Chemistry of .alpha.-nitro sulfones. V. Electron spin resonance spectroscopic study of arylsulfonylalkyl alkoxy nitroxides, the spin adducts of arylsulfonylalkanenitronic acid esters

Abstract

Arylsulfonylalkanenitronic acid esters were obtained upon reaction of five -nitro sulfones with diazomethane or diazoethane. Four of these products readily add a variety of radicals to produce arylsulfonylalkyl alkoxy nitroxides which were studied by ESR spectroscopy. If the trapped radical is bulky, two nitrogen hyperfine splitting constants are observed. We infer that these nitroxides occur in two favored conformations, both with the -carbon to sulfonyl bond eclipsed with the half-filled orbital on nitrogen. The same types of nitroxides could also be generated by reaction of -nitro sulfones with alkoxycarbinyl radicals. When the -nitro sulfone contains a chiral center and the groups attached to the carbinyl radical site are different from each other, diastereomeric nitroxides are formed. The dependence of the nitrogen hyperfine splitting constant on the substitution pattern in the nitroxides is discussed. The reaction of several nitronic acid esters with lead tetraacetate led to the production of -sulfonyl iminoxy radicals. This reaction most likely proceeds via thermal decomposition into ti-oximino sulfones and subsequent oxidation.The spin trapping technique2-3 has proven to be extremely useful for the detection and identification in solution of paramagnetic species which are too short-lived to be studied directly by electron spin resonance (ESR) spectroscopy

Highly Efficient One‐Step Synthesis of N‐Trimethylsiloxy Alkyl Imidothioates

“…Nitroalkanes are an important class of compounds and characterized by their versatile reactivity. Unfortunately, only few examples are known for the use of nitro compounds to obtain oximes and their analogues (Figure ) …”

“…Unfortunately, only few examples are known for the use of nitro compounds to obtain oximes and their analogues ( Figure 1). [24][25][26][27][28][29][30][31][32] Hexamethyldisilazane (HMDS) has been used in innumerable synthetic procedures, [33][34][35][36][37][38] as it is easy to handle, commercially available, and relatively inexpensive. A large drawback, however, is its poor silylating power, which demands the use of a catalyst or high temperature.…”