RU2522460C1 - Method of producing alkenyl anthraquinones - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method involves reacting 1-iodo- or 2-iodo-anthraquinones with unsaturated compounds selected from a methyl acrylate, methyl methacrylate and styrene, in an inert atmosphere in the presence of palladium acetate, triphenylphosphine and a base. The process is carried out in the presence of a quaternary ammonium salt and sodium acetate as a base in the medium of dimethyl formamide at temperature of 70-85°C. The quaternary ammonium salt used is triethylbenzylammonium chloride.

EFFECT: method increases output of the desired alkenyl anthraquinones.

2 cl, 1 tbl, 10 ex

Description

The invention relates to an improved method for producing alkenylanthraquinones of the formula

where with radicals 1-anthraquinonyl or 2-anthraquinonyl R ₁ = H, CH ₃ , R ₂ = COOCH ₃ , C ₆ H ₅ ,

which can be used as intermediates for the production of redox polymers, biologically active substances, dyes, and other practically valuable substances and materials.

The literature describes the synthesis of 2-vinylanthraquinone, a monomer for the production of redox polymers, from 2-methylanthraquinone [Refojo M. et al. J. Org. Chem., 1960. Vol. 25. P.416], from 2-ethylanthraquinone [Etienne A. et al. Franz US Pat. 1335713 (1963)], as well as the synthesis of 1-vinyl- and 2-vinylanthraquinones from anthracene and anthraquinone [Manecke G., Storck W. Chem. Ber., 1961. B.94. S.300, 3239]. These syntheses are either multistage or require harsh conditions.

Closest to the proposed is a method for producing alkenylanthraquinones by reacting 1-iodo- or 2-iodoanthraquinones with unsaturated compounds selected from the group: methyl acrylate, methyl methacrylate, styrene, in an inert atmosphere in the presence of palladium acetate, triphenylphosphine and a base in which the process is carried out in the presence of quaternary ammonium salt and sodium acetate in dimethylformamide at a temperature of 70 ° C [V.Ya. Denisov et al. Obtaining and properties of alkenyl substituted anthraquinones // Bulletin of the Kemerovo State University, 2010. - No. 2. (42). - S.144-147]. In this case, tetraoctyl and tetramethylammonium bromides were used as a quaternary ammonium salt. The main disadvantage of this method is the relatively low yield of the target compounds obtained, not exceeding 50%.

Thus, the objective of the invention is to increase the yield of target alkenylanthraquinones, which can serve as the basis for the creation of industrial technologies.

The problem is solved by obtaining alkenylanthraquinones by reacting 1-iodo- or 2-iodoanthraquinones with unsaturated compounds selected from the group: methyl acrylate, methyl methacrylate, styrene, in an inert atmosphere in the presence of palladium acetate, triphenylphosphine and a base, in which the process is conducted in the presence of sodium acetate as a base and a quaternary ammonium salt in a medium of dimethylformamide at a temperature of 70-85 ° C. Moreover, triethylbenzylammonium chloride is used as a quaternary ammonium salt.

The process is carried out at a molar ratio of reactants: 1-iodo- or 2-iodantraquinone: unsaturated compound: palladium acetate: sodium acetate: triphenylphosphine: triethylbenzylammonium chloride, equal to 1: 2: 0.05: 0.1: 1.

The substitution reaction of halogen atoms in aromatic molecules for an alkene residue in the presence of palladium is known as the ethylene condensation reaction or the Heck reaction (after its discoverer) [Heck R.F. Pure and Apple. Chem., 1978. Vol.50. P.691-700; Heck R., Nolly J.J. Org. Chem., 1972. Vol. 27. P.2320-2325]. The reaction mechanism is complex, the influence of various factors on the course of the reaction has not been sufficiently studied, and the application of the ethylene condensation reaction in the series of haloanthraquinones was first begun by us [Denisov V.Ya., Stukalova EV, Chuikova TV Bulletin of KuzSTU, 2009. No. 2. S.75-76].

As a result of our recent studies, it was found that the use of phase transfer catalysts, such as quaternary ammonium salts, can significantly increase the efficiency of the process of replacing the iodine atom in the anthraquinone core with an alkene residue in the presence of a palladium salt: the reaction can be carried out at a temperature of 70-90 ° C at atmospheric pressure and in a short time (4-8 hours): the yield of target compounds in some cases more than 80%. Based on these results, the proposed method for producing alkenylanthraquinones is developed.

