Polysubstituted Pyridazinones from Sequential Nucleophilic Substitution Reactions of Tetrafluoropyridazine
作者:Graham Pattison、Graham Sandford、Dmitry S. Yufit、Judith A. K. Howard、John A. Christopher、David D. Miller
DOI:10.1021/jo9006943
日期:2009.8.7
polyfunctional systems can be readily accessed by sequential nucleophilic substitution methodology which may have applications in the drug discovery arena. For example, reaction of 4,5,6-trifluoropyridazin-3(2H)-one with nitrogen nucleophiles leads to a mixture of aminated products arising from substitution of fluorine located at the 4- and 5-positions. The ratio of isomers obtained depends on the nucleophile where
Polysubstituted and ring-fused pyridazine systems from tetrafluoropyridazine
作者:Graham Pattison、Graham Sandford、Ian Wilson、Dmitrii S. Yufit、Judith A.K. Howard、John A. Christopher、David D. Miller
DOI:10.1016/j.tet.2016.12.006
日期:2017.2
substitution of fluorine para to ring nitrogen. Subsequent reaction of the trifluoropyridazine derivatives 2 gave a range of 4,5-di- and tri-substituted products 3 and 6. Related reactions of tetrafluoropyridazine 1 with difunctional nucleophiles gave [6,6]-, [5,6]- and [6,5,6]-polycyclic ring fused pyridazine scaffolds 4 and 9. Further functionalisation of scaffolds 4 by nucleophlic aromatic substitution
Mechanisms for reactions of halogenated compounds. Part 4.[1] activating influences of ring-nitrogen and trifluoromethyl in nucleophilic aromatic substitution
作者:R.D. Chambers、P.A. Martin、J.S. Waterhouse、D.L.H. Williams、B. Anderson
DOI:10.1016/s0022-1139(00)82276-9
日期:1982.6
determined. Ring-nitrogen activates the system at points ortho-, meta- and para- to the point of substitution, in the ratios ortho- 6.2 × 104, meta- 8.5 × 102, and para- 2.3 × 105. Similarly a trifluoromethyl substituent is activating by a factor of 2.4 × 103 ortho- and 4.5 × 103 para- to the point of substitution.
Reactions involving fluoride ion. Part 33 [1]. Perfluoroaza-alkylation of fluorinated heteroaromatics with perfluoro-1-methyl-1,3-diazacyclopent-2-and -3-ene
(1), generated by reaction of fluorideion with (2), can be trapped by fluorinated heteroaromatics. Reaction of (1) with pentafluoropyridine gives a mono-substituted product. Mono- and di-substituted products are obtained with tetrafluoro-pyridazine and -pyrimidine, and fluorideion catalysed isomerisation is observed. The mechanistic consequences of this are discussed. Reaction of (1) with trifluoro-1
The application of perfluoroheteroaromatic reagents in the preparation of modified peptide systems
作者:Diana Gimenez、Caitlin A. Mooney、Anica Dose、Graham Sandford、Christopher R. Coxon、Steven L. Cobb
DOI:10.1039/c7ob00283a
日期:——
The perfluoroheteroaromatic reagent pentafluoropyridine has proved to be a highly reactive electrophile, undergoing SNAr arylation reactions in the presence of a range of nucleophilic peptide side chains (i.e. cysteine, tyrosine, serine and lysine) under mild conditions. Moreover, we have shown how one-step peptide-modification using perfluoroheteroaromatics can deliver enhanced proteolytic stability
已证明全氟杂芳族试剂五氟吡啶是高度反应性的亲电子试剂,在温和条件下,在一系列亲核肽侧链(即半胱氨酸,酪氨酸,丝氨酸和赖氨酸)存在下,会经历S N Ar芳基化反应。此外,我们已经显示了使用全氟杂芳香族化合物一步一步修饰多肽如何在药物相关肽(如催产素)中提供增强的蛋白水解稳定性。