Products of catalytic hydrogenation

Fig. 6.1.2 Absorption spectra of Latia luciferin (1), the product of catalytic hydrogenation (2), the product of ammonolysis (3), and the product of hydrolysis (4), all in ethanol at the same molar concentration (89 pM). Latia luciferin has an e value of 13,700 at 207nm, and a bioluminescence activity of approximately 7.6x 1015 photons/mg. From Shimomura and Johnson, 1968b, with permission from the American Chemical Society.

Flash fires and explosions which frequently occurred on discharge of the hot products of catalytic hydrogenation of vegetable oils were attributed to formation of phosphine from the phosphatides present to a considerable extent in, e.g., rape-seed and linseed oils. 

Problem 18.47 What is the product of catalytic hydrogenation of (a) acetone oxime, b) propane-1,3-dinitrile, (c) propanal and methylamine M... 

Catalytic hydrogenation of trarcs-a-fluorostilbene and of difluoromaleic acid does not give products expected from the addition of hydrogen across the double bonds. What are the products of catalytic hydrogenation of compounds D, and E, and F ... 

The von Braun degradation (85, 67) was reinvestigated and fully worked out by Boit (86). The reaction of strychnine with cyanogen bromide in hot benzene leads to the formation of two products, the amorphous bromocyanamide-I (LXXX) and the crystalline bromo-cyanamide-II (LXXXI). Dihydrostrychnine, on the other hand, gives only one product (LXXXII), which is identical with the product of catalytic hydrogenation (platinum in ethyl acetate) of bromocyan-amide-II. The corresponding brucine compounds behave analogously. 

Table 1. Products of catalytic hydrogenation (in toluene) depending on catalyst basicity...

PREDICTING THE PRODUCTS OF CATALYTIC HYDROGENATION I LEARN the skill Predict the products of each of the following reactions ... 

Give the expected major product of catalytic hydrogenation of each of the following alkenes. Clearly show and explain the stereochemistry of the resulting molecules. 

The situation is more complex in the hydrogenation of the aromatic ring D of the tetracyclic compound (234) [98, 99] (see Scheme 96). Oxidation of the products of catalytic hydrogenation led to two ketones of which... 

In vitro and in vivo antimicrobial activities have been reported for tolypomycin Y (43, 57), but few derivatives have been tested. The most important of these is tolypomycin R (the hydroquinone form of tolypomycin Y), which was obtained as one of the products of catalytic hydrogenation of tolypomycin Y. 

Under the circumstance of catalytic hydrogenation of piperidine derivatives 190 in MeOH over Pd/C catalyst afforded an isomeric mixture of perhydropyrido[l,2-c]pyrimidines 174-177 (98TL7021, 00JA5017). The main product was 174 (66%). 

An alternate scheme for preparing these compounds starts with a prefabricated pyrimidone ring. Aldol condensation of that compound (95), which contains an eneamide function, with pyridine-3-aldehyde (80), gives the product 96. Catalytic hydrogenation gives the product of 1,4 reduction. The resulting pyrimidinedione, of course exists in the usual tautomeric keto (97a) and enol (97b) forms. Reaction with phosphorus oxyxchloride leads to the chloro derivative 98. Displacement with methoxide gives 99. Reaction of this last intermediate with the furylalkylamine derivative 92 leads to the H-2 blocker lupitidine (100) [22]. 

Coke is a hydrogen deficient residue left on the catalyst as a by-product of catalytic reactions. 

Compound 172 exhibited typical indolenine UV absorptions and mass Spectral fragmentation very similar to those of 15,20-anhydrocapuronidine (303), obtained by concentrated H2S04 dehydration of 170. Upon reduction with NaBH4, the indolenine 172 was converted to its 1,2-dihydro derivative, identical to the natural product 173. Catalytic hydrogenation gave a tetrahydro derivative, characterized by a peak at m/z 190 in the mass spectrum, typical of pseudoaspido-spermatane alkaloids. 

To improve the efficiency of combined hydrogen production and C02 capture, several technologies are in development that combine catalytic reactions and the separation of either hydrogen or C02. Major targeted areas of application are the production of bulk hydrogen as a transport fuel and electricity production with pre-combustion C02 capture. 

In addition to the physical interactions described above, the tip may also be used to alter the local chemical conditions within the tunnel junction. For example, catalytic rehydrogenation of carbonaceous fragments on Pt(lll) by tip-directed production of atomized hydrogen in vacuum at the Pt-Ir tip has been described [524]. Similar modification schemes may also be envisioned based on limiting the transport of reactants and products into or away from the partly occluded tunnel junction. As noted earlier, such effects may be important in the study of electrodeposition and etching process [126-131]. Nonetheless, much remains to be understood about the detailed physics and chemistry of the immersed tunnel junction. 

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