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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%.
I got a huge OChem final tomorrow and need to know how to identify whether something is ortho, para or meta from an H-NMR spectrum. We didn't cover this in class and I'm having trouble finding an answer for this online.
2 Φεβ 2018 · We’ll look at a generic electrophilic aromatic substitution reaction of benzene with an ortho-, para- director (methoxybenzene) and examine the intermediates that are obtained from attack at the ortho, meta, and para positions.
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.
Isomerism in disubstituted benzenes can be described by numbering the substituents (1,2- etc) or by the relationships ortho-, meta– and para-. There are two positions ortho – to the initial substituent and two positions meta – to it.
The three possible disubstituted products—ortho, meta, and para—are usually not formed in equal amounts. Instead, the nature of the substituent initially present on the benzene ring determines the position of the second substitution.
In the following practice problems, we will go over the ortho-, para-, and meta – directors in Electrophilic Aromatic Substitution. The first exercise is to make sure you know which groups are activators and deactivators as well as how that relates to the Ortho-, Para-, and Meta – directing effects.
