2018年1月29日 · We call the substituents which lead to this result “ meta- directors”. Examples of meta – directors include nitriles, carbonyl compounds (such as aldehydes, ketones, and esters), sulfones, electron-deficient alkyl groups, nitro groups, and alkylammoniums.

2023年2月9日 · Those groups that direct incoming groups to meta position are called meta-directing groups. We can also define it as “Electron withdrawing groups in the aromatic ring are called meta-directing groups.” For better understanding also read my article on ortho-para directing groups.

2017年9月26日 · In contrast to aniline, which is very reactive in EAS compared to benzene, the anilinium ion (which is easily formed in acidic media) is deactivated. As the acidity of the medium increases, the amount of meta product obtained from nitration of aniline increases, indicating that the reaction is proceeding via the anilinium ion (PhNH 3 ...

Meta-directing deactivating groups are those that either do not donate electrons by resonance (sulfonic acid groups and ammonium ion groups) or actually withdraw electrons by resonance (carbonyl, nitrile, and nitro groups). They are meta-directing not because they stabilise the intermediate for meta-substitution: far from it.

2018年2月2日 · Another class of substituents avoids directing the electrophile E to those positions, with the result that the meta- product (1,3) is major. These are called, “meta- directors”. The ultimate factor which determines whether a substituent is ortho-, para-or meta-directing is how well it stabilizes an adjacent carbocation.

2023年11月13日 · Meta directors are deactivating groups on benzene that direct the electrophile E to the meta position. In comparison to hydrogen, deactivating groups slow down the rate of electrophilic aromatic substitution.

Meta directing groups: These groups direct the electrophilic attack on “meta” positions of the associated benzene ring. Generally deactivating groups are meta directors, for example –NO 2, –CN, –CHO, –COR, –COOH, –COOR, –SO 3 H, etc. Nitro group is a ring deactivating group; they decrease the electron density of the benzene ring attached.

2022年2月8日 · The groups which direct the incoming group to meta positions are called meta directing groups. e.g. [Note: All meta directing groups have positive (or partial positive) charge on the atom which is directly attached to an aromatic ring.]

2022年10月1日 · All activators AND halogens are ortho-para directors; Deactivators (not halogens) are meta-directing. Therefore, depending on the character of the initial substituent (R), a subsequent substituent would be placed at the ortho or para position if R is an activator/halogen or at the meta position if it is a deactivator (but not a halogen).

Let us understand the concept of meta directors in organic chemistry as follows:- Meta directors: It is a substituent that favors electrophilic attack at meta position with respect to the substituent in electrophilic substitution reactions.