1. Field of Invention
The present invention relates to a process for producing pyripyropene derivatives useful as pest control agents and more specifically relates to a process for producing pyripyropene derivatives that have acyloxy at the 1-position and 11-position and hydroxyl at the 7-position thereof.
2. Background Art
Pyripyropene derivatives having acyloxy at the 1-position and 11-position and hydroxyl at the 7-position thereof are compounds that have control effects against pests, as described in WO 2006/129714.
WO 2006/129714 and Japanese Patent Application Laid-Open No. 259569/1996 disclose a process for producing pyripyropene derivatives having acyloxy at the 1-position and 11-position and hydroxyl at the 7-position thereof. According to the production process, the pyripyropene derivatives are purified or isolated from a plurality of products produced by nonselective hydrolysis of acyloxy using a 1,7,11-triacyloxy compound as a starting compound.
Further, Japanese Patent Application Laid-Open No. 259569/1996 describes the use of a combination of protective groups for the synthesis of pyripyropene derivatives. Journal of Antibiotics Vol. 49, No. 11, p. 1149 (1996), Bioorganic Medicinal Chemistry Letter Vol. 5, No. 22, p. 2683 (1995), and Japanese Patent Application Laid-Open No. 269065/1996 disclose a synthesis example that introduces acyl into the 7-position by utilizing a protective group.
WO 2009/022702 discloses a process for producing 1,11-diacyl-7-deacetylpyripyropene from 1,7,11-trideacetylpyripyropene utilizing a protective group.
Pyripyropene derivatives having acyloxy at the 1-position and 11-position and hydroxyl at the 7-position have hitherto been produced through a plurality of steps using non-selective hydrolysis of a 1,7,11-triacyloxy compound and using a protective group. Accordingly, in the production of pyripyropene derivatives on a commercial scale, a further enhancement in production efficiency, for example, through a reduction in production cost, an improvement in yield, simplification of purification and isolation, or a reduction in number of steps has been desired.