7α-Alkylation and 7,7-bis-alkylation of 20-hydroxyecdysone with propargyl bromide in a lithium–ammonia solution and catalytic reductive spirocyclization of 7,7-bis(2-propyn-1-yl)-14-deoxy-Δ8(14)-20-hydroxyecdysone

• A convenient method for spirocyclization of 20-hydroxyecdysone was proposed.
• For the first time an alkynylation of 20-hydroxyecdysone with propargyl bromide was accomplished.
• The structures of compounds were confirmed by 1D and 2D NMR analysis and MALDI TOF.

7α-Alkylation and 7,7-bis-alkylation of 20-hydroxyecdysone with propargyl bromide in a lithium–ammonia solution resulted in the formation of 7α-(2-propyn-1-yl)- and 7,7-bis(2-propyn-1-yl)-14-deoxy-Δ8(14)-20-hydroxyecdysone in 92% and 75% yield respectively. Upon catalytic hydrogenation (10% Pd–C) of 7,7-bis(2-propyn-1-yl) derivative spirocyclization occurs by geminal 2-propyn-1-yl groups.

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