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