Batrachotoxinin bromobenzoate

Fig. 9. Sections from a three-dimensional electron-density map for the O-p-bromobenzoate derivative of batrachotoxinin A (2). The contours are spaced by 2e/A3.

Batrachotoxin, not unexpectedly in view of its use as a dart poison by South American Indians, is an extremely toxic substance. The LDjq on subcutaneous injection in mice is about 40 ng. Homobatrachotoxin is only slightly less toxic, while batrachotoxinin A is 500-fold less toxic. The nature of the ester function at the 20a position is of critical importance to toxicity. Thus, the 20a-benzoate of batrachotoxinin A is fully as toxic as batrachotoxin, whereas the 20a-4-bromobenzoate has very low toxicity. For a summary of the toxicides of natural and synthetic batrachotoxins, see Ref. 5. 

Gilardi, R. D. The absolute configuration of a steroidal substance, the 0-p-bromobenzoate derivative of batrachotoxinin A. Acta Crystallogr. B26, 440—441 (1970). 

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