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1.
Intermolecular stacking in pyrazolo[3,4‐d]pyrimidine‐based pentamethylene‐linked flexible molecules
Kamlakar Avasthi Sheikh M. Farooq Ashish K. Tewari Ashoke Sharon Prakas R. Maulik 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(1):o42-o45
The crystal structures of 1‐{5‐[4,6‐bis(methylsulfanyl)‐2H‐pyrazolo[3,4‐d]pyrimidin‐2‐yl]pentyl}‐6‐methylsulfanyl‐4‐(pyrrolidin‐1‐yl)‐1H‐pyrazolo[3,4‐d]pyrimidine, C22H29N9S3, and 6‐methylsulfanyl‐1‐{5‐[6‐methylsulfanyl‐4‐(pyrrolidin‐1‐yl)‐2H‐pyrazolo[3,4‐d]pyrimidin‐2‐yl]pentyl}‐4‐(pyrrolidin‐1‐yl)‐1H‐pyrazolo[3,4‐d]pyrimidine, C25H34N10S2, which differ in having either a pyrrolidine substituent or a methylsulfanyl group, show intermolecular stacking due to aromatic π–π interactions between the pyrazolo[3,4‐d]pyrimidine rings. 相似文献
2.
《Acta Crystallographica. Section C, Structural Chemistry》2018,74(6):734-741
The combination of cobalt, 3,5‐di‐tert‐butyldioxolene (3,5‐dbdiox) and 1‐hydroxy‐1,2,4,5‐tetrakis(pyridin‐4‐yl)cyclohexane (tpch) yields two coordination polymers with different connectivities, i.e. a one‐dimensional zigzag chain and a two‐dimensional sheet. Poly[[bis(3,5‐di‐tert‐butylbenzene‐1,2‐diolato)bis(1,5‐di‐tert‐butyl‐4‐oxocyclohexa‐2,5‐dien‐1‐yl‐3‐olato)[μ4‐1‐hydroxy‐1,2,4,5‐tetrakis(pyridin‐4‐yl)cyclohexane]cobalt(III)]–ethanol–water 1/7/5], {[Co2(C14H20O2)4(C26H24N4O)]·7C2H5OH·5H2O}n or {[Co2(3,5‐dbdiox)4(tpch)}·7EtOH·5H2O}n, is the second structurally characterized example of a two‐dimensional coordination polymer based on linked {Co(3,5‐dbdiox)2} units. Variable‐temperature single‐crystal X‐ray diffraction studies suggest that catena‐poly[[[(3,5‐di‐tert‐butylbenzene‐1,2‐diolato)(1,5‐di‐tert‐butyl‐4‐oxocyclohexa‐2,5‐dien‐1‐yl‐3‐olato)cobalt(III)]‐μ‐1‐hydroxy‐1,2,4,5‐tetrakis(pyridin‐4‐yl)cyclohexane]–ethanol–water (1/1/5)], {[Co(C14H20O2)2(C26H24N4O)]·C2H5OH·5H2O}n or {[Co(3,5‐dbdiox)2(tpch)]·EtOH·5H2O}n, undergoes a temperature‐induced valence tautomeric interconversion. 相似文献
3.
Marko kof Jurij Svete Branko Stanovnik Simona Goli
‐Grdadolnik 《Helvetica chimica acta》2000,83(4):760-766
(3E,5S)‐1‐Benzoyl‐5‐[(benzoyloxy)methyl]‐3‐[(dimethylamino)methylidene]pyrrolidin‐2‐one ( 9 ) was prepared in two steps from commercially available (S)‐5‐(hydroxymethyl)pyrrolidin‐2‐one ( 7 ) (Scheme 1). Compound 9 gave, in one step, upon treatment with various C,N‐ and C,O‐1,3‐dinucleophiles 10 – 18 , the corresponding 3‐(quinolizin‐3‐yl)‐ and 3‐(2‐oxo‐2H‐pyran‐3‐yl)‐substituted (2S)‐2‐(benzoylamino)propyl benzoates 19 – 27 (Schemes 1 and 2). 相似文献
4.
