Accelerated reduction of organic substances with boranes

An organic substrate, borane technology, applied in organic chemistry methods, preparation of organic compounds, organic reduction, etc., can solve problems such as chiral oxazolborane catalysts that cannot be obviously tried

Inactive Publication Date: 2010-09-15
BASF AG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Because the reduction of amides and esters does not provide new chiral centers, it is obvious that available chiral oxazoboridine catalysts cannot be tried in this type of reduction

Method used

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  • Accelerated reduction of organic substances with boranes
  • Accelerated reduction of organic substances with boranes
  • Accelerated reduction of organic substances with boranes

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0067] Process Example 1: Reduction of Esters and Amides at 50°C

[0068] The reactor was charged with 200 ml dry THF and 0.1 mol ester or amide and heated to 50°C under 20 psi nitrogen pressure with a back pressure regulator (BPR) set at 25 psi. DEANB (number of moles, substrate dependent) was added subsurface at 30 psi over 1 hour while maintaining a reaction temperature of 50°C. Completion of the reaction is determined by the disappearance of the carbonyl stretching vibration (wavenumber, depending on the substrate). After all data were collected and analyzed, the reaction was quenched with 50 ml of MeOH at 7-10°C.

Embodiment 2

[0069] Process Example 2: Reduction of Esters and Amides at 85°C

[0070] The reduction at 85°C was performed in a pressure vessel with a nitrogen pressure of 30 psi, a BPR of 35 psi and a feed pressure of 40 psi. Concentration and addition time are the same as in Process Example 1.

Embodiment 3

[0071] Process Example 3: Reduction of the matrix in glassware at 50°C

[0072] Shielding reactions on a smaller scale are done in glassware. equipped with a lead to N 2 Add 0.05 mol of ethyl butyrate or ethyl benzoate and 10 ml of THF to a 100 ml three-neck round bottom flask (clean, oven-dried) of the bubbler condenser, shielding plate and thermocouple and stir for 15 minutes. After heating the flask to 50°C, a mixture of 0.05 mol of DEANB (with or without additives) was slowly added to the flask. To determine the reduction time, a 1 ml sample was hydrolyzed with 0.5 ml methanol, and the carbonyl stretching vibration (1734-1654 cm -1 , depends on the disappearance of the matrix).

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Abstract

In a process for the accelerated reduction of organic substrates, selected from the group consisting of ester, amides, nitriles, acids, ketones, imines or mixtures thereof, the substrates are reacted with an amine borane, sulfide borane or ether borane complex as a borane source in the presence of organic accelerator compounds containing both Lewis acidic and Lewis basic sites in their structure, of which the Lewis acidic site can coordinate with the carbonyl or nitrile or imine group of the substrate and the Lewis basic site can coordinate with the borane.

Description

field of invention [0001] The present invention relates to a method for promoting the reduction of organic substrates such as esters and amides using boranes such as amineboranes in the presence of catalytic amounts of additives. Background of the invention [0002] The reduction of organic substrates such as esters, acids or ketones to alcohols and the reduction of amides, nitriles or imides to amines are key transformation reactions in the development of drugs such as antibiotics, HIV inhibitors and ocular hypertensive drugs. These transformations are difficult to achieve selectively in the presence of other sensitive reducible functional groups. New methods for the reduction of these organic substrates, especially esters and amides, are highly desired. [0003] Amine borane complexes are very stable sources of borane. Borane complexes of amines are easy to use on a large scale, but are generally less reactive than borane complexes of ethers or thioethers. Some amine bo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C29/143C07C29/147C07C209/48C07C209/50
CPCC07C209/48C07C29/147C07C31/12C07C29/143C07F5/022C07B31/00C07C209/50C07C33/22C07C31/10C07C211/07C07C211/08C07C31/08
Inventor E·伯克哈特
Owner BASF AG
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