Question

Convert Benzaldehyde to aplha hydroxy phenyl acetic acid.Give full reaction please.

Answer 1

First of all identify what you need to prepareThe number of carbon atoms are same or notIf the number of carbon are not same then you either need to add or remove Carbon.To add carbon there only a few reactions..

If you need to increase only one carbonAdd HCN/KCN in alkylhalide, alcohol, aldehyde/ketone(cyanohydrin)If you need to double the carbonwurtz and aldol condensationIf you need to increase the carbon chain by any other numberUse Grignard ReagentCross Aldol(if the reactant is aldehyde)

To remove CarbonDecarboxylationOzonolysisHoffman Brommamide Degradation ReactionKeep in mind all the reactions and try to link them together that how to convert from group to other..

Now to your question

Benzaldehyde to 3-Phenylpropan-1-ol

So you need to add 2 carbon

Benzaldehyde with acetaldehyde do the aldol condensationNow you have one double bond and one aldehydeNow do the hydrogenation (reduction) it will convert alkene to alkane and aldehyde to alcohol in a single step.

Your first conversion is done in two steps.

Benzaldehyde to alpha-Hydroxyphenylacetic acid

Seems difficult right?? Let's think about the product… so we need to add one COOH(one carbon) and Alcohol. How we can get both from aldehyde?? We can get alcohol by reduction but how we can get this carboxylic group???

Here comes the part where you need to remember the reactions you have learnt so far

The complete hydrolysis of CN gives COOHAldehyde gives cyanohydrin (addition of HCN to carbonyl group resulting in the additional of both CN(Cyano) and OH(hydrin) )Step1 Add HCN in presence of H+ ionsStep 2 complete Hydrolysis (H3O+ and ∆)

Answer 2

Here is the solution...
I hope it will help u...