- Reactivity and substituent effects in the cyclization of N-aryl-2-nitrosoanilines to phenazines
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Reactivity of variously substituted N-aryl-2-nitrosoanilines in the reaction of cyclization leading to phenazine derivatives, carried out in the presence of N,O-bis(trimethylsilyl)acetamide (BSA), was estimated on the base of the observed reaction times. A strong opposite effect of substituents located at position para to the nitroso group and those located para to the amino group in the side ring was observed. Mechanistic explanation, based on the electronic properties of the substituents and their mesomeric effects, was presented. The usefulness of the obtained data for the designed syntheses of phenazines was exposed.
- Wróbel, Zbigniew,Plichta, Karolina,Kwast, Andrzej
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p. 3147 - 3152
(2017/05/08)
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- THE REACTION OF QUINOXALINE- AND PHENAZINE-N-OXIDES WITH THIONYL CHLORIDE AND PARATOLUENESULFONYL CHLORIDE
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2,3-Diphenylquinoxaline-N-oxide 1 with thionyl chloride gives only 5-chloro- and 6-chloroquinoxaline and very little deoxygenation.Phenazine-N5-oxide 2, in the same conditions, gives mainly 2-chlorophenazine and minor amounts of 1-chlorophenazine, but here deoxygenation is an important pathway.Freshly recrystallized para-toluenesulfonyl chloride gives a high chlorination-to-tosyloxylation ratio.All these results point to a variable ability of acid chlorides to yield homocycle chlorination or acyloxylation; this is confirmed by the observation that phenazine-N5-oxide and phosphoryl chloride give fair amounts of aryl phosphate.
- Nasielski, J.,Heilporn, S.,Chauveheid, E.,Poppe, K.,Nasielski-Hinkens, R.
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p. 783 - 788
(2007/10/02)
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