Annabelle Gillig Somi Reddy Majjigapu Bernard Sordat Pierre Vogel 《Helvetica chimica acta》2012,95(1):34-42
FK866 (also named APO866 or WK175) is a potent NAMPT inhibitor being evaluated (Phase II) as a potential anticancer drug. The preparation of the C‐iminoribofuranoside analog (2E)‐N‐[4‐(1‐benzoylpiperidin‐4‐yl)butyl]‐3‐{3‐[(2S,3S,4R,5R)‐3,4‐dihydroxy‐5‐(hydroxymethyl)pyrrolidin‐2‐yl]phenyl}prop‐2‐enamide ((?)‐ 1 ) is reported. 相似文献
5.
Anna Doga Katarzyna Baranowska Agnieszka Pladzyk Katarzyna Majcher 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(7):m259-m263
The complexes [2‐(1H‐imidazol‐4‐yl‐κN3)ethylamine‐κN]bis(tri‐tert‐butoxysilanethiolato‐κS)cobalt(II), [Co(C12H27O3SSi)2(C5H9N3)], and [2‐(1H‐imidazol‐4‐yl‐κN3)ethylamine‐κN]bis(tri‐tert‐butoxysilanethiolato‐κS)zinc(II), [Zn(C12H27O3SSi)2(C5H9N3)], are isomorphous. The central ZnII/CoII ions are surrounded by two S atoms from the tri‐tert‐butoxysilanethiolate ligand and by two N atoms from the chelating histamine ligand in a distorted tetrahedral geometry, with two intramolecular N—H...O hydrogen‐bonding interactions between the histamine NH2 groups and tert‐butoxy O atoms. Molecules of the complexes are joined into dimers via two intermolecular bifurcated N—H...(S,O) hydrogen bonds. The ZnII atom in [(1H‐imidazol‐4‐yl‐κN3)methanol]bis(tri‐tert‐butoxysilanethiolato‐κ2O,S)zinc(II), [Zn(C12H27O3SSi)2(C4H6N2O)], is five‐coordinated by two O and two S atoms from the O,S‐chelating silanethiolate ligand and by one N atom from (1H‐imidazol‐4‐yl)methanol; the hydroxy group forms an intramolecular hydrogen bond with sulfur. Molecules of this complex pack as zigzag chains linked by N—H...O hydrogen bonds. These structures provide reference details for cysteine‐ and histidine‐ligated metal centers in proteins. 相似文献
6.
Gerson Lpez L. Marina Jaramillo Rodrigo Abonia Justo Cobo Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(4):o168-o173
The molecules of N‐(3‐tert‐butyl‐1‐phenyl‐1H‐pyrazol‐5‐yl)‐2‐chloro‐N‐(4‐methoxybenzyl)acetamide, C23H26ClN3O2, are linked into a chain of edge‐fused centrosymmetric rings by a combination of one C—H...O hydrogen bond and one C—H...π(arene) hydrogen bond. In N‐(3‐tert‐butyl‐1‐phenyl‐1H‐pyrazol‐5‐yl)‐2‐chloro‐N‐(4‐chlorobenzyl)acetamide, C22H23Cl2N3O, a combination of one C—H...O hydrogen bond and two C—H...π(arene) hydrogen bonds, which utilize different aryl rings as the acceptors, link the molecules into sheets. The molecules of S‐[N‐(3‐tert‐butyl‐1‐phenyl‐1H‐pyrazol‐5‐yl)‐N‐(4‐methylbenzyl)carbamoyl]methyl O‐ethyl carbonodithioate, C26H31N3O2S2, are also linked into sheets, now by a combination of two C—H...O hydrogen bonds, both of which utilize the amide O atom as the acceptor, and two C—H...π(arene) hydrogen bonds, which utilize different aryl groups as the acceptors. 相似文献
7.