As haloanthraquinones, 1-iodo- and 2-iodoanthraquinones were selected. This is due to the higher mobility of iodine atoms compared to bromine and chlorine atoms under the conditions of the Heck reaction (chlorantraquinones do not react with alkenes in the conditions of the Heck reaction). The starting compounds are readily prepared from aminoanthraquinones by diazotization and substitution of the diazo group with an iodine atom.

In preliminary experiments, the interaction of iodantraquinones with alkenes was carried out in an inert atmosphere (under nitrogen) in the presence of palladium acetate, triphenylphosphine and sodium acetate in dimethylformamide at 70 ° C. The reaction time is 4 hours. The molar ratio of reagents is iodantraquinone: alkene: palladium acetate: sodium acetate: triphenylphosphine: tetraalkylammonium salt = 1: 2: 0.05: 2.5: 0.1: 1.

The results of preliminary experiments for 1-iodantraquinone are presented in table 1.

As can be seen from the table, the most effective catalyst for phase transfer is triethylbenzylammonium chloride, produced by the domestic chemical industry. In the case of ethylene condensation using 2-iodantraquinone, this ammonium salt is also the most effective catalyst for interfacial transfer.

The inventive method is carried out in the following order: sodium acetate, tetraalkylammonium salt, dimethylformamide are placed in a four-necked flask equipped with a stirrer, refrigerator, dropping funnel and bubbler and stirred for 15 minutes in a stream of nitrogen. Then, iodantraquinone, tripheniphosphine, an ethylene compound are added to the flask and again stirred for 15 minutes in a stream of nitrogen. After that, palladium acetate is added to the mixture, heated in a glycerin bath to 80 ° C and stirred at this temperature in a stream of nitrogen for 4-8 hours. Cooled to 10-15 ° C, the reaction mixture was poured into 300 ml of 10% hydrochloric acid and left for a day. The precipitate formed is filtered off, washed with water, dried in air and chromatographed on a column filled with aluminum oxide (eluent is toluene). After evaporation of the eluate, a pure target compound is obtained. Yield up to 84%.

The structure of reaction products is confirmed by their comparison with known samples, as well as IR and PMR spectra.

The inventive method in comparison with the prototype has the following advantages:

allows to obtain alkenylanthraquinones with good yields (the yield in most cases is 71-84%).

Examples of the proposed method are given below.

Example 1. Comparative

0.4100 g (5 mmol) of sodium acetate, 1.0920 g (2 mmol) of tetraoctylammonium bromide, 40 ml of dimethylformamide were placed in a four-necked flask equipped with a stirrer, a refrigerator, a dropping funnel and a bubbler, and stirred for 15 min in a stream of nitrogen. Then 0.6680 g (2 mmol) of 1-iodantraquinone, 0.0524 g (0.2 mmol) of triphenylphosphine, 0.4000 g (4 mmol) of methyl methacrylate were added to the flask and again stirred for 15 minutes under a stream of nitrogen. Thereafter, 0.0224 g (0.1 mmol) of palladium acetate was added to the mixture and stirred at a temperature of 70-75 ° C. in a glycerin bath in a stream of nitrogen for 4 hours.

Cooled to 10-15 ° C, the reaction mixture was poured into 300 ml of 10% hydrochloric acid (pH = 2) and left for a day. The precipitate was filtered off, washed with water, dried in air and passed through a layer of alumina (eluent - toluene). As a result, 0.2326 g (38%) of β- (1-anthraquinonyl) -α-methyl methacrylate was isolated, m.p. 185-186 ° C.

Example 2. Comparative

0.4100 g (5 mmol) of sodium acetate, 0.3080 g (2 mmol) of tetramethylammonium bromide, 40 ml of dimethylformamide were placed in a four-necked flask equipped with a stirrer, a refrigerator, a dropping funnel and a bubbler, and stirred for 15 min in a stream of nitrogen. Then 0.6680 g (2 mmol) of 1-iodantraquinone, 0.0524 g (0.2 mmol) of triphenylphosphine, 0.4000 g (4 mmol) of methyl methacrylate were added to the flask and again stirred for 15 minutes under a stream of nitrogen. Thereafter, 0.0224 g (0.1 mmol) of palladium acetate was added to the mixture and stirred at a temperature of 70-75 ° C. in a glycerin bath in a stream of nitrogen for 4 hours.

