(Hive Bee)
03-25-03 16:47
No 421248
      direct transformation of aldehydes into nitriles
(Rated as: excellent)

Direct transformation of aldehydes into nitriles using iodine in ammonia water

From Tetrahedron Letters, 42, 2001, 1103-1105:

Treatment of aromatic, heterocyclic, aliphatic, conjugated and polyhydroxy aldehydes with iodine in ammonia water at RT for a short period gave the corresponding nitriles in high yields.

Formation of nitriles from the corresponding aldehydes is an important functional group transformation. Many methods involve the initial conversion of aldehydes to aldoximes, which are subjected to dehydration to give nitriles. Direct conversion of aldehydes into nitriles without isolation of nitrogen-containing intermediates has also been explored. In most cases, aromatic aldehydes are preferably converted to aromatic nitriles, whereas the transformations of enolizable aliphatic aldehydes often give unsatisfactory yields of aliphatic nitriles. The problem can be somewhat circumvented by using less available reagents (eg sulfimide) or unconventional approaches (eg microwave irradiation).

On the basis of NH3/oxidant protocols, we wish to develop a practical and enviromentally begign method for direct transformation of aldehydes into nitriles. We found that treatment of various aldehydes with iodine (1.1 mol proportions) in ammonia water (28% sol) at RT for a short period afforded the desired nitriles in very high yields (table 1).

According to previous reports we speculated that the reaction proceeded via oxidation of aldimine with iodine to give a N-iodo aldimine intermediate, which eliminated a HI molecule in ammonia sol. to afford the nitrile product. The aldehydes examined in this study included benzaldehydes, heterocyclic aldehydes, alpha,beta-unsaturated aldehydes, aliphatic aldehydes and saccharide aldehydes.

The following procedure is typical: Iodine (1.1 mmol) was added to a stirring solution of aldehyde (1 mmol) in ammonia water (10 ml of 28% sol.) and THF (1 ml) at RT. The dark solution became colorless (or light gray in some cases) after stirring for 5-73 min, an indication that the reaction was complete. The reaction mixture was charged with aqueous Na2S2O3 (5 ml of a 5% sol.), followed by extraction with ether (2x15 ml), to give a practically pure nitrile product.

CAUTION: It is known that iodine reacts with ammonia water under certain conditions to give a black powder of nitrogen triiodide monoamine (NI3.NH3). The dry powder explodes readily by mechanical shock, heat or irradiation. Although we did not have any incidents when handling the reactants in this study, one should avoid using excess reagent. tongue

In summary, a variety of aldehydes were succesfully transformed into nitriles by treatment with iodine in ammonia water. This method is simple, economic, and enviromentally begign. This method is especially useful for the transformation of water-soluble aldehydes such as carbohydrates.

Table 1

Substrate  -  Cosolvent  -  Reaction time (min.)  -  Yield

PhCHO  -  THF  -  30  -  96%
4-BrC6H4CHO  -  THF  -  45  -  95%
4-MeOC6H4CHO  -  THF  -  20  -  95%
4-O2NC6H4CHO  -  THF  -  30  -  96%
4-NCC6H4CHO  -  THF  -  10  -  89%
2-Furaldehyde  -  THF  -  7  -  88%
2-Thiophenecarboxaldehyde  -  THF  -  5  -  97%
2-Pyridinecarboxaldehyde  -  THF  -  15  -  85%
CH3(CH2)7CHO  -  THF  -  73  -  90%
t-C6H11CHO  -  THF  -  10  -  94%
Cinnamaldehyde  -  THF  -  5  -  96%
Crotonaldehyde  -  Et2O  -  60  -  57%
2-Deoxy-D-ribose  -  none  -  30  -  83%
Perbenzyl-D-glucose  -  none  -  30  -  85%


Other than phenylacetaldehydes I don't know right away where it could be useful for, for our purposes, but it seemed such a beautiful and clean reaction, had to post it. You never know where it might come in handy.
(Hive Addict)
03-25-03 18:09
No 421284
      Ammonium Triiodide (misnomer)  Bookmark   

As one with personal experience with this chemical, I cannot bring enough attention to the Caution portion of Vitus_Verdegast's post. 

CAUTION: It is known that iodine reacts with ammonia water under certain conditions to give a black powder of nitrogen triiodide monoamine (NI3.NH3). The dry powder explodes readily by mechanical shock, heat or irradiation. Although we did not have any incidents when handling the reactants in this study, one should avoid using excess reagent

just thought i'd include it in red to make it more noticable.  helps for those who like to skim and forget VERY important details.
03-25-03 18:15
No 421285
      Easily Detonated Compound  Bookmark   

Nitrogen triiodide can be detonated by a fly landing on the dry crystals crazy

Chemistry is our Covalent Bond
(Hive Bee)
03-25-03 18:36
No 421289
      it's very dangerous when dry  Bookmark   

Normally it shouldn't decompose when wet (still if handled carefully), but when filtered the solid dries out rapidly.

A friend of mine told me, when working night-shift in a lab, he and his collegues were getting bored and decided to make some nitrogen triiodide. They made at least half a pound of the stuff cool. Not really knowing what do to next with it, they noticed that their solid was drying out fast, so they quickly placed it under the fume hood. It eventually decomposed violently, and the liberated iodine gave everything a nice yellow layer smile. They had to spend the next hours cleaning everything with a thiosulfate solution. LOL!
(Chief Bee)
03-25-03 18:40
No 421291
      units?  Bookmark   

Half a pound of that inside a lab would blow out the windows and damage the fume hood extensively... You don't mean half an ounce or something?
(Hive Bee)
03-25-03 19:18
No 421310
      I thought he said half a pound  Bookmark   

Thought he said half a pound,  it was most probably
weighed when wet, don't know much much it decreases in weight when drying .

They seemed to amuse themselves alot during these night-shifts, like sprinkling some sodium azide on the floor before the cleaning people arrived.

He also threw a sigarette away once in a sink where someone had accidentely poured away some CS2 (back in the seventies when smoking was still allowed).
(Hive Addict)
03-25-03 19:31
No 421315
      HAHAHA!  Bookmark   

Was smoking allowed back then?? I thought that it was only allowed in the early 1900! When those old geezers from Astra that developed lidocaine smoked pipe at the same time as they poured Et-O-Et from a 10 L flask into a 5 L round bottom. Those were the times. I even have a picture of them pouring ether and smoking pipe! LOL!

Accept No Imitations, There Can Only Bee One;
(Chief Bee)
03-25-03 20:02
No 421323
      Self-experimentation leading to problems  Bookmark   

Lidocaine? Is that Nils Lofgren? I've read some tales about his self-experimentation with lidocaine, he injected a dose into each of his fingers to see how large dose gave how much of an effect, and this resulted in ALL his fingers going numb, so he had to go home as he couldn't work anymore that evening... When he came home, he wanted to take  his keys out of the pocket in his pants, but he couldnt feel the keys, and even if he did, he couldn't grasp them tight enough to get them out with his limp fingers... This resulted in him having to take his pants off on the street outside his apartment and shake them out of the pocket. Naturally someone saw a him with his pants off in the middle of the street and called the police (this was in the 1950's or so), and he really had some explaining to do that evening... crazy
(Hive Addict)
03-28-03 22:55
No 422189
      Yeah, Nils Löfgren/Bengt Lundquist (1943)  Bookmark   

a.k.a "Crazy Duo" laugh

Especially "Nisse" always got in trouble. But he never menaged to blow up his own mustach with an classic ether explosion...

Accept No Imitations, There Can Only Bee One;