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Search for "Schiff bases" in Full Text gives 44 result(s) in Beilstein Journal of Organic Chemistry.

Synthesis, fluorescence properties and the promising cytotoxicity of pyrene–derived aminophosphonates

  • Jarosław Lewkowski,
  • Maria Rodriguez Moya,
  • Anna Wrona-Piotrowicz,
  • Janusz Zakrzewski,
  • Renata Kontek and
  • Gabriela Gajek

Beilstein J. Org. Chem. 2016, 12, 1229–1235, doi:10.3762/bjoc.12.117

Graphical Abstract
  • preliminary form [9], fluorescence emission of their azomethine precursors was reported for pyrene-1-carboxaldehyde thiosemicarbazone and Schiff bases as well as their metal complexes [16][17][18][19][20][21]. Such properties were described for, e.g., ruthenium(II) complexes of (5-chloropyridin-2-yl)-(pyren-1
  • Synthesis of aminophosphonic acid derivatives 3, 4 and 5 Schiff bases 1a–h were prepared by refluxing pyrene-1-carboxaldehyde with an amine in methanol, hexane or dichloromethane for 24 hours and were used for further conversions as obtained. This harsh method to prepare imines had to be used, because the
  • further reaction without purification. Aminophosphonates 3Aa–h, 3Ba–e and 3Ca–d, 3Cg have been synthesized via an aza-Pudovik reaction [22], i.e., the addition of the appropriate phosphite 2A–C to the azomethine bond of the Schiff bases 1a–h. Nevertheless, the important modifications had to be introduced
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Published 16 Jun 2016

Olefin metathesis in air

  • Lorenzo Piola,
  • Fady Nahra and
  • Steven P. Nolan

Beilstein J. Org. Chem. 2015, 11, 2038–2056, doi:10.3762/bjoc.11.221

Graphical Abstract
  • quantitative yields in the RCM, CM and ene–yne reactions. Furthermore, complexes 33 and 85 were able to perform the RCM reactions under the same conditions, with yields ranging from moderate to excellent (Figure 15). Schiff bases Schiff bases in metathesis are usually O,N-bidentate ligands and represent an
  • atoms, O (hard) and N (soft), offer different features and therefore can stabilize, respectively, high and low oxidation states. Ruthenium carbene complexes bearing Schiff bases were synthesized originally by the Grubbs’ group and applied in RCM reactions [95], showing lower activity then the Grubbs 1st
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Review
Published 30 Oct 2015

Recent advances in the electrochemical construction of heterocycles

  • Robert Francke

Beilstein J. Org. Chem. 2014, 10, 2858–2873, doi:10.3762/bjoc.10.303

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  • . described an indirect electrochemical method for the generation of 2-substituted benzoxazoles from Schiff bases (Scheme 19) [64]. Using 20 mol % NaI as redox mediator, the electrolysis is conducted under galvanostatic conditions in an undivided cell. A two-phase system composed of a sodium carbonate buffer
  • ). Electrosynthesis of 39 as part of the total synthesis of alkaloids 40 and 41. Wacker-type cyclization of alkenyl phenols 42. Cathodic synthesis of indol derivatives. Fluoride mediated anodic cyclization of α-(phenylthio)acetamides. Synthesis of 2-substituted benzoxazoles from Schiff bases. Synthesis of euglobal
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Review
Published 03 Dec 2014

(2R,1'S,2'R)- and (2S,1'S,2'R)-3-[2-Mono(di,tri)fluoromethylcyclopropyl]alanines and their incorporation into hormaomycin analogues

  • Armin de Meijere,
  • Sergei I. Kozhushkov,
  • Dmitrii S. Yufit,
  • Christian Grosse,
  • Marcel Kaiser and
  • Vitaly A. Raev

Beilstein J. Org. Chem. 2014, 10, 2844–2857, doi:10.3762/bjoc.10.302

Graphical Abstract
  • of Schiff bases derived from glycine and (S)- or (R)-2-N-(N'-benzylprolyl)aminobenzophenone (BPB) [30][31], aminoacetophenone (BPA) [32] or aminobenzaldehyde (BPH) [33] can be used as chiral nucleophilic glycine equivalents in reactions with alkyl halides or carbonyl compounds. The most versatile one
  • is the nickel(II) aminobenzophenone derivative. It is interesting that nickel(II) complexes of Schiff bases derived from 2-bromoglycine and (S)-BPB can be used as electrophilic glycine equivalents [34]. Alkylations of the nickel(II) complexes of Schiff bases derived from glycine and (S)- or (R)-BPB
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Published 03 Dec 2014