Cooled to 10-15 ° C, the reaction mixture was poured into 300 ml of 10% hydrochloric acid (pH = 2) and left for a day. The precipitate was filtered off, washed with water, dried in air and passed through a layer of alumina (eluent - toluene). As a result, 0.2999 g (49%) of β- (1-anthraquinonyl) -α-methyl methacrylate was isolated, mp. 185-186 ° C.

A mixed sample with the sample obtained in example 1 did not give a melting point depression.

Example 3

0.4100 g (5 mmol) of sodium acetate, 0.4550 g (2 mmol) of triethylbenzylammonium chloride, 40 ml of dimethylformamide were placed in a four-necked flask equipped with a stirrer, a refrigerator, a dropping funnel and a bubbler, and stirred for 15 min in a stream of nitrogen. Then 0.6680 g (2 mmol) of 1-iodantraquinone, 0.0524 g (0.2 mmol) of triphenylphosphine, 0.4000 g (4 mmol) of methyl methacrylate were added to the flask and again stirred for 15 minutes under a stream of nitrogen. Thereafter, 0.0224 g (0.1 mmol) of palladium acetate was added to the mixture and stirred at a temperature of 70-75 ° C. in a glycerin bath in a stream of nitrogen for 4 hours.

Cooled to 10-15 ° C, the reaction mixture was poured into 300 ml of 10% hydrochloric acid (pH = 2) and left for a day. The precipitate was filtered off, washed with water, dried in air and passed through a layer of alumina (eluent - toluene). As a result, 0.4406 g (72%) of β- (1-anthraquinonyl) -α-methyl methacrylate was isolated, m.p. 185-186 ° C.

Mixed samples with the samples obtained in examples 1 and 2 did not give a melting point depression.

IR spectrum of KBr (ν, cm ^-1 ): 1670 (C = O _chin ), 1610 (C = C _aliph ), 1710 (C = O _aliph ).

₁ H-NMR spectrum: δ = 7.57 (d, H ₁ ), 7.68 (t, H ₂ ), 8.37 (d, H ₃ ), 7.76 (2H, H _α ), 8.25 ( 2H, H _β ), 7.24 (s, HC = C), 1.90 (s, 3H, C = CCH ₃ ), 3.78 (s, 3H, COOCH ₃ ).

Example 4

0.4100 g (5 mmol) of sodium acetate, 0.4550 g (2 mmol) of triethylbenzylammonium chloride, 40 ml of dimethylformamide were placed in a four-necked flask equipped with a stirrer, a refrigerator, a dropping funnel and a bubbler, and stirred for 15 min in a stream of nitrogen. Then, 0.6680 g (2 mmol) of 2-iodantraquinone, 0.0524 g (0.2 mmol) of triphenylphosphine, 0.4000 g (4 mmol) of methyl methacrylate were added to the flask, and again stirred for 15 min in a stream of nitrogen. Thereafter, 0.0224 g (0.1 mmol) of palladium acetate was added to the mixture and stirred at a temperature of 70-75 ° C. in a glycerin bath in a stream of nitrogen for 4 hours.

Cooled to 10-15 ° C, the reaction mixture was poured into 300 ml of 10% hydrochloric acid (pH = 2) and left for a day. The precipitate was filtered off, washed with water, dried in air and passed through a layer of alumina (eluent - toluene). As a result, 0.4100 g (67%) of β- (2-anthraquinonyl) -α-methyl methacrylate was isolated, mp. 139-140 ° C.

IR spectrum of KBr (ν, cm ^-1 ): 1670 (C = O _chin ), 1610 (C = C _aliph ), 1710 (C = O _aliph ).

₁ H-NMR spectrum: δ = 8.12 (s, H ₁ ), 7.64 (d, H ₂ ), 8.22 (d, H ₃ ), 7.77 (2H, H _α ), 8.29 ( 2H, H _β ), 7.24 (s, HC = C), 2.16 (s, 3H, C = CCH ₃ ), 3.78 (s, 3H, COOCH ₃ ).

