1502610 Cyclopenta[b]furanones IMPERIAL CHEMICAL INDUSTRIES Ltd 3 Nov 1975 [12 Dec 1974] 53757/74 Heading C2C The invention comprises a process for the preparation of racemic cyclopenta[b]furanones of the Formula VI wherein RSP2/SP is a phenyl or naphthyl radical which is optionally substituted by one or more substituents selected from halogen atoms, C 1-4 haloalkyl, C 1-4 alkoxy, C 1-4 alkyl, C 2-4 alkenyl, di-(C 1-4 alkyl)amino, hydroxy or phenyl radicals, and RSP3/SP is benzoyl or 4-phenylbenzoyl by (1) the hydrogenolysis of racemic 4#-dimethoxymethyl - 3,3a#,4,5,6,6a# - hexahydro - 5α - hydroxy - 6# - iodo - 2H - cyclopenta[b]furan - 2- one to give racemic 4#-dimethoxymethyl-3,3a#,4,- 5,6,6a# - hexahydro - 5α - hydroxy - 2H - cyclopenta[b]furan-2-one; (2) the hydrolysis of the product from stage (1) to give racemic 3,3a#,4,- 5,6,6a# - hexahydro - 5α - hydroxy - 2 - oxo - 2H- cyclopenta[b]furan - 4# - carbaldehyde; (3) the reaction of the product from stage (2) with phosphonates of the formula wherein RSP4/SP is C 1-6 alkyl, in the presence of bases, to give racemic cyclopenta[b]furan-2-ones of the Formula VI above in which RSP3/SP is hydrogen; (4) the acylation of the products from stage (3) with reactive derivatives of benzoic acid or 4- phenylbenzoic acid; and the racemic cyclopenta[b]furan-2-ones of the Formula VI above in which RSP3/SP is hydrogen. Reference has been directed by the Comptroller to Specifications 1,409,842 and 1,427,541.
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