide (VI), m.p. 246-248*, vmax 3360

(hydrolryl) and 1645 on" (cycl h o exenone), prepared with acetone in the preeenoe of ptoluenesul-

fonio acid, wae oxidised with chromium trioxide-pyrldine complex the ketone (VII), m.p. 247448.5*,

Y 111(11 3400 (hydroxyl), 1731 (cyclopentanone), and 1677 cn-' (cyolohexenone), was obtained. Treat-

ment of the acetonide (VII) with aqueous ethanol under reflux furnished the diketo-trlol, a.p. .

246448' (decomp.), Y_ 3410 (hydroxyl), 1741 (oyclopentanone), and 1641 cm" (oyclohexenone),

which wae Identified ae the natural rubmetemne (I).

Preparation of theee intemedlatee (II-VII) with a variety of struotural modifications led

ue to exemine their biological activities. In the %rOODhWS teet, however, none of then gave

positive reeponeee when lnjeoted in a doeage of 1 ug per irolated larval abdcmen. On the other

hand, the methyl ketone (III) Induced enhancement of protein anabolien in mouee liver, though the

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4256 No.40

0

AC XLP IhI &

0 II

other analoguee (II, IV-VII) mhowed no activity. These data will oontribate to the mtruoture-

activity correlation atudy on the eodyaone derivativee.

We thank &of. M. Uohiymaq thin Institute, for the biological ammay (moume).

FCOTNOTE AND REFERENCES

* Melting points are unoorreoted. IR epeotra were determined in KRr dimk.

1) T. Takemoto, Y. Hikino, H. Hikino, S. Osawp, and N. Nimhimoto , Tetrmhedron Lettmrr, in premm.

2) T. hlcmmoto, 9. Ogawa, N. Nimhimoto, md S. Taniguohi, Yakunaka 'Zamahi, 6J, 1478 (1967).

3)

4)

5)

T. Wmmoto, S. Ogawa, 1. Nishimoto, B. Rirayama, and 9. Taniguohi, uapublimhed data.

T. luemoto, S. Ogawa, and N. Nimhiaoto, Yakwaku Zmmhi, 8J, 325, 1469, 1474 (1967).

T. T&moto, Y. Hikino, 5. Arihara, H. Hikino, S. Ogawa, and N. Nimhimoto, Mirahedron Letterm,

&$e,t 2475.

6) C. Hiippi and J. B. Siddall, J. her. Cham. Soo-., t3$ 6790 (1967).

7) J. B. Siddall, D. H. 9. Horn, and E. J. Middleton, Chem. COPI., 2!6,& 899.