Pyrrole is less basic than pyridine. The orbital having the lone pair of electrons on nitrogen in pyrrole is:
The nitrogen atom is sp2 hybridized. The N electron pair is on a p orbital, perpendicular to the plane of the ring and overlapping with the other p orbitals. There are a total of 6 π electrons, which is a Hückel number (Hückel numbers are 2, 6, 10, etc.) and, therefore,
the molecule is aromatic.
The heterocyclic diene employed in cyclo – addition reactions is:
Furan on prolonged heating with dimethyl acetylenedicarboxylate yields:
The structures of the products A and B formed in the above reaction scheme respectively are:
The decreasing order of the reactivity of the following compounds towards electrophiles is:
Pyridine undergoes electrophilic nitration at elevated temperature to given the following as a major product:
There is a relatively less partial positive charge on meta positions of Pyridine. Hence, when an electrophile attacks it attacks on meta position.
Hence D is correct.
A pyridine derivative (P) reacts with (Y). (Y) can be a free radical, cation or anion. The structure of intermediate (Q) formed in the reacts is given below. (P) and (Y) respectively are:
Pyrrole + PhMgBr → E + F
E + MeCl → G + H
F + MeCl → no reaction without a catalyst.
The structure of products E–H, respectively are:
Chose the correct answer fro m the fo llowing four cho ices.
Statement: Pyridine is more basic than pyrrole.
Reason: The nitrogen in pyrrole carries a proton while the nitrogen in pyridine does not. Assertion: Nitrogen in trigonal geo metry are generally more basic than the nitrogen’s in tetrahedral geometry.
In the following sequence of reactions, the major product Q is:
What will be the reagent used for the completion of the following reaction?
The corrects order of the basicity of the following compound is:
Identify the major Product P in the following two–step reaction:
Match the structures in List–I with their correct names in List–II.
The most acidic species is:
The compound that is NOT oxidized by KMnO4 is:
Thiophene reacts with HCHO in presence of aqueous HCl to give:
The CH2O/HCl reagent is suitable for chloromethylation of various polycyclic aromatic hydrocarbons as well as heterocyclic aromatic compounds. Thiophene gives 2-(chloromethyl)thiophene in 40-41% isolated yield, and 4-methylimidazole gives the 5-chloromethyl derivative (51-68%).
The reaction of 2-methylfuran with DMF-POCl3 would give:
In the following reaction the major product (X) is:
Two regions of cimetidine are susceptible to metabolism. Which regions?