Ethane-1,2-diol reaction with

The reaction appears to be general and the additions are regiospecific and stereoselective. The product from the reaction with 2-propanol has been used for the synthesis of cis-chrysanthemic acid,8 and the product with methanol has been used for the construction of novel 2, 3 -dideoxy-3 -hydroxymethylnucleosides.9 In addition, ethane-1,2-diol provides the expected photoadduct as a 1 1 mixture of the two possible diastereoisomers, and these can be easily separated as their acetonides, to provide compounds with three contiguous chiral centers emanating from furan-ones with only one chiral center.9 More recently, we have shown that photoinduced-... 

This scheme of interrelated primary photochemical and subsequent radical reactions is comphcated by the back reaction of hydrogen atoms and hydroxyl radicals with formation of water (Fig. 7-16, reaction 2) or the dimerization of the latter with formation of hydrogen peroxide (Fig. 7-16, reaction 3). Furthermore, hydroxyl radicals are scavenged by hydroperoxyl radicals with formation of oxygen and water (Fig. 7-16, reaction 5) or by hydrogen peroxide to yield hydroperoxyl radicals and water (Fig. 7-16, reaction 4). In addition, hydroxymethyl radicals (HOCH ) formed by reaction 1 (Fig. 7-16) are able to dimerize with formation of 1,2-ethane-diole (Fig. 7-16, reaction 7) or they disproportionate to yield methanol and formaldehyde (Fig. 7-16, reaction 8). 

The first kinetic investion of the ethane-1,2-diol reaction was carried out by Price and Knell . However, these workers did not detect the typical mixed-order kinetics which were later established by Duke °, and investigated over a wide range of conditions by Buist and Bunton With excess diol Duke showed that the reaction is first-order with respect to periodate, and that the first-order rate coefficient k is a function of diol concentration, viz. 

The kinetics of the oxidation of methyl substituted ethane-1,2-diols are generally similar to those observed for ethane-l,2-diol itself, with the exception of the oxidation of pinacol (see section 1.3.6). However, under certain conditions the rate of formation of the diester intermediate is comparable with its rate of decomposition to the reaction products, i.e. the ester is no longer in equilibrium with the reactants. The formation of the ester is buffer-catalysed (section 1.3.6) so equilibrium conditions are more likely to be attained when the reaction is carried out in a buffer. 

Analyses were performed on a Varian 9010 instrument equipped with a Varian 9050 UV detector (210 nm) using a Merck Lichrospher 100 RP18 (5 tm) column. An aqueous nBu4NHS04 5mM (1 ml/min) as the eluent was used for ethane-1,2-diol reaction products... 

Under our reaction conditions the Ir on carbon catalyst, prepared according to the literature [11], was inactive (entry 5). Thus, due to the different experimental conditions no comparison between our and the previously reported ethane-l,2-diol oxidation with Ir/C [11] was possible. 

Hydration in the presence of mercury(II) sulphate yields an (oxoalkyl) compound (equation The treatment of the phosphonic ester 364 (R = Et, Z= P03Et2) with a thiolate leads, via diethyl ethynylphosphonate, to the ethenylphosphonic diester 365 with the concomitant formation of thiophosphate ester in this particular case, the product 365 as initially formed, is of Z geometry, but isomerizes when distilled . In other cases of the reactions with thiols, for instance with 364 (R = Et, Z = Cl), the direct replacement of Z is accompanied by overall displacement plus addition at each carbon to give products of types 366 (as a mixture of E and Z stereoisomers) and 367. The same substrate 364 (R = Et, Z = Cl) with the monosodium salt of ethane-1,2-diol represents an alternative route (substitution followed by addition) to 361, but with more basic nucleophiles such as Bu O, and even MeO , cleavage of the phosphorus-carbon bond occurs, although the extent of this decreases, and the extent of addition (with EtO and PhO ) increases, when R = Me is replaced by R = Et. The additions of arylsulphenyl chlorides to 364 (R = Et, Z = Me) occur stereoselectively to give only the E products . 

