The total synthsis off linear anthrasteroids.
The aim of the project was to synthesize linear anthrasteroid analogues of testosterone, 19-nortestosterone and estradiol. A total synthesis of (+/-)-7,11-cyclo-8,9-seco-19-nor-testosterone, (+/-)-7,11-cyclo-8,9-secoestradiol and (+/-)-1beta-t-butoxy-9a,11abeta-dimethyl-1,2,3, 3aalpha, 4, 4aalpha, 5,8,9, 9a,10,10alphabeta,11,11a-tetradecahydro-7-cyclopent[b]anthrac-enone was accomplished. The synthesis presented provides a short, direct route to linear anthrasteroid analogues. This compares favourably with the synthesis reported by S. Aoyama and K. Sasaki, which involves complex transformations of steroids.The synthetic route involved the synthesis of the trans-bicyclic hydrindan, (+/-)-1beta-t-butoxy-7abeta-methyl-3aalpha,4,7,7a-tetrahydro-5(6H)-indanone, using the synthetic pathway developed by Z.G. Hajos and D.R. Parrish. This intermediate was regiospecifically annulated to give the novel tricyclic enone, (+/-)-1beta-t-butoxy-9abeta-methyl-l,2,3,3aalpha,4,7,8,8abeta,9,9a-decahydro-6-benz[f]indenone via two different routes. Thestereochemistry of the new ring junction was elucidated by using H n.m.r. spectroscopy and the lanthanide shift reagent Eu(FOD)[3].Further regiospecific annulation of the tricyclic enone gave the novel linear tetracyclic compound, (+/-)-1beta-t-butoxy-lla-methyl-1,2,3,3abeta,4,4abeta,5,8,9,9abeta,10,10abeta,11,11a-tetradecahydro-7-cyclopent[b]anthracenone. The t-butyl group of this compound was removed to give (+/-)-7,11-cyclo-8,9-seco-19-nortestosterone, or the A-ring was aromatized and the t-butyl group cleaved to give (+/-)-7,11-cyclo-8,9-seco estradiol.The synthesis of linear anthrasteroid analogues of testosterone was accomplished by regiospecific methylation of the tricyclic enone to give the novel compound (+/-)-1betat-butoxy-7,9abeta-dimethyl-1,2,3,3a?,4,7,8,8abeta,9,9a-decahydro-6-benz[f]indenone. Regiospecific annulation of this compound gave a mixture of stereoisomers,(+/-)-1beta-t-butoxy-9abeta,11aB-dimethyl-1,2,3,3abeta,4,4a,5,8,9,9a,10,10abeta, 11, 11a-tetradecahydro-7-cyclopent[b]anthracenone and (+/-)-1beta-t-butoxy-9ad, 11abeta-di-methy 1-1,2,3,3aA, 4,4aA, 5,8,9,9a,10,10abeta,11, 11a-tetra-decahydro-7-cyclopent[b]anthracenone.
Networked Digital Library of Theses and Dissertations
Sheffield Hallam University (United Kingdom).