IV Ammonium Nitrate

Alternate Name ammonium cerium(IV) nitrate ceric ammonium nitrate CAN. 

Form Supplied in orange crystals widely available. 

Handling, Storage, and Precautions solid used as supplied. No toxicity data available, but cerium is reputed to be of low toxicity. 

National Chiao-Tung University, Hsinchu, Taiwan, Republic 

Cerium(IV) sulfate and a few other ligand-modified CAN reagents have been used for the oxidation. The differences in their oxidation patterns are small, and consequently it is quite safe to replace one particular oxidizing system with another. More rarely employed is cerium(rV) perchlorate. 

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Cerium(IV) ammonium nitrate in methanol has been used to oxidize phenazine to the mono-N-oxide (41) in good yield (75JCS(P1)1398), but no other reports on the application of this reagent to the pyrazine or quinoxaline series have appeared. 

Generation of radicals by redox reactions has also been applied for synthesizing block copolymers. As was mentioned in Section II. D. (see Scheme 23), Ce(IV) is able to form radical sites in hydroxyl-terminated compounds. Thus, Erim et al. [116] produced a hydroxyl-terminated poly(acrylamid) by thermal polymerization using 4,4-azobis(4-cyano pentanol). The polymer formed was in a second step treated with ceric (IV) ammonium nitrate, hence generating oxygen centered radicals capable of starting a second free radical polymeriza-... 

Cerium, D. of as oxide via iodate, (g) 453 Cerium(IV) ammonium nitrate see Ammonium cerium(IV) nitrate Cerium(IV) ammonium sulphate see Ammonium cerium(IV) sulphate Cerium(IV) hydroxide 380 preparation of, 380... 

The use of cerium(IV) ammonium nitrate (CAN) as a catalyst for an aza-Diels-Alder reaction was reported in two different publications. In one report Perumal and co-workers react a variety of anilines 86 and aldehydes 87 with enamine 88 in the presence of 5 mol% CAN to form a series of tetrahydroquinolines 89. The reactions were performed at room temperature with very short reaction times and in good yields. In addition, the resulting tetrahydroquinolines could be oxidized to the corresponding substituted quinolines using 2.5 eq of CAN in high yields <06TL3589>. 

Partially or fully reduced thiadiazoles can be oxidized to yield 1,3,4-thiadiazoles. The 2,5-disubstituted 3-acyl-l,3,4-thiadiazole 157 can be deacylated by numerous methods <2004H(63)2243>. The oxidative deacylation of compound 157 to thiadiazole 158 can be achieved using oxidants such as KMn04, cerium(iv) ammonium nitrate (CAN), and (diacetoxy)iodobenzene (Equation 58). Better yields and cleaner products are obtained using CAN as oxidant. 

An interesting sequence, again overall an isomerization, is the stoichiometric formation of the manganese complexes 68, which, on basic alumina, isomerize to the allenyl complexes 69 from the latter the allenes 70 can be liberated with cerium(IV) ammonium nitrate (CAN) in good yields [128] (Scheme 1.30). 

The use of cerium(IV) salts as catalytic oxidation mediator is restricted by their insolubility in non-aqueous media. Cerium(IV) ammonium nitrate (CAN) may be used in organic solvents upon the addition of quaternary ammonium salts, but cerium(IV) sulphate is not transferred under analogous conditions. Bis(tetra-/t-butyl-ammonium) hexanitratocerate(IV) is obtained in a solid form by metathesis of CAN... 

The catalytic effects and versatility of cerinm(IV) ammonium nitrate as a single-electron oxidant were recently reviewed (Nair and Deepthi 2007, Maulide et al. 2007). However, it should be kept in mind that this oxidative reagent is very powerful and some sensitive fnnctions are not compatible with it. Particularly, some amines are at least as easily oxidizable as the starting molecule bearing the protected group. Anodic oxidation was proposed as a usefnl alternative (De Lamo Martin et al. 2005). 

Formation of complex 26 by oxidation of the allenylidene-acetylide derivative 25 with cerium(IV) ammonium nitrate merits to be highlighted since 26 represents a unique example in which two allenylidene ligands are bonded to a metal (Scheme 10) [181]. 

Partial oxidation of 158 by bromine yields bromine-free 159 together with mono-, di-, and tribromo derivatives. Other useful reagents are nitrous acid (54JCS286) or the one-electron oxidants silver acetate (in substoichio-metric quantity) and cerium(IV) ammonium nitrate (only for the methyl ether of 158 86BCJ511). 

More recently, Menendez et al. reported a closely related four-component access to tetrahydropyridines, the amino alcohol being replaced by a primary amine and an alcohol. Thus, the cerium(IV) ammonium nitrate (CAN)-catalyzed reaction between primary aliphatic amines, 1,3-dicarbonyls, cx,p-unsaturated aldehydes, and alcohols resulted in the formation of 6-aUcoxy-2-methyl-l,4,5,6-tetrahydropyridines with... 

Sridharan V, Maiti S, Menendez JC (2009) A very efficient cerium(IV) ammonium nitrate catalyzed, four-component synthesis of tetrahydropyridines and its application in the concise generation of functionalized homoquinolizine frameworks. Chem Eur J 15 4565 572... 

