Weygand/Hilgetag Preparative Organic Chemistry

Replacement of oxygen by nitrogen 501
Technique: 851 The diol bissulfonate is heated and stirred with the secondary amine (20 equivalents)
for 20 h under anhydrous conditions, then the secondary amine is distilled off and
the solution is treated with an excess of 40% sodium hydroxide solution. The oily layer is
separated and the aqueous phase is extracted with ether. The organic phases are united and
dried over potassium carbonate. The ether is removed and the residue is distilled in a vacuum.
In this way were prepared, inter alia: AWA^N'-tetracyclohexylethylenediamine (86%), m.p.
102-104°; TV^A^AT-tetraethylenediamine (55%), b.p. 89731.5 mm; AWA^iV'-tetraisopropyltrimethylenediamine
(86%), b.p. 83710-11 mm; AWA/^Ar'-tetrabutyltetramethylenediamine
(78%), b.p. 107-10871 mm; A^iV^'^'-tetraphenyltrimethylenediamine (65%), b.p.
118-121°/0.3 mm; and bis[2-(diethylamino)ethyl] ether (13%), b.p. 69-7071 mm.
iV-Alkylated heterocyclic compounds can be built up in one operation by
treating diol bissulfonates with primary amines. For instance, 1-cyclohexylpiperidine,
b.p. 234°, is obtained in 81% yield from 1,5-pentanediol bis-
(benzenesulfonate) and cyclohexylamine, and 4-benzylmorpholine, b.p. 79°/
2 mm, from 2,2 / -oxybis(ethyl benzenesulfonate) and benzylamine. 852
H2C CH2 H2C CH2
H2C CH2 > H2 %/CH2
C6H5SO2O OSO2C6H5 R
H H
R (R = C6H5CH2)
Such cyclizations are achieved by the following technique: 852 The primary amine (1.5moles)
is dropped within 2 h into a solution of the diol bisarenesulfonate (0.5 mole) in dry dioxan
(500 ml) boiling under reflux. Then an aqueous solution of sodium hydroxide (60 g, 1.5 moles)
is added and the mixture is concentrated to half its volume. The residue is cooled, stirred
with ether, filtered, and fractionated.
In general it is not possible to perform arylations by aryl arenesulfonates,
but some nitroaryl esters form exceptions, as was found by Ullmann. 853 ' 854
For instance, passing ammonia into a boiling solution of 2,4-dinitro-l-naphthyl /7-toluenesulfonate
gives 2,4-dinitro-l-naphthylamine quantitatively, and 2,4-dinitro-iV-phenyl-lnaphthylamine
is obtained in 98% yield by use of aniline. 854
Primary amines have occasionally been prepared, e.g., allylamine, 839 by
alkylation of urotropine and hydrolysis of the resulting quaternary urotropinium
salt.
An important method of preparing pure primary or secondary amines is to
alkylate sulfonamides and hydrolyse the products.
For monoalkylation of arenesulfonamides containing an unsubstituted
SO2NH2 group it is best that the medium should contain sodium carbonate,
since dialkylated products are readily formed in alkali hydroxide solutions. 855
852 D. D. Reynolds and W. O. Kenyon, /. Amer. Chem. Soc, 72, 1597 (1950).
853 F. Ullmann and G. Nadai, Ber. Deut. Chem. Ges., 41, 1870 (1908).
854 F. Ullmann and W. Bruck, Ber. Deut. Chem. Ges., 41, 3932, 3939 (1908).
855 D. Klamann, G. Hofbauer, and F. Drahowzal, Monatsh. Chem., 83, 870 (1952);
cf. D. Klamann and H. Bertsch, Chem. Ber., 89, 2007 (1956).