Organic compounds -- part of the class 532-570 series – Organic compounds – Nitriles
Patent
1987-08-04
1990-07-17
Brust, Joseph Paul
Organic compounds -- part of the class 532-570 series
Organic compounds
Nitriles
548505, 558339, 558352, 558378, 558389, 558428, 558430, 558432, 558447, 558452, 558454, C07C25330, C07C25308
Patent
active
049422219
DESCRIPTION:
BRIEF SUMMARY
SUMMARY OF THE INVENTION
It relates more especially to a process for preparing .alpha.-aminonitrile which consists in transforming a nitrile into its upper homologue bearing an amine function in .alpha.-position, by a one-stage process.
Thus, the present invention provides a process for obtaining .alpha.-aminonitriles of the general formula I: ##STR1## wherein R represents an aliphatic, aromatic or cyclanic radical, R' represents a hydrogen atom, an unsubstituted or substituted alkyl radical, or an aryl radical, in which an aliphatic, aromatic or cyclanic nitrile of the general formula II of a metallic reducing agent, in order to form a metallic imine of the general formula III ##STR2## wherein R and R' have the meanings previously defined; Me is a metal atom; Z is a lower alkyl radical or a halogen atom, and n is an integer equal to the valence of the metal diminished by one; and the latter is reacted with a cyaniding agent.
In a preferred way, the metallic reducing agent is a metal hydride as an aluminohydride having at least one free hydrogen atom. It may also be an alkylating or arylating reducing agent such as an organomagnesian salt of the formula radical, or an organozinc salt of the formula atom, and R' has the meaning previously given or organocadminum salt or an organo copper salt. As preferred agent; there may be mentioned disiobutyaluminum hydride, diterbutoxyaluminum hydride or sodium bis (2-methoxyethoxy) aluminum hydride.
The cyaniding agent is selected from the group consisting of trimethylsilyl cyanide, diethylaluminum cyanide, and tributylstannicyanide (Bu).sub.3 Sn-CN. This list is not limiting and other cyaniding agents able to give up a CN group may also be used such, for example, as an alkaline or alkaline-earth metal cyanoborohydride, an alkaline metal cyanide in the presence of a brown Ether, or hydrocyanic acid in solution in an oxygen-bearing solvent, as for Example THF.
The following table gives a comparison between the different reducing agent and the different cyaniding agents.
COMPARISON OF YIELDS OBTAINED BY HYDROCYANATION OF NITRILES Cyaniding
Agents Nitriles (C.sub.2 H.sub.5).sub.2 AlCN (CH.sub.3).sub.3 SiCN
(C.sub.4 H.sub.9).sub.3
SnCn HCN/THF LiCN/DMF NaCN/DM .alpha. aminonitriles
##STR3##
65 550 24 70 60 60
##STR4##
##STR5##
22 2720
##STR6##
##STR7##
20 33
##STR8##
##STR9##
20
##STR10##
##STR11##
70 70 50
##STR12##
##STR13##
6257
##STR14##
##STR15##
?
A: Yield in % obtained with Diisobutyl aluminum hydride (DIBA)
B: Yield in % obtained with sodium bis(2methoxyethoxy) aluminum hydride
(nitride.sup.R)
*Reaction carried out at 60.degree. C.
Without limiting the invention, the process of the present invention may be illustrated by the two following reaction schemes
(1) Using an aluminohydride as metallic reducing agent: ##STR16## (R'=hydrogen).
(2) Using an organometal halide as alkylating reducing agent ##STR17## (R'=alkyl or aryl).
In these two schemes, R is a substituted or unsubstituted alkyl radical having from 1 to 30 carbon atoms, a mono-or bi-cyclic aryl radical, an alkenyl radical having from 2 to 30 carbon atoms, a mono- or bi-cyclic hetero-aryl radical; an aryl-alkyl radical in which the alkyl moiety has from 1 to 15 carbon atoms and the aryl moiety may carry from 1 to 3 substituents, an aryloxy-(lower)alkyl radical optionally substituted by one to three substituents on the aryl moiety, or a cycloalkenyl radical having from 4 to 7 carbon atoms lower alkyl.
As much as the invention is concerned, the term lower alkyl means a hydrocarbonic radical having from 1 to 6 carbon atoms, in a straight or branched chain. There may be mentioned as example: butyl, terbutyl, neopentyl, n-hexyl, methyl or ethyl radicals.
When the alkyl radical is substituted, it may carry a group functional towards organometal compound as a halogen atom, or an amino radical as a chain of the formula ##STR18## in which R.sub.1 and R.sub.2 each represent a hydrogen atom, an alkyl radical, an aryl radical or an alkylene chain and n is an integer from 1 to 30. It may a
REFERENCES:
patent: 3265745 (1966-08-01), Seyferth et al.
patent: 3660416 (1972-05-01), Vit
patent: 4517130 (1985-05-01), Baer
Lancaster Synthesis 89, 90, p. 268.
Imbert Thierry
Moinet Gerard
Albert Rolland S.A.
Brust Joseph Paul
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