Zhong-Xuan Xu Guo-Guo Chen Li-Feng Li 《Acta Crystallographica. Section C, Structural Chemistry》2020,76(2):125-132
The reactions of (R)‐ and (S)‐4‐(1‐carboxyethoxy)benzoic acid (H2CBA) with 1,3‐bis(2‐methyl‐1H‐imidazol‐1‐yl)benzene (1,3‐BMIB) ligands afforded a pair of homochiral coordination polymers (CPs), namely, poly[[[μ‐1,3‐bis(2‐methyl‐1H‐imidazol‐1‐yl)benzene][μ‐(S)‐4‐(1‐carboxylatoethoxy)benzoato]zinc(II)] monohydrate], {[Zn(C10H8O5)(C14H14N4)]·H2O}n or {[Zn{(S)‐CBA}(1,3‐BMIB)]·H2O}n ( 1‐L ), and poly[[[μ‐1,3‐bis(2‐methyl‐1H‐imidazol‐1‐yl)benzene][μ‐(R)‐4‐(1‐carboxylatoethoxy)benzoato]zinc(II)] monohydrate] ( 1‐D ). Three kinds of helical chains exist in compounds 1‐D and 1‐L , which are constructed from ZnII atoms, 1,3‐BMIB ligands and/or CBA2? ligands. When the as‐synthesized crystals of 1‐L and 1‐D were further heated in the mother liquor or air, poly[[μ‐1,3‐bis(2‐methyl‐1H‐imidazol‐1‐yl)benzene][μ‐(S)‐4‐(1‐carboxylatoethoxy)benzoato]zinc(II)], [Zn(C10H8O5)(C14H14N4)]n or [Zn{(S)‐CBA}(1,3‐BMIB)]n ( 2‐L ), and poly[[μ‐1,3‐bis(2‐methyl‐1H‐imidazol‐1‐yl)benzene][μ‐(R)‐4‐(1‐carboxylatoethoxy)benzoato]zinc(II)] ( 2‐D ) were obtained, respectively. The single‐crystal structure analysis revealed that 2‐L and 2‐D only contained one type of helical chain formed by ZnII atoms and 1,3‐BMIB and CBA2? ligands, which indicated that the helical chains were reconstructed though solid‐to‐solid transformation. This result not only means the realization of helical transformation, but also gives a feasible strategy to build homochiral CPs. 相似文献
8.
David B. Cordes Guoxiong Hua Alexandra M. Z. Slawin J. Derek Woollins 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(12):o509-o514
Two polymorphs of 2,5‐diphenyl‐1,3,4‐selenadiazole, C14H10N2Se, denoted (Ia) and (Ib), and a new polymorph of 2,5‐bis(thiophen‐2‐yl)‐1,3,4‐selenadiazole, C10H6N2S2Se, (IIb), form on crystallization of the compounds, prepared using Woollins' reagent (2,4‐diphenyl‐1,3‐diselenadiphosphetane 2,4‐diselenide). These compounds, along with 2‐(4‐chlorophenyl)‐5‐phenyl‐1,3,4‐selenadiazole, C14H9ClN2Se, (III), and 2‐(furan‐2‐yl)‐5‐(p‐tolyl)‐1,3,4‐selenadiazole, C13H10N2OSe, (IV), show similar intermolecular interactions, with π–π stacking, C—H...π interactions and weak hydrogen bonds typically giving rise to molecular chains. However, the combination of interactions differs in each case, giving rise to different packing arrangements. In polymorph (Ib), the molecule lies across a crystallographic twofold rotation axis, and (IV) has two independent molecules in the asymmetric unit. 相似文献
9.
A series of new chiral (S)‐3‐ary1‐6‐pyrrolidin‐2‐yl‐[1,2,4]triazolo[3,4‐b]thiadiazole (II1‐5), (S)‐1‐(3‐aryl‐[1,2,4]triazolo[3,4‐b][1,3,4]thiadiazol‐6‐yl)‐ethylamine (II6‐8) and (S)‐1,2‐bis(3‐aryl‐[1,2,4]triazolo‐[3,4‐b][1,3,4]thiadiazol‐6‐yl)‐ethylamine (II9‐11) were prepared by the condensation of 3‐aryl‐4‐amino‐5‐mercapto‐1,2,4‐triazoles with different L‐amino acids in the presence of phosphorus oxychloride and evaluated for their antibacterial activity. 相似文献
10.
Yuekun Zhao Madeleine Helliwell John A. Joule 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(6):714-715
Vilsmeier formylation of trans‐1‐(4‐methylphenylsulfonyl)‐2,5‐bis(pyrrol‐2‐yl)pyrrolidine leads to cleavage of the central ring then a reclosure resulting in the formation of trans‐N‐[2‐formyl‐4‐(5‐formylpyrrol‐2‐yl)‐4,5,6,7‐tetrahydroindol‐7‐yl]toluenesulfonamide, C21H21N3O4S. 相似文献
11.
