Síntesis de espirobrasinoesteroides análogos de la 6-desoxocastasterona Synthesis of spirobrassinosteroids analogs of the 6-desoxocastasterone

• Main Authors: Martín A. Iglesias Arteaga, Vivian Leliebre Lara, Carlos Pérez Martínez, Francisco Coll Manchado
• Format: Article
• Language: English
• Published: Sociedade Brasileira de Química 1997-08-01
• Series: Química Nova
• Subjects: Spirobrassinosteroids; synthesis; RMN
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40421997000400004

<abstract language="eng">The synthesis of two new spirostanic analogs of the natural occurring brassinosteroid 6-desoxocastasterone (1) is described. The scheme consists in the formation and elimination of tigogenin mesylate followed by catalytic dihydroxylation of the resulting D2-steroid (3) and acetylation of the 2a, 3a-diol introduced.Treatment diacetate (5) with NaNO2/BF3.Et2O and chromatography in alumina led to a 23-keto (6) which on reduction produced the 23S alcohol (8) as major product. Saponification of the 2a, 3a-diacetoxy-23-keto compound (6) and the 2a,3a-diacetoxy-23-hydroxy compound (8) led to the spirobrasinosteroids (7) and (9).13C NMR and ¹H RMN characteristics derived from substitution at C23 are briefly discussed.