p-Toluenesulfonic acid → Acetal

HRID 714002

Reaction equation

HRID 714002 reaction equation
[Cl-].[Al+3].[Cl-].[Cl-].[CH2:5]([O:7][CH:8]([O:16][CH2:17][CH3:18])[CH:9]([CH3:15])[CH:10](OCC)[CH3:11])[CH3:6].C1C2C(=CC=CC=2)C=CN=1.C1(C)C=CC(S(O)(=O)=O)=CC=1>>[CH2:5]([O:7][CH:8]([O:16][CH2:17][CH3:18])[CH3:9])[CH3:6].[CH3:5][O:7][CH:8]=[C:9]([CH3:15])[CH:10]=[CH2:11]

Participants

6

Reactant 4

HCID 6101p-Toluenesulfonic acidHCID 8405IsoquinolineHCID 6451240Aluminum(III) ChlorideHCID 118305441,1,3-Triethoxy-2-methyl-butane

Product 2

HCID 7765AcetalHCID 541432591-Methoxy-2-methyl-1,3-butadiene

Procedure

According to the present invention, a method for synthesizing 2,7-dimethyl-2,4,6-octatriene-1,8-dialdehyde comprises the following steps: (1) adding acetaldehyde diethyl acetal (abbreviation: acetal) and ethyl-(1-propenyl)-ether under effects of a catalyst at a temperature of −10° C.˜0° C. to produce 1,1,3-triethoxy-2-methyl-butane; wherein the catalyst is ferric chloride or aluminum chloride; acetaldehyde diethyl acetal is prepared by the Chinese Patent No. ZL97115390.6 of Hoffmann-La Roche Ltd; (2) pyrolysis synthesizing 1,1,3-triethoxy-2-methyl-butane under catalytic effects of isoquinoline and p-Toluenesulfonic acid at a temperature of 180-200° C. to produce 1-methoxy-2-methyl-1,3-butadiene; but the catalyst used in the Chinese Patent ZL97115390.6 of Hoffmann-La Roche Ltd. is silicon-aluminum ball, to pyrolysis produce 1-methoxy-2-methyl-1,3-butadiene at high temperature, its conversion rate is only 41%, and its selectivity is 90%; (3) dissolving 1-methoxy-2-methyl-1,3-butadiene in anhydrous ethanol solvent for synthesis with a phase transfer catalyst and a chlorinating agent at a temperature of −5˜0° C. to generate 4,4-diethoxy-3-methyl-1-chloro-butene; wherein the phase transfer catalyst is cetyl-trimethyl ammonium bromide, the chlorinating agent is trichloroisocyanuric acid; (4) combining 4,4-diethoxy-3-methyl-1-chloro-butene with a triphenylphosphine salt at a temperature of 60˜65° C. to produce a phosphonic salt; and (5) condensing the phosphonic salt under effects of hydrogen peroxide at a temperature of 0˜5° C. in conjunction with sodium carbonate solution to generate 1,1,8,8-tetramethyl-2,7-dimethyl-2,4,6-octatriene at pH=8˜10; and then hydrolyzing under acidic conditions to synthesize 2,7-dimethyl-2,4,6-octatriene-1,8-dialdehyde.

Sources & evidence

ORD record
ord-40a8d8aecef740cbbcaf63c912828db6
Source dataset
uspto-grants-2015_11
Patent number
US09187394B2

Linked notes

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