Susanne Flock Clemens Bruhn Heinrich Fink Herbert Frauenrath 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(2):o101-o103
The title enantiomorphic compounds, C16H23NO4S, have been obtained in an enantiomerically pure form by crystallization from a diastereomeric mixture either of (2S,4S)‐ and (2R,4S)‐ or of (2R,4R)‐ and (2S,4R)‐2‐tert‐butyl‐4‐methyl‐3‐(4‐tolylsulfonyl)‐1,3‐oxazolidine‐4‐carbaldehyde. These mixtures were prepared by an aziridination rearrangement process starting with (S)‐ or (R)‐2‐tert‐butyl‐5‐methyl‐4H‐1,3‐dioxine. The crystal structures indicate an envelope conformation of the oxazolidine moiety for both compounds. 相似文献
12.
Fan Yu 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(10):m331-m334
Two mononuclear copper complexes, {bis[(3,5‐dimethyl‐1H‐pyrazol‐1‐yl‐κN2)methyl]amine‐κN}(3,5‐dimethyl‐1H‐pyrazole‐κN2)(perchlorato‐κO)copper(II) perchlorate, [Cu(ClO4)(C5H8N2)(C12H19N5)]ClO4, (I), and {bis[(3,5‐dimethyl‐1H‐pyrazol‐1‐yl‐κN2)methyl]amine‐κN}bis(3,5‐dimethyl‐1H‐pyrazole‐κN2)copper(II) bis(hexafluoridophosphate), [Cu(C5H8N2)2(C12H19N5)](PF6)2, (II), have been synthesized by the reactions of different copper salts with the tripodal ligand tris[(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)methyl]amine (TDPA) in acetone–water solutions at room temperature. Single‐crystal X‐ray diffraction analysis revealed that they contain the new tridentate ligand bis[(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)methyl]amine (BDPA), which cannot be obtained by normal organic reactions and has thus been captured in the solid state by in situ synthesis. The coordination of the CuII ion is distorted square pyramidal in (I) and distorted trigonal bipyramidal in (II). The new in situ generated tridentate BDPA ligand can act as a meridional or facial ligand during the process of coordination. The crystal structures of these two compounds are stabilized by classical hydrogen bonding as well as intricate nonclassical hydrogen‐bond interactions. 相似文献
13.
《Acta Crystallographica. Section C, Structural Chemistry》2017,73(1):36-46
As an important class of heterocyclic compounds, 1,3,4‐thiadiazoles have a broad range of potential applications in medicine, agriculture and materials chemistry, and were found to be excellent precursors for the crystal engineering of organometallic materials. The coordinating behaviour of allyl derivatives of 1,3,4‐thiadiazoles with respect to transition metal ions has been little studied. Five new crystalline copper(I) π‐complexes have been obtained by means of an alternating current electrochemical technique and have been characterized by single‐crystal X‐ray diffraction and IR spectroscopy. The compounds are bis[μ‐5‐methyl‐N‐(prop‐2‐en‐1‐yl)‐1,3,4‐thiadiazol‐2‐amine]bis[nitratocopper(I)], [Cu2(NO3)2(C6H9N3S)2], (1), bis[μ‐5‐methyl‐N‐(prop‐2‐en‐1‐yl)‐1,3,4‐thiadiazol‐2‐amine]bis[(tetrafluoroborato)copper(I)], [Cu2(BF4)2(C6H9N3S)2], (2), μ‐aqua‐bis{μ‐5‐[(prop‐2‐en‐1‐yl)sulfanyl]‐1,3,4‐thiadiazol‐2‐amine}bis[nitratocopper(I)], [Cu2(NO3)2(C5H7N3S2)2(H2O)], (3), μ‐aqua‐(hexafluorosilicato)bis{μ‐5‐[(prop‐2‐en‐1‐yl)sulfanyl]‐1,3,4‐thiadiazol‐2‐amine}dicopper(I)–acetonitrile–water (2/1/4), [Cu2(SiF6)(C5H7N3S2)2(H2O)]·0.5CH3CN·2H2O, (4), and μ‐benzenesulfonato‐bis{μ‐5‐[(prop‐2‐en‐1‐yl)sulfanyl]‐1,3,4‐thiadiazol‐2‐amine}dicopper(I) benzenesulfonate–methanol–water (1/1/1), [Cu2(C6H5O3S)(C5H7N3S2)2](C6H5O3S)·CH3OH·H2O, (5). The structure of the ligand 5‐methyl‐N‐(prop‐2‐en‐1‐yl)‐1,3,4‐thiadiazol‐2‐amine (Mepeta ), C6H9N3S, was also structurally characterized. Both Mepeta and 5‐[(prop‐2‐en‐1‐yl)sulfanyl]‐1,3,4‐thiadiazol‐2‐amine (Pesta ) (denoted L ) reveal a strong tendency to form dimeric {Cu2L 2}2+ fragments, being attached to the metal atom in a chelating–bridging mode via two thiadiazole N atoms and an allylic C=C bond. Flexibility of the {Cu2(Pesta )2}2+ unit allows the CuI atom site to be split into two positions with different metal‐coordination environments, thus enabling the competitive participation of different molecules in bonding to the metal centre. The Pesta ligand in (4) allows the CuI atom to vary between water O‐atom and hexafluorosilicate F‐atom coordination, resulting in the rare case of a direct CuI…FSiF52− interaction. Extensive three‐dimensional hydrogen‐bonding patterns are formed in the reported crystal structures. Complex (5) should be considered as the first known example of a CuI(C6H5SO3) coordination compound. To determine the hydrogen‐bond interactions in the structures of (1) and (2), a Hirshfeld surface analysis has been performed. 相似文献