Example 5

0.4100 g (5 mmol) of sodium acetate, 0.4550 g (2 mmol) of triethylbenzylammonium chloride, 40 ml of dimethylformamide were placed in a four-necked flask equipped with a stirrer, a refrigerator, a dropping funnel and a bubbler, and stirred for 15 min in a stream of nitrogen. Then, 0.6680 g (2 mmol) of 1-iodantraquinone, 0.0524 g (0.2 mmol) of triphenylphosphine, 0.3440 g (4 mmol) of methyl acrylate were added to the flask and again stirred for 15 min in a stream of nitrogen. Thereafter, 0.0224 g (0.1 mmol) of palladium acetate was added to the mixture and stirred at a temperature of 70-75 ° C. in a glycerin bath in a stream of nitrogen for 4 hours.

Cooled to 10-15 ° C, the reaction mixture was poured into 300 ml of 10% hydrochloric acid (pH = 2) and left for a day. The precipitate was filtered off, washed with water, dried in air and passed through a layer of alumina (eluent - toluene). As a result, 0.4039 g (66%) of β- (1-anthraquinonyl) methyl acrylate was isolated, mp. 136-137 ° C.

IR spectrum of KBr (ν, cm ^-1 ): 1670 (C = O _chin ), 1610 (C = C _aliph ), 1710 (C = O _aliph ).

Example 6

0.4100 g (5 mmol) of acetate was placed in a four-necked flask equipped with a stirrer, a refrigerator, a dropping funnel and a bubbler.

sodium, 0.4550 g (2 mmol) of triethylbenzylammonium chloride, 40 ml of dimethylformamide and stirred for 15 min in a stream of nitrogen. Then, 0.6680 g (2 mmol) of 2-iodantraquinone, 0.0524 g (0.2 mmol) of triphenylphosphine, 0.3440 g (4 mmol) of methyl acrylate were added to the flask, and again stirred for 15 min in a stream of nitrogen. Thereafter, 0.0224 g (0.1 mmol) of palladium acetate was added to the mixture and stirred at a temperature of 70-75 ° C. in a glycerin bath in a stream of nitrogen for 4 hours.

Cooled to 10-15 ° C, the reaction mixture was poured into 300 ml of 10% hydrochloric acid (pH = 2) and left for a day. The precipitate was filtered off, washed with water, dried in air and passed through a layer of alumina (eluent - toluene). As a result, 0.3550 g (58%) of β- (2-anthraquinonyl) methyl acrylate was isolated, mp. 197-198 ° C.

IR spectrum of KBr (ν, cm ^-1 ): 1670 (C = O _chin ), 1610 (C = C _aliph ), 1710 (C = O _aliph ).

Example 7

0.4100 g (5 mmol) of sodium acetate, 0.4550 g (2 mmol) of triethylbenzylammonium chloride, 40 ml of dimethylformamide were placed in a four-necked flask equipped with a stirrer, a refrigerator, a dropping funnel and a bubbler, and stirred for 15 min in a stream of nitrogen. Then, 0.6680 g (2 mmol) of 1-iodantraquinone, 0.0524 g (0.2 mmol) of triphenylphosphine, 0.416 g (4 mmol) of methyl methacrylate were added to the flask and again stirred for 15 min in a stream of nitrogen. Thereafter, 0.0224 g (0.1 mmol) of palladium acetate was added to the mixture and stirred at a temperature of 85 ° C in a glycerin bath in a stream of nitrogen for 8 hours.

Cooled to 10-15 ° C, the reaction mixture was poured into 300 ml of 10% hydrochloric acid (pH = 2) and left for a day. The precipitate was filtered off, washed with water, dried in air and passed through a layer of alumina (eluent - toluene). As a result, 0.562 g (84%) of β- (1-anthraquinonyl) -α-methyl methacrylate was isolated, m.p. 185-186 ° C.

IR spectrum of KBr (ν, cm ^-1 ): 1670 (C = O _quin ), 1610 (C = C _aliph ).

Example 8

0.4100 g (5 mmol) of sodium acetate, 0.4550 g (2 mmol) of triethylbenzylammonium chloride, 40 ml of dimethylformamide were placed in a four-necked flask equipped with a stirrer, a refrigerator, a dropping funnel and a bubbler, and stirred for 15 min in a stream of nitrogen. Then, 0.6680 g (2 mmol) of 2-iodantraquinone, 0.0524 g (0.2 mmol) of triphenylphosphine, 0.416 g (4 mmol) of methyl methacrylate were added to the flask, and again stirred for 15 min in a stream of nitrogen. Thereafter, 0.0224 g (0.1 mmol) of palladium acetate was added to the mixture and stirred at a temperature of 85 ° C in a glycerin bath in a stream of nitrogen for 8 hours.

