5. Which of the following is not a meta-directing substituent
when presenbt on the benzene ring? Please give explanation,
too.
a)-NHCOCH3
The amino (-NH2) and hydroxyl (-OH) groups are strongest activating and ortho/para-directing substituents in electrophilic aromatic substitution reaction. This ability is due the presence of lone pair of electrons present on the heteroatom of these groups. The amine delocalises these electrons on the aromatic ring to produce this effect.
The activating ability of these strongly activating groups can be attenuated by acetylating the heteroatom. e.g. Aniline is converted to acetanilide
C6H5–NH2 + (CH3CO)2O |
pyridine (a base) |
C6H5–NHCOCH3 |
The acetyl derivative is still an ortho/para-directing and activating group but with moderate activating effect. The lone pair electrons on the nitrogen atom of the amide are conjugated with the carbonyl group decreasing the activating effect of NH2 group. The acetyl derivative still can delocalize its lone pair electrons on the aromatic ring although less efficiently to make it ortho para directing group.
The other groups such as NO2, N(CH3)3+, CN, CO2H are elctron withdrawing groups & hence they are meta directing.
5. Which of the following is not a meta-directing substituent when presenbt on the benzene ring?...
21. Which of the following is NOT a m-directing substituent when present on the benzene ring (a)-NHCOCH3 (b) –NO2 (c) –N(CH3)3+ (d)-CN 23. The relationship of propanone and propen-2-ol is called (a) tautomers (b) conformational isomers (c)distereomers (d)resonance structures 24. Which reagent can be used to distinguish an aldehyde and a ketone? (a) Br2/CCl4 (b) KMnO4/OH- (c) Ag2O/NH4OH (d)None of these 25. The proper name for the molecule below is: (a) 2-chloro-5-aldehydotoluene (b) 6—chloro-3-aldehydotoluene (c) 3-methyl-4-chloro-benzaldehyde (d) 4-chloro-3-methylbenzaldehyde
An NH2 substituent in an aromatic ring is: Select one: a. activating ortho-, meta- and para-directing b. deactivating and ortho- and para-directing c. deactivating and meta-directing d. activating and meta-directing e. activating and ortho- and para-directing
If a benzene ring has one methyl group as a substituent, will the next substituent add to the benzene ring in the ortho, meta, or para position? Select one: a. para or meta b. para only c. meta only d. ortho only e. ortho or meta f. Ortho or para
When installing a substituent on a benzene ring that already has 2 substituents on it, my textbook says that the stronger activator will determine where the new substituent is installed. What about in the case of the a benzene ring that has 2 deactivators? What is the rule in that case? Does the stronger deactivator determine where the new substituent is installed? How does that work? Here is an example of what im talking about: React the following ring with...
Moving to dll Choose the correct answer for the metal directing substitutent on the benzene ring -OH OA. -CH3 OB. Ос. -CI -CO2H D. -OCH2CH3 E. 30 MacBd
437 Predict whether the following substituents on the benzene ring are likely to be ha para directing or meta directing and whether they are like to be ring activating or ring deactivating deact vabang a) - NH(CH 4.38 For each of the monosabstituted benenes shown below, (1) Indicate whether the substituent is ortho, para directing or meta directing (2) Draw the structure of the main monosubstitution product for each of the reactions indicated orth. OCH3 + HCl -OCHE (fecutulys ortho...
Predict the effect the substituent attached to the benzene ring below would have on electrophilic aromatic substitution reactions? CH, CH3 a) meta director, deactivator b) ortho/para director, activator c) meta director, activator d) ortho/para director, deactivator
In a phenol, which group is the substituent on the benzene ring? a. carbonyl ]b alcohol C carboxyl d amino ts 4 ?
10. (12 points) Cua CHaCHa Les eb Predict whether the following substituents on the benzene ring are likely to be ortho/para directing or meta directing and whether they are likely to be ring activating or ring deactivating ..n(CH3)2 CEN ОСН з -NO C-OCH 11. (6 points) Starting with benzene as the only aromatic starting material, devise a
Which of the following is NOT a meta director? A) -CO2H B) -COCH3 C) -NO2 D) -OH