Process for preparing 4-hydroxy-2-cyclopenten-I-ones, 2-methyl-2,5-dimethoxy-2,5-dihydrofurans and a process for their preparation.

摘要

A novel process for producing cyclopentenolones, useful intermediates for producing agricultural chemicals and prostaglandins of the formula (I),
<Chemistry id="chema01" num="0001"><Image id="ia01" he="23" wi="57" file="IMGA0001.TIF" imgContent="chem" imgFormat="TIFF" inline="no" /></Chemistry>wherein R<Sub>1</Sub> is a hydrogen atom or a lower alkyl group, and R<Sub>2</Sub> is a hydrogen atom, a lower alkyl, lower alkenyl or lower alkynyl group or a group of the formula,
<Chemistry id="chema02" num="0002"><Image id="ia02" he="12" wi="25" file="IMGA0002.TIF" imgContent="chem" imgFormat="TIFF" inline="no" /></Chemistry>(in which R<Sub>4</Sub> is a hydrogen atom, a methyl group or a halogen atom), -CH<Sub>2</Sub>-CH=CH-(CH<Sub>2</Sub>)<Sub>3</Sub>-CO<Sub>2</Sub>R<Sub>5</Sub>, or -(CH<Sub>2</Sub>)<Sub>5</Sub>-CO<Sub>2</Sub>R<Sub>5</Sub> (in which R<Sub>5</Sub> is a hydrogen atom or a lower alkyl group), but R<Sub>1</Sub> and R<Sub>2</Sub> are not a hydrogen atom at the same time, characterized in that said cyclopentenolones are derived from a starting material of the formula (III),
<Chemistry id="chema03" num="0003"><Image id="ia03" he="24" wi="51" file="IMGA0003.TIF" imgContent="chem" imgFormat="TIFF" inline="no" /></Chemistry>through intermediates of the formulae (IV), (V) and (II),
<Chemistry id="chema04" num="0004"><Image id="ia04" he="33" wi="88" file="IMGA0004.TIF" imgContent="chem" imgFormat="TIFF" inline="no" /></Chemistry>Many of the intermediates are novel compounds.