In the synthesis of complex natural substances and drugs, it will be possible to obtain essential amino groups with the help of this reaction developed at the Weizmann Institute, directly from the corresponding salts
Amines are required in the preparation of pharmaceuticals, fine chemicals, agro-chemicals, plastics, dyes, dyes and additives of all kinds. The most important of these are the primary amines - those containing an extreme amine (NH2) group.
However, the selective synthesis of primary amines remains a challenge. David Milstein and Chidambaram Gunanathan from the Weizmann Institute of Science in Israel have now developed a new catalyst that enables the synthesis of primary amines directly from solvents and ammonia under mild conditions.
As can be learned from their article in the scientific journal Angewandte Chemie, their process involves a complex in which a central ruthenium ion is wrapped by a ligand as a sort of pincer.
The preparation of primary amines is complex because these products are highly active and therefore able to continue to react to obtain secondary and tertiary amines as by-products. Previous preparation methods for primary amines often require large amounts of toxic reagents. Most large-scale industrial methods are based on the reaction between alkalis with ammonia and require very high temperatures and pressures. These conditions lead to obtaining a mixture of amines, alkanes and alkanes as by-products. Selective catalytic synthesis of primary amines from solvents and ammonia under mild conditions, without waste materials, would have significant ecological and economic advantages.
The Israeli scientists have now developed a catalyst that fulfills these wishes - a new ruthenium bracelet, stable in air. Using two "arms" containing phosphorus, an organic ligand grips the ruthenium ion on both sides like a pincer. A third binding site for the metal ion is provided by a nitrogen atom located in an aromatic ring system in the center of the ligand.
By using this "pincer" coupling the researchers were able to selectively synthesize primary amines from solvents and ammonia under mild conditions; large amounts of toxic compounds are not required and the generation of harmful waste is avoided. The reactions take place in the solvent toluene. Surprisingly, even as reactive water-insoluble solutions Pretty good without solvent in the presence of water.
This simple and applicable reaction leads to obtaining primary amines in good utilization and can represent an interesting alternative not only for laboratory syntheses, but also for industrial scale. In the synthesis of complex natural substances and drugs, it will be possible to obtain essential amino groups with the help of this reaction directly from the corresponding alcohols.
