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Pivalic acid, oxidation with

Piperazine, N-alkylation with benzyl chloride, 42, 19 Piperazine, 1-benzyl-, 42,19 Piperidine, addition to ethylene, 43, 45 as catalyst for Claisen-Schmidt condensation, 41, 40 Piperidine, 1-ethyl-, 43, 45 Piperidine, 1-(2-naphthyl)-, 40,74 Pivalic acid, oxidative coupling to a,a,-a, a -tetramethyladipic add, 40, 92... [Pg.120]

Complementary to the work with aqueous acidic media is the study of the homolytic decompositions of Co(III) carboxylates in carboxylic acid media by Lande and Kochi . For example, Co(III) is reduced in pivalic acid media with first-order kinetics with E = 30.6 kcal.mole , AS = 8 eu and k ko = 1.28+0.10 (69 °C). The main oxidation products were found to be isobutylene and tert-butyl pivalate, which suggests that (CH3)3C- is an intermediate. Oxidative decarboxylation is the probable course in the analogous oxidations of n-butyric and isobutyric acids, in view of the production of propane and CO2 under normal... [Pg.384]

Similar kinetics are given by phenylacetic acid, but with isobutyric and pivalic acids the rates are given by the simple expression k2[Co(IIl)][RC02H]/[H ]. The oxidation of C6H5CD2CO2H proceeds at 80% of the rate of the protio compound. The relative rates of oxidation of a series of acids of formula RCO2H at 10 C° are... [Pg.384]

The pinacolone may be employed for the preparation of trimethylacetlc acid (pivalic acid) by oxidation with sodium hypobromite solution ... [Pg.350]

To complete our survey of structurally-characterized oxide-bridged Mn complexes, we describe species with nuclearities >4. Three distinct types have been reported hexanuclear, nonanuclear and dodecanuclear. The hexanuclear complex Mn602(piv)10(pivH)4 results from the treatment of MnC03 with pivalic acid in reflux-... [Pg.247]

The alkylation products are synthetically useful because simple subsequent transformations furnishes precursors of important natural products as illustrated in Scheme 8E.23. Simple oxidative cleavage of allylic phthalimide 45 generates protected (5)-2-aminopimelic acid, whose dipeptide derivatives have shown antibiotic activity. The esterification via deracemization protocol is not limited to the use of bulky pivalic acid. The alkylation with sterically less hindered propionic acid also occurs with high enantioselectivity to give allylic ester 116, which has been utilized as an intermediate towards the antitumor agent phyllanthocin and the insect sex excitant periplanone. Dihydroxylation of the enantiopure allylic sulfone gives diol 117 with complete diastereoselectivity. Upon further transformation, the structurally versatile y-hydroxy-a,(f-un-saturated sulfone 118 is readily obtained enantiomerically pure. [Pg.620]

We can conclude that a comparison of the respective catalytic results of these new heterogeneous catalysts and their homogeneous counterparts showed that the entrapment of the organometallic complex was achieved without considerable loss of activity and selectivity. The immobilised catalysts are reusable and do not leach. The oxidation system applies only O2 at RT instead of sodium hypochloride at 0°C. A disadvantage is the use of pivalic aldehyde for oxygen transformation via the corresponding peracid. This results in the formation of pivalic acid which has to be separated from the reaction mixture. The best results so far - 100 % conversion, 96 % selectivity and 91 % de - were achieved with the immobilised Cobalt(salen-5) complex in the epoxidation of (-)-a-pinene. [Pg.81]

The toxiferine-like hybrid, C-alkaloid H (LXXV), is converted into C-alkaloid F by aerial oxidation in the presence of pivalic acid and pyridine irradiation of solid C-alkaloid H in the presence of oxygen gives a product identical with natural C-alkaloid G. The properties of these transformation products confirm that C-alkaloids F and G stand in the C-alkaloid H family, as do C-calebassine and C-curarine in the C-dihydrotoxiferine I family. The tertiary alkaloid caracurine VI is the nor base corresponding to C-alkaloid H. [Pg.554]

What is now known as C-alkaloid A was first isolated by King (14) from S. toxifera bark and named toxiferine IV when it was again isolated from a calabash (16), its identity (15) with King s alkaloid was not known, and the second name has become established. C-Alkaloid A, picrate, mp 228°-229°, [a]D +64° (chloride in water), is formed from toxiferine I under the same conditions that produce C-calebassine from C-dihydrotoxiferine I. These include aerial oxidation in a mixture of pyridine, water, and isobutyric acid (127) or pivalic acid (114) when the acid used is acetic acid, C-alkaloid A is produced along with its 0,0-diacetyl derivative (114) as described earlier in the case of toxiferine I. Most of the properties of C-alkaloid A and its UV-spectrum in neutral, alkaline, and strongly acidic solution are identical with those of C-calebassine. Also, its NMR-spectrum corresponds with that of C-calebassine, with the exception of those signals owing to the hydroxylated side chains. C-Alkaloid A therefore has structure CXXIII (Ri = R2 = OH) C-alkaloid F (see Section III, F) is CXXIII (Ri = H, R2 = OH). [Pg.567]

