Chromo- and fluorophoric water-soluble polymers and silica particles by nucleophilic substitution reaction of poly(vinyl amine)

• Katja Hofmann,
• Ingolf Kahle,
• Frank Simon and
• Stefan Spange

Beilstein J. Org. Chem. 2010, 6, No. 79, doi:10.3762/bjoc.6.79

• chromophoric and fluorescent carbonitrile-functionalized poly(vinyl amine) (PVAm) and PVAm/silica particles were synthesized by means of nucleophilic aromatic substitution of 8-oxo-8H-acenaphtho[1,2-b]pyrrol-9-carbonitrile (1) with PVAm in water. The water solubility of 1 has been mediated by 2,6-O-β

• potential which can be used for versatile subsequent derivatization reactions [17][19][20][21]. In previous articles we reported the nucleophilic aromatic substitution of activated fluoroaromatic compounds with PVAm [22][23][24]. Reactions of PVAm with derivatization agents seem at first glance to be simple

• with nitrogen-, oxygen-, or sulfur-containing nucleophiles by nucleophilic aromatic substitution reactions (SNArH) [32][33][34][35][36]. The reaction of 1 with 3-thiopropionic acid has used to produce a fluorescent sensor for cys/Hcy with a 75-fold fluorescence enhancement [34]. The SNArH reaction of 1

9,10-Dioxa-1,2-diaza-anthracene derivatives from tetrafluoropyridazine

• Graham Pattison,
• Graham Sandford,
• Dmitrii S. Yufit,
• Judith A. K. Howard,
• John A. Christopher and
• David D. Miller

Beilstein J. Org. Chem. 2010, 6, No. 45, doi:10.3762/bjoc.6.45

• systems. Keywords: benzodioxinopyridazine; 9,10-dioxa-1,2-diaza-anthracene; heterocyclic synthesis; nucleophilic aromatic substitution; perfluoroheteroaromatic; tetrafluoropyrazine; Introduction Drug discovery programmes are continually searching for viable synthetic routes to highly novel classes of

• highly novel classes of polyfunctional heterocyclic compounds. Several dipyrido[1,2-a:3′,4′-d]imidazole analogues 2 were prepared by the displacement of the remaining ring fluorine atoms by nucleophilic aromatic substitution processes (Scheme 1). We were interested in further expanding the use of highly

• regioselectivity of the nucleophilic aromatic substitution processes (Scheme 2). Both 5 and 6 have ring fluorine atoms present that may, in principle, be displaced by nucleophiles which could lead to the synthesis of many analogues of these systems. The dioxa-1,2-diaza-anthracene (or 3,4-difluorobenzo[5,6][1,4

Preparation, structures and preliminary host–guest studies of fluorinated syn-bis-quinoxaline molecular tweezers

• Markus Etzkorn,
• Jacob C. Timmerman,
• Matthew D. Brooker,
• Xin Yu and
• Michael Gerken

Beilstein J. Org. Chem. 2010, 6, No. 39, doi:10.3762/bjoc.6.39

• reported procedures [29][30][31][32] did not significantly alter the outcome. It should be noted that all fluorinated bis-quinoxalines are stable compounds which do not show any decomposition over extended periods of time; loss of fluorine has only been observed under typical nucleophilic aromatic

• substitution conditions. Although the new compounds, in particular the cyclohexadiene-derived species 15b–c, were reasonably soluble in dipolar aprotic solvents (DMSO, DMF) or halogenated aromatic solvents (C6H5Cl), they only displayed poor solubility in several standard organic solvents (CHCl3, CH2Cl2, CH3OH

Perhalogenated pyrimidine scaffolds. Reactions of 5-chloro- 2,4,6-trifluoropyrimidine with nitrogen centred nucleophiles

• Emma L. Parks,
• Graham Sandford,
• John A. Christopher and
• David D. Miller

Beilstein J. Org. Chem. 2008, 4, No. 22, doi:10.3762/bjoc.4.22

• in parallel synthesis. 5-Chloro-2,4,6-trifluoropyrimidine may be used as a scaffold for the synthesis of polyfunctional pyrimidine systems if sequential nucleophilic aromatic substitution processes are regioselective. Results Use of 5-chloro-2,4,6-trifluoropyrimidine as a core scaffold for the

• synthesis of functionalised pyrimidine systems is assessed in reactions with a small range of nitrogen centred nucleophiles. Mixtures of products arising from nucleophilic aromatic substitution processes are formed, reflecting the activating effect of ring nitrogen and the steric influences of the chlorine

• derivatives can be isolated in acceptable yields using this methodology. Keywords: pyrimidine; rapid analogue synthesis; perfluoroheteroaromatic; nucleophilic aromatic substitution; Introduction Highly functionalised pyrimidine derivatives are of great importance to the life-science industries and, indeed