These common heterocyclic compound, 314084-61-2, name is 2-Bromo-1,3-diethyl-5-methylbenzene, its traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route. Formula: C11H15Br
Under a nitrogen atmosphere, 13.9 G of malonic acid dinitrile are added at normal pressure and room temperature to 20.4 g of pulverulent sodium hydroxide in 240 g of 1-methyl-2- pyrrolidone. After the addition of 45.5 g of 2-bromo-1, 3-diethyl-5-methylbenzene, the reaction mixture is heated to 125C with stirring. At that temperature, a mixture of 1.3 g of triphenylphosphine, 1.06 g of a commercially AVAILABLE PALLADIUM (II) chloride solution in concentrated hydrochloric acid (20% Pd content corresponding to 0.354 g of Pd (LI) chloride and 0.708 g of concentrated hydrochloric acid) and 97.6 g of 1-methyl-2-pyrrolidone is added. Stirring is carried out for a further 3 hours at from 125 to 130C, and 283 g of diluent are distilled off at reduced pressure (from 17 to 100 mbar). After cooling to room temp- erature, the reaction mixture is added to 70 g of water. Following the addition of 38 g of concentrated hydrochloric acid (a pH value of less than 5 is then established), the precipitated solid is filtered off and washed with 60 g of water. After drying, 42.4 G of 2- (2, 6- diethyl-4-methylphenyl) malonic acid dinitrile (content 92.3%, yield 92.3%) having a melting point of from 74 to 78C are obtained.Example P4: Preparation of 2- (2, 6-diethyl-4-methylphenyl) malonic acid dinitrile Under a nitrogen atmosphere and at normal pressure, 14 g (217 MMOL) of malonic acid dinitrile dissolved in 7 ml of 1-methyl-2-pyrrolidone are added dropwise in the course of 30 minutes, at from 20 to 25C, to a mechanically stirred mixture of 24.1 g (600 MMOL) of sodium hydroxide (pellets) in 300 ml of 1-methyl-2-pyrrolidone. Evacuation to from 10 to 30 mbar is carried out and, at from 80 to 100C, 113 g of solvent are distilled off. After establishing normal pressure, 48 g (content 94.9% ; 200 MMOL) of 2-bromo-1, 3-DIETHYL-5- METHYLBENZENE are added and the reaction mixture is heated to 130C. At that temperature, a mixture of 0.26 g (1 MMOL) of triphenylphosphine, 0.21 g of a commercially available palladium (li) chloride solution in concentrated hydrochloric acid (20% Pd content corresponding to 0.071 g (400 UMOL) of PALLADIUM (II) CHLORIDE in 0.142 g of concentrated hydrochloric acid) and 19.5 g of 1-methyl-2-pyrrolidone is added. The reaction mixture is stirred for from 2 to 3 hours at from 125 to 140C, nitrogen being introduced below the surface. A further 165 g of solvent are distilled off at from 20 to 60 mbar. 2.3 g of Hyflo and 150 ml of water are added to the residue which has been cooled to 50C. The reaction mixture is stirred vigorously for 10 minutes and then clarified by filtration over Hyflo. The filter is subsequently washed with 55 ml of water. The combined aqueous phases are extracted once with 91 g of toluene. The organic phase is separated off and discarded. 30 g of toluene/water are distilled off from the aqueous phase at from 20 to 70C and from 200 to 250 mbar. At from 20 to 25C there are added to the distillation sump, in the course of from 60 to 80 minutes, 45.7 g of 32% hydrochloric acid, during the course of which the product crystallises out and the pH value falls to from 4.0 to 4.5. Filtration with suction is carried out, followed by washing with 120 ml of water (divided into 2 portions). The product is dried in a vacuum drying cabinet for 16 hours at from 100 to 250 mbar. 42.2 g (content 98.2% ; yield 97.6%) of 2- (2, 6-DIETHYL-4-METHYLPHENYL) MALONIC acid dinitrile are obtained.
The synthetic route of 2-Bromo-1,3-diethyl-5-methylbenzene has been constantly updated, and we look forward to future research findings.
Reference:
Patent; SYNGENTA PARTICIPATIONS AG; WO2004/50607; (2004); A1;,
Bromide – Wikipedia,
bromide – Wiktionary