Дифенилметанимин

Description

Diphenylmethanimine (benzophenoneimine) is ketimine formed by the condensation of benzophenone with ammonia, Ph2C=NH. English name diphenylmethanimine, formula C13H11N, CAS 5319-67-5. The values ​​of molecular weight and physical constants in the supplier’s passport correspond to the form of the hydrochloride, which is reflected in the list of product synonyms (“Diphenylmethanimine hydrochloride”, “Benzophenimine hydrochloride”).

Basic Attributes

• CAS No.: 5319-67-5
• Chemical formula: C13H11N
• Molecular weight: 217.7
• Exact weight: 217.06600
• UNII: M8RM3S474H
• NSC Number: 143525
• DSSTox ID: DTXSID10201248
• HS code: 2925290090
• PSA specifications: 23.8

Physico-chemical characteristics

• Density: 0.99 g/cm3
• Melting point: 230-250 °C (with sublimation)
• Boiling point: 220-225 °C
• Flash point: 124.3 °C

Scope of application

Benzophenonymine is a multifunctional reagent in organic synthesis, its key role is as an ammonia equivalent and a protecting group for primary amines. It is used in the preparation of nitrilylide dimers and serves as an intermediate in the synthesis of organic compounds. A classic application example is the catalytic enantioselective alkylation of benzophenonymine glycine tert-butyl ester using phosphazene bases and chiral quaternary ammonium salts, yielding both enantiomers of amino acid derivatives in high yield.

Toxicity and danger

A detailed hazard classification, GHS phrases and transport codes are not provided in the supplier’s passport for this position.

Storage and transportation conditions

Store in a dry, cool, hermetically sealed room - the imine bond is sensitive to hydrolysis by air moisture. Wear gloves and avoid prolonged contact with skin and inhalation of dust.

Role in protecting amino groups

The use of benzophenonymine as an ammonia equivalent solves the classic problem of direct ammonia alkylation - low chemoselectivity and tendency to transalkylation. The reagent is introduced into the molecule through condensation with an electrophilic center, after which alkylation occurs at an adjacent position, and in the final stage, acid hydrolysis of the imine bond releases the primary amino group along with benzophenone as a by-product, which is easily separated from the target product.

Importance for amino acid synthesis

The reagent is of particular value in the production of enantiomerically pure non-protein amino acids - the benzophenoneimine-protected glycine ester is alkylated in the presence of chiral catalysts, after which the removal of the imine gives the target amino acid with high enantiomeric purity, which is in demand in the synthesis of pharmaceutical substances and agrochemicals.

Byproduct recovery

Benzophenone, released upon final hydrolysis of the imine bond, is a stable compound that is easily separated from the target amine by standard purification methods; in some technological schemes it is regenerated to re-produce benzophenonymine, which reduces the total consumption of the initial reagent in large-scale production processes.

By-product and its fate

During acid hydrolysis of the imine bond, along with the target amine, benzophenone is released - a stable compound that is easily separated from the product, which is regenerated in separate technological schemes and returned to the benzophenonymine re-production cycle, reducing the total consumption of feedstock in large-scale production of amino acid intermediates.