14.
Hua Cai Na Li Nan Zhang Zhenyun Yang Jing Cao Yating Lin Nan Min Jia Wang 《Acta Crystallographica. Section C, Structural Chemistry》2020,76(2):118-124
By the solvothermal reactions of 2,5‐bis(1H‐1,2,4‐triazol‐1‐yl)terephthalic acid (H2L) with transition‐metal ions, two novel polymeric complexes, namely, poly[diaqua[μ4‐2,5‐bis(1H‐1,2,4‐triazol‐1‐yl)terephthalato]cobalt(II)], [Co(C12H6N6O4)(H2O)2]n, ( 1 ), and poly[[diaqua[μ4‐2,5‐bis(1H‐1,2,4‐triazol‐1‐yl)terephthalato]nickel(II)] dihydrate], {[Ni(C12H6N6O4)(H2O)2]·2H2O}n, ( 2 ), were isolated. Both polymers have been characterized by FT–IR spectroscopy, elemental analysis and single‐crystal X‐ray diffraction analysis. The complexes have similar two‐dimensional layered structures and coordination modes. Furthermore, the two‐dimensional layered structures bear distinct intermolecular hydrogen‐bonding interactions and π–π stacking interactions to form two different three‐dimensional supramolecular networks based on 44‐subnets. The structural variation depends on the nature of the metal cations. The results of variable‐temperature magnetization measurements (χMT?T and χM?1?T) show that complexes ( 1 ) and ( 2 ) display antiferromagnetic behaviour. 相似文献
15.
Katherine A. Bussey Annie R. Cavalier Jennifer R. Connell Margaret E. Mraz Kayode D. Oshin Tomislav Pintauer Allen G. Oliver 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(7):526-533
The structures of five compounds consisting of (prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine complexed with copper in both the CuI and CuII oxidation states are presented, namely chlorido{(prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine‐κ3N,N′,N′′}copper(I) 0.18‐hydrate, [CuCl(C15H17N3)]·0.18H2O, (1), catena‐poly[[copper(I)‐μ2‐(prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine‐κ5N,N′,N′′:C2,C3] perchlorate acetonitrile monosolvate], {[Cu(C15H17N3)]ClO4·CH3CN}n, (2), dichlorido{(prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine‐κ3N,N′,N′′}copper(II) dichloromethane monosolvate, [CuCl2(C15H17N3)]·CH2Cl2, (3), chlorido{(prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine‐κ3N,N′,N′′}copper(II) perchlorate, [CuCl(C15H17N3)]ClO4, (4), and di‐μ‐chlorido‐bis({(prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine‐κ3N,N′,N′′}copper(II)) bis(tetraphenylborate), [Cu2Cl2(C15H17N3)2][(C6H5)4B]2, (5). Systematic variation of the anion from a coordinating chloride to a noncoordinating perchlorate for two CuI complexes results in either a discrete molecular species, as in (1), or a one‐dimensional chain structure, as in (2). In complex (1), there are two crystallographically independent molecules in the asymmetric unit. Complex (2) consists of the CuI atom coordinated by the amine and pyridyl N atoms of one ligand and by the vinyl moiety of another unit related by the crystallographic screw axis, yielding a one‐dimensional chain parallel to the crystallographic b axis. Three complexes with CuII show that varying the anion composition from two chlorides, to a chloride and a perchlorate to a chloride and a tetraphenylborate results in discrete molecular species, as in (3) and (4), or a bridged bis‐μ‐chlorido complex, as in (5). Complex (3) shows two strongly bound Cl atoms, while complex (4) has one strongly bound Cl atom and a weaker coordination by one perchlorate O atom. The large noncoordinating tetraphenylborate anion in complex (5) results in the core‐bridged Cu2Cl2 moiety. 相似文献
16.
