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US 5,296,617 AGranted
Process for preparing 1,3-dioxoles
AssigneeAusimont S.p.A.
InventorsWalter Navarrini, Simonetta Fontana
Life of this patent
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Abstract
A process for preparing 1,3-dioxoles of formula: ##STR1## in which X.sub.1 and X.sub.3, like or different from each other, are F or H, X.sub.5 and X.sub.6, like or different from each other, are F or CF.sub.3, by dehalogenation reaction of the corresponding 4,5-dihalodioxolanes in the presence of a dehalogenation agent at a temperature ranging from +30.degree. to +130.degree. C. The starting dioxolanes are essentially in the isomeric form anti.
Claims10
A process for preparing 1,3-dioxoles of formula:
- ##STR7## wherein:
- X.sub.1 and X.sub.3, like or different from each other, are F or H,
- X.sub.5 and X.sub.6, like or different from each other, are F or CF.sub.3,
- which comprises the steps of:
- a) preparing a dioxolane of formula:
- ##STR8## wherein:
- X.sub.2 and X.sub.4, like or different from each other, are Cl or Br,
- X.sub.1, X.sub.3, X.sub.5 and X.sub.6 have the meaning defined hereinbefore, starting from reagents in which the halogens X.sub.2 and X.sub.4 are substantially in trans position, or by a process such that the anti/syn isomeric ratio in the resulting dioxolane is higher than the trans/cis isomeric ratio of the starting reagents;
- b) reacting said dioxolane with at least a dehalogenating agent at a temperature ranging from +30.degree. to +130.degree. C.;
- c) separating the dioxol (I) from the reaction product of step b).
7 more elements
Dependencies are inferred from the claim text.