ISSN:
1042-7163
Keywords:
Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Photolysis of nitroaromatics in the presence of t-BuHgI/KI in Me2SO or DMF leads to products formed by t-Bu• addition to the nitroso compounds. Similar products are formed in the dark in the presence of K2S2O8. Nitroso or nitrobenzene is converted into N,O-di-tert-butylphenylhydroxylamine by a process involving N-tert-butylphenylhydroxylamine as an intermediate. In the presence of PTSA and KI, N-tert-butylphenylhydroxylamine predominates in Me2SO, but in DMF, the phenylhydroxylamine is reduced to N-tert-butylaniline. In a similar fashion, o-nitrosotoluene is converted into o-MeC6H4N(Bu-t)OBu-t, o-MeC6H4N(Bu-t)OH, and o-MeC6H4NHBu-t. p-Nitroso-N,N-dimethylaniline forms the N,O-di-tert-butylated derivative in the absence of acid but in the presence of PTSA/KI yields p-Me2NC6H4NHBu-t. Excellent yields of the N,O-di-tert-butylated arylhydroxylamines are formed in DMF from the nitroaromatics with para Me2N, OH, I, Br, Cl, and ortho Ph or PhNH substituents. Nitrobenzenes with p-CHO, p-PhCO, or p-CN substituents are deoxygenated to the nitroso compounds which react with t-Bu• to form the tert-butoxyamino radicals (ArṄOBu-t). In Me2SO, the amino radicals react to form ArN(HgI)OBu-t compounds which condense with the nitroso compounds to yield the azoxy compounds. With the p-CN substituent, the azoxy compound is subsequently deoxygenated and tert-butylated to yield p-NCC6H4N(Bu-t)NHC6H4CN-p. In the presence of PTSA/KI, the amino radicals are reduced to p-Y-ArNHOBu-t (Y = PhCO, CN). The compounds Y-ArN(Bu-t)OBu-t undergo photochemical degradation to yield Y-ArNHBu-t with Y = p-PhCO or p-CN in a reaction that is inhibited by I-. With PTSA/H2O/KI in Me2SO, p-Me2NC6H4N(t-Bu)OBu-t is converted into 4-(N-tert-butylimino)-2,5-cyclohexadien-1-one, p-Me2NC6H4NHBu-t, and p-tert-butylamino-m-tert-butoxy-N,N-dimethylaniline. o-MeC6H4N(Bu-t)OH reacts with PTSA/KI to form o-MeC6H4N(Bu-t)H in DMF or a mixture of the aniline and 4-(N-tert-butylimino)-3-methyl-2,5-cyclohexadien-1-one in Me2SO. In the absence of KI, only the cyclohexadienone is formed in Me2SO.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hc.520040505
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