Xiang‐Wen Wu Wan‐Fu Wu Shi Yin Jian‐Ping Ma 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(8):683-689
Three coordination complexes with CuI centres have been prepared using the symmetrical flexible organic ligands 1,3‐bis{[5‐(quinolin‐2‐yl)‐1,3,4‐oxadiazol‐2‐yl]sulfanyl}propane (L1) and 1,4‐bis{[5‐(quinolin‐2‐yl)‐1,3,4‐oxadiazol‐2‐yl]sulfanyl}butane (L2). Crystallization of L1 with Cu(SO3CF3)2 and of L2 with Cu(BF4)2 and Cu(ClO4)2 in a CH2Cl2/CH3OH mixed‐solvent system at room temperature afforded the coordination complexes catena‐poly[[copper(I)‐μ‐1,3‐bis{[5‐(quinolin‐2‐yl)‐1,3,4‐oxadiazol‐2‐yl]sulfanyl}propane] methanesulfonate dichloromethane 0.6‐solvate], {[Cu(C25H18N6O2S2)](CF3SO3)·0.6CH2Cl2}n, (I), bis(μ‐1,4‐bis{[5‐(quinolin‐2‐yl)‐1,3,4‐oxadiazol‐2‐yl]sulfanyl}butane)dicopper(I) bis(tetrafluoridoborate)–dichloromethane–methanol (1/1.5/1), [Cu2(C26H20N6O2S2)2](BF4)2·1.5CH2Cl2·CH3OH, (II), and bis(μ‐1,4‐bis{[5‐(quinolin‐2‐yl)‐1,3,4‐oxadiazol‐2‐yl]sulfanyl}butane)dicopper(I) bis(perchlorate)–dichloromethane–methanol (1/2/1), [Cu2(C26H20N6O2S2)2](ClO4)2·2CH2Cl2·CH3OH, (III). Under the control of the dumbbell‐shaped CF3SO3− anion, complex (I) forms a one‐dimensional chain and neighbouring chains form a spiral double chain. Under the control of the regular tetrahedron‐shaped BF4− and ClO4− anions, complexes (II) and (III) have been obtained as bimetallic rings, which further interact viaπ–π interactions to form two‐dimensional networks. The anions play a decisive role in determining the arrangement of these discrete molecular complexes in the solid state. 相似文献
17.
