Ishwarane synthesis

Ishwarane (371) has been isolated from the petals of Cymbopetalum penduli-forum (Dunal) Baill. Last year, Kelly et al. reported the synthesis of isoish-warane (372) which they have now extendedto the synthesis of ishwarane itself. The enone (373) was converted in five steps into the ketol (374). Treatment of the tosylate of (374) with dimsyl sodium afforded the cyclized ketone (375) which gave ishwarane on Wolff-Kishner reduction. The complete details of the elegant synthesis of hinesol (376) by Marshall and Bradyhave now been published. 

A new type of. seco-ishwarane alcohol (724) has been identified in the roots of Aristolochia indica.326 This compound, which co-occurs with (+)-ledol (725), has antifertility properties when tested on mice. Its structure was deduced on the basis of spectral analysis together with its correlation with a derivative of ishwarane (726). A full report on the synthesis of ishwarone (727) has been presented.327... 

An alternative shorter synthetic route to ( )-ishwarane (512) cf. Vol. 8, p. 118) has been achieved by using a carbene insertion reaction to construct the tetracyclic framework (Scheme 49)/ The first synthesis of ( )-ishwarone (518),... 

Ishwarane (20) and ishwarone (25) are two novel tetracyclic sesquiterpenes which have been isolated from Aristolochia indica Linn, and other tropical plants a synthesis of ishwarane was reported by Kelly and his co-workers in 1971. Kelly and Alward have now effected an improved synthesis of the hydrocarbon, which... 

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