Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Patent
1997-06-25
1998-09-15
Raymond, Richard L.
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
423295, 548110, 564 9, C07F 502
Patent
active
058080708
DESCRIPTION:
BRIEF SUMMARY
CROSS REFERENCE TO RELATED APPLICATION
This application is the U.S. National Phase of PCT/EP95/04500 filed 16 Nov., 1995.
BACKGROUND OF THE INVENTION
DESCRIPTION
This invention relates to a process for preparing alkaline aminoborohydrides and alkaline aminoborohydride complexes.
From the U.S. Pat. No. 2,999,864 metal derivatives of borohydride addition products are known. The preparation of these compounds is effected by reacting metal hydrides with borohydride addition products. For instance, lithium dimethylaminoborohydride should be accessible in the same way as sodium dimethylaminoborohydride through direct reaction of the corresponding alkali hydride with dimethylamineborane in dry ethylene glycol dimethyl ether. However, the publication by Keller, "Inorganic Chemistry" (1975), Vol. 14 (2), p. 140, discloses that the reaction of lithium hydride with dimeric dimethylamineborane at room temperature in diethyl ether will only lead to lithium dimethylaminoborohydride after several months reaction time. Whereas examinations by Hutchins et al, "Journal of Organic Chemistry" (1984), Vol. 49, p. 2438, confirm the smooth reaction of sodium hydride with dimethylamineborane in tetrahydrofuran to form sodium dimethylaminoborohydride, Singaram et al, Tetrahedron Letters (1992), Vol. 33, p. 4533, indicate that lithium aminoborohydrides can be prepared through reaction of n-butyllithium with amineborane addition products. The process proposed by Singaram is virtually restricted to the preparation of lithium aminoborohydrides, as only lithium alkyl compounds are stable and commercially available.
OBJECT OF THE INVENTION
As in the prior art non-uniform and in part contradictory statements are made with respect to the preparation of alkaline aminoborohydrides, it is the object underlying the invention to provide a process for preparing alkaline aminoborohydrides and their complex compounds from inexpensive raw materials, which provides high product yields within short reaction times and is suited for the preparation of a multitude of homologues.
SUMMARY OF THE INVENTION
The object underlying the invention is solved on the one hand by a process for preparing alkaline aminoborohydrides of the general formula aromatic solvent, wherein residue or a cycloaliphatic residue, residue or a cycloaliphatic residue, and
As alkali amides, the compounds MNR.sup.3 R.sup.4 are used, where R.sup.3 and R.sup.4 are each H or an organic residue or the trimethylsilyl residue.
The process in accordance with the invention, which is performed at 0.degree.to 100.degree. C., thus yields alkaline aminoborohydrides by reacting addition products, which consist of borohydride and amines, with alkali metals or certain alkali compounds, which alkaline aminoborohydrides are generally hardly soluble in the nonpolar solvents, so that they are obtained as colourless, amorphous or crystalline precipitates. From the reaction mixtures the end products can either be obtained through solid-liquid separation or through evaporation of the solvent. The products are easy to handle, and they are in particular not self-igniting upon contact with air and/or water. The reaction generally takes place with a high yield of alkaline aminoborohydrides.
The object underlying the invention is on the other hand solved by a process for preparing alkaline aminoborohydride complexes of the formula aliphatic or aromatic solvent is replaced wholly or in part by a dipolar aprotic solvent, and wherein residue, or a cycloaliphatic residue, resdiue, or a cycloaliphatic residue, and
As alkali amides the compounds MNR.sup.3 R.sup.4 are used, where R.sup.3 and R.sup.4 are each H or an organic residue or the trimethylsilyl residue.
The reaction is performed at temperatures between 0 and 100.degree. C., preferably between 20 and 60.degree. C. In the dipolar aprotic solvents the alkaline aminoborohydrides form defined complexes, which either isolated in solid form or directly in dissolved form can be used for organic syntheses. In some cases it is expedient to use mixtures fro
REFERENCES:
patent: 5466798 (1995-11-01), Singaram et al.
patent: 5565615 (1996-10-01), Holzner et al.
Noth Heinrich
Rittmeyer Peter
Thomas Steffen
Wietelmann Ulrich
Dubno Herbert
Metallgesellschaft Aktiengesellschaft
Raymond Richard L.
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