Quassinoid bitter principles

The rearrangement of 19 - 20, used in the synthesis of the quassinoid bitter principle ( )-amarolide (quassinoids is a generic name for terpenoids having the picrasanc skeleton, which show cytotoxic and antincoplastic properties)604, the rearrangements 0f 21fi05-607 and 22608 609 are further examples of (5,6 rearrangements. 

Contents R. Southgate and S. Elson Naturally Occurring P-Lactams. — I. Howe and M. Jarman New Techniques for the Mass Spectrometry of Natural Products. — P. G. McDougal and N. R. Schmuff Chemical Synthesis of the Trichothecenes. — J. Polonsky Quassinoid Bitter Principles II. 

Polonsky J, Baskevitch Z, Gottlefb HE, Hagamman EW, Wenkert E (1975) Carbon-13 Nuclear Magnetic Resonance Spectral Analysis of Quassinoid Bitter Principles. J Org Chem 40 2499-2504... 

Polansky J 1973 Quassinoid bitter principles. Fortschr Chem Org Naturst 30 101-150... 

Polonsky, J. Quassinoid Bitter Principles. In Fortschr. Chem. Organ. Naturstoffe Vol.30 (L. Zechmeister, ed.), p. 101. Wien-New York Springer. 1973. 

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