CN-117700326-B - Method for catalyzing hydrocracking of carbamate compounds and preparation method of nitrogen-phosphine tridentate ligand ruthenium catalyst

CN117700326BCN 117700326 BCN117700326 BCN 117700326BCN-117700326-B

Abstract

The invention provides a method for catalyzing hydrocracking of carbamate compounds and a preparation method of a nitrogen-phosphine tridentate ligand ruthenium catalyst, wherein the method for catalyzing hydrocracking uses the nitrogen-phosphine tridentate ligand ruthenium catalyst as a catalyst, in a reaction system containing organic alkali and toluene, catalyzing carbamate compounds to carry out hydrocracking reaction under the hydrogen atmosphere to generate amine and alcohol. The preparation method comprises three steps of preparing diphenylphosphino-acetaldehyde hydrobromide dimer, preparing a nitrogen phosphine ligand and preparing a nitrogen phosphine tridentate ligand ruthenium catalyst. According to the invention, hydrogen is used as a green reducing agent to crack the carbamate compound into alcohol and amine with high added value, and the ruthenium catalyst shows high catalytic activity in hydrogenation fracture of an amide bond.

Inventors

SONG PEIDONG
Rong Haojie
MAO MINGZHEN
CHEN TAO
ZHENG XIAORUI
XU ZEGANG
MENG TINGTING
WANG WEI
SU TIANDUO

Assignees

西安近代化学研究所

Dates

Publication Date: 20260505
Application Date: 20231117

Claims (1)

1. A method for catalyzing hydrocracking of carbamate compounds is characterized in that the method takes a nitrogen-phosphine tridentate ligand ruthenium catalyst as a catalyst, and the carbamate compounds are catalyzed to carry out hydrocracking reaction in a reaction system containing organic alkali and toluene in a hydrogen atmosphere to generate amine and alcohol; The chemical structural formula of the carbamate compound is shown as the following formula II or formula III: A formula II; In formula II: R 3 is selected from methyl, ethyl, isopropyl, n-butyl, phenyl and benzyl; R 4 is selected from phenyl, 2-pyridyl, 1-naphthyl, alpha-methylbenzyl, benzyl, n-hexyl, indole, piperidine and morpholine; R 5 is selected from hydrogen, methyl, and phenyl; formula III; In formula III: n is a positive integer of 26 or more and 32 or less; The hydrocracking reaction condition is that the hydrogen pressure is 20-30 bar, the reaction temperature is 110-130 ℃, and the reaction time is 2-6 hours; the mass ratio of the carbamate compound to the nitrogen phosphine tridentate ligand ruthenium catalyst is (300-500): 5-15; the preparation method of the nitrogen-phosphine tridentate ligand ruthenium catalyst specifically comprises the following steps: step one, preparing disubstituted phosphino-acetaldehyde hydrobromide dimer: Adding the organic phosphorus salt solution into a reaction container, then dropwise adding 2-bromoacetaldehyde diethyl acetal under stirring at the temperature of minus 30 ℃, adding hydrobromic acid aqueous solution after the system naturally heats to 20-30 ℃, stirring for 6-8 hours at the temperature of 40 ℃, distilling off the solvent after the reaction liquid is cooled, and then suction filtering to obtain a filter cake, and leaching, pumping the solvent and drying the filter cake to obtain the disubstituted phosphino-acetaldehyde hydrobromide dimer; the chemical structural formula of the organic phosphorus salt is shown as the following formula IV: A formula IV; In formula IV: m is selected from ions corresponding to hydrogen and alkali metal elements; r 1 is selected from methyl, ethyl, isopropyl, tert-butyl, cyclohexyl, and phenyl; Step two, preparing a nitrogen-phosphine ligand: Adding the disubstituted phosphino-acetaldehyde hydrobromide dimer prepared in the first step, an aminoquinoline compound, sodium triacetoxyborohydride and a solvent into a reaction container, stirring for 8-12 hours at the temperature of 20-30 ℃ in a nitrogen protection atmosphere, adding a saturated ammonium chloride aqueous solution into a reaction solution after the reaction is finished for quenching reaction, extracting a product by adopting ethyl acetate, back-extracting an organic phase obtained by extraction by adopting saturated saline solution, and finally sequentially drying, concentrating the organic phase and purifying by column chromatography to prepare a nitrogen-phosphine ligand; the chemical structural formula of the aminoquinoline compound is shown as the following formula V: A formula V; In formula V: R 2 is selected from the group consisting of hydrogen, alkoxy, alkyl, and dimethylamino; preparing a nitrogen-phosphine tridentate ligand ruthenium catalyst: Adding the phosphine ligand, the tris (triphenylphosphine) carbonyl ruthenium chloride and the solvent prepared in the step two into a reaction vessel, stirring for 9-12 hours at the temperature of 110 ℃ in a nitrogen protection atmosphere, carrying out suction filtration on the reaction solution after the reaction is finished to obtain a filter cake, and leaching and drying the filter cake to prepare the phosphine tridentate ligand ruthenium catalyst; the chemical structural formula of the nitrogen-phosphine tridentate ligand ruthenium catalyst is shown as the following formula I: A formula I; In formula I: r 1 is selected from methyl, ethyl, isopropyl, tert-butyl, cyclohexyl, and phenyl; R 2 is selected from the group consisting of hydrogen, alkoxy, alkyl, and dimethylamino; in the first step, the mol ratio of the 2-bromoacetaldehyde diethyl acetal, the organic phosphorus salt and the hydrobromic acid is 1:1-2:1.5-3; In the second step, the molar ratio of the disubstituted phosphino-acetaldehyde hydrobromide dimer, the aminoquinoline compound and the sodium triacetoxyborohydride is 1:1-2:2-4; In the third step, the molar ratio of the nitrogen phosphine ligand to the tris (triphenylphosphine) carbonyl ruthenium chloride is (1-1.5): 1; the solvent is selected from tetrahydrofuran, toluene, 2-methyltetrahydrofuran, ethyl acetate, dichloromethane, chloroform and methanol.

