CS242064B1

CS242064B1 - Process for the production of tertiary aminboranes

Info

Publication number: CS242064B1
Application number: CS848695A
Authority: CS
Inventors: Jaromir Plesek; Bohumil Stibr; Eva Drdakova; Tomas Jelinek
Original assignee: Jaromir Plesek; Bohumil Stibr; Eva Drdakova; Tomas Jelinek
Priority date: 1984-11-15
Filing date: 1984-11-15
Publication date: 1986-04-17
Also published as: CS869584A1

Abstract

Vynález patří do oboru chemie sloučenin boru a řeší způsob výroby terciárních aminboranů. Podstata vynálezu spočívá v tom, že se suspenzí tetrahydroboratu kovu v organickém rospouštědle probublává plynný oxid uhličitý v přítomnosti terciárního aminu za intenzivního míchání do dobu 1 až 5 h v rozmezí teplot 0 až 50 °C. čistý produkt se získá promytím organické vrstvy vodou, jejím vysušením a odpařením rozpouštědla. Terciární aminborany nacházejí použití například při redukci organických sloučenin s vazbou C = 0, při hydroboračních reakcích a při inserčních reakcích v chemii boranů.The invention belongs to the field of chemistry of boron compounds and solves the method of production of tertiary amine boranes. The essence of the invention consists in bubbling carbon dioxide gas through a suspension of metal tetrahydroborate in an organic solvent in the presence of a tertiary amine under intensive stirring for a period of 1 to 5 h in the temperature range of 0 to 50 °C. The pure product is obtained by washing the organic layer with water, drying it and evaporating the solvent. Tertiary amine boranes are used, for example, in the reduction of organic compounds with a C = 0 bond, in hydroboration reactions and in insertion reactions in borane chemistry.

Description

The invention relates to a process for the production of tertiary aminboranes.

Tertiary aminboranes are important boron compounds which find a variety of technical applications, for example, in the reduction of organic compounds containing C = O, in hydroboration reactions and in borane chemistry reactions.

These compounds can be prepared by various methods, for example, by direct reaction between the appropriate amine and diborane (Niedenzu K., Dawson JW: Boron-Nitrogen Compounds, Academic Press, New York 1965; Geanangel RA, Shore SG: Prep.Inorg.React. 3, 133 (1966)), by reacting tetrahydroborates with ammonium salts (Shaeffer GW, Anderson ER: J.Amer.Chem.Soc. 71, 2143 (1949)), by amino-aminotrans-amination (Baldwin RA, Washburn RM: J. Org. Chem. 26, 3549 (1961)), by displacement of tetrahydrofuran from the adduct which has been previously prepared from boron etherate and sodium tetrahydroborate (Moore RC, White SS, Jr., Keller HC: Inorg.Syn. , 109 (1970)) by reacting sodium borohydrides with iodine in the presence of an amine (Nainan KC, Ryschkewitsch GE: Inorg. Syn. 15, 122 (1974)) by reacting sodium borohydride with carbon dioxide or acids in aqueous medium in the presence of an amine and an organic solvents (Haberland H., Stroh R .: Brit.Pat. 822,229 (1960)), optionally less preferred methods such as reduction of the boron compound with hydrogen or tetrahydroborates (Koster R .: Angew.Chem. 69, 64 (1957); Ashby EC, Foster WE: J.Amer.Chem.Soc. 84, 3407 (1962); Lang K., Schubert F .: US Pat. 3,037,985 (1962)).

These methods have various disadvantages, for example relatively low yields, based on toxic or relatively expensive starting materials (diborane, complex hydrides of aluminum) or

solvents (1,2-dimethoxyethane), etc.

These drawbacks are avoided by carrying out the reaction of the present invention, according to which tertiary aminboranes are prepared in high yields. that carbon dioxide gas in the presence of a tertiary amine is bubbled through the suspension of tetrahydrofuran, preferably in an organic solvent, preferably ethyl acetate, with vigorous stirring for 1 to 5 hours in a temperature range of 0 to 50 ° C. the pure product is obtained after washing the organic layer with water, drying it and evaporating the solvent.

The reaction proceeds according to the equation:

This reaction differs significantly from the Brit.Pat method. 822,229, based on the reaction of the scheme

in that it has a completely different course. In the anhydrous environment, carbon dioxide detaches NaH from the borohydride molecule with the immediate formation of formate and releases the BH4 fragment which reacts immediately with the amine to form tertiary aminborane. Another difference is that in the reaction according to the invention, hydrogen is not released which often complicates the reaction (foaming of the reaction mixture, danger of explosion). Moreover, the reaction according to the invention proceeds with higher yields, since there is no danger of hydrolysis of the released BH3 fragment with water in the anhydrous environment. This reaction is particularly suitable for the preparation of tertiary aminboranes enriched with 10B, for example for the preparation of Na2O2 Bi2 ^ 12.

The process of the invention and its advantages are illustrated by the following examples.

Example 1 To a suspension of sodium borohydride (18.9 g; 0.5 mol) in ethyl acetate (250 mL) was added triethylamine (50 g, 0.5 mol) and carbon dioxide was bubbled through the mixture with vigorous stirring for 4 h while the reaction temperature is maintained at 20 to 35 ° C by cooling. Water (250 mL) was then added, the aqueous layer was separated and the organic layer was shaken with 20 KgCO 3 (100 mL), dried with K 2 CO 3 and filtered. After evaporation of the ethyl acetate from the filtrate, the residue was distilled at 90 ° C (bath) and 1.3 Pa. 52 g (91 $) (C 8 H 5 N 2 OHHp whose identity was demonstrated and NMR spectra) were obtained. Example 2 Pyridine was added to a suspension of potassium borohydride (13.4 g; 0.24 mol) in ethyl acetate (200 mL). (19.8 g; 0.25 mol) and carbon dioxide was bubbled through the mixture with stirring for 5 h at 20-40 ° C »Further work-up of the reaction mixture was carried out as in the previous example except that the final product was not distilled (decomposes) but obtained after evaporation of ethyl acetate from the final filtrate and drying of the product at 25 ° C / 1.3 Pa. 20.7 g (89 $) of C N NNBHp were identified and identified by NMR spectra.

He was prepared in the same way

Example 3 1-Dimethylamino-2-cyano-ethane (9.8 g; 0.1 mol) was added to a suspension of sodium borohydride (3.8 g; 0.1 mol) in ethyl acetate (100 ml) and stirred with stirring. carbon dioxide was bubbled through the mixture. The crude product obtained by treating the reaction mixture as above was crystallized from n-hexane. 9.5 g (85%) (CH 2 N 2 CH 3 CBL) ^, whose structure was demonstrated by BH 3 and β B NME spectra, was obtained.

Claims

Original document published without claims.