Producing substituted 2-cyclopentenones
AssigneeSCM Corporation
InventorT. L. Ho
Life of this patent
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Abstract
A process is provided for producing substituted 2-cyclopentenones represented by the general formula: ##STR1## where R.sup.1, R.sup.2, R.sup.3, R.sup.4, and R.sup.5 are hydrogen or lower aliphatic hydrocarbyl groups. The process comprises treating a nitroalkane with a substituted acrylic acid ester in the presence of a base, followed by saponification, to yield a substituted 4-nitropentanoic acid which acid is then treated with strong acid under dehydrative conditions to yield the subject 2-cyclopentenone.
Claims12
A process for preparing a 2-cyclopentenone which comprises the steps of chemically adding an alpha,beta-unsaturated aliphatic carboxylic acid ester to a secondary nitroalkane containing at least 2 carbon atoms in the liquid phase and in the presence of a basic catalyst selected from an alkali metal hydroxide, pyridine, and a quaternary ammonium hydroxide to form a nitroalkanoate ester, converting said nitroalkanoate ester into the corresponding carboxylic acid by saponification and acidification and dehydratively cyclizing said corresponding acid in the presence of a strong mineral acid to form said 2-cyclopentenone.
A process for preparing a 2-cyclopentenone represented by the general formula:
- ##STR10## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, and R.sup.5 are independently selected from hydrogen and C.sub.1 -c.sub.10 aliphatic hydrocarbyl groups;
- which comprises the steps of chemically adding an alpha, beta-unsaturated aliphatic carboxylic acid ester represented by the general formula:
- ##STR11## where R.sup.2 and R.sup.5 have the meaning defined above, and R.sup.6 is a C.sub.1 -C.sub.6 aliphatic hydrocarbyl group, to a secondary nitroalkane represented by the general formula:
- ##STR12## where R.sup.3 and R.sup.4 are as defined above, in the liquid phase and in the presence of a basic catalyst selected from an alkali metal hydroxide, pyridine, and a quaternary ammonium hydroxide to yield a nitroalkanoate ester represented by the general formula:
- ##STR13## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are as defined above, converting said nitroalkanoate ester (IV) to the corresponding carboxylic acid by replacing the R.sup.6 radical with hydrogen by saponification and acidification;
- and dehydratively cyclizing said corresponding acid in the presence of a strong mineral acid to yield said 2-cyclopentenone (I) of formula above.
The process for preparing a 2-cyclopentenone which comprises treating a nitropentanoic acid with a strong mineral acid under dehydrative conditions to effect cyclizing to form a 2-cyclopentenone.
A process for preparing a 2-cyclopentenone which comprises the step of dehydratively cyclizing a compound having the general formula:
- ##STR14## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, and R.sup.5 are independently selected from hydrogen and C.sub.1 -C.sub.10 aliphatic hydrocarbyl groups, with a strong mineral acid under dehydrative conditions to effect cyclization and form a 2-cyclopentenone.
Dependencies are inferred from the claim text.