Lichtabsorption und Tautomerie der Harnsäure und der Cyanursäure

Abstract

Nr. 7/1938] Agallidis, .Fromherz, Hartmann. 1391 Das Chinoxalin-carbonsaure-toluidid wird wie das Anilid erhalten. E s krystalfisiert aus Akohol in schwachgelben Nadeln. Schmp. 1.500. Das gelbe Xylidid-(1.3.4) schmilzt bei 1320. Chinoxalin-carbonsaure-athylester: 1 g Saurechlorid wird in 5 ccm Athanol erwarmt, dann mit Wasser verdunnt und ausgeiithert. Aus &her farblose Nadeln, a m p . 850. Aus Methanol gut umkrystallisierbar. 5.137 mg Sbst.: 0.605 ccm N (19O, 760 mm). CllH,oO,N,. Ber. N 13.86. Gef. N 13.77. 228. Elly Agallidis, Hans Fromherz und Adolf Hartmann: Lichtabsorption und Tautomerie der Harn&ure und der Cyanursilure.

Hydrogen-Bonded Anionic Host Lattices Constructed with Isocyanurate and Thiourea/Urea

“…In addition, essentially planar host layers (Figure 7 and Figure 13) exhibiting the fused-rosette pattern are observed in thiourea complex (3) and urea complex (6). The anion and the cationic guest template are identical in the both complexes, but the same type of rosette layer is formed despite the fact that thiourea forms a much longer N−H•••SC acceptor hydrogen bond.…”

“…S5. (6). The independent isocyanurate ion and thiourea molecule make full use of their hydrogen-bonding donor and acceptor sites to generate the anionic host layer of (6) (Figure 13).…”

“…2,4,6-Trihydroxy-1,3,5-triazine N 3 (COH) 3 ( I ), commonly named cyanuric acid ( I ), is among the oldest reported organic compounds. This enolized form only occurs to the extent of 5.6% in neutral solution . The triketo tautomer (NH) 3 (CO) 3 ( II ), commonly known as isocyanuric acid, exists almost exclusively in acidic solution and is the dominant species that participates in chemical reactions. …”

“…This enolized form only occurs to the extent of 5.6% in neutral solution. 6 The triketo tautomer (NH) 3 (CO) 3 (II), commonly known as isocyanuric acid, exists almost exclusively in acidic solution and is the dominant species that participates in chemical reactions.…”

“…If the powder was filtered and the filtrate subjected to further evaporation, the stable cage-type inclusion complex (1) in the form of small rectangular prisms would be obtained after 1 week. For ( 6) and (7), similar procedures as those for (1)−(5) were empolyed, except that different amounts of urea was added in each case: four molar equivalents for (6) and two molar equivalents for (7). Colorless crystals in the form of large blocks were obtained in nearly quantitative yield after about one month.…”