Description

Method for catalyzing hydrocracking of carbamate compounds and preparation method of nitrogen-phosphine tridentate ligand ruthenium catalyst Technical Field The invention belongs to the technical field of organic synthesis, relates to a catalyst for hydrocracking, and in particular relates to a method for catalyzing hydrocracking of carbamate compounds and a preparation method of a nitrogen-phosphine tridentate ligand ruthenium catalyst. Background Reduction of carboxylic acids and derivatives thereof is important in scientific and industrial applications, and conventional reduction methods often require the use of stoichiometric amounts of hydrogenation reagents (e.g., lithium aluminum hydride, sodium borohydride, borane, etc.) to produce equivalent amounts of hydrogenation byproducts. Hydrogen is used as a green reducing agent, has the characteristics of high atom economy, less three wastes and the like, and is widely applied to the catalytic hydrogenation reaction of unsaturated carbon-carbon bonds, carbon-oxygen bonds, carbon-nitrogen bonds and other functional groups. However, the hydrogenation of carboxylic acids and their derivatives under mild conditions using hydrogen is very challenging, and especially carbamates are one of the most difficult compounds to reduce among all carbonyl compounds, essentially because the carbonyl groups of carbamates are conjugated to oxygen and nitrogen atoms and the hydrogenation activity of carbon-oxygen double bonds is much lower than in common carbonyl compounds. The report of success cases related to carbamate catalytic hydrogenation at present is that D.Milstein uses bipyridine type nitrogen phosphine tridentate ligand-ruthenium catalytic system to realize the catalytic hydrogenation of carbamate, important chemical raw materials alcohol and amine are obtained, but the application range of the substrate is narrow, and the reaction at 110 ℃ by using tetrahydrofuran solvent has safety risks. M.Ito use CpThe Ru catalytic system realizes the catalytic hydrogenation of specific cyclic carbamates, and the chiral alcohol of the raw material is obtained, but the catalytic system has poor universality. T.Werner uses bis-diphenylphosphine to replace diethylamine-manganese catalytic system, isopropanol is used as hydrogen source, and catalytic hydrogenation of carbamate is realized through transfer hydrogenation way, the catalytic system has wider substrate application range, but lower catalytic efficiency, and the catalyst has high requirement on water-oxygen sensitive operation and is difficult to scale up. Disclosure of Invention Aiming at the defects and shortcomings in the prior art, the invention aims to provide a method for catalyzing hydrocracking of a carbamate compound and a preparation method of a nitrogen-phosphine tridentate ligand ruthenium catalyst, and solves the technical problems of low hydrocracking catalytic efficiency and poor substrate applicability of the carbamate compound in the prior art. In order to solve the technical problems, the invention adopts the following technical scheme: The method takes a nitrogen-phosphine tridentate ligand ruthenium catalyst as a catalyst, and catalyzes the carbamate compound to carry out hydrocracking reaction in a reaction system containing organic alkali and toluene in hydrogen atmosphere to generate amine and alcohol, wherein the chemical structural formula of the nitrogen-phosphine tridentate ligand ruthenium catalyst is shown as the following formula I: A formula I; In formula I: r 1 is selected from methyl, ethyl, isopropyl, tert-butyl, cyclohexyl, and phenyl; R 2 is selected from the group consisting of hydrogen, alkoxy, alkyl, and dimethylamino; the chemical structural formula of the carbamate compound is shown as the following formula II and formula III: A formula II; In formula II: R 3 is selected from methyl, ethyl, isopropyl, n-butyl, phenyl and benzyl; R 4 is selected from phenyl, substituted phenyl, 2-pyridyl, 1-naphthyl, alpha-methylbenzyl, benzyl, n-hexyl, indole, piperidine and morpholine; R 5 is selected from hydrogen, methyl, and phenyl; formula III; In formula III: n is a positive integer of 26 or more and 32 or less; the preparation method of the nitrogen-phosphine tridentate ligand ruthenium catalyst specifically comprises the following steps: Step one, preparing diphenylphosphino-acetaldehyde hydrobromide dimer: Adding the organic phosphorus salt solution into a reaction container, then dropwise adding 2-bromoacetaldehyde diethyl acetal under stirring at the temperature of minus 30 ℃, adding hydrobromic acid aqueous solution after the system naturally heats to 20-30 ℃, stirring for 6-8 hours at the temperature of 40 ℃, distilling off the solvent after the reaction liquid is cooled, and then suction filtering to obtain a filter cake, and leaching, pumping the solvent and drying the filter cake to obtain diphenylphosphino-acetaldehyde hydrobromide dimer; the chemical structural formula of the org