BUCHERER REACTION PDF

Last updated December 23, The Bucherer reaction in organic chemistry is the reversible conversion of a naphthol to a naphthylamine in the presence of ammonia and sodium bisulfite. The German chemist Hans Theodor Bucherer — discovered independent from Lepetit its reversibility and its potential especially in industrial chemistry. Bucherer published his results in and his name is connected to this reaction. The organic reaction also goes by the name Bucherer-Lepetit reaction or wrongly the Bucherer-Le Petit reaction.

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Reaction Mechanism[ edit ] Reaction mechanism for the Bucherer—Bergs reaction Following condensation of the carbonyl with the ammonium, the formed imine is attacked by the isocyanide to form the aminonitrile. Nucleophilic addition of aminonitrile to CO2 leads to cyano-carbamic acid, which undergoes an intramolecular ring closing to 5-imino-oxazolidinone. The 5-imino-oxazolidinone rearranges to form the hydantoin product via an isocyanate intermediate. In , Bergs issued a patent that described his own synthesis of a number of 5-substituted hydantoins.

Bucherer and Steiner also found that cyanohydrins would react just as well as carbonyl compounds to produce hydantoins. With this solvent, aldehydes reacted well, and ketones gave excellent yields. In Bucherer and Steiner proposed a mechanism for the reaction.

While there were some issues with the mechanism, it was mostly accurate. Only changes in the structure of the starting ketone or aldehyde will lead to variations in the final hydantoin. One way to increase the number of points of diversity is by combining a reaction with 2-Methyleneaziridine with the Bucherer—Bergs reaction in a one-pot synthesis see Figure 1. First, the reaction of 2-Methyleneaziridine 1 with Grignard reagent , catalytic Cu I , and R2-X causes the 2-Methyleneaziridine to ring open and form a ketimine 2.

This reaction has three points of chemical diversity as the structure of the aziridine starting compound, the organometallic reagent, and the electrophile can all be varied to synthesize a different hydantoin. More recently, many organic reactions have been accelerated by ultrasonic irradiation.

In the past, the Bucherer—Bergs reaction has had problems with polymerization, long reaction time, and difficult work-up. Compared with reports in the literature, this makes so the reaction can be carried out at a lower temperature, have a shorter reaction time, a higher yield, and a more simple work-up. However, in other cases, there is no selectivity at all, resulting in a ratio of stereoisomers.

While the end product of the Bucherer—Bergs reaction is a hydantoin , the hydantoin can undergo hydrolysis to form an aminio acid. This is what is assumed in the example below.

For comparison, the amino acid product for the Strecker synthesis has also been included. They: are useful in carbohydrate chemistry.

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Bucherer–Bergs reaction

Mauktilar This page was last edited on 8 Marchat Nucleophilic addition of aminonitrile to CO 2 leads to cyano-carbamic acid, which undergoes an intramolecular ring closing to 5-imino-oxazolidinone. One limitation of the Bucherer—Bergs reactions is that it only has one point of diversity. With this solvent, aldehydes reacted well, and ketones gave excellent yields. In the past, the Bucherer—Bergs reaction bersg had problems with polymerization, long reaction time, and difficult work-up. InBergs issued a patent that described his own synthesis of a number of 5-substituted hydantoins. The addition of KCN to the carbonyl compound gives rise to the cyanohydrin. Only changes in the structure of the starting ketone or aldehyde will lead to variations in the final hydantoin.

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Reaction Details

Reaction Mechanism[ edit ] Reaction mechanism for the Bucherer—Bergs reaction Following condensation of the carbonyl with the ammonium, the formed imine is attacked by the isocyanide to form the aminonitrile. Nucleophilic addition of aminonitrile to CO2 leads to cyano-carbamic acid, which undergoes an intramolecular ring closing to 5-imino-oxazolidinone. The 5-imino-oxazolidinone rearranges to form the hydantoin product via an isocyanate intermediate. In , Bergs issued a patent that described his own synthesis of a number of 5-substituted hydantoins.

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