Common features of the tetrakis(pyridine)silver dichromate oxidations of vicinal and non-vicinal diols and their monoethers, aliphatic aldehydes, a-hydroxy acids (glycolic, lactic, malic and few substituted mandelic acids), and aliphatic primary alcohols in DMSO are = a + h[H+], fractional order in the substrates, = 5.91 (ethane diol), 5.80 (MeCHO), 5.78 (mandelic acid), and 5.85 (ethanol). The solvent effects have been analysed using Taft and Swain multiparametric equations for all the substrates except mandelic acid, for which the Kamlet and Swain multiparametric equation is used. The rate constants for aldehydes correlated with Taft s a values with a negative reaction constant. The rate-determining step for oxidation of aldehydes and hydroxy acids is the transfer of H ion. For diol oxidation, the... 

The effect of pH on the periodate oxidation of seven anilines has been investigated. " The kinetics of periodate oxidation of aromatic amines have been studied. " - " Periodate oxidation of oxalic acid is catalysed by Mn(II). " The reaction of ethane-1,2-diol with periodate has been investigated under a variety of conditions and the results compared with those of earlier work and analogous studies on pinacol. " The 104 ion is the primary reactant, with H5IO6 as a secondary reactant the reverse is true for pinacol. The complex observed in previous work is shown not to be an intermediate, but rather to deactivate the reactants. 

This heme-dependent enzyme [EC 1.11.1.14], also known as diarylpropane peroxidase, diarylpropane oxygenase, and ligninase I, catalyzes the reaction of 1,2-bis(3,4-dimethoxyphenyl)propane-l,3-diol with hydrogen peroxide to produce veratraldehyde, l-(3,4-dimeth-ylphenyl)ethane-l,2-diol, and four water molecules. The enzyme brings about the oxidative cleavage of C—C bonds in a number of model compounds and also oxidizes benzyl alcohols to aldehydes or ketones. 

The 6,7-dihydro-5/f -1,4-dioxepin (266) has been prepared (54CR(38)982). and more recently it has been shown that the 2,3-dihydro-5jF/-l,4-dioxepins (263) and (265) can be produced from 1,4-dioxine-halocarbene adducts (264), either by heating under reflux in xylene or by treatment with bases. The allylic chlorine atom in (263) is readily substituted by alkoxide or cyanide ions (77ZC331, 76UKZ968). Saturated rings of type (267) have been prepared by the treatment of cyclic acetals of ethane-1,2-diol with vinyl ethers in the presence of boron trifluoride, and l,4-dioxepan-5-one (268) has been prepared by the reaction of bromoform and silver nitrate with aqueous dioxane (60AG415). 

Aldehyde (5 mmol), ethane 1,2-diol (5 mmol) and metal sulfate (5 mmol) supported on silica gel (1.65 g) were mixed in a Pyrex test tube and subjected to microwave irradiation for 36 min. After complete conversion, as indicated by TLC, the reaction mass was charged directly on small silica gel column (100-200 mesh) and eluted with ethylacetate-hexane (2 8) to afford pure acetal in 80-98% yield. 

The catalytic performance of Nafion SAC-13 in the formation of 1,1-diacetates,677 in turn, is very similar to that of HBF4-silica. In the acetalization of carbonyl compounds with ethane-1,2-diol and propane-1,3-diol, products are isolated in good to excellent yields. The formation of THP ethers of alcohols is fast and protected alcohols are isolated in high yields [Eq. (5.238)]. Nafion SAC-13 can also be used in the removal of the THP ether group677 although the transformation requires somewhat longer reaction times (30 min-6 h, 81-97% yield). Furthermore, the catalyst could be recycled in all three processes with practically no loss of activity. 

We can obtain different polymers with different properties if we carry out condensation polymerisation reactions between other monomer molecules. For example, if we react ethane- 1,2-diol with benzene-1,4-dicarboxylic acid, then we produce a polymer called Terylene. 

Procedure for 1,3-dioxolane formation with ethyl acetoacetate by azeotropic removal of water.128a Ethyl acetoacetate (30 g, 0.23 mol), ethane-1,2-diol (16g, 0.248 mol), a crystal of toluene-p-sulphonic acid and benzene (50 ml) (CAUTION) were placed in a round-bottomed flask fitted with a Dean and Stark water separator (Fig. 2.31(a)) and a reflux condenser. The reaction mixture was heated until no more water collected. The product was fractionally distilled under reduced pressure to give the cyclic acetal (35 g, 87%), b.p. 99.5-101 °C/17-18 mmHg. 

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