Cooled to 10-15 ° C, the reaction mixture was poured into 300 ml of 10% hydrochloric acid (pH = 2) and left for a day. The precipitate was filtered off, washed with water, dried in air and passed through a layer of alumina (eluent - toluene). As a result, 0.546 g (81.7%) of β- (anthraquinonyl-2) -α-methyl methacrylate was isolated, m.p. 139-140 ° C.

IR spectrum of KBr (ν, cm ^-1 ): 1670 (C = O _quin ), 1610 (C = C _aliph ).

Example 9

0.4100 g (5 mmol) of sodium acetate, 0.4550 g (2 mmol) of triethylbenzylammonium chloride, 40 ml of dimethylformamide were placed in a four-necked flask equipped with a stirrer, a refrigerator, a dropping funnel and a bubbler, and stirred for 15 min in a stream of nitrogen. Then 0.6680 g (2 mmol) of 1-iodantraquinone, 0.0524 g (0.2 mmol) of triphenylphosphine, 0.4160 g (4 mmol) of styrene were added to the flask and again stirred for 15 min in a stream of nitrogen. Thereafter, 0.0224 g (0.1 mmol) of palladium acetate was added to the mixture and stirred at a temperature of 70-75 ° C. in a glycerin bath in a stream of nitrogen for 4 hours.

Cooled to 10-15 ° C, the reaction mixture was poured into 300 ml of 10% hydrochloric acid (pH = 2) and left for a day. The precipitate was filtered off, washed with water, dried in air and passed through a layer of alumina (eluent - toluene). As a result, 0.4406 g (84%) of β- (1-anthraquinonyl) styrene was isolated, mp. 175-176 ° C.

Example 10

0.4100 g (5 mmol) of sodium acetate, 0.4550 g (2 mmol) of triethylbenzyl ammonium chloride, 40 ml of dimethylformamide were placed in a four-necked flask equipped with a stirrer, a refrigerator, a dropping funnel and a bubbler, and stirred for 15 min in a stream of nitrogen. Then 0.6680 g (2 mmol) of 2-iodantraquinone, 0.0524 g (0.2 mmol) of triphenylphosphine, 0.4160 g (4 mmol) of styrene were added to the flask and again stirred for 15 min in a stream of nitrogen. After that, 0.0224 g (0.1 mmol) of palladium acetate was added to the mixture and stirred at a temperature of 70-75 ° C in a glycerol bath in a stream of nitrogen for 4 hours.

Cooled to 10-15 ° C, the reaction mixture was poured into 300 ml of 10% hydrochloric acid (pH = 2) and left for a day. The precipitate was filtered off, washed with water, dried in air and passed through a layer of alumina (eluent - toluene). As a result, 0.4402 g (71%) of β- (2-anthraquinonyl) styrene was isolated, mp. 196-198 ° C.

Table 1. The results of the interaction of 1-iodantraquinone with methyl methacrylate under nitrogen in the presence of palladium acetate, triphenylphosphine, sodium acetate and tetraalkylammonium salts in dimethylformamide Tetraalkylammonium salt Reaction conditions The yield of the target compound, in% Tetramethylammonium bromide 70 ° C, 4 hours 49 Triethylbenzylammonium chloride - "- 72 Tetraoctylammonium bromide - "- 38

Claims (2)

1. A method of producing alkenylanthraquinones by reacting 1-iodo- or 2-iodoanthraquinones with unsaturated compounds selected from the group of methyl acrylate, methyl methacrylate, styrene, in an inert atmosphere in the presence of palladium acetate, triphenylphosphine and a base, the process being carried out in the presence of a quaternary ammonium salt and acetate sodium as a base in dimethylformamide medium at a temperature of 70-85 ° C, characterized in that triethylbenzylammonium chloride is used as a quaternary ammonium salt. 2. The method according to claim 1, characterized in that the process is carried out at a molar ratio of reagents 1-iodo- or 2-iodoanthraquinone: unsaturated compound: palladium acetate: sodium acetate: triphenylphosphine: triethylbenzylammonium chloride, equal to 1: 2: 0.05: 2.5: 0.1: 1.