Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
  • C07C29/56—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by isomerisation
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C67/00—Preparation of carboxylic acid esters
  • C07C67/28—Preparation of carboxylic acid esters by modifying the hydroxylic moiety of the ester, such modification not being an introduction of an ester group
  • C07C67/293—Preparation of carboxylic acid esters by modifying the hydroxylic moiety of the ester, such modification not being an introduction of an ester group by isomerisation; by change of size of the carbon skeleton

Definitions

• 3-methylbut-2-en-1-ol or 3- methylbut-Z-en-l-yl acetate can be obtained in a simple way and in high yields by treating 3-methylbut-3-en-1-ol or 3-methylbut-3-en-1-yl acetate with a catalytic amount of a carbonyl compound of a metal of subgroups 6 to 8 of the Periodic System.
• the starting compounds are known and obtainable particularly advantageously by reaction of isobutene with formaldehyde followed if necessary by acetylation.
• Suitable compounds which act as isomerization catalysts are particularly those of zerovalent metals in accordance with the definition, more particularly, complexes having one or two central atoms such as chromium hexacarbonyl, iron pentacarbonyl, diiron nonacarbonyl, and nickel tetracarbonyl.
• complexes having one or two central atoms such as chromium hexacarbonyl, iron pentacarbonyl, diiron nonacarbonyl, and nickel tetracarbonyl.
• Compounds in which some of the carbonyl groups have been replaced by other ligands, as in dihydrogen iron tetracarbonyl or hydrogen cobalt tetracarbonyl are also suitable.
• Suitable ligands in such compounds are those which bear basic nitrogen or phosphorus atoms.
• Examples of such carbonyl compounds are bistriphenylphosphine iron tricarbonyl and tripyridine diiron tetracarbonyl.
• Iron pentacarbonyl is particularly preferred as the catalyst.
• the amount of carbonyl compound required for the isomerization is from 0.01 to 20% by weight, preferably from 1 to by weight, with reference to the amount of starting material to be isomerized. It is possible however to use larger or smaller amounts of these catalysts, the isomerization merely being accelerated or retarded thereby.
• the reaction may be carried out at temperatures of from about 100 to 300 C., preferably from 150 to 200 C. at atmospheric pressure or at superatmospheric pressure up to about 50 atmospheres with or without a solvent and batchwise or continuously.
• Suitable basic compounds include, in addition to inorganic bases such as sodium hydroxide, barium hydroxide or ammonia and in addition to the salts of strong bases and weak acids such as sodium carbonate or ammonium carbonate, particularly nitrogenous basic compounds such as alkylamines or arylamines and also compounds which are capable of splitting ofl bases, such as piperidine acetate or acid amides such as acetamide or urea.
• Hexamethylenetetramine (urotropine) is preferred as the basic compound.
• the basic compound is generally used in an amount of from 0.01 to 20%, preferably from 1 to 10%, by weight with reference to the compound to be isomerized.
• Hydrocarbons which are liquid under the reaction conditions concerned, as for example hexane, heptane, ligroin, benzene, toluene or xylene, are especially suitable as solvents.
• high boiling point ether' such as diphenyl ether, 2,2'-dimethoxydiethyl ether and 2,2'-diet.hoxydiethyl ether are also suitable.
• reaction mixture When the isomerization is over, the reaction mixture may be worked up by conventional methods, preferably by distillation.
• the products of the process are valuable intermediates for organic synthesis, particularly for the production of compounds of the carotenoid and vitamin A series and of perfumes.
• EXAMPLE 1 A mixture of 50 g. of 3-methylbut-3-en-l-yl acetate and 3.5 g. of iron pentacarbonyl is heated for fifteen hours at 150 C. and the desired product (3-methylbut-2-en-1-yl, B.P. to 112 C. at 200 mm.) is isolated from the mixture in the usual way by fractional distillation. The yield of pure products is 86% at a conversion of 42%.
• EXAMPLE 3 A mixture of 1000 g. of 3-methylbut-3-en-1-ol, 10 g. of iron pentacarbonyl and 50 g. of urotropine is heated for ninety minutes at 200 C. and the desired product is isolated from this mixture in the usual way by fractional distillation.
• EXAMPLE 4 A mixture of g. of 3-methylbut-3-en-1-ol, 22 g. of iron pentacarbonyl and 9 g. of urotropine is heated for thirty minutes at 200 C. and B-methylbut-Z-en-l-ol is isolated in the usual way by fractional distillation. The yield of pure product is 89% at a conversion of 31%.
• EXAMPLE 5 A mixture of 1000 g. of 3-methylbut-3-en-1-ol, 15 g. of iron pentacarbonyl and 60 ml. of liquid ammonia is heated at 175 C. in an autoclave for two hours and the 3-methylbut-2-en-1-ol is then isolated by fractional distillation. The yield of pure product is 73% at a conversion of 40%.
• EXAMPLE 6 An isomerizing process for the production of 3-methylbut-Z-en-l-ol or 3-methylbut-2-en-1-y1 acetate which comprises treating 3-methylbut-3-en-1-ol or 3-methyl-3-enl-yl acetate at a temperature of about 100 C. to 300 C. with a catalytic amount of iron pentacarbonyl and in the presence of a catalytic amount of a basic reacting compound selected from the class consisting of sodium hydroxide, barium hydroxide, ammonia, sodium carbonate, ammonium carbonate, piperidine acetate, acetamide, urea, alkyl and aryl amines and phosphines.
• a basic reacting compound selected from the class consisting of sodium hydroxide, barium hydroxide, ammonia, sodium carbonate, ammonium carbonate, piperidine acetate, acetamide, urea, alkyl and aryl amines and phosphines.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
• Catalysts (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=25755486

Family Applications (1)

Country Status (7)

Cited By (7)

• 1967
  • 1967-12-08 DE DE19671643709 patent/DE1643709B1/de not_active Withdrawn - After Issue
• 1968
  • 1968-03-22 DE DE19681768023 patent/DE1768023C3/de not_active Expired
  • 1968-12-06 GB GB1239434D patent/GB1239434A/en not_active Expired
  • 1968-12-06 BE BE725088D patent/BE725088A/xx not_active IP Right Cessation
  • 1968-12-06 NL NL6817562.A patent/NL167408C/nl not_active IP Right Cessation
  • 1968-12-09 US US782420A patent/US3655735A/en not_active Expired - Lifetime
  • 1968-12-09 FR FR1594968D patent/FR1594968A/fr not_active Expired
  • 1968-12-09 CH CH1835968A patent/CH525173A/de not_active IP Right Cessation

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