- Self-Immolative System for Disclosure of Reactive Electrophilic Alkylating Agents: Understanding the Role of the Reporter Group
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The development of stable, efficient chemoselective self-immolative systems, for use in applications such as sensors, requires the optimization of the reactivity and degradation characteristics of the self-immolative unit. In this paper, we describe the effect that the structure of the reporter group has upon the self-immolative efficacy of a prototype system designed for the disclosure of electrophilic alkylating agents. The amine of the reporter group (a nitroaniline unit) was a constituent part of a carbamate that functioned as the self-immolative unit. The number and position of substituents on the nitroaniline unit were found to play a key role in the rate of self-immolative degradation and release of the reporter group. The position of the nitro substituent (meta- vs para-) and the methyl groups in the ortho-position relative to the carbamate exhibited an influence on the rate of elimination and stability of the self-immolative system. The ortho-methyl substituents imparted a twist on the N-C (aromatic) bond leading to increased resonance of the amine nitrogen's lone pair into the carbonyl moiety and a decrease of the leaving character of the carbamate group; concomitantly, this may also make it a less electron-withdrawing group and lead to less acidification of the eliminated β-hydrogen.
- Chippindale, Ann M.,Gavriel, Alexander G.,Hayes, Wayne,Khurana, Gurjeet S.,Leroux, Flavien,Lewis, Viliyana G.,Russell, Andrew T.,Sambrook, Mark R.
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p. 10263 - 10279
(2021/08/16)
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- SELF-IMMOLATIVE SYSTEMS
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The present invention is concerned with self-immolative recognition and/or responsive systems for electrophilic compounds, especially alkylating agents, which systems may comprise disclosure or detection of the alkylating agent. The present invention is especially concerned with non-protic triggered self-immolative systems, molecules, and methods, and in particular for detection of non- protic electrophilic agents, and especially alkylating agents, for example alkyl or benzylic halides, which may be found in pesticides or fumigants, or chemical warfare agents.
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Page/Page column 22; 23
(2020/05/28)
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- N-Methylation of poorly nucleophilic aromatic amines with dimethyl carbonate
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Abstract: Dimethyl carbonate (DMC), an environmentally friendly methylation agent, is a substitute for traditional methylation agents such as methyl halides (CH3X, X?=?I, Br, Cl) or dimethyl sulfate. An efficient, convenient, and green method has been developed for N-methylation of poorly nucleophilic aromatic amines with DMC. It was found that the couple PEG400/K2CO3 provides good selectivity for the N-methylation product. Finally, the mechanism for reaction of amines with DMC was investigated, and a plausible multistep mechanism proposed and verified. Graphical Abstract: [Figure not available: see fulltext.]
- Yan, Huidong,Zeng, Liufang,Xie, Yaqiang,Cui, Yu,Ye, Liyi,Tu, Song
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p. 5951 - 5960
(2016/06/01)
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- Compounds which are ethylenically unsaturated in the terminal position, and the use thereof in nonlinear optics
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The novel compounds of the general formula I STR1 where X is straight-chain or branched alkanediyl having from 1 to 20 carbon atoms or X is straight-chain or branched alkanediyl having from 2 to 20 carbon atoms, whose carbon chain is interrupted by --O--,
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- Organophosphorus Compounds. XX. Approaches to the Synthesis of 2,3-Dihydro-1H-1.2-benzazaphospholes Involving C-C and C-P Ring Closure
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Reaction of chloromethylphosphonic dichloride (9) with N-methylaniline gave N,N'-dimethyl-N,N'-diphenylchloromethylphosphonodiamide (10) which upon treatment with aluminium chloride underwent intramolecular Friedel-Crafts alkylation to afford 1-methyl-2-(N'-methyl-N'-phenylamino)-2,3-dihydro-1H-1,2-benzazaphosphole 2-oxide (13a).Similarly, N-methyl-N-phenyl(chloromethyl)phenylphosphinamide (15) was cyclized to give 1-methyl-2-phenyl-2,3-dihydro-1H-1,2-benzazaphosphole 2-oxide (13b). Some unsuccessful approaches to this heterocyclic ring system are also reported.
- Collins, David J.,Drygala, Peter F.,Swan, John M.
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p. 1009 - 1021
(2007/10/02)
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- Oxidative hair dye compositions
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Oxidative hair dye composition containing as "para component" compounds of the formula: SPC1 Or their acid addition salts, in which: R1 is alkyl or hydroxyalkyl; R2 is hydrogen or hydroxyalkyl; R3 is hydrogen, alkyl, alkoxy or halogen; and R4 occupies any one of the remaining positions on the benzene radical and is hydrogen, alkyl, alkoxy or halogen; providing that R2 is hydrogen when R3 is alkyl, alkoxy or halogen and providing that at least two of R1, R2, R3 or R4 are other than hydrogen.
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