Αποτελέσματα Αναζήτησης
Due to the decoupling in 13 C NMR, the number of absorptions due to aromatic carbons can easily be observed. This can be used to determine the relative positions (ortho, meta, or para) for di-substituted benzenes.
Significant correlations were obtained between field and resonance parameters and 13 C chemical shifts of C-o and C-p, and C-i, C-o, C-m and C-p of the non-substituent bearing phenyl rings in ortho- and para-substituted phenyldiphenylamines, respectively.
17 Οκτ 2022 · The effect of a meta substituent depends on the electronic character, as measured by the Hammett substituent constant σ m or, better yet, σ + m. Similarly, the effect of a para or ortho substituent correlates with σ + p (= σ + ).
17 Απρ 2024 · Because of these ortho -, para -directing effects, meta -substituted phenols have historically been more difficult to synthesize. Here we describe a procedure to transpose phenols that hinges...
29 Ιαν 2018 · Examples of ortho-, para – directors are hydroxyl groups, ethers, amines, alkyl groups, thiols, and halogens. Here’s a concrete example: the nitration of methoxybenzene (also known as anisole). ortho- and para- products dominate, while meta – products comprise less than 3%.
26 Αυγ 2014 · Research Article. Rapid differentiation of ortho -, meta -, and para -isomers of halogenated phenylmethylidene hydrazinecarbodithioates by metal complexation and electrospray ionization mass spectrometry. Yanqing Wu, Cheng Guo, Ningwen Zhang, Gaofeng Bian, Kezhi Jiang. First published: 26 August 2014. https://doi.org/10.1002/rcm.6991.
4 Απρ 2023 · Our research enables facile elaboration of all cubane isomers into drug candidates, thus enabling ideal bioisosteric replacement of ortho-, meta- and para-substituted benzenes.