A novel 4-aminoantipyrine-Pd(II) complex catalyzes Suzuki–Miyaura cross-coupling reactions of aryl halides

  • Claudia A. Contreras-Celedón,
  • Darío Mendoza-Rayo,
  • José A. Rincón-Medina and
  • Luis Chacón-García

Beilstein J. Org. Chem. 2014, 10, 2821–2826, doi:10.3762/bjoc.10.299

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  • develop a stable and efficient Pd catalyst for these reactions. Recently, palladium complexes containing imidazole-imines [12], binary nanoclusters [13], N-heterocyclic carbenes (NHCs) [14], nanoparticles [15], palladacycles [16], and Schiff bases [17] have been developed as highly effective phosphine
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Letter
Published 01 Dec 2014

Aza-Diels–Alder reaction between N-aryl-1-oxo-1H-isoindolium ions and tert-enamides: Steric effects on reaction outcome

  • Amitabh Jha,
  • Ting-Yi Chou,
  • Zainab ALJaroudi,
  • Bobby D. Ellis and
  • T. Stanley Cameron

Beilstein J. Org. Chem. 2014, 10, 848–857, doi:10.3762/bjoc.10.81

Graphical Abstract
  • isoindolo[2,1-a]quinolone derivatives involves N-acyliminium ions or appropriate electron-deficient Schiff bases and subsequent [4 + 2] inverse-demand hetero-Diels–Alder cycloadditions with alkenes [11][12][13][14][15][16][17]. Vinylic systems from isoeugenol [11], cyclopentadiene [12], enones [13], vinyl
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Published 14 Apr 2014

A novel family of (1-aminoalkyl)(trifluoromethyl)- and -(difluoromethyl)phosphinic acids – analogues of α-amino acids

  • Natalia V. Pavlenko,
  • Tatiana I. Oos,
  • Yurii L. Yagupolskii,
  • Igor I. Gerus,
  • Uwe Doeller and
  • Lothar Willms

Beilstein J. Org. Chem. 2014, 10, 722–731, doi:10.3762/bjoc.10.66

Graphical Abstract
  • protocol [19][20][21]. An alternative to this approach involves the simple addition of alkyl H-phosphinates or H-phosphinic acids to Schiff bases [5][22]. In this paper we exploit both routes to prepare (1-aminoalkyl)(trifluoromethyl)- and -(difluoromethyl)phosphinic acids using P–H compounds bearing CF3
  • removed during the reaction due to the high acidity of the CF3 phosphinic acid group. The variability of Schiff bases ensures access to a range of structurally diverse phosphinic acid analogues of amino acids in the relatively simple way. Thus, we investigated the hydrophosphinylation of some Shiff bases
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Published 26 Mar 2014

Synthesis and stereochemical assignments of diastereomeric Ni(II) complexes of glycine Schiff base with (R)-2-(N-{2-[N-alkyl-N-(1-phenylethyl)amino]acetyl}amino)benzophenone; a case of configurationally stable stereogenic nitrogen

  • Hiroki Moriwaki,
  • Daniel Resch,
  • Hengguang Li,
  • Iwao Ojima,
  • Ryosuke Takeda,
  • José Luis Aceña and
  • Vadim A. Soloshonok

Beilstein J. Org. Chem. 2014, 10, 442–448, doi:10.3762/bjoc.10.41

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  • observed depending on the substituent R introduced in the starting ligand, and stereochemical assignments were based on X-ray analysis, along with NMR studies and optical rotation measurements. Keywords: amino acids; asymmetric synthesis; Ni(II) complexes; Schiff bases; stereogenic nitrogen; Introduction
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Published 19 Feb 2014

Silica sulfuric acid: a reusable solid catalyst for one pot synthesis of densely substituted pyrrole-fused isocoumarins under solvent-free conditions

