Process for preparing cyclopropyl alkyl ketones and 4,5-dihydroalkylfurans
AssigneeHuels Aktiengesellschaft
InventorsManfred Kaufhold, Marcel Feld
Life of this patent
Estimating the term…
Abstract
The invention relates to a novel process for the simultaneous preparation of cyclopropyl alkyl ketones and 4,5-dihydroalkylfurans from 3-acyltetrahydrofuran-2-ones using a metal salt according to the diagram ##STR1## In the reaction, N-alkyllactams and/or N-acylmorpholines which are high-boiling and only slightly miscible with water are used. By charging the solvent, the metal salt and the 3-acyltetrahydrofuran-2-one in a molar excess with respect to the metal salt, heating the mixture to 160.degree. to 220.degree. C. and metering in further 3-acyl-tetrahydrofuran-2-one, the desired products are obtained in high yields. The metal salt can moreover be recovered in a simple manner by washing with water.
Claims7
A process for the simultaneous preparation of cyclopropyl alkyl ketones of formula I and 4,5-dihydro-2-alkylfurans of formula II from 3-acyltetrahydrofuran-2-ones of formula III ##STR7## where R.sub.1 is alkyl having 1 to 4 carbon atoms, cyclohexyl or phenyl and R.sub.2 is H, alkyl having 1 to 4 carbon atoms or phenyl, which comprises reacting a 3-acyltetrahydrofuran-2-one of formula III with a metal salt in a high-boiling solvent at 160 to 220.degree. C., wherein the solvent is at least one of an N-alkyllactam of formula IV ##STR8## where R.sub.3 is alkyl having 4 to 12 carbon atoms, cycloalkyl, benzyl or substituted benzyl according to ##STR9## R.sub.4 is alkyl having 1 to 4 carbon atoms, and n=1 to 6, and or an N-acylmorpholine of formula V ##STR10## where R.sub.5 is alkyl having 4 to 12 carbon atoms, cycloalkyl, benzyl or substituted benzyl according to ##STR11## R.sub.8 alkyl having 1 to 4 carbon atoms, R.sub.6 and R.sub.7 are independently H or alkyl having 1 to 4 carbon atoms and
- n+m=1 to 10,
- and wherein the reaction is initially carried out by combining a molar excess of 3-acyltetrahydrofuran-2-one of formula III with respect to the metal salt, with the metal salt and solvent, heating to 160.degree. to 220.degree. C., then adding additional 3-acyltetrahydrofuran-2-one of formula III, while at the same time distilling off cyclopropyl alkyl ketone of formula I and 4,5-dihydro-2-alkylfuran of formula II.
Dependencies are inferred from the claim text.