Sonn-Muller method

This is redueed with anhydrous SnCl2 to RCH=NH, which precipitates as a complex with SnC and is then hydrolyzed (16-2) to the aldehyde. The Stephen reduction is most successful when R is aromatic, but it can be done for aliphatic R up to about six carbons. It is also possible to prepare 21 in a different way, by treating ArCONHPh with PCI5, which can then be converted to the aldehyde. This is known as the Sonn-Muller method. 

Sonn-Muller method. Preparation of aromatic aldehydes from anilides by conversion of an acid anilide with phosphorus pentachloride to an imido chloride, reduction of the imido chloride with stannous chloride, and hydrolysis of the obtained anil. 

As in the previous chapter, the material will be organized according to substrate category, starting with the carboxylic acids themselves and then moving on to the various derivatives. The methods have been placed generally in sections corresponding to the immediate precursors of the aldehydes. Thus, the hydrolysis of Reissert compounds appears under amides as opposed to acyl chlorides, and the Sonn-Muller appears under imidoyl chlorides and not amides. 

One of the classical reductive aldehyde syntheses is the Sonn-MUller reduction of imidoyl chlorides. The method is closely related to the Stephen reduction described in the previous section. As shown in Scheme 16, substrates (53) may be prepared either by the treatment of anilides with phosphorus pentachloride or sulfinyl chloride, or less usually via the Beckmann rearrangement. They are... 

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