Organic compounds -- part of the class 532-570 series – Organic compounds – Heavy metal containing
Patent
1990-08-15
1992-05-05
Dees, Jose G.
Organic compounds -- part of the class 532-570 series
Organic compounds
Heavy metal containing
260665R, 568383, 568407, 568409, 423 49, 423499, C07F 1300, C07C 4500
Patent
active
051109620
DESCRIPTION:
BRIEF SUMMARY
The invention relates to the preparation of brominated organomanganese compounds, as well as their application to the synthesis of organic compounds particularly ketones.
Recent developments in the chemistry of manganese halides, regarding the formation of organomanganase compounds, have mainly concerned MnCl.sub.2 and MnI.sub.2. Manganese iodide, because of its good solubility in diethyl ether, a commonly used solvent, has been much used in laboratory research. Mixed iodinated organomanganese compounds are rapidly and quantitatively prepared by the reaction of organolithium or organomanganese compounds with manganese iodide MnI.sub.2 in ether. Nonetheless, the use of iodinated organomanganese compounds presents a number of drawbacks. They are prepared from manganese iodide, which is the most expensive halide and is not commercially available in a sufficiently pure form, which in some cases leads to significant decreases in yield. For industrial reasons, manganese chloride was used, which is much more economical and stable. It is nonetheless necessary to work in a solvent such as tetrahydrofuran. In fact, MnCl.sub.2 is insoluble in diethyl ether and it is thus very difficult to obtain mixed chlorinated organomanganese compounds in a satisfactory manner in ether. As for MnBr.sub.2, its insolubility in diethyl ether has not yet been overcome. As we will see later, it is often advantageous to use brominated organomanganese compounds in ether for organic syntheses, as yields and selectivities are better than in tetrahydrofuran. This problem (insolubility of MnBr.sub.2 in ether) is surmounted by the present invention.
According to the invention, manganese bromide is complexed with lithium halides in an acyclic ether, which gives complexes soluble in diethyl ether, easily leading to the formation of brominated organomanganese solutions or suspensions in ether. The latter allow a wide variety of organic compounds to be obtained with excellent yields. In comparison to iodinated compounds, the brominated compounds obtained according to the invention have the advantage of being more economical and stable.
In comparison to chlorinated organomanganese compounds, they allow some syntheses for the preparation of these chlorinated compounds to be carried out with much better yields, whatever the solvent used: in tetrahydrofuran and in diethyl ether, in which MnCl.sub.2 remains insoluble. In comparison to brominated manganese compounds in THF, they also allow better yields or better selectivities to be obtained. Acylation of RMnBr (and RMnCl) in THF gives yields which do not exceed 80% in many cases. In ether, the same reactions with RMnBr under the same conditions give yields in the order of 98%. It is also interesting to note that acylation of RmnBr (and RMnCl) in THF by mixed anhydrides (R'COOCOOR") essentially leads to the formation of esters instead of the expected ketone, whereas in ether, the same reactions with RMnBr give good yields of the ketone. Finally, the brominated compounds according to the invention make it feasible to envisage and/or carry out the preparation of certain elaborate ketones such as acetylene ketones, for example Bu--C.tbd.C--CO--CH--CH.dbd.CH--Mg which could not be prepared with RMnI as polymers are formed, nor with RMnCl, and particularly acetylene ketones with functional groups such as, for example (Et.sub.2 O).sub.2 CHC.tbd.C--CO(CH.sub.2).sub.5 OCHO and CH.sub.3 OCH.sub.2 C.dbd.C--CO--(CH.sub.2).sub.5 Cl. Thus, with the brominated compounds of manganese according to the invention, it is now possible to make fine products, often fragile, by working under mild conditions, at temperatures generally ranging from -10.degree. to +20.degree. C., particularly from 0.degree. to 20.degree. C.
The compounds according to the invention are comprised of complexes of one molecule of MnBr.sub.2 with 1 to 4 moles of a lithium halide. These are compounds generally having the formula MnBr.sub.2.nLiX wherein X is a halogen, n being 1 to 4. The especially efficacious compounds (MnBr.sub.4 Li.sub.2 and MnBr.
REFERENCES:
patent: 4827044 (1989-05-01), Tozzolino et al.
Cahiez et al., Tetrahedron Letters, vol. 26, No. 37, pp. 4441-4448, issued 1986.
G. Friour et al., Synthesis, vol. 1, pp. 37-40 (1984).
G. Friour et al., Tetrahedron, vol. 40, No. 4, pp. 683-693 (1984).
G. Cahiez et al., Tetrahedron Letters, No. 38, pp. 3383-3384 (1977).
Cahiez Gerard
Laboue Blandine
Tozzolino Pierre
Dees Jos,e G.
Nazario Porfirio
Societe Nationale Elf Aquitaine
LandOfFree
Preparation and application of brominated compounds of manganese does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Preparation and application of brominated compounds of manganese, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Preparation and application of brominated compounds of manganese will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1413589