  • Sudipta Pathak,
  • Kamalesh Debnath and
  • Animesh Pramanik

Beilstein J. Org. Chem. 2013, 9, 2344–2353, doi:10.3762/bjoc.9.269

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  • ninhydrin to form Schiff bases. To overcome the above problems we have designed an operationally simple one-pot reaction for the synthesis of pyrrole-fused isocoumarins (5 or 8) from the ninhydrin adducts of acetylacetone/ethyl acetoacetate (6 or 7) [43] and primary amines 2 under solvent-free conditions
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Published 04 Nov 2013

Complete σ* intramolecular aromatic hydroxylation mechanism through O2 activation by a Schiff base macrocyclic dicopper(I) complex

  • Albert Poater and
  • Miquel Solà

Beilstein J. Org. Chem. 2013, 9, 585–593, doi:10.3762/bjoc.9.63

Graphical Abstract
  • isomeric species was not located, probably due the higher rigidity that is imposed by the Schiff bases bsH2m with respect to the similar, previously described system H3m [40]. The two possible routes from d to e (C–O bond formation) corresponding to the attacks on the two phenyl rings are basically
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Published 20 Mar 2013

Spin state switching in iron coordination compounds

  • Philipp Gütlich,
  • Ana B. Gaspar and
  • Yann Garcia

Beilstein J. Org. Chem. 2013, 9, 342–391, doi:10.3762/bjoc.9.39

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Published 15 Feb 2013

Mechanochemistry assisted asymmetric organocatalysis: A sustainable approach

  • Pankaj Chauhan and
  • Swapandeep Singh Chimni

Beilstein J. Org. Chem. 2012, 8, 2132–2141, doi:10.3762/bjoc.8.240

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  • . Alkylation of imine Alkylation of glycine imine by using a chiral phase-transfer catalyst emerged as a very good strategy for the asymmetric synthesis of amino-acid derivatives [59][60][61]. Lamaty and co-workers prepared a series of glycine Schiff bases 22 in excellent yield (97–98%) in short reaction time
  • Michael reaction assisted by pestle and mortar grinding. C-2 symmetric thiourea catalysed enantioselective MBH reaction. Quinine-catalysed ring opening of meso-anhydride by ball-milling. Ball-milling-assisted (A) synthesis of glycine schiff bases and (B) their organocatalytic asymmetric alkylation
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Published 06 Dec 2012

Design and synthesis of quasi-diastereomeric molecules with unchanging central, regenerating axial and switchable helical chirality via cleavage and formation of Ni(II)–O and Ni(II)–N coordination bonds

  • Vadim A. Soloshonok,
  • José Luis Aceña,
  • Hisanori Ueki and
  • Jianlin Han

Beilstein J. Org. Chem. 2012, 8, 1920–1928, doi:10.3762/bjoc.8.223

Graphical Abstract
  • optimized conditions, we decided to take advantage of our experience in the chemistry of Ni(II)-chelated amino acid Schiff bases [41][42][43][44][45][46][47][48] and to develop an indirect approach for the preparation of asymmetric ligands of type 13. To this goal, we studied the reactions of biscarbonyl
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Published 13 Nov 2012

N-Heterocyclic carbene-catalyzed direct cross-aza-benzoin reaction: Efficient synthesis of α-amino-β-keto esters

  • Takuya Uno,
  • Yusuke Kobayashi and
  • Yoshiji Takemoto

Beilstein J. Org. Chem. 2012, 8, 1499–1504, doi:10.3762/bjoc.8.169

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  • the privileged structure (Figure 1), and two main distinct approaches based on the bond-forming position have been developed. One approach utilizes Cα–Cβ bond formations, such as (a) acylation of Schiff bases or α-isocyano esters with acyl halides [4][15][16][17], and (b) intramolecular N–C acyl
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Letter
Published 10 Sep 2012

Laterally substituted symmetric and nonsymmetric salicylideneimine-based bent-core mesogens

  • Sonja Findeisen-Tandel,
  • Wolfgang Weissflog,
  • Ute Baumeister,
  • Gerhard Pelzl,
  • H. N. Shreenivasa Murthy and
  • Channabasaveshwar V. Yelamaggad