Another transient aminoxyl radical has been generated , and employed in H-abstraction reactivity determinations" . Precursor 1-hydroxybenzotriazole (HBT, Table 2) has been oxidized by cyclic voltammetry (CV) to the corresponding >N—O species, dubbed BTNO (Scheme 9). A redox potential comparable to that of the HPI —PINO oxidation, i.e. E° 1.08 V/NHE, has been obtained in 0.01 M sodium acetate buffered solution at pH 4.7, containing 4% MeCN". Oxidation of HBT by either Pb(OAc)4 in AcOH, or cerium(IV) ammonium nitrate (CAN E° 1.35 V/NHE) in MeCN, has been monitored by spectrophotometry , providing a broad UV-Vis absorption band with A-max at 474 nm and e = 1840 M cm. As in the case of PINO from HPI, the absorption spectrum of aminoxyl radical BTNO is not stable, but decays faster (half-life of 110 s at [HBT] = 0.5 mM) than that of PINO . An EPR spectrum consistent with the structure of BTNO was obtained from equimolar amounts of CAN and HBT in MeCN solution . Finally, laser flash photolysis (LFP) of an Ar-saturated MeCN solution of dicumyl peroxide and HBT at 355 nm gave rise to a species whose absorption spectrum, recorded 1.4 ms after the laser pulse, had the same absorption maximum (ca 474 nm) of the spectrum recorded by conventional spectrophotometry (Scheme 9)59- 54... 

The study of the mechanism of the fast SCR over V-W-Ti-0 catalysts was addressed first by Koebel and co-workers [65-68]. They suggested that (i) the reoxidation ofthe catalyst is rate determining at low temperature in the redox cycle of standard SCR catalyst, (ii) NO2 reoxidizes the catalyst faster than O2 the NO2-enhanced reoxidation of the catalyst was demonstrated by in situ Raman experiments, (hi) the reaction occurs via the nitrosamide intermediate in both standard and fast SCR and (iv) ammonium nitrate is considered an undesired side-product. 

Smooth conversion of ( )-(—)-neocarazostatin B (268) to carquinostatin A (278) was achieved by oxidation using ceiium(IV) ammonium nitrate (CAN). The identity of the absolute configuration of both alkaloids, and also the enantiopurity of neocarazostatin B (>99% ee), has been additionally confirmed by the transformation of carquinostatin A (278) to the (l ,l )-]VIosher ester 822 by reaction with (S)-(+)-a-methoxy-a-(trifluoromethyl)phenylacetyl (MTPA) chloride (613) (Scheme 5.97). 

Sridharan V, Avendano C, Menendez JC (2008) New findings on the cerium(IV) ammonium nitrate catalyzed Povarov reaction stereoselective synthesis of 4-alkoxy-2-aryl-l,2,3,4-tetrahydroquinoline derivatives. Synthesis 1039-1044... 

An alternative, but effective, method for preparing furo[2,3-r/ pyrimidines with the potential for polysubstitution in the furan ring is shown in Equation (108). Here -dimethylbarbituric acid 299 is treated with a variety of alkenes in MeCN containing cerium(iv) ammonium nitrate to produce 300 with complete regioselectivity (Equation 108) <2000SC4277>. 

Furopyranopyrandiones have been prepared by the cerium(iv) ammonium nitrate-mediated reaction of 4-hydroxy-277,577-pyrano[4,3- ]pyran-2,5-diones with alkenes (Scheme 14) <2003H(60)939>. 

A recently described method for insertion of a carbon monoxide molecule into the monoepoxide of a conjugated diene gives /3-lactones in high yield. This is achieved by reaction of iron pentacarbonyl with the starting vinyloxirane to give the 7r-allyl iron complex (66), which on oxidation with cerium(IV) ammonium nitrate gives the /3-lactone. In some cases, y-Iactone products can also be obtained from this reaction (8lJCS(Pi)270). 

Ates, A., Gautier, A., Leroy B., Plancher, J.-M., Quesnel, Y, Vanherck, J.-C. and Marko, I.E. (2003) Mild and chemo-selective catalytic deprotection of ketals and acetals using cerium(IV) ammonium nitrate. Tetrahedron, 59 (45),... 

Cerium(IV) ammonium nitrate, Ceric ammonium nitrate [16774-21-3]... 

Oxidation states higher than + 3 are exhibited by Ce, Pr, and Tb, but only Ce4+ is stable (kinetically) in water. It is a very strong oxidizing agent in aqueous solution ( ° = 1.74 V) and is used as a volumetric standard in redox titrations. Some of its salts [e.g., cerium(IV) ammonium nitrate, cerium(IV) sulfate] find application in... 

Cerium(IV) ammonium nitrate (CAN) is effective for oxidative hydrolysis of phenyl esters substituted by hydroxyl, methoxyl, and dimethylamino groups in CH3CN-H20 at 0°. 

Diethylamino)sulfur trifluoride, 110 Formylation (see also Carbonylation) Vilsmeier reagent, 341 Fragmentation reactions Cerium(IV) ammonium nitrate, 67 Copper(II) acetate-Iron(II) sulfate, 85 Lead tetraacetate, 155 Friedel-Crafts alkylation Aluminum chloride, 15... 

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