《Acta Crystallographica. Section C, Structural Chemistry》2018,74(1):82-93
An efficent access to a series of N‐(pyrrol‐2‐yl)amines, namely (E)‐1‐tert‐butyl‐5‐[(4‐chlorobenzylidene)amino]‐1H‐pyrrole‐3‐carbonitrile, C16H16ClN3, (7a), (E)‐1‐tert‐butyl‐5‐[(2,4‐dichlorobenzylidene)amino]‐1H‐pyrrole‐3‐carbonitrile, C16H15Cl2N3, (7b), (E)‐1‐tert‐butyl‐5‐[(pyridin‐4‐ylmethylene)amino]‐1H‐pyrrole‐3‐carbonitrile, C15H16N4, (7c), 1‐tert‐butyl‐5‐[(4‐chlorobenzyl)amino]‐1H‐pyrrole‐3‐carbonitrile, C16H18ClN3, (8a), and 1‐tert‐butyl‐5‐[(2,4‐dichlorobenzyl)amino]‐1H‐pyrrole‐3‐carbonitrile, C16H17Cl2N3, (8b), by a two‐step synthesis sequence (solvent‐free condensation and reduction) starting from 5‐amino‐1‐tert‐butyl‐1H‐pyrrole‐3‐carbonitrile is described. The syntheses proceed via isolated N‐(pyrrol‐2‐yl)imines, which are also key synthetic intermediates of other valuable compounds. The crystal structures of the reduced compounds showed a reduction in the symmetry compared with the corresponding precursors, viz. Pbcm to P from compound (7a) to (8a) and P21/c to P from compound (7b) to (8b), probably due to a severe change in the molecular conformations, resulting in the loss of planarity observed in the nonreduced compounds. In all of the crystals, the supramolecular assembly is controlled mainly by strong (N,C)—H…N hydrogen bonds. However, in the case of (7a)–(7c), C—H…Cl interactions are strong enough to help in the three‐dimensional architecture, as observed in Hirshfeld surface maps. 相似文献
18.
Olivier Vallat Ana‐Maria Buciumas Reinhard Neier Helen Stoeckli‐Evans 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(4):o171-o175
The title compounds, rac‐(1′R,2R)‐tert‐butyl 2‐(1′‐hydroxyethyl)‐3‐(2‐nitrophenyl)‐5‐oxo‐2,5‐dihydro‐1H‐pyrrole‐1‐carboxylate, C17H20N2O6, (I), rac‐(1′S,2R)‐tert‐butyl 2‐[1′‐hydroxy‐3′‐(methoxycarbonyl)propyl]‐3‐(2‐nitrophenyl)‐5‐oxo‐2,5‐dihydro‐1H‐pyrrole‐1‐carboxylate, C20H24N2O8, (II), and rac‐(1′S,2R)‐tert‐butyl 2‐(4′‐bromo‐1′‐hydroxybutyl)‐5‐oxo‐2,5‐dihydro‐1H‐pyrrole‐1‐carboxylate, C13H20BrNO4, (III), are 5‐hydroxyalkyl derivatives of tert‐butyl 2‐oxo‐2,5‐dihydropyrrole‐1‐carboxylate. In all three compounds, the tert‐butoxycarbonyl (Boc) unit is orientated in the same manner with respect to the mean plane through the 2‐oxo‐2,5‐dihydro‐1H‐pyrrole ring. The hydroxyl substituent at one of the newly created chiral centres, which have relative R,R stereochemistry, is trans with respect to the oxo group of the pyrrole ring in (I), synthesized using acetaldehyde. When a larger aldehyde was used, as in compounds (II) and (III), the hydroxyl substituent was found to be cis with respect to the oxo group of the pyrrole ring. Here, the relative stereochemistry of the newly created chiral centres is R,S. In compound (I), O—H...O hydrogen bonding leads to an interesting hexagonal arrangement of symmetry‐related molecules. In (II) and (III), the hydroxyl groups are involved in bifurcated O—H...O hydrogen bonds, and centrosymmetric hydrogen‐bonded dimers are formed. The Mukaiyama crossed‐aldol‐type reaction was successful when using the 2‐nitrophenyl‐substituted hydroxypyrrole, or the unsubstituted hydroxypyrrole, and boron trifluoride diethyl ether as catalyst. The synthetic procedure leads to a syn configuration of the two newly created chiral centres in all three compounds. 相似文献
19.
