RU2309952C1 - Method for preparing 2,3-dialkylquinolines - Google Patents

Abstract

FIELD: organic chemistry, organic synthesis, chemical technology.

SUBSTANCE: invention relates to a method for synthesis of 2,3-dialkylquinolines. Invention describes a method for synthesis of 2,3-dialkylquinolines of the general formula:

wherein R means C₂H₅, C₃H₇, C₄H₉ by interaction of aniline of the formula: C₆H₅NH₂ with aliphatic aldehydes of the general formula: R-CH₂CHO (wherein R has above given values) in the presence of a catalyst and wherein terbium nitrate crystal hydrate of the formula: Tb(NO₃)₃ x 6 H₂O in the mole ratio C₆H₅NH₂ : R-CH₂CHO : Tb = 45:100:1.2, and reaction is carried out in dimethylsulfoxide (DMSO) medium as a solvent under atmosphere pressure and temperature 20°C for 10 min. Invention provides simplifying technology in synthesis of the end product.

EFFECT: improved method of synthesis.

1 tbl, 1 ex

Description

The present invention relates to methods for producing heterocyclic compounds, specifically to a method for producing 2,3-dialkylquinolines of the general formula

where R = C ₂ H ₅ , C ₃ H ₇ , C ₄ H ₉

Quinoline and its derivatives are used in the synthesis of cyanine dyes as extractants, sorbents, and corrosion inhibitors.

A known method (F.A. Selimov, U.M. Dzhemilev, O.A. Ptashko. Metal complex catalysis in the synthesis of pyridine bases. - M .: Chemistry, 2003, p.223-233.) To obtain alkyl derivatives of quinoline in the condensation reaction of aniline with aliphatic aldehydes under the action of the ternary system LnCl _3: PPh _3: dimethylformamide (DMF) at a molar ratio of 0.4: 1.2: 13 and a reaction temperature of 100 ° C, in an autoclave, for 6 hours, in organic solvents. As lanthanides (Ln), Pr, Nd, Sm, Dy, Yb, Gd, Eu, Ho, La, Er, Lu, Tm were used. The maximum selectivity for 2,3-dialkylquinoline (91%) is achieved using PrCl ₃ and a solvent ethanol.

The disadvantages of this method include high energy costs (high temperature, pressure and duration of the process), the need to use special equipment (autoclave) and the activator ligand PPh ₃ , as well as the high cost of anhydrous LnCl ₃ (inaccessible), which necessitates their preliminary production (energy-intensive, laborious synthesis, in an aggressive environment).

The known method (RF patent 2249476, published: 10.04.2005, Bull. No. 10) for producing 2,3-dialkylquinolines in the condensation reaction of aniline with aliphatic aldehydes in the presence of a catalyst complex [Sm (NO ₃ ) ₅ ] · [C ₅ H ₅ NH] ₂ . The reaction is carried out in an autoclave, at a temperature of 100 ° C, in benzene, for 6 hours. The yield of 2,3-dialkylquinolines is 51-66%.

The disadvantages of this method include high energy consumption (high temperature, pressure and duration of the process), the need to use special equipment (autoclave), low yield of dialkyl quinolines, as well as the preliminary synthesis of [Sm (NO ₃ ) ₅ ] · [C ₅ H ₅ NH] ₂ (in an aggressive environment - HNO ₃ ).

A new method for producing 2,3-dialkylquinolines is proposed. The essence of the method consists in the interaction of aniline with aliphatic aldehydes in the presence of a catalyst Tb (NO ₃ ) ₃ · 6H ₂ O, taken in a molar ratio of 45: 100: 1.2. The reaction is carried out at 20 ° C, atmospheric pressure, for 10 minutes. As a solvent, DMF was used. The reaction proceeds according to the scheme.

R = C ₂ H ₅ , C ₃ H ₇ , C ₄ H ₉ .

