Question

The major product in the following reaction is:

A.

B.

C.

D.

Answer 1

Heterocyclic chemistry is that branch of organic chemistry which deals with the synthesis, properties and applications of heterocyclic compounds and heterocyclic compounds are those cyclic compounds that has atoms of at least two different elements as a member of its ring these have generally ring type structure.
Complete answer:
Structure given in the reaction is heterocyclic structure in which two rings are present and it may be known by the name purine. Purines are water soluble and are the most widely occurring nitrogen-containing heterocycles in nature. Purines and pyrimidines both are made up of two groups of nitrogenous bases which include the two groups of nucleotide bases. Both purine and pyrimidine are self-inhibiting and activating in nature and when purines are formed they inhibit the enzymes required for more purine formation.
Reaction given above is the type of electrophilic substitution in this case attack will occurs on 5-membered ring i.e. on the 3rd position of ring if 3rd position is already occupied then substitution occurs on 2nd position and if both 2nd and 3rd is occupied then substitution occurs at 6-position. So the product formed in this reaction is given by:

Hence, we say that option B is the correct answer.
Note:
Purines play an important role in adenine and guanine as in DNA and RNA and it is also an important component in a number of other important biomolecules such as ATP, GTP, NADH and coenzyme A.They may also function directly as neurotransmitters, acting upon purinergic receptors. Adenosine activates adenosine receptors.