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Oxons structure

The name 5-azaorotic acid should be given to allantoxanic (oxonic) acid but it is not yet commonly used. The elucidation of the correct structure of this compound was closely linked to the solution of the course of oxidation of uric acid mentioned earlier. [Pg.199]

The structure (5) originally proposed by Ponomarev appeared to be confirmed by the conversion of dihydrooxonic acid to allantoin performed by Biltz and Giesler. Biltz and RobP showed later that oxonic acid is identical with allantoxanic acid obtained on oxidation of allantoin. Since that time both these trivial names are in usage. [Pg.199]

Works on the oxidation of uric acid has unequivocally established the triazine structure > ° (9) of oxonic acid. This is further confirmed by the straightforward synthesis described by Piskala and Gut. ° The reaction of biuret (11) with potassium ethyloxalate yielded a potassium salt (24), that with ethyl oxamate, the amide of oxonic acid (25). Both these compounds were converted to 5-azauracil. An analogous reaction with diethyloxalate which should produce an ester of oxonic acid resulted in a mixture of urethane and parabanic acid, however. [Pg.200]

Hence, by this pathway the formation of allantoin is not at variance with the triazine structure of oxonic acid. [Pg.201]

The epoxidation of olefins catalyzed by iminium salts and amines (or ammonium salts) is emerging as a new technique for the functionalization of simple aUcenes. These catalysts have relatively simple structures and hence are easily produced at scale they offer potential as green oxidation catalysts. These organic salts are effective oxygen transfer reagents towards electron-rich unfunctionalized olefins. For the iminium salt systems oxone oxidizes an iminium salt to the oxaziridi-nium intermediate, which then transfers oxygen to the olefin and as oxone reacts readily with iminium ions to regenerate the oxaziridinium species catalyti-cally, efficient oxidation is possible. [Pg.25]

A series of dihydoisoquinolium salts (3) based on a dioxane-containing structure have been synthesized and used in the asymmetric epoxidation of alkenes with Oxone... [Pg.104]

This paper establishes toxicologically-safe levels for total residues of parathion, azinphosmethyl, methidathion and their oxons on tree foliage and reports these levels in terms of absorbance units as determined by the rapid field method. Safe levels for a new insecticide, chlorthiophos, are also proposed based on preliminary residue data. Chemical structures of the four insecticides mentioned above are shown in figures 1, 2, 3 and 6. [Pg.25]

In the reaction of Oxone with l-substituted-l//-5-alkylsulfanyltetrazoles 436, the yield of the corresponding sulfone 437 depends on the structure of the substituent attached to sulfur. For instance, 5-( -butyl)sulfanyl-l-(/-butyl)tetrazole with Oxone in methanol gave the corresponding sulfone in 81% yield, whereas the oxidation of 5-benzylsulfanyl-l-(/-butyl)tetrazole formed only 12% of the sulfone <2000SL365>. [Pg.363]

Another strategy for positioning a catalytic center across the entrance of a conical cavity is to employ a cavitand functionalized at one entrance by a pendent chelate arm (Scheme 13.16). Enantioselective epoxidations of aromatic alkenes was realized with catalysts 62, 63, and 64, 65, although the enantioselectivity remained modest [46]. (For experimental details see Chapter 14.13.11). The reaction requires the slow addition (over 1 h) of a solution of alkene 66 and Oxone to a solution of the catalyst. Both the size of the cavity and the structure of the bridged ketone influenced the reactivity. Hence, whilst the formation of the diol 68 was observed when 62 and 63 were used, the presence of 64 and 65 resulted only in the formation of epoxide 67. [Pg.441]

The reaction of the 6,7-dithiabicyclo[3.1.1]heptane exo- and endo-6-oxides 1 with 2KHS05KHS04K2S04 (OXONE) in CH2C12-H20 gave the first isolable dithiirane 1-oxides 2 and 3 (93JA4914).The two isomeric dithi-irane 1-oxides are colorless, crystalline compounds and stable up to 124° and 110°C, respectively. X-Ray crystallography confirmed their structure unambiguously. [Pg.223]

A very broad class of primary oxidants act as oxygen atom transfer agents, the most widely nsed oxidants in oxidation catalysis. These inclnde peracids or their anion forms, snch as MCPBA or oxone (O-OSOs ) as well as A-oxides snch as A-methyl morpholine A-oxide or hypochlorite ion. They all have general structure XO, where X is a good leaving gronp. [Pg.3380]

The isolation of allantoin (7), after lead peroxide oxidation of uric acid was followed by the recognition of other oxidation products, the main product of which are oxonic acid (8), allantoxaidine (9) and oxaluric acid (HjNOCHNCOCOjH). Their structures have been clarified by comprehensive studies using isotopically labeled compounds. ... [Pg.541]

A range of structurally different chiral primary amines was converted into the corresponding iminium tetraphenylborate salts (Fig. 5.3) and tested in the asymmetric epoxidation of a standard test substrate, 1-phenylcyclohexene, using Oxone (4 equiv) as the stoichiometric oxidant, sodium carbonate (8 equiv) as base, in acetonitrile/water (2 1) at 0 °C (Table 5.1) [19,21]. [Pg.186]


See other pages where Oxons structure is mentioned: [Pg.223]    [Pg.223]    [Pg.194]    [Pg.197]    [Pg.248]    [Pg.588]    [Pg.114]    [Pg.107]    [Pg.26]    [Pg.26]    [Pg.73]    [Pg.341]    [Pg.290]    [Pg.348]    [Pg.80]    [Pg.184]    [Pg.223]    [Pg.1025]    [Pg.657]    [Pg.671]    [Pg.222]    [Pg.157]    [Pg.187]    [Pg.378]    [Pg.158]    [Pg.89]    [Pg.425]    [Pg.462]    [Pg.231]    [Pg.281]    [Pg.98]    [Pg.423]    [Pg.161]   
See also in sourсe #XX -- [ Pg.194 , Pg.195 ]




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