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The reaction is generally performed in an aqueous solution at close to boiling. The first methylation of the amine begins with imine formation with formaldehyde. The formic acid acts as a source of hydride and reduces the imine to a secondary amine. Loss of carbon dioxide gas renders the reaction irreversible. Despite being more hindered, the ...
In recent years, several reagents such as Tris(2,2,2-trifluoroethyl)borate [B(OCH 2 CF 3) 3], [14] pyrrolidine [15] or titanium ethoxide [Ti(OEt) 4] [16] have been shown to catalyse imine formation. Rarer than primary amines is the use of ammonia to give a primary imine. [17] In the case of hexafluoroacetone, the hemiaminal intermediate can be ...
The Staudinger synthesis, also called the Staudinger ketene-imine cycloaddition, is a chemical synthesis in which an imine 1 reacts with a ketene 2 through a non-photochemical 2+2 cycloaddition to produce a β-lactam 3. [1] The reaction carries particular importance in the synthesis of β-lactam antibiotics. [2]
First phosphine imine-forming reaction is conducted involving treatment of the azide with the phosphine. The intermediate, e.g. triphenylphosphine phenylimide, is then subjected to hydrolysis to produce a phosphine oxide and an amine: R 3 P=NR' + H 2 O → R 3 P=O + R'NH 2. The overall conversion is a mild method of reducing an azide to an amine.
The Forster–Decker method is a series of chemical reactions that have the effect of mono-alkylating a primary amine (1), forming a secondary amine (6). [1] [2] The process occurs by way of transient formation of an imine (3) that undergoes the actual alkylation reaction.
The intermediate imine can be isolated or reacted in-situ with a suitable reducing agent (e.g., sodium borohydride) to produce the amine product. [2] Intramolecular reductive amination can also occur to afford a cyclic amine product if the amine and carbonyl are on the same molecule of starting material.
In Mechanism I, the elimination occurs with imine formation after cyclization; while in Mechanism II, the elimination yields the nitrilium intermediate prior to cyclization. Currently, it is believed that reaction conditions affect the prevalence of one mechanism over the other (see reaction conditions ).
Balanced equations for the individual steps are as follows. Imine formation through condensation: Me(Et)C=O + NH 3 → Me(Et)C=NH + H 2 O. Oxidation of the imine to the oxaziridine: Me(Et)C=NH + H 2 O 2 → Me(Et)CONH + H 2 O. Condensation of the oxaziridine with a second molecule of ammonia to give the hydrazone: Me(Et)CONH + NH 3 → Me(Et)C ...