ISSN:
0009-2940
Keywords:
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
Pyrimidines, VIII Synthesis and Properties of Uracil-4-carbaldehyde Hydrazone. The First Inner Orbital Complex of a Pyrimidine with CopperUracil-4-carbaldehyde (1) reacts with stoechiometric amounts of hydrazine to yield the azine 2. Under mild conditions (30 per cent hydrazine, room temperature) the azine is cleaved to uracil-4-carbaldehyde hydrazone (3). This cleavage by hydrazine is typical for the azomethine group in position 4 of the uracil ring. In aqueous or aqueous-alcoholic solution 3 reacts readily with aliphatic, aromatic and heterocyclic aldehydes to form mixed azines in good yield. With copper(II)-acetate 3 yields in aqueous solution a new type of symmetrical inner orbital complex in which the ratio of pyrimidine to copper is 2 :1. The crystalline and insoluble paramagnetic complex 13 presumably has a planar structure. Substitution of the amino group, even with a methyl group, prevents complex formation. 13 is decomposed by mineral acids to the respective copper salt and azine 2. In analogy to 1 2-thiouracil-4-carb-aldehyde forms the corresponding hydrazone 12.
Notes:
Uracil-carbaldehyd-(4) (1) liefert mit stöchiometrischer Menge Hydrazin das symmetrische Azin 2, welches unter milden Bedingungen (30proz. Hydrazin, Raumtemperatur) zum Uracil-carbaldehyd-(4)-hydrazon (3) gespalten wird. Die schonende Hydrazinolyse ist spezifisch für die Azomethingruppe in 4-Stellung des Uracilrings. 3 liefert in wäßriger bzw. Wäßrig-alkoholischer Lösung mit aliphatischen, aromatischen und heterocyclischen Aldehyden in guter Ausbeute gemischte Azine. Mit Kupfer(II)-acetat bildet 3 einen neuartigen symmetrischen Innerkomplex der Art Pyrimidin : Kupfer = 2:1. Analog zu Uracil-carb-aldehyd-(4) (1) erhält man aus 2-Thio-uracil-carbaldehyd-(4) mit Hydrazin das entsprechende Hydrazon 12.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19701030104
