Question

pleas i need quick help this assigment is due after one hour please help me and send me typing answer becouse i dont understand hand wrrrting .thanks

1)write three paragraghphs and Discuss the importance of solvent and temperature control in Organic Synthesis.

Answer 1

Now solvent and temp. control in vast field of organic chemistry is very important. Now there could be several factors and can be discussed widely or just selecting a series of examples.

1. Reaction with sensitive conditions are one of the perfect example of solvent and temp control in a single reaction. e.g, Now we can take an example of peptide coupling reaction or amino acid coupling reaction. Lets say, we have taken two arginine moeties to prepare Arg-Arg. So one Arg is Boc protected and one will be esterificated to precise the yield. Now normally this reaction will take place in a sealed R.B at a temp zero degree in a perfectly dried condition and dry DCM will be used as a solvent while several coupling agents can be used (like HoBt or HBTU). The reaction is very sensitive to moisture and temp. so if the temp is increased a little bit the product might be different or the yield will be far less than what we can expect. Also any moisture presence will be dramatically decrease the yield as as a side product there will be water.

2. Some times reflux conditions are a quiet good examples of temp and solvent control. e.g, We can take Fischer-Speier esterification reaction as one of the example, Normally in this reaction a carboxylic acid will be taken in presence of alcohol to prepare an ester. Now the reaction is following Le Chatelier's principle and can be increased or decreased the product depending on the refluxing temp and solvent nature. the reaction is normally occured in a refluxing condition at a certain temp and for a certain time depending upon the starting material. The solvent should be dry as a byproduct water is already forming.

3. Sometimes kinetically controlled and thermodynamically controlled reactions are best example of temp dependence of a reaction with a specific tamp. At a certain solvent environment, achieving one activation energy is totally depend upon temp. and hence the naming will be thermodynamically controlled or kinetically. e.g, The Diels-Alder reaction of cyclopentadiene with furan can produce two isomeric products, depending upon the temp. the yield will be different.