New Aspects of the Hofmann-Loeffler N-Chloramine Rearrangement in Acetic Acid

Abstract

bonate solution, and filtration and acidification of the bicarbonate extract gave a yellow precipitate. Recrystallization from ethanol and from methyl ethyl ketone-hexane afforded 1.0 g. of yellow and red crystals of the presumed 2-anthrylglyoxylic acid, m.p. 24Ck 284" dec., which was not purified further.A solution of 0.5 g. of the glyoxylic acid in 0.5 ml. of N,N-dimethyl-p-toluidine was heated gently until decarboxylation commenced. The temperature was raised from 150 to 190" over 0.5 hr. until gas evolution ceased. Work-up as above yielded a product which was crystallized from ethanol to give 0.3 g. of yellow flakes, m.p. 208.5-21 1.5 ". Several recrystallizations from abolute ethanol gave impure IVa as pale yellow flakes, m.p. 209-210.5", lit.' m.p. 203-204". Combustion analysis indicated that this sample was contaminated with anthracene.B. McFadyen-Stevens Method. Methyl 2-anthroate, m.p. 193.5-194" (lit. m.p. 128°42 and 192-19304">, was prepared by esterification of the acid in dry methanol with hydrogen chloride. This ester (26 g., 0.11 mole) and 150 ml. of hydrazine hydrate (85%) were refluxed for 36 hr. T o the cooled mixture 600 ml. of water was added. Filtration afforded 20 g.(77 %) of yellow crystals, m.p. 245-248.5" dec. Four recrystallizations from pyridine produced an analytical sample of 2-anthroylhydrazine as long, flat, yellow plates, m.p. 241-244" dec., with subsequent resolidification.

N‐chloro amides, lactams, carbamates, and imides. New classes of initiators for the metal‐catalyzed living radical polymerization of methacrylates

“…CS σ‐bond is 56.55 Kcal/mol, CN σ‐bond is 64.03 Kcal/mol, and CC σ‐bond is 72.34 kcal/mol 78. While the primary requirement for the synthesis of polymers with narrow molecular weight distributions is achieved, the quantitative initiation observed for the case of arenesulfonyl radicals9 cannot be matched by the N‐centered radicals for at least three reasons: their increased tendency to undergo dimerization,79, 80 their higher electrophilicity,80, 81 and their side reactions 82–92. The possible side reactions of N‐centered radicals are illustrated in Scheme .…”

Environmental health sciences center task force review on halogenated organics in drinking water

“…The chlorammonium ion results from reaction of chloramines in acidic solutions (94) yielding a chlorine atom [Eq. (16) …”

Halogenation with N-haloamines in strong acids. II. Kinetics and rate constants

“…-3Previous workers have reported that the ;ate of the immediately prior to, or during the course of, intran~olecular (Hoffman-Loffler) reaction is increased reaction with the other radical. It is unfortunate (18) and decreased (19) by an increase in solvent acidity. that the absolute rate constants could not be However, in neither piece of uork was the rate of initiation in the different solvents estimated.…”

“…They suggested that this resulted from the fact that the self-reaction of two protonated, positively charged nitrogen radicals was far slower than the self-reaction of the neutral radicals which were assumed to be [he species actually responsible for termination. However, as Neale and Walsh have pointed out (19), this requires that the basicity of the amino radical be less than that of the corresponding chloroamine, since the latter is protonated even in the most weakly acidic solutions used. The available evidence (19,23) suggests that the radical is a much stronger base than the chloroamine.…”

“…However, as Neale and Walsh have pointed out (19), this requires that the basicity of the amino radical be less than that of the corresponding chloroamine, since the latter is protonated even in the most weakly acidic solutions used. The available evidence (19,23) suggests that the radical is a much stronger base than the chloroamine. Gorey and Hertler's suggestion that the coupling of two charged radicals is disfavored relative to the neutral radicals may well apply to two "free" radicals though it is by no means certain that it applies to geminate pairs of radicals formed in a solvent cage.4 Our own results show that reaction [4] is rapid but is probably not as fast as the reaction of two uncharged radicals.…”