Intramolecular oxidative

Hydrogen molecule, carbon oxide intramolecular energy, 110 clathrates, 12, 20 correlated wave function, 300... 

In a similar manner, 47/-[l,2,5]oxadiazolo[3,4- /]pyrimidine-5,7-dione 1-oxides 344 are conveniently prepared in high yields by the oxidative intramolecular cyclization of 6-amino-5-nitro-l/7-pyrimidine-2,4-diones 343 employing iodosylbenzene diacetate as an oxidant in the presence of lithium hydride (Equation 80) <1998JOG6947>. 

The oxidative coupling/cyclization process occurs via stoichiometric carbo-palladation using a Pd(II) species, typically Pd(OAc)2. In an early example, submission of diphenylamines 3 to the palladium(II)-promoted oxidative intramolecular cyclization conditions yielded carbazoles 4 [15-... 

Benzothiazolylhydrazones 281 react with the thianthrene cation radical to give [l,2,4]triazolo[3,4- ]benzothiazoles 282 in an oxidative intramolecular cylization reaction (Equation 36) <2000BKC425>. 

The existence of diazonium ion 95b is confirmed by controlled potential oxidation of 95 in CH3CN-O.I mol/1 Bu4NPF6 solution in an undivided cell [134]. The diazonium ion 95b reacts with the cathodically formed 3-aminoc-rotononitrile in a paired-type electrolysis to form enamine 96 which undergoes either hydrolysis to give 98 or oxidative intramolecular cyclization to give triazole 97 (Scheme 53). 

We planarized the appropriate oligophenylene derivative via oxidative intramolecular cyclodehydrogenation, which has been introduced by Kovacic and... 

Several 2-thiazolyl- (194) and 2-benzothiazolyl- (197) hydrazones of aromatic aldehydes undergo oxidative intramolecular cyclization to form 1,2,4-triazolo-bridgehead heterocycles 195 (95SC3363) (Scheme 53) and 198 [93JCR(S)244] (Scheme 54), respectively. In the case of 194, l-acetoxy,l-(4-aryl-2-thiazolyl)-2-aroylhydrazines (196) are formed as minor products (Scheme 53). 

In this reaction, oxalate ion may be oxidized intramolecularly by cobalt(III) ion, but it is interesting to compare the three different systems in w hich there are three, two, or one oxalate ions with the cobalt(III) cation. The last one can be boiled in l.OM add for an hour and nothing happens. In the first one, decomposition will occur very readily in aqueous solution at 50°C., so that oxalate exchange can t be measured, for instance. The middle one has not been studied in any detail yet, as far as I know, but there is oxidation-reduction in this too, though much slower than in the first. I wonder if this inhibiting effect of the nonreacting ligand, the diamine, on the oxidation has any simple explanation. 

In his classical studies on melanin formation from DOPA (3), Raper proposed the following scheme for the formation of the red pigment now known to be the aminochrome dopachrome (4). The first stage involved the oxidation of the catechol nucleus of-3 to give the quinone dopa-quinone (16). The second stage was the non-oxidative intramolecular cyclization of 16 to leuco-dopachrome (17), which was in turn oxidized to dopachrome (4).72,73 Since... 

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