Ceric ammonium nitrate derivatives

Evans, W.J., Deming, T.J., and Ziller, J.W. (1989) The utility of ceric ammonium nitrate-derived alkoxide complexes in the synthesis of organometallic cerium(lV) complexes. Synthesis and first X-ray crystallographic determination of a tetravalent cerium cyclopentadienide complex, (C5H5)3Ce(OCMe3). Organometallics, 8, 1581. 

Ozonolysis, then reduction with Na2S204 at 50°, 57% yield.The 3,4-dimethoxyphenyl derivative was cleaved in 71% yield using these conditions. Ceric ammonium nitrate was reported not to work in this example. 

Furoquinones, such as naphtho[2,3-b]fiiran-4,9-dione, naphtho[l,2-b]fiiran-4,5-dione, benzofuran-4,7-dione and benzofiiran-4,5-dione derivatives are available by the ceric ammonium nitrate mediated [3+2] cycloaddition of 2-hydroxy-1,4-naphthoquinones and 2-hydroxy-1,4-benzoquinones with alkenes or phenylacetylene <96CL451>. 

The success of this transformation depends upon the oxidation potential of the ESE group (Eox 1.5 V), which is lower than that of the alkyl silyl ether group (Eax 2.5 V). Recently, Schmittel et al.35 showed (by product studies) that the enol derivatives of sterically hindered ketones (e.g., 2,2-dimesityl-1-phenyletha-none) can indeed be readily oxidized to the corresponding cation radicals, radicals and a-carbonyl cations either chemically with standard one-electron oxidants (such as tris(/>-bromophenyl)aminium hexachloroantimonate or ceric ammonium nitrate) or electrochemically (equation 10). 

The diester 110 (E = CC Et) reacts with a mixture of trimethyltin chloride and sodium cyanoborohydride under AIBN catalysis to give the cyclopentane 111 as a 4 1 mixture of cis- and fraws-isomers. The products are destannylated to the acetals 112 by treatment with methanolic ceric ammonium nitrate (CAN). The 1,7-octadienyl derivative 113 was similarly converted into the cyclohexanes 114 (cis/trans = 1 1) (equation 60)67. 

Grafting and networking may modify the mechanical, chemical, and functional properties of polymers and enhance their utilization for some purposes, such as for water treatment (Kumar and Verma, 2007 Mishra et al., 2003). Psyllium derivatives were prepared by grafting acrylonitrile onto psyllium molecules using a ceric ammonium nitrate and nitric acid system (Mishra et al., 2003). The resulted grafted psyllium samples were not soluble in commonly used solvents or their combinations. In 2007, methacrylic acid derivatives of psyllium were prepared using ammonium persulfate as initiator and cross-linked using N,N-methylenebisacryla-mide as the crosslinker (Kumar and Verma, 2007). The modified psyllium... 

Solid-phase synthesis of pyrido[2,3 pytirtiidines 514 was achieved by Hantzsch condensation of Wang resin-supported Knoevenagel derivative 513 with 6-aminouracil derivatives 512 as an a-oxo enamine component in the presence of ceric ammonium nitrate (CAN) in DMA followed by hydrolysis with TFA in CH2GI2. Compound 513 was prepared by treatment of a hydroxylated polymer, such as Wang or Sasrin resin, with diketene, followed by condensation with benzaldehyde (Equation 41) <1996TL4643>. 

Antioquine (466), C37H40N206, mp 197°C [a]D +214° (c 0.9, CHC13), was isolated from a sample of Pseudoxandra aff. lucida Fries (Annonaceae) collected in Colombia. Structure proof was by spectral characterization of the O,O-diacetate, the 0,0-dimethyl ether, and the 7-O-methyl ether, and by degradation of derivatives with KMn04/Me2C0, with ceric ammonium nitrate, and with Na/NH3 (551). 

Thalibrunine and thalibrunimine have been isolated from Thalictrum rochebrunianum together with the new bases norhernandezine, IV -northalibrunine, oxothalibrunimine, thalictrine, and dihydrothalictrine.51 These bases have been related as follows. Thalibrunine has been assigned the revised structure of 2 -hydroxy-hernandezine (26) on the basis of the oxidation of its O-acetyl derivative with ceric ammonium nitrate to the dialdehyde (27) and with... 

A ceric ammonium nitrate (CAN) mediated stereoselective cyclization of epoxypropyl cinnamyl ethers 352 provides a facile route to 3,4,5-trisubstituted tetrahydropyran derivatives 353 (Equation 149) <2004TL2413>. 

O-tethered P-keto esters, through the intermediacy of aiylidene keto esters, have been efficiently utilized for the construction of immobilized dihydropyridines. Ceric ammonium nitrate (CAN) oxidation to pyridines followed by acidolytic cleavage provides a facile entry into nicotinic acid derivatives 57 [42], A three-component Biginelli cyclization of ureas on resin with a solution mixture of aldehydes and P-keto esters provides dihydropyrimidines 58 in high yield and purity [43], Heterocycles such as dihydropyridines and pyrimidines have historically proven to be a rich source of antimicrobial, antitumor, antiviral, and cardiovascular agents. 

A series of azophenol acerands 4 was prepared by condensation of crowned benzoquinones 10 with 2,4-dinitrophenylhydrazine in ethanol [7b], The quinone was derived from p-methoxyphenol (6) as shown in Scheme 1 [8]. By bis(hy-droxymethylation) (67% yield of 6, followed by methylation (92%) of the phenol group and Williamson-type reaction with ditosylates of oligoethyleneglycol in the presence of sodium hydride, crowned 1,4-dimethoxybenzene 9 was obtained in reasonable yields. Oxidative demethylation of 9 with ceric ammonium nitrate (CAN) in aqueous acetonitrile at 50 °C gave the desired crowned benzoquinones 10 in good yields. 

Oxidation of these complexes releases the apical carbon atom and its substituent in the form of an organic derivative.2 Thus ceric ammonium nitrate oxidation of an RCCo3(CO)9 complex produces the carboxylic acid, RC02H, when the reaction is carried out in aqueous acetone. Thermolysis of RCCo3(CO)9 produces acetylenes or acetylene hexacarbonyl dicobalt complexes, depending on the reaction conditions. Useful applications of these cluster complexes in organic synthesis remain to be developed. 

The reaction of indoles and pyrrole with pyrylium catalyzed by ceric ammonium nitrate in methanol furnishes the indole- and pyrrole-substituted xanthene derivatives in high yields <2007SL2222>. 

Direct nitration of benzo[ ]furan 82 is another important reaction to provide benzo[/ ]furan derivatives. Because of its electronic richness, benzo[ ]furan 82 can undergo regioselective nitration to give 2-nitrobenzo[/ ]furan in 62% yield by using sodium nitrate and ceric ammonium nitrate under ultrasonic conditions (Equation 76) <19960M499>. 

One of the effective reagents for highly chemoselective dithioacetalization of carbonyl compounds is ceric ammonium nitrate (CAN) in chloroform. When a mixture of benzaldehyde and acetophenone was allowed to react with 1,2-ethanedithiol and a catalytic amount of CAN, the 1,3-dithiolane derived from the aldehyde was obtained in 84% yield while the ketone was recovered unchanged. It is noteworthy that aromatic ketones, 7-lactones, and acylic ketones did not react at all under these conditions and even at elevated temperatures for longer reaction times <1995T7823>. 

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