The reaction of 1H‐imidazole‐4‐carbohydrazides 1 , which are conveniently accessible by treatment of the corresponding esters with NH2NH2?H2O, with isothiocyanates in refluxing EtOH led to thiosemicarbazides (=hydrazinecarbothioamides) 4 in high yields (Scheme 2). Whereas 4 in boiling aqueous NaOH yielded 2,4‐dihydro‐3H‐1,2,4‐triazole‐3‐thiones 5 , the reaction in concentrated H2SO4 at room temperature gave 1,3,4‐thiadiazol‐2‐amines 6 . Similarly, the reaction of 1 with butyl isocyanate led to semicarbazides 7 , which, under basic conditions, undergo cyclization to give 2,4‐dihydro‐3H‐1,2,4‐triazol‐3‐ones 8 (Scheme 3). Treatment of 1 with Ac2O yielded the diacylhydrazine derivatives 9 exclusively, and the alternative isomerization of 1 to imidazol‐2‐ones was not observed (Scheme 4). It is important to note that, in all these transformations, the imidazole N‐oxide residue is retained. Furthermore, it was shown that imidazole N‐oxides bearing a 1,2,4‐triazole‐3‐thione or 1,3,4‐thiadiazol‐2‐amine moiety undergo the S‐transfer reaction to give bis‐heterocyclic 1H‐imidazole‐2‐thiones 11 by treatment with 2,2,4,4‐tetramethylcyclobutane‐1,3‐dithione (Scheme 5). 相似文献
20.
The influence of the carbohydrate moiety on the formation of 2‐[4‐oxo‐3‐(pyrrolidin‐1‐yl)cyclopent‐2‐en‐1‐ylidene]furan‐3(2H)‐one chromophores during food‐related Maillard reactions from pentoses, hexoses, and disaccharides is reported. The orange compounds 1a , b and 2a , b , detected in a roasted xylose/ L ‐proline mixture, were identified as (2E)/(2Z)‐4‐hydroxy‐5‐methyl‐2‐[4‐oxo‐3‐(pyrrolidin‐1‐yl)cyclopent‐2‐ene‐1‐ylidene]furan‐3(2H)‐one and (2E)/(2Z)‐5‐methyl‐2‐[4‐oxo‐3‐(pyrrolidin‐1‐yl)cyclopent‐2‐en‐1‐ylidene]‐4‐(pyrrolidin‐1‐yl)furan‐3(2H)‐one, respectively, by 1D‐ and 2D‐NMR, LC/mass, and UV/VIS spectroscopy, as well as by synthetic experiments. Studies on their formation revealed that 1a , b and 2a , b are formed upon condensation of pentose‐derived 4‐hydroxy‐5‐methyl‐ ( 3 ) and 5‐methyl‐4‐(pyrrolidin‐1‐yl)furan‐3(2H)‐one ( 4 ), respectively, with 2‐hydroxycyclopenta‐2,4‐dien‐1‐one ( 5 ) and L ‐proline (Scheme 1). Further condensation reaction of 1a , b with furan‐2‐carbaldehyde yielded the red (2Z)‐2‐{(5Z)‐5‐[(2‐furyl)methylidene]‐4‐oxo‐3‐(pyrrolidin‐1‐yl)cyclopent‐2‐en‐1‐ylidene}‐4‐hydroxy‐5‐methylfuran‐3(2H)‐one ( 6 ) as an additional novel Maillard chromophore. Replacement of the pentose by glucose in the mixture with L ‐proline led, after dry‐heating, to the identification of the structurally related colored (2Z)/(2E)‐2‐[5‐hydroxy‐5‐methyl‐4‐oxo‐3‐(pyrrolidin‐1‐yl)cyclopent‐2‐en‐1‐ylidene]‐4‐hydroxy‐5‐methylfuran‐3(2H)‐one ( 7a / 7b ) and to the characterization of 2,4,5‐trihydroxy‐5‐methylcyclopent‐2‐en‐1‐one ( 10 ) and 5‐hydroxy‐5‐methylcyclopent‐3‐ene‐1,2‐dione ( 11 ) as key intermediates in chromophore formation from hexoses. Comparative studies on disaccharides revealed that not 7a / 7b , but the colorless 4‐(α‐D ‐glucopyranosyloxy)‐2‐hydroxy‐2‐methyl‐6H‐pyran‐3(2H)‐one ( 8 ) and 2‐(α‐D ‐glucopyranosyloxy)‐4,5‐dihydroxy‐5‐methylcyclopent‐2‐en‐1‐one ( 9 ) were formed amongst the major degradation products of maltose (Scheme 4). The aglycons of 8 and 9 could not be liberated under food‐related heating conditions, thus, inhibiting the formation of the color precursors 10 and 11 and, in consequence, of 7a / 7b (Scheme 6). These data strongly suggest that the 1,4‐glycosidic linkage of disaccharides is responsible for their lower efficiency in browning development compared to pentoses or hexoses. 相似文献