Beilstein J. Org. Chem. 2012, 8, 129–154, doi:10.3762/bjoc.8.15

Graphical Abstract
  • azomethine group (Schiff bases) often show interesting polymorphism. Relationships between molecular structure and the formation of banana phases have been summarized, together with the structure and the behaviour of these phases, in several reviews, see e.g., [8][9][10][11]. It is well-known that a hydroxy
  • stabilization effect is already well-known from calamitic Schiff bases and is caused by the intramolecular hydrogen bond, which could also reduce the flexibility of this molecular leg. Halogen substituents in position X have only a modest effect on the mesophase stability. A slight decrease in the clearing
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Published 24 Jan 2012

Achiral bis-imine in combination with CoCl2: A remarkable effect on enantioselectivity of lipase-mediated acetylation of racemic secondary alcohol

  • K. Arunkumar,
  • M. Appi Reddy,
  • T. Sravan Kumar,
  • B. Vijaya Kumar,
  • K. B. Chandrasekhar,
  • P. Rajender Kumar and
  • Manojit Pal

Beilstein J. Org. Chem. 2010, 6, 1174–1179, doi:10.3762/bjoc.6.134

Graphical Abstract
  • -imines in combination with CoCl2 [16] in the lipase-mediated acetylation of a benzylic secondary alcohols. Accordingly, a number of achiral bis-imines were prepared and used to generate the desired complex. While a number of methods have been reported to prepare Schiff bases by reacting an amine with a
  • carbonyl compound [20][21][22][23][24], in our hands the reaction of 1,2-amines with aromatic aldehydes under these reaction conditions provided a mixture of mono and bis-Schiff bases. We therefore developed a new and efficient method for the preparation of bis-imines 3 by reacting ethane-1,2-diamine (1
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Letter
Published 10 Dec 2010

2-Phenyl- tetrahydropyrimidine- 4(1H)-ones – cyclic benzaldehyde aminals as precursors for functionalised β2-amino acids

  • Markus Nahrwold,
  • Arvydas Stončius,
  • Anna Penner,
  • Beate Neumann,
  • Hans-Georg Stammler and
  • Norbert Sewald

Beilstein J. Org. Chem. 2009, 5, No. 43, doi:10.3762/bjoc.5.43

Graphical Abstract
  • acyclic resonance stabilised Schiff bases are preferentially formed. Consequently, one pot cyclisation protocols employing conditions such as KOH in protic solvents deliver the desired six-membered ring only in unsatisfactory yields [30][39]. An alternative approach to cyclise benzaldehyde-derived imines
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Published 14 Sep 2009

Asymmetric aza-Diels- Alder reaction of Danishefsky's diene with imines in a chiral reaction medium

  • Bruce Pégot,
  • Olivier Nguyen Van Buu,
  • Didier Gori and
  • Giang Vo-Thanh

Beilstein J. Org. Chem. 2006, 2, No. 18, doi:10.1186/1860-5397-2-18

Graphical Abstract
  • relation to the asymmetric process. Among them are: the zirconium-binaphthol complexes developed by Kobayashi et al., [8][9][10][11] the silver catalysts of phosphine peptide Schiff bases reported by Snapper and Hoveyda,[12] as well as the copper complexes of BINAP and phosphino-oxazolidines described by
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Preliminary Communication
Published 18 Sep 2006

The first salen- type ligands derived from 3',5'-diamino- 3',5'-dideoxythymidine and -dideoxyxylothymidine and their corresponding copper(II) complexes

  • Daniel Koth,
  • Michael Gottschaldt,
  • Helmar Görls and
  • Karolin Pohle

Beilstein J. Org. Chem. 2006, 2, No. 17, doi:10.1186/1860-5397-2-17

Graphical Abstract
  • as xylo-configuration and the preparation of copper(II) complexes derived from their corresponding Schiff bases. Starting from thymidine, the amino derivatives were prepared in a three and four step reaction sequence respectively. The absolute configuration of the ligands was proved by the three-bond
  • reaction time led to the desired 3',5'-diamino-3',5'-dideoxy-β-D-xylo-thymidine 6 in 90% yield. Although this compound is easy to synthesize, it has not been described yet. Subsequent condensation of 6 and 7 with salicylic aldehyde provides compounds 8–11 as crystalline solids. The Schiff bases 8–11 of the
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Published 25 Aug 2006
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