22-02-09 Protecting aldehyde/ Ketone

This is a very standard question If I can dare to put it that way.

Edit: sorry used alcohol instead of aldehyde :((

What do we do if we have to reduce only the ketone group in a compound that contains both ketone and aldehyde?

and vice versa!

Suggestions invited.

24 Answers

21
tapanmast Vora ·

I m a lil sceptical abt MPV...
THOUGH I KNOW THAT IN MOST(99.99%) EG. MPV REDUCES KETONE

BUT if u c its mech. the alkyl grps do not play a majpr role in it....
so I feel it wud reduce aldehyde as well...........

39
Dr.House ·

and phenol group by acylation i.e eithr acetylation or benzoylation.

39
Dr.House ·

triple bond also same way as double bond. we get tetra bromo derivative and it also goes away by same method.

11
Mani Pal Singh ·

THIS COULD SOLVE THE PROBLEM

11
Mani Pal Singh ·

THIS COULD SOLVE THE PROBLEM

33
Abhishek Priyam ·

no aldehyde first gets protected..

use R-OH

not a diol...

21
tapanmast Vora ·

if u wont to totally reduce it.... my method contd.... after step 3....

4') add conc H2SO4, heat, and then hydrogenate.....

21
tapanmast Vora ·

mazak kar rahe ho kya??

wen u prot. ald wudnot even keto get protected buddy????

1
voldy ·

protect aldehyde and then wolf kishner reduction. will reduce ketone.

21
tapanmast Vora ·

sum1 help yar!!!!!!!

39
Dr.House ·

i am sorry, initially sir posted to oxidise ketone in presence of alcohol.

sorry, i didnt see the edit.

and ya mpv main both will pakka get oxidised, no way aldehyde is left away

21
tapanmast Vora ·

matlab??

can u tell me wats conversion precisely!!!

39
Dr.House ·

alcohol can be protected in the form of ester, then we can oxidise alone the ketone.

21
tapanmast Vora ·

sorry i din c it!!!

now i am havin a look at it!! [1]

21
tapanmast Vora ·

perform Tollen's test!!!

1) aldehyde is oxidized to carboxylic acid.....ketone unaffected

2)protect keto by addin ethylene glycol (ketal formation)

3)Add Lithium Aluminium Hydride (LAH) to reduce acid to alcohol..... ketal unaffected

4) Add H+ to convert ketal to keto.....

u get ur keto unaffected and aldehyde to alcohol [1]

39
Dr.House ·

humaare institute main aise hiii bekhaar cheez padaate hain........

{bekaar logon ko bekaar cheez}

3
iitimcomin ·

""""MEERWEIN PONDORFF VERLY REDUCTION"""""" kahan se yeh sab padthe ho yaar!!!!!

39
Dr.House ·

wait, i am trying to remember if we have any other method

1
skygirl ·

hehe :D its okie... :P

62
Lokesh Verma ·

sorry i meant aldehyde.. was sleeping when typing :(

1
skygirl ·

>> to kp ketone grp safe. ... do acetal reaction .

and wat do you want to make by reducing alcohol ??

39
Dr.House ·

in mpv redn

aluminium isoprpoxide in opresence of isoprpyl alcohol is used, it reduces only ketone

39
Dr.House ·

or in general, if we have to reduce onle a ketone group in a polyfunctional compound, we need to use

MEERWEIN PONDORFF VERLY REDUCTION

1
prateek punj ·

dibal-H

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