The reaction is conveniently carried out in an inert organic solvent in {HEAD ~ the presence} of {TAIL ~ a catalytic amount} of an organic or inorganic acid such as p toluenesulphonic acid or dry hydrochloric acid 
of
The reaction is conveniently carried out in an inert organic solvent in { HEAD ~ the presence } of { TAIL ~ a catalytic amount } of an organic or inorganic acid such as p toluenesulphonic acid or dry hydrochloric acid
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH