# US 5,344,995 A · Preparation of cyclic acetals of 3-formyl-2-butenyltriphenylphosphonium chloride

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- Number: US 5,344,995 A
- Document ID: US5344995A
- Status: Granted
- Kind: A
- Application number: 08/085,903
- Filed: 1993-07-06
- Granted: 1994-09-06
- Earliest claimed: 1992-07-14
- Assignees: BASF SE
- Inventors: Wolfgang Krause; Joachim Paust; Walter Dobler; Hagen Jaedicke
- Web page: https://patentgrep.com/patent/US5344995A

## CPC

- C07F 9/6552: {the oxygen atom being part of a six-membered ring}
- C07D 319/06: not condensed with other rings
- C07F: ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM (metal-containing porphyrins C07D487/22)
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)

## Abstract

An improved process for preparing cyclic acetals of 3-formyl-2-butenyltriphenylphosphonium chloride by acetalization of 3-formyl-2-butenyl acetate with an aliphatic 1,3-diol, conversion of the resulting 4-acetoxy acetal into the corresponding 4-hydroxy acetal, Vilsmeier chlorination to give the corresponding 4-chloro acetal and subsequent reaction with triphenylphosphine entails carrying out the first 3 steps in an aliphatic or cycloaliphatic hydrocarbon or mixture of hydrocarbons with 6-8 carbons and the reaction with triphenylphosphine in an alkanol with 1-3 carbons and/or in aliphatic or cycloaliphatic hydrocarbon with 6-8 carbons or a corresponding mixture of hydrocarbons. The process is particularly advantageous when conversion of the 4-acetoxy acetal into the 4-hydroxy acetal is carried out with an aqueous alkali metal hydroxide solution in the presence of phase-transfer catalysts, and the first three, or all four, reaction stages are carried out in the same C.sub.6 -C.sub.8 -hydrocarbon.

## Claims

### Claim 1

An improved process for preparing cyclic acetals of 3-formyl-2-butenyltriphenylphosphonium chloride of the formula I ##STR6## where R.sup.1, R.sup.2 , R.sup.3 and R.sup.4 are each H or CH.sub.3, comprising
a) acetalizing 3-formyl-2-butenyl acetate of the formula II ##STR7## with 1,3-diols of the formula III ##STR8## where R.sup.1, R.sup.2 , R.sup.3 and R.sup.4 have the abovementioned meanings,
b) converting the resulting acetoxy acetals of the formula IV into the corresponding hydroxy acetals of the formula V ##STR9## by treating the acetoxy acetal with aqueous sodium hydroxide or potassium hydroxide solution,
c) subjecting the resulting hydroxy acetals of the formula V to Vilsmeier chlorination to form the 4-chloro acetals of the formula VI ##STR10## and d) reacting the 4-chloro acetals of the formula VI with triphenylphosphine,
wherein steps a) to c) are carried out in an aliphatic or cycloaliphatic hydrocarbon or mixture of hydrocarbons with 6-8 carbons, and step d) is carried out in an alkanol with 1-3 carbons, in an aliphatic or cycloaliphatic hydrocarbon with 6-8 carbons, a mixture of an alkanol with 1-3 carbons and an aliphatic or cycloaliphatic hydrocarbon with 6-8 carbons, or in a mixture of hydrocarbons with 6-8 carbons.

### Claim 2 (depends on 1)

The process of claim 1, wherein steps a) to c) or a) to d) are carried out in the same hydrocarbon or mixture of hydrocarbons.

### Claim 3 (depends on 1)

The process of claim 1, wherein the conversion of the acetoxy acetals of the formula IV into the corresponding hydroxy acetals of the formula V in step b) is carried out with at least 5% strength aqueous sodium hydroxide or potassium hydroxide solution.

### Claim 4 (depends on 3)

The process of claim 3, wherein the conversion of the acetoxy acetals of the formula IV into the corresponding hydroxy acetals of the formula V in step b) is carried out with aqueous sodium hydroxide or potassium hydroxide solution in the presence of phase-transfer catalysts.

### Claim 5 (depends on 1)

The process of claim 1, wherein the reaction in step d) of the 4-chloro acetals of the formula VI with triphenylphosphine is carried out in a mixture of methanol and an aliphatic or cycloaliphatic hydrocarbon or mixture of hydrocarbons with 6-8 carbons as solvent.

### Claim 6

An improved process for preparing cyclic acetals of 3-formyl-2-butenyltriphenylphosphonium chloride of the formula I ##STR11## where R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each H or CH.sub.3, which comprises reacting the 4-chloro acetals of the formula VI ##STR12## with triphenylphosphine in an alkanol with 1-3 carbons, in an aliphatic or cycloaliphatic hydrocarbon with 6-8 carbons, or in a mixture of an alkanol with 1-3 carbons and an aliphatic or cycloaliphatic hydrocarbon with 6-8 carbons, as solvent.