110187-19-4

The cyclopropanation of 2-n-hexylfuran with ethyl 8-diazo-7-oxooctanoate catalyzed by dirhodium tetraacetate as a key step for synthesis of ostopanic acid is reported.This reaction allowed the preparation of ethyl ostopanate (5) and its unstable regioisomer (10) in 58percent yield.Exposure of the mixture to a catalytic amount of iodine in dichloromethane afforded pure ethyl ostopanate, which was converted to the target compound in two steps.

A new and stereoselective synthesis is described as an easy route to ostopanic acid using a versatile reagent: (2E,4E)-5-bromopentadienal.

Ostopanic acid and ethyl 6-oxodocosa-2,4-dienoate were synthesized by a short route based on the palladium catalyzed isomerization of ynone and ynoic ester, respectively, using pent-4-ynal as a starting material.

The invention relates to ostopanic acid, ostopanic acid analogues and their preparation method and use. The preparation method provided by the invention is characterized in that based on a characteristic that the reaction of a Weinreb amide and a Grignard reagent can selectively stay in a ketone stage so that the overreaction is avoided, two side chains of the ostopanic acid analogue can be constructed and thus a series of the ostopanic acid analogues can be synthesized fast. The preparation method provided by the invention adopts easily acquired raw materials, allows mild reaction conditions and has simple processes. The ostopanic acid and the ostopanic acid analogues obtained by the preparation method have obvious antitumor effects.

Based on the discovery that phosphines could catalyse the isomerisation of triple bonds, the isomerisation of acetylenic derivatives was differentiated into two types: phosphine-catalysed and transition metal-catalysed.

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