With an increase in the temperature of the solution, the content of the resinous products increases.

Significant differences of the proposed method

In the proposed method, commercial terbium nitrate Tb (NO ₃ ) ₃ · 6H ₂ O is used as a catalyst. The reaction proceeds at atmospheric pressure, at 20 ° C, in a DMF solvent, with a higher yield of the target product. In the known methods use more expensive compounds: anhydrous LnCl ₃ (inaccessible) or [Sm (NO ₃ ) ₅ ] · [C ₅ H ₅ NH] ₂ (not commercially available) and requiring special preliminary synthesis.

The proposed method has the following advantages:

1. The method does not require prior preparation of anhydrous salts of LnCl ₃ or the complex [Sm (NO ₃ ) ₅ ] · [C ₅ H ₅ NH] ₂ (laborious, lengthy synthesis in an aggressive environment).

2. The method allows to reduce the yield (90-94%) of the target product by reducing the interaction temperature.

3. The method allows to significantly reduce the temperature (from 100 to 20 ° C), the synthesis time (from 6 hours to 10 minutes), does not require special equipment (autoclave), and thereby significantly simplifies the synthesis and reduce the cost of the target product.

The method is illustrated by the following examples:

EXAMPLE 1. In a 50 ml glass flask mounted on a magnetic stirrer, 8 ml of DMF and 0.54 mmol of Tb (NO ₃ ) ₃ · 6H ₂ O crystalline hydrate are placed. After complete dissolution of Tb (NO ₃ ) ₃ · 6Н ₂ O (1- 2 min), 20 mmol of aniline, 44 mmol of butyric aldehyde are added at 20 ° C and stirred for 10 minutes. The cooled reaction mass was extracted three times with ether (3 × 50 ml), the combined extracts were dried over anhydrous MgSO ₄ , the solvent was distilled off, and the residue was fractionated in vacuo. The yield of 2-propyl-3-ethyl quinoline is 94% (3.82 g).

Other examples confirming the method are given in the table.

Table Example Aldehyde Catalyst T, ° C Min time Exit % Target product one Oil C ₄ H ₈ O Tb (NO ₃ ) ₃ · 6H ₂ O twenty 10 94 2-Propyl-3-ethylquinoline 2 Valeryanovy C ₅ N ₁₀ O Tb (NO ₃ ) ₃ · 6H ₂ O twenty 10 90 2-butyl-3-protylquinoline 3 Kapron C ₆ H ₁₂ O Tb (NO ₃ ) ₃ · 6H ₂ O twenty 10 87 2-amyl-3-butylquinoline

All experiments were performed in DMF at a molar ratio of C ₆ H ₅ NH ₂ : RCH ₂ CHO: Tb equal to 45: 100: 1.2.

The resulting compounds have the following physicochemical characteristics:

2-Propyl-3-ethylquinoline. Oily liquid with a characteristic odor. T _bale = 118 ° C (1 mmHg). Found,%: C 84.64; N, 7.01; H, 8.35. C ₁₄ H ₁₇ N. Calculated,%: C 84.42; N, 7.04; H, 8.54. ¹ H NMR Spectrum (CDCl ₃ , δ, ppm): 1.08 t (3H, CH ₃ ); 1.23 t (3H, CH ₃ ); 1.71 m (2H, CH ₂ ); 2.68 q (2H, CH ₂ ); 2.85 t (2H, CH ₂ ); 7.3-8.1 m (5H, arom.). ¹³ C NMR spectrum (CDCl ₃ , δ, ppm): 13.91 q (C ¹³ ); 14.0 k (C ¹⁵ ); 23.4 t (C ¹² ); 24.7 t (C ¹⁴ ); 37.22 t (C ¹¹ ); 125.05 s (C ¹⁰ ); 125.15 d (C ⁸ ); 126.48 d (C ⁶ ); 127.0 d (C ⁵ ); 128.1 d (C ⁷ ); 133.2 d (C ⁴ ); 134.7 s (C ³ ); 146.07 s (C ⁹ ); 161.33 s (C ² ).

