42132-09-2Relevant articles and documents
Construction of Aromatic Multilayered Structures Based on the Conformational Properties of N,N’-Dimethylated Squaramide
Arimura, Maiko,Tanaka, Kimiko,Kanda, Midori,Urushibara, Ko,Fujii, Shinya,Katagiri, Kosuke,Azumaya, Isao,Kagechika, Hiroyuki,Tanatani, Aya
, p. 198 - 205 (2021/02/02)
Squaramide is a highly rigid four-membered ring system bearing two carbonyl and two amino groups, and its derivatives have found applications in many fields. We synthesized several N,N’-dimethylated oligosquaramides linked via phenyl groups, and investigated their structures in the crystalline state and in solution. Compounds 1, 2 (bissquaramides), and 13 (trissquaramide) exist as folded structures in the crystalline state, in which the aromatic rings are located in a face-to-face position. In their multilayered structures, the benzene rings are more nearly parallel and are closer to each other, compared with those in N,N’-dimethylated oligoureas. Individual molecules of meta-connected compounds 2 and 13 show a helical structure with all-R or all-S axis chirality, but afford only racemic crystals. The NMR spectra indicated that these compounds retain well-ordered folded structures in solution. The unique steric and electronic properties of N,N’-dimethylated squaramide can provide access to novel functional aromatic multilayered and helical foldamers.
Kinetic Analysis and Mechanism of the Hydrolytic Degradation of Squaramides and Squaramic Acids
Ximenis, Marta,Bustelo, Emilio,Algarra, Andrés G.,Vega, Manel,Rotger, Carmen,Basallote, Manuel G.,Costa, Antonio
, p. 2160 - 2170 (2017/02/26)
The hydrolytic degradation of squaramides and squaramic acids, the product of partial hydrolysis of squaramides, has been evaluated by UV spectroscopy at 37 °C in the pH range 3-10. Under these conditions, the compounds are kinetically stable over long time periods (>100 days). At pH >10, the hydrolysis of the squaramate anions shows first-order dependence on both squaramate and OH-. At the same temperature and [OH-], the hydrolysis of squaramides usually displays biphasic spectral changes (A → B → C kinetic model) with formation of squaramates as detectable reaction intermediates. The measured rates for the first step (k1 ≈ 10-4 M-1 s-1) are 2-3 orders of magnitude faster than those for the second step (k2 ≈ 10-6 M-1 s-1). Experiments at different temperatures provide activation parameters with values of ΔH? ≈ 9-18 kcal mol-1 and ΔS? ≈ -5 to -30 cal K-1 mol-1. DFT calculations show that the mechanism for the alkaline hydrolysis of squaramic acids is quite similar to that of amides.
Therapeutically Active Thiazolo-Pyrimidine Derivatives
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Paragraph 0240, (2014/10/29)
A series of thiazolo[5,4-d]pyrimidine derivatives of formula (I) or an N-oxide thereof, or a pharmaceutically acceptable salt or solvate thereof: (I) Q represents a group of formula (Qa), (Qb), (Qc), (Qd) or (Qe) are beneficial in the treatment and/or prevention of various human ailments, including inflammatory, autoimmune and oncological disorders; viral diseases; and organ and cell transplant rejection.
