The Condensation of 2,4-Diamino-4-Methylpentane With Carbonyl Compounds

Abstract

E. Matter (1) has recently described, as one product of interaction between acetone and ammonia, 2,2,4,6,6-pentamethyl-1,2,5,6-tetrahydropyrimidine, which could be reduced by means of sodium and alcohol to the corresponding hexahydro compound (I).1 Its structure derives from the observation that both dilute hydrochloric acid and alcoholic sodium hydroxide solution decompose it into 2,4-diamino-4-methylpentane (II) and acetone, in the manner indicated in (I). Veer (3) had observed the same degradation, by acids, of the condensation products from 1,3-dianilinopropane and aldehydes, which he also considered as hexahydr opyrimidines.We wish to report in this connection that substances of the type (I) are obtained easily and in good yield, when a 1,3-diamine such as (II) is heated with a ketone in benzene solution in such a way that the water liberated is continuously removed in form of its azeotrope with benzene. Obviously, acetone which boils below that azeotrope (63°) cannot be condensed with (II) by this method; but 3-methyl-3-butanol-2-one (III) and cyclohexanone reacted in the desired manner.

The Chemistry of the 2-Imidazolines and Imidazolidines.

“…Acetone was the only ketone found to react with this 1,2-diamine (11). Ethylenediamine does not usually react with ketones to yield imidazolidines; however, imidazolidine formation has been reported with cyclohexanone (9). No reaction was found between 1,2-diamines containing one primary and one secondary amino group and common ketones, such as acetone and acetophenone (102).…”

The Synthesis of Hexahydropyrimidines From 1,3-Diamines and Ketones or Aldehydes

“…Presumably in these reactions the hexahydropyrimidine of type II is first formed followed by the interaction of 2 moles of the hexahydropyrimidine and 1 mole of formaldehyde with the loss of 1 mole of water. A number of hexahydropyrimidines were prepared using the same general procedure, which was essentially that used byBergmann, et al (4). Only one needs to be given in detail.…”

A Study of the Reaction Products of 1,2-Diamines With Aldehydes

“…Bergmann and others (7) have shown recently that cyclohexanone will react with a 1,2-diamine to produce the corresponding imidazolidine. In the present work, several attempts were made to substitute ketones for aldehydes in these reactions, but in all instances only the starting materials were recovered.…”