2-butyl-3-propylquinoline. Oily liquid with a characteristic odor. T _bale = 143 ° C (1 mmHg). Found,%: C 84.35; N, 6.02; H, 9.63. C ₁₆ H ₂₁ N. Calculated,%: C 84.58; N, 6.17; H, 9.25. ¹ H NMR Spectrum (CDCl ₃ , δ, ppm): 1.1 t (3H, CH ₃ ); 1.25 t (3H, CH ₃ ); 1.68 m (2H, CH ₂ ); 1.73 m (2H, CH ₂ ); 1.82 t (2H, CH ₂ ); 2.71 q (2H, CH ₂ ); 7.28-8.07 m (5H, arom.). ¹³ C NMR spectrum (CDCl ₃ , δ, ppm): 13.80 k (C ¹⁴ ); 13.90 to (C ¹⁷ ); 22.80 t (C ¹³ ); 23.20 t (C ¹⁶ ); 31.10 t (C ¹² ); 33.70 t (C ¹⁵ ); 35.00 t (C ¹¹ ); 125.10 d (C ⁸ ); 126.20 d (C ⁶ ); 126.80 s (C ¹⁰ ); 128.10 d (C ⁵ ); 128.15 d (C ⁷ ); 133.10 d (C ⁴ ); 134.20 s (C ³ ); 145.80 s (C ⁹ ); 161.10 s (C ² ).

2-amyl-3-butylquinoline. Oily liquid with a characteristic odor. T _bale = 156 ° C (1 mmHg). Found,%: C 85.5; N, 5.2; H 9.3. C ₁₈ H ₂₅ N. Calculated,%: C 84.70; N 5.5; H 9.8. ¹ H NMR Spectrum (CDCl ₃ , δ, ppm): 1.12 t (3H, CH ₃ ); 1.27 t (3H, CH ₃ ); 1.78 m (2H, CH ₂ ); 1.86 m (2H, CH ₂ ); 1.86 m (2H, CH ₂ ); 1.97 m (2H, CH ₂ ); 2.13 m (2H, CH ₂ ); 2.38 m (2H, CH ₂ ); 2.83 q (2H, CH ₂ ); 2.97 t (2H, CH ₂ ); 7.3-8.12 m (5H, arom.). ¹³ C NMR spectrum (CDCl ₃ , δ, ppm): 14.02 k (C ¹⁵ ); 14.07 k (C ¹⁹ ); 22.55 t (C ¹⁴ ); 22.72 t (C ¹⁸ ); 28.39 t (C ¹³ ); 29.76 t (C ¹⁷ ); 31.98 t (C ¹² ); 32.44 t (C ¹⁶ ); 35.70 t (C ¹¹ ); 123.70 d (C ⁸ ); 124.70 d (C ⁶ ); 125.10 s (C ¹⁰ ); 126.80 d (C ⁵ ); 128.10 d (C ⁷ ); 132.80 d (C ⁴ ); 132.70 s (C ³ ); 141.50 s (C ⁹ ); 160.70 s (C ² ).

Claims (1)

The method of obtaining 2,3-dialkylquinoline general formula

where R = C ₂ H ₅ , C ₃ H ₇ , C ₄ H ₉ , by reacting aniline C ₆ H ₅ NH ₂ with aliphatic aldehydes of the general formula RCH ₂ CHO (where R has the above meanings) in the presence of a catalyst, characterized in that terbium nitrate crystalline hydrate Tb (NO ₃ ) ₃ · 6Н ₂ O is used as a catalyst at a molar ratio of C ₆ H ₅ NH ₂ : RCH ₂ CHO: Tb equal to 45: 100: 1.2, and the reaction is carried out at atmospheric pressure of 20 ° C, for 10 min, in a solvent of DMF.