2,4-DNP spot test for solid-supported aldehydes; hydrazonesSyntheticPage 119 (2001)
Submitted 22nd Aug 2001, published 22nd Aug 2001
A contribution from the Caddick Group, Sussex
2,4-dinitrophenylhydrazine solution in
This test is used to look for the disappearance of an aldehyde after a solid phase reductive amination or reduction.
2,4-Dinitrophenylhydrazine reagent: Dissolve 3 g of 2,4-Dinitrophenylhydrazine in 15 mL of conc. sulfuric acid. This solution is then added with stirring to 20 mL of water and 70 mL of 95% ethanol. This solution is mixed thoroughly and filtered.
A few beads of resin are swollen in a drop of DMF and a single drop of 2,4-DNP solution is added. A positive result is orange-red.
It is best to wash the beads with DMF in an Alltech tube (or a Pasteur pipette with a cotton wool plug) to remove the coloured 2,4-DNP solution. Also, perform the colour test on a negative control resin containing no carbonyl functionality as well as on the starting aldehyde resin to gauge the colour change.
Despite the fact that the resin tends to also be a yellow colour, this test is actually pretty reliable providing you also perform the control experiments mentioned above.
1. Furniss, Hannaford, Smith and Tatchell: Vogel's Practical Organic Chemistry, 5th Edition, John Wiley & Sons, New York p1218 and 1257.
2. Anal. Biochem. 1972, (49), 436.
3. Anal. Chim. Acta., 1974, (69), 481.
This page has been viewed approximately 331 times since records began.
Get CDX file (Choose "Open this file from its current location" TWICE)
SyntheticPagesTM are for use
exclusively by those with training and experience in synthetic chemistry. While contributors
are asked to identify hazards and to use methods designed to reduce risk, no formal hazard
or risk assessments are included, and these procedures must be conducted at one's own risk.
SyntheticPages, its editors, owners and associates do not warrant or guarantee the safety of
individuals using these procedures and hereby disclaim any liability for any injuries or damages
claimed to have resulted from or related in any way to the procedures herein. Copyright ©2004 Synthetic Pages
Comment on this page!
Registered users may add comments to other pages. If you have already registered, please
log in, otherwise you may
Back to List