Preparation of halogenovinyl-.gamma.-butyrolactones
AssigneeBayer Aktiengesellschaft
InventorReinhard Lantzsch
Life of this patent
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Abstract
Halogenovinyl-.gamma.-butyralactones, used as intermediates in the preparation of insecticidally active cyclopropanecarboxylic acid esters, and of the formula ##STR1## in which Hal represents F, Cl or Br, X represents H, F, Cl or Br and R.sup.1 and R.sup.2, which may be identical or different, each represents C.sub.1-4 -alkyl or R.sup.1 and R.sup.2, together with the adjacent C atom, form a cycloaliphatic ring with up to 7 C atoms, are produced by basic de-acetylation of the novel corresponding .alpha.-acetyl compounds. Syntheses are given for preparing the acetyl compounds, including novel intermediates of the formulas ##STR2##
Claims14
A process for the preparation of a halogenovinyl-.gamma.-butyrolactone of the formula ##STR20## in which Hal is F, Cl or Br,
- X is H, F, Cl or Br and
- R.sup.1 and R.sup.2 each independently is C.sub.1-4 -alkyl or R.sup.1 and R.sup.2, together with the adjacent C atom, form a cycloaliphatic ring with up to 7 C atoms, comprising deacetylating an acetyl lactone of the formula ##STR21## with a hypohalite at a temperature from -20.degree. to 100.degree. C.
An acetyl lactone of the formula ##STR39## in which Hal is F, Cl or Br,
- X is H, F, Cl or Br and
- R.sup.1 and R.sup.2 each independently is C.sub.1-4 -alkyl or R.sup.1 and R.sup.2 together with the adjacent C atom, form a cycloaliphatic ring with up to 7 C atoms.
Dependencies are inferred from the claim text.