Schmidt lactams from ketones

Schiff bases s. Azomethines Schlotterbeck s. Buchner Schmidt reaction 17, 524 —, amines from carboxylic acids 19, 305 20, 366 —, lactams from ketones, cyclic, ring expansion... 

The Schmidt reaction of carboxylic acids with hydrazoic acid has the advantage over Curtius rearrangement that it is only one step from the acid to the amine, but the conditions are more drastic (usually sulphuric acid plus sodium azide). Under these harsh conditions, the isocyanate intermediate is rarely isolated. For these reasons, the Curtius rearrangement is frequently employed to convert acids to amines. The Schmidt reaction of ketones with hydrazoic acid is a powerful method for the synthesis of amides and lactams. TTiis process is somewhat related to the Beckmann rearrangement of oximes however, the Schmidt reaction is more succinct, allowing the conversion of ketones to amides in a single operation. Considering its widespread... 

Poly phosphoric acid sodium azide Lactams from cyclic ketones by Schmidt reaction and from cyclic oximes by Beckmann rearrangement Ring expansion... 

Lactams from cyclic ketones—Electrostatic effects on the Schmidt reaction s. 13, 379 bicyclic lactams s. R. J. Michaels and H. E. Zaugg, J. Org. Ghem. 25, 637 (1960)... 

The Schmidt reaction is closely related to the Beckmann reaction (equation 34). Acyclic and cyclic ketones are transformed to amides and lactams by treatment with hydrogen azide. With bridged bi-cyclic ketones, the regioselectivity of the migration is opposite to the direction of the Beckmann reaction. The Schmidt reaction has been applied to asymmetric synthesis starting from optically active a,a-dialkylated -keto esters. High chemical and optical yields have been obtained (equation 35). ... 

The reactions of HN3 with cyclic alcohols to yield mixtures of ketones, amines, and products with an enlarged ring are catalyzed by H2SO4 [1]. Tertiary alcohols are converted to azides in the presence of acid [12] or TiCU [13]. Aldehydes and ketones with HN3 undergo a Schmidt-type reaction by liberating N2 and inserting NH In the presence of H or Lewis acids [14]. Ketones yield secondary amides and, in the case of cyclic ketones, lactames. Aldehydes are converted to nitriles or N-formylamines. Tetrazole derivatives result with excess HN3 [1, 15]. However, a-azido ethers are obtained from aldehydes and HN3 in the presence of alcohols by catalysis of TiC [16]. Carboxylic acids and anhydrides form amines, N2, and CO2 in Schmidt reactions with HN3. Intermediates are carbamic acids which form by insertion of NH into the R-COOH bond [1, 14]. High yields result for acids of arenes [17]. 

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