Substitution of mobile halogen atoms in some halogenonitrobenzenes with glycol and glycerol

Abstract

. FOHR1).T h e mobile halogen atom in l-chloro-2:4-dinitrobenzene and other halogenonitrobenzenes can be replaced, by interaction with sodium glycolate or sodium glycerolate, by the p-hydroxyethyl-, OCH,.CH,OH and By-dihydroxypropyl, OCH,.CH~OH.CH,OH group, respectively. Glycol and glycerol are sweet but 2 : 4-dinitrophenyl B-hydroxyethyl ether and 2 : 4-dinitrophenyl Ppdihydroxypropyl ether, obtained frcm them, are bitter and these compounds on partial reduction with sodium distilphide afford 2-amino-4-nitrophenyl P-hydroxyethyl ether, which is twenty times as sweet as cane sugar and 2-amino-4-nitrophrnyl-py-dihydroxypropyl ether, which is thirteen times as sweet as cane sugar. Since 2-amino-4-nitrophenyl ethyl ether is 1,400 times and 2-amino-4-nitro-phenyl n-propyl ether, 5.000 times a s sweet as sugar, the replacement of the ethoxy group by a p-hydroxy-ethoxy group and the replacement of n-propoxyby a dihydroxypropoxy group leads to a very considerable decrease in the intensity of the sweet taste. For the development of the sweet taste, in the compound:; mentioned, a free amino group is necessary, since the corresponding acylated derivatives are tasteless, which is in agreement with the observations made previously wifh I-alkoxy-2-amino-4-nitrob-n~enes 2).2 : 4-Dinitrophenyl ,$-hydroxyethyl ether.A solution of sodium (1.8 g ) , in glycol (30 cm3), is prepared and added slowly in portions to a solution of l-chloro-2 : 4-dinitrobenzene (14 g ) , in glycol (25 cm3), and the mixture is then heated on a boiling water-bath for *an hour, poured out into 500 cm3 water, and, after standing overnight, the precipitate is filtered off and recrystallized from water: yield 15 grams (95 "/o).2 : 4-Dinitrophenyl p-hydroxyethyl ether forms colourless needles, m.p. 1 10'. The substance tastes bitter. The compound had previously been prepared by F a i r b o u r n e and T o m s 3 ) . who used a solution of caustic soda in glycol instead of one of sodium in slycol. In this case the solution also reacts as caustic soda and a considerable quantity of 2 : 4-dinitrophenol is produced as a by-product, with the result that the yield of ether is only 60 %, considerably less than when sodium is used. When 2 : 4-dinitrophenyl p-hydroxyethyl ether is heated for a short time with methylamine in alcoholic solution, the glycol residue is replaced by the methylamino group with the production of 2 : 4-dinitro-N-methylaniline, m.p. 175'.2 : 4-Dinitrophenyl p-hydroxyethyl ether acetate. This compound is prepared by dissolving 2 : 4-dinitrophenyl 1-hydroxyethyl ether (0.5 gm.), in acetic anhydride ( 4 cm3). and then adding a drop of concentrated sulphuric acid. The mixture is heated to the boil, poured out ') Part I of Dissertation, F. G.

Über die elektrooptische Modulation von Licht in Polymerfestkörpern

“…In the case of a-PVDF, such phase transitions a t 16 and 43°C were observed earlier in [12]. Such a transition is noticed in or-PVDF a t -39°C and in p-PVDF a t -42°C.…”

Amination by Reduction

“…Verkade and co-workers (9C,1BC,16C) did considerable work on the partial• reduction of dinitroalkoxybenzenes by means of sodium disulfide, in their search for sweetening agents. They found that the 2,4-dinitroalkoxybenzenes gave 2-amino-4nitroalkoxybenzenes and that the 2,5-derivatives gave the 2alkoxy-4-nitroanilines.…”

A Search For Phenolic Protection in Virginiamycin S

“…The alloc group as protection for amino and hydroxylgroups finds its reviva112-17345 since the development of the chemistry of n-allylpalladium'8 and that it thus easily removed with tributyltin hydride (Bu3SnH) in the presence of catalytical tetrakis(tripheny1phosphine)palladium (0) or dichlorobis(tripheny1-phosphine)palladium (11). whereas previously, although this protection has been reported since 1950" it had only limited applicationz0.…”