Carboxylate-bridged Cr dimers are synthesized from chromocene. Benzoic acid, pivalic acid, and 9-anthracenecarboxylic acid react with (f/ -CsH5)2Cr to form Cr2(02CR)4 dimers. Chromium hexacarbonyl is oxidized to dimeric Cr(II) complexes by 2,4-dimethyl-6-hydroxypyrimidine and A, A -(3,5-xylyl) formamidine in refluxing... [Pg.137]

Pyridine-N-oxide [1, 966]. a-Bromo and a-chloro carboxylic acids are oxidatively decarboxylated by treatment with pyridine-N-oxide (4 equiv.) in refluxing benzene or toluene.3 Cohen et at. note that, since pivalic acid is completely inert to pyridine-N-oxide, an u-hydrogen atom appears to be essential, for example in the reaction of phenylacetic acid. They suggest that an a-pyridinium ion is an intermediate ... [Pg.453]

Imidazole /V-oxide substrates may be used in a similar fashion. Initial investigations revealed that the use of palladium acetate in conjunction with an electron deficient 4-fluorophenylphosphine in acetonitrile at 70 °C provides C2 arylation in high yields. With the goal of achieving the same reactivity at or near room temperature it was determined that the use of palladium acetate in conjunction with a Buchwald ligand, catalytic copper bromide and 30 mol% pivalic acid in acetonitrile could also achieve high yields of C2 arylation at 25 °C. As was the case with thiazole V-oxides. if the C2 and C5 positions of the imidazole are blocked C4 arylation may also be achieved in synthetically useful yield (Scheme 15). [Pg.48]

O/t/20-arylation of benzoic acids is often preferable to ortho-arylation of benzamides if conversion of the amide moiety to other functional groups is desired. However, only a few reports have dealt with the orf/io-functionalization of free benzoic acids due to challenges that involve such transformations. The reactions can be complicated by decarboxylation of the product and the starting material. Despite those difficulties, several methods for direct o/t/io-arylation of benzoic acids have been developed. Yu has shown that arylboronates are effective in arylation of benzoic acids under palladium catalysis [59], The reactions require the presence of palladium acetate catalyst, silver carbonate oxidant, and benzoquinone. Even more interestingly, the procedure is applicable to the arylation of unactivated sp3 C-H bonds in tertiary carboxylic acids such as pivalic acid (Scheme 13) if aryl iodide coupling partner is used. Aryl trifluoroborates can also be used [60],... [Pg.68]

PIVALIC ACID (75-98-9) Combustible solid (flash point 147°F/64°C). Dust or powder forms explosive mixture with air. Incompatible with sulfuric acid, caustics, ammonia, amines, isocyanates, alkylene oxides, epichlorohydrin, oxidizers. [Pg.994]

Koch Reacdon. C-6-neoacids are readily available from amji alcohols by the Koch reaction. Greater than 95% 2,2-dimethylbutyric acid [595-37-9] was obtained from 2-meth5i-1-butene at 304 kPa (3 atm) CO and 35°C for 1 h with cupric oxide and sulfuric acid catalyst (31). Likewise, 2,2-dimethylbutyric acid can be obtained in high yidd (75—80%) from 1- or 2-pentanol or neopentyl alcohol from the Koch-Haaf reaction (32,33). tert-Amy. alcohol gives a mixture of trimethyl acetic acid [75-98-9] (pivalic acid), 2,2-dimeth5ibutyric acid, C-7 acids, and C-11 acids under similar Koch-Haaf conditions (33). [Pg.372]


See other pages where Pivalic acid, oxidation with is mentioned: [Pg.316]    [Pg.375]    [Pg.119]    [Pg.134]    [Pg.222]    [Pg.1307]    [Pg.226]    [Pg.587]    [Pg.749]    [Pg.503]    [Pg.481]    [Pg.925]    [Pg.356]    [Pg.150]    [Pg.151]    [Pg.152]    [Pg.48]    [Pg.74]    [Pg.189]    [Pg.369]    [Pg.370]    [Pg.364]    [Pg.882]   
See also in sourсe #XX -- [ Pg.152 ]




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