{HEAD ~ The reaction time} required may depend upon various factors including the mole ratio of compounds and and the nature of organic groups R2 and R3 and may generally be in the range of {TAIL ~ 5 30 minutes} 
{ HEAD ~ The reaction time } required may depend upon various factors including the mole ratio of compounds and and the nature of organic groups R2 and R3 and may generally be in the range of { TAIL ~ 5 30 minutes }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL