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US 7,351,851 B2Granted
Method for the production of 6,6,6-trihalo-3,5-dioxohexanoic acid esters
AssigneeLonza Ltd.
InventorsPaul Hanselmann, Wolfgang Wenger
Life of this patent
Estimating the term…
Abstract
A method for the production of 6,6,6-trihalo-3,5-dioxohexanoic acid esters of formula (I): in addition to the enols thereof and <I>E</I> and <I>Z</I> isomers, wherein X independently represents fluorine, chlorine or bromine and R1 represents alkyl, cycloalkyl, aryl or aralkyl. A method for the production of enol ethers of formula (Ib): and the enols thereof (E and Z isomers) wherein X and R1 have the above-mentioned meanings.
Claims3
A method for preparing compounds of formula:
- or an enol thereof, or an E or Z isomer thereof,
- in which X is in each case independently of one another fluorine, chlorine or bromine, and in which R1 is alkyl, cycloalkyl, aryl or aralkyl comprising (a) initially converting a compound of formula:
- in which X has the stated meaning, by reacting the hydroxyl group of the compound of formula II with a compound of the formula (R2O)2SO2 or with a compound of the formula Y—R2 in which Y is tosyl, chlorine, bromine or iodine, and in which R2 is in each case alkyl, cycloalkyl, allyl or benzyl, into a compound of formula:
- in which R2 and X each has the above-mentioned meaning, and (b) converting the compound of formula III by reaction with a metal alcoholate of the formula
- R
- 1
-
- O
- -
-
- 1
- n
-
- M
- n
- +
- in which R1 has the above-mentioned meaning and Mn+ is an alkali metal or alkaline earth metal cation and n =1 or 2, and (c) further treating with a strong acid, into a compound of formula I and/or an enol thereof and/or an E or Z isomer thereof.
14 more elements
A method for preparing an enol ether of the formula:
- or an enol thereof or, in each case, the E or Z isomer thereof, in which X is in each case independently of one another F, Cl or Br, and in which R1 is alkyl, cycloalkyl, aryl or aralkyl, and R2 is alkyl, cycloalkyl, allyl or benzyl, comprising (a) initially converting a compound of the formula:
- in which X has the stated meaning, by reaction of the hydroxyl group of the compound of formula II with a compound of the formula (R2O)2SO2 or with a compound of the formula Y—R2 in which Y is tosyl, chlorine, bromine or iodine, and in which R2 in each case has the above-mentioned meaning, into a compound of the formula:
- in which R2 and X each has the above-mentioned meaning, and (b) converting the compound of formula III by reaction with a metal alcoholate of the formula
- R
- 1
-
- O
- -
-
- 1
- n
-
- M
- n
- +
- in which R1 is alkyl, cycloalkyl, aryl or aralkyl and Mn+ is an alkali metal or alkaline earth metal cation and n =1 or 2 and (c) optionally further treating with a weak acid into an enol ether of formula Ib and/or an enol thereof.
13 more elements
Dependencies are inferred from the claim text.