Method for reducing amide compounds
A technology for reducing amides and amides, which is applied in the preparation of organic compounds, the preparation of amino compounds, chemical instruments and methods, etc., can solve the problems of troublesome post-processing, high reaction cost, breakage, etc., and achieves low reagent cost, simple reaction operation, good compatibility
Patent Information
- Authority / Receiving Office
- CN · China
- Current Assignee / Owner
- Publication Date
- 2013-12-11
- Estimated Expiration
- Not applicable · inactive patent
Smart Images
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Abstract
Description
technical field
[0001] The invention relates to a new method for reducing amides. In the method, low-valent titanium reagent is used as a reducing agent to reduce various types of amides to obtain corresponding amine compounds.
[0002] Background technique
[0003] Amide reduction is one of the important organic reactions, widely used in chemistry, biology, materials and other fields. The partial amide reduction method is widely used, but there are still many shortcomings.
[0004] The reduction of amides by catalytic hydrogenation is an earlier and more ideal and economical method. However, the reaction conditions are harsh, and the reaction is generally carried out at high temperature and high pressure (Angew. Chem. Int. Ed. 52 (2013) 2231-2234). Transition metal-catalyzed organosilicon reduction, high reaction temperature, mainly suitable for tertiary amides (J. Am. Chem. Soc. 132 (2010) 1770-1771), partly suitable for secondary amides (J. Am. Chem. Soc . 134 (2012) ...
Examples
Embodiment 1
[0026] Example 1: Reduction of benzanilide
[0027]
[0028] Under the protection of Ar gas, Mg powder (10mmol) and THF (60mL) were added to the reaction flask, stirred in an ice bath, and TiCl was injected into the system. 4 (5 mmol), the reaction system was raised to room temperature and reacted for two hours to obtain a black suspension. The system was placed in an ice bath, and a solution of benzanilide (1 mmol) in THF (15 mL) was slowly added dropwise. After the dropwise addition, the mixture was raised to room temperature for reaction. After the reaction was completed, the reactant was placed in an ice bath, and saturated aqueous sodium bicarbonate solution was added thereto, and then 20% aqueous sodium hydroxide solution was added until the pH > 9. The reactant was filtered, the filtrate was extracted with dichloromethane, and the extract was concentrated to obtain a crude amine compound, which was then subjected to silica gel column chromatography to obtain N-ben...
Embodiment 2
[0029] Example 2: Reduction of 4-methyl-N-phenylbenzamide
[0030]
[0031] The experimental operation was similar to that of Example 1, and N-(4-methylbenzyl)aniline was obtained as a colorless oil with a yield of 82%. 1 H NMR (400 MHz, CDCl 3 ) δ (ppm): 7.16 (d, J = 8.0 Hz, 2H), 7.03-7.10 (m, 4H), 6.61 (t, J = 8.0 Hz, 1H), 6.52 (d, J = 8.0 Hz, 2H), 4.15 (s, 2H), 3.77 (brs, 1H), 2.24 (s, 3H). 13 C NMR (100 MHz, CDCl 3 ) δ (ppm): 148.3, 136.9, 136.5, 129.4, 129.3, 127.6, 117.6, 112.9, 48.1, 21.2. HRMS (ESI): m / z calcd for C 14 h 16 N[M+H] + : 198.1283, found: 198.1287.
Embodiment 3
[0032] Example 3: Reduction of 4-methoxy-N-phenylbenzamide
[0033]
[0034] The experimental operation was similar to Example 1, and a colorless solid N-(4-methoxybenzyl)aniline was obtained with a yield of 86%. 1 H NMR (400 MHz, CDCl 3 ) δ (ppm): 7.28 (d, J = 8.0 Hz, 2 H), 7.16 (t, J = 8.0 Hz, 2H), 6.87 (d, J = 8.0 Hz, 2 H), 6.70 (t, J = 8.0 Hz, 1H), 6.63 (d, J = 8.0 Hz, 2H), 4.23 (s, 2H), 3.78 (s, 3H), 3.60 (brs, 1H). 13 C NMR (100 MHz, CDCl 3 ) δ (ppm): 158.9, 148.2, 131.4, 129.3, 128.9, 117.6, 114.1, 112.9, 55.3, 47.9. HRMS (ESI): m / z calcd for C 14 h 16 NO [M+H] + : 214.1232, found: 214.1238.