A”-Unsaturated brassinosteroids

For the synthesis of the corresponding A -unsaturated brassinosteroid analogue 86 the A5-7-keto derivative 82 was reacted with toluene-4-sulfonohydrazine in dry tetrahydrofuran under anaerobic conditions at 75° C to give the corresponding tosylhydrazone, 85. Reductive elimination of compound 85 with lithium hydride in toluene at 100° C7 yielded (22R,23R,24S)-22,23-dihydroxy-28-homoergosterol (86), the structure of which was confirmed by spectral data.7 ... 

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