Lactams Ruthenium tetroxide

Ruthenium tetroxide, 268 Silver(I) tetrafluoroborate, 273 8-Lactams Iodine, 148... 

The applications of ruthenium tetroxide range from the common types of oxidations, such as those of alkenes, alcohols, and aldehydes to carboxylic acids [701, 774, 939, 940] of secondary alcohols to ketones [701, 940, 941] of aldehydes to acids (in poor yields) [940] of aromatic hydrocarbons to quinones [942, 943] or acids [701, 774, 941] and of sulfides to sulfoxides and sulfones [942], to specific ones like the oxidation of acetylenes to vicinal dicarbonyl compounds [9JS], of ethers to esters [940], of cyclic imines to lactams [944], and of lactams to imides [940]. 

A similar oxidation converts lactams into imides. The reaction can be carried out with ruthenium tetroxide [940, 944] or with /ert-butyl hydroperoxide or peroxyacetic acid in the presence of manganese dichloride or diacetyl ace tonate [225, 255] (equation 527). 

With the powerful formylation reagent IV -diformylacetamide imides are obtained from amides or lactams in good yield (equation 56). Oxidation reactions also have found some application in the synthesis of imides. For example, catalytic amounts of ruthenium tetroxide and 10% aqueous NaI04 as cooxidant in an optimized reaction medium (ethyl acetate-water) oxidize acyclic amides to imides. The reaction rate is inversely related to the electron-withdrawing power of the acyl group, i.e. the electron density at the nitrogen atom (equation 57). 

Oxidation of cyclic amines. Sheehan and Tulis have examined the oxidation of acylated cychc amines with ruthenium tetroxide in a chlorinated solvent (single-phase system) or with ruthenium dioxide—sodium metaperiodate in CHCI3-H2O (two-phase system). Lactams can be obtained in good yield by oxidation of 1-methyloxalylpiperidine or l-methyloxalylpyrroUdine (1) with RUO4. Tlih, protective group is cleaved with sodium methoxide in methanol. The N-carboethoxy derivative of azetidine (n = 0) is oxidized in low yield... 

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