Trans-hydrogenation product

A mixture of cis- and /ra 5-l, 4-cycIohexanediols obtained from the hydrogenation of hydroquinone can be converted into the bridged 1,4-oxide by dehydration over alumina. The oxide, which is required to have a cis geometry, can then be cleaved by hydrohalic acids to give stereospecifically the trans disubstituted products. 

The hydrogenation of toluene, aniline, /r-toluidine, and 4-tert-butylaniline was examined over catalyst M1273. The reaction profile for the reactions is shown in Figure 2. From this it can be seen that the order of reactivity is aniline > toluene > /Moluidinc > 4-fer f-butylaniline. The hydrogenation products were methylcyclohexane from toluene, cyclohexylamine from aniline, 4-methyl-cyclohexylamine (4-MCYA) from /Holuidine. and 4-feri-butylcyclohexylamine (4-tBuCYA) from 4-tert-butylaniline. At 50 % conversion the cis trans ratio of 4-MCYA was 2, while tBuCYA it was 1.6. 

Hayes, D., Grieser, F., and Furlong, D.N., Kinetics of hydrogen production form illuminated CdS/Pt/Na2S03 and ZnS/Pt/Na2S03 dispersions, /. Chem. Soc. Faraday Trans., 86, 3637, 1990. 

Darwent, J. R. (1981), "Hydrogen Production Photosensitized by Aqueous Semiconductor Dispersions", J. Chem. Soc., Faraday Trans. 2 77/9, 1703-1709. 

The reverse of reactions (2) and (3) can yield an olefin isomeric with the initial substrate if the hydrogen atom abstracted in (3) is different from the one originally added. Thus, to explain the formation of trans-dimethylcycloalkane, the 1,2-dimethylcycloalkene must be transformed to the 2,3 isomer which yields both cis and trans saturated products via CIS addition (Fig. 6). 

The structure, and the trans-relative stereochemistry, of dihydroarcyriarubin B (352) was confirmed by comparison of the product obtained from arcyriarubin B (350) by palladium-catalyzed hydrogen transfer from cyclohexene in boiling xylene. Under these conditions, only the thermodynamically more stable trans-diastereomer was formed. Based on these data, and the spectroscopic comparison with the hydrogenation product of arcyriarubin B (350), the structure 352 was assigned to dihydroarcyriarubin B (252) (Scheme 2.90). 

The known preference for transoid elimination of the elements of water from alcohols such as (6-3) controls the stereochemistry of the product. The arrangement in the starting material of the groups about the incipient olefin actually determines the steric identity of the product. The two rotamers of alcohol (6-3) that have the trans hydrogen and hydroxyl shown as their Newman projections (6-3a) and (6-3b) are equally probable since they differ only in the placement of the remote basic ether. The dehydration in fact gives a mixmre of the trans isomer (7-2) and the cis isomer (7-3) presumably from rotamers (6-3a) and (6-3b), respectively. Reaction... 

Cycloalkyl and secondary alkyl bromides react with N02 BF4 in pyridinium poly(hydrogen fluoride) solution to yield /J-fluorinated compounds in moderate to good yields. In the case of the cyclic starting materials like 1-bromocyclohexane only trans-substituted products are formed (see Table 22). 

If the benzylic site is chiral with a labile hydrogen, epimerization reactions may also occur. As shown in Figure 97, sertraline HC1 API in solution degrades under photo conditions to the trans sertraline product. This is... 

Four model compounds, n-undecane, tetralin, cis/trans decalin and mesitylene, and a natural gas condensate from the North Sea were also cracked. Analyses and the reference code key of the coal-based feedstocks and the gas condensate are given in Table 1. Paraffin, naphthene, and aromatic-type analyses were calculated from gas chromatographic analyses of the partially hydrogenated anthracene oil and gas condensate whereas, mass spectrometric analysis was performed on the two coal extract hydrogenates and their further hydrogenated products. 

Terada, A., et al. (2006), Development of Sulfuric Acid Decomposer for Thermochemical Hydrogen Production IS Process , Trans. Atom. Energy Soc.Jpn., Vol. 5, pp. 68-75. 

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