{"title":"C9 conformation of N-(N alpha-[(tert.-butyloxy)-carbonyl]-L-alanyl)-N,N'-dicyclohexylu rea in solid and solution.","authors":"C Sudarsanakumar, S Srinivasan, R Jayakumar","doi":"","DOIUrl":null,"url":null,"abstract":"<p><p>An X-ray diffraction study was carried out on a single crystal of N-(N alpha-[(tert.-butyloxy)-carbonyl]-L-alanyl)-N,N'-dicyclohexylur ea belonging to the tetragonal space group P4(1)2(1)2, having cell dimensions a = b = 10.102(3) A, c = 46.067(7) A, V = 4701.2 A3, Z = 8. The crystal structure was solved by direct methods and refined to an R value of 0.056 for 1602 unique reflections with I greater than 2.5 sigma(I). Crystal structure analysis shows the presence of an intramolecular N-H ... O=C H-bond stabilizing the molecule in a folded form similar to that of a beta turn, forming a nine-membered ring. IR and 1H-NMR studies in CDCl3 solution confirm the stable folded conformation found in the crystalline state, as well as the existence of N-H ... O=C H-bonds in the title compound, as in peptides.</p>","PeriodicalId":14204,"journal":{"name":"International journal of peptide and protein research","volume":"39 4","pages":"285-90"},"PeriodicalIF":0.0000,"publicationDate":"1992-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"International journal of peptide and protein research","FirstCategoryId":"1085","ListUrlMain":"","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
An X-ray diffraction study was carried out on a single crystal of N-(N alpha-[(tert.-butyloxy)-carbonyl]-L-alanyl)-N,N'-dicyclohexylur ea belonging to the tetragonal space group P4(1)2(1)2, having cell dimensions a = b = 10.102(3) A, c = 46.067(7) A, V = 4701.2 A3, Z = 8. The crystal structure was solved by direct methods and refined to an R value of 0.056 for 1602 unique reflections with I greater than 2.5 sigma(I). Crystal structure analysis shows the presence of an intramolecular N-H ... O=C H-bond stabilizing the molecule in a folded form similar to that of a beta turn, forming a nine-membered ring. IR and 1H-NMR studies in CDCl3 solution confirm the stable folded conformation found in the crystalline state, as well as the existence of N-H ... O=C H-bonds in the title compound, as in peptides.
N-(N α -[(叔丁氧基)羰基]- l -丙烯基)-N,N'-双环己基脲在固体和溶液中的C9构象。
用x射线衍射研究了N-(N α -[(叔丁氧基)羰基]- l -丙烯基)-N,N'-双环己基a单晶,该单晶属于四方空间群P4(1)2(1)2,晶胞尺寸a = b = 10.102(3) a, c = 46.067(7) a, V = 4701.2 A3, Z = 8。用直接法求解晶体结构,得到1602个I大于2.5 σ (I)的唯一反射的R值为0.056。晶体结构分析表明分子内存在N-H…O=C氢键稳定分子的折叠形式类似于β转,形成一个九元环。在CDCl3溶液中的IR和1H-NMR研究证实了在晶体状态下发现的稳定的折叠构象,以及N-H…在标题化合物中,如肽中的O=C氢键。