Question

Help with o Chem questions please !

Outline the synthetic route. Think of the necessary reagents and the order of the steps where applicable). Predict the products of the nitration reactions. Example why such products are formed in each case, by drawing valid resonance structures of the aromatic intermediates.

Answer 1

1. Benzene gives butyl benzene(alkyl benzene) upon alkylation , reagent R-Cl i.e., CH₃-CH₂CH₂CH₂-Cl in the presence of catalysts like anhydrous AlCl₃. This reaction is called Friedel-Crafts alkylation.

CH3-CH2-CH2-CH2-Cl anhydrous Alc13 +HC benzene butyl benzene

benzene upon acetylation gives benzaldehyde with acetyl chloride and anyhydrous aluminium chloride,which later upon halogenation gives meta bromo benzaldehyde, because acetyl groupis meta directing group. First part of eaction is called Fridel Crafts acetylation, second part halogenation.

CH3-CO-Cl Br2 anhydrous Alc13 anhydrous Alc13 benzene Br

aniline to cyano benzene is given by, first diazotization of aniline with HNO₂, followed by treatment of formed bezene diazonium chloride with KCN, CuSO₄. Second part of reaction is called as Sandmeyer's reaction.

NH2 CA NaNO2 HCI N2+C 0-5 degree Celsius KCN CuS04

3. Phenol upon nitration gives ortho-nitro phenol and para -nitro phenol, it is due to increase of electron density at ortho and para positions of phenol due to electron donating nature of-OHwhich can be seen in its resonance structures.

OH :ОН OH "ОН , он

as at ortho and para positions electron density is more the incoming electrophile attaches at ortho and para positions to give the product.

он IH NIYP HNO3+ H2SO4 NITRATION ORTHO PARA