Der Aufbau der Xanthinbasen aus der Cyanessigsäure. Synthese des Hypoxanthins und Adenins

Abstract

Die Constitution der im thierischen und pflanzlichen Organismus vorkommenden wichtigen Rasen, Santhin., Guanin., Hypoxanthin und Adenilz ist belmnntlich von E r n i l F i s c h e r erschlossen worden, dem es gleichzeitig gelang, die Tier Verbindungen auf kiiizstlichena Wege, namlich durch Umwcwdlufiy cler Harnsaure, zu gewinnen l).Von den rnethylirten HarnsLuren ausgehend gelangte E. F i s c h e r auch zur synthetischen Derstellung zahlreicher Metkylderit:nte2) jener Basen, unter denen die in der Natur vorkoinmenden Derivate des Xanthins , das Caffeiiz, Tlzeobrornira, l'heophyllin, Paraxanthin. und Heterozagzthiia besondere Wichtiglreit besitzen.Durch Pstentschriften der E'irma C. I?. B o e h r i n g e r und S ii h n e in Waldhof 3, sind spater eiiiige weitere Methoden zur Gewinnung des Xanthins und seiner Methylablrommlinge beltannt geworden, die ihren Ausgangspunkt ebenfalls von der Ha,r.nsiizc+e und den methylirteiz l€amsduren nehmen.Vor einigen .Jahrcn4) habe ich nun gezeigt, dass man Santhinbasen auch direct von einem einfachen Sabstitutionsproducte der Essigsaure, der C~~~f i e s s~g s~u r e , aus in wenigen Operationen synthetisch gewinnen liann.

Structure-Based Design, Synthesis, and in vitro Evaluation of Bisubstrate Inhibitors for CatecholO-Methyltransferase (COMT)

“…The syntheses of N-benzoylated adenine and cytosine for the subsequent nucleosidation reaction have been reported, [35] whereas 6-benzoylamino-3,4-dihydropyrimidin-4-one (18) was obtained in three steps by reacting thiourea and ethyl cyanoacetate in the presence of base to give 19, [36] desulfurization with Raney-Ni to 20, [37] and benzoylation (Scheme 4).…”

“…The suspension was left in the refrigerator at 4 8C overnight, then the white precipitate was filtered off and washed with THF (5 mL 6-Amino-2-sulfanyl-3,4-dihydropyrimidin-4-one (19): [36] Thiourea (4.56 g, 60.00 mmol) and ethyl cyanoacetate (6.40 mL, 60.00 mmol) were added to EtONa (4.29 g, 63.00 mmol) in EtOH (44 mL), and the mixture was heated to reflux for 2 h. The formed precipitate was filtered off, and the solvents were evaporated in vacuo. The resulting solid residue and the initial precipitate were dissolved in H 2 O (50 mL), then HOAc was added until complete precipitation of 19 as a white powder (8.00 g, 93 % (20): [37] An aqueous suspension of Ra-Ni (12.00 g) was added to a vigorously stirred mixture of 19 N-(6-Oxo-1,6-dihydropyrimidin-4-yl)benzamide (18).…”

A C-13 nuclear magnetic resonance study of the pyrimidine synthesis by the reactions of 1,3-dicarbonyl compounds with amidines and ureas

“…It was undertaken with a view to identify the intermediates on the reaction pathways, and represents a continuation of our earlier studies of the mechanisms of heterocyclic ring formation (9,3 11. '…”

A new synthesis of adenine and 4‐aminoimidazole‐5‐carboxamide

“…Takehiko Ichikawa, Tetsuya Kato and Tadao Takenishi Numerous methods have been reported for the synthesis of adenine, most of which a r e modifications of Traube's method (1) via 2-substituted 4,5,6-triaminopyrimidines. One distinctly different route using malonodiamidine as an intermediate was reported by Shaw (2).…”