Effect on hydrogenolysis

When mixture effects on hydrogenolysis or hydrogenation reactions are considered, the most successful models are often the based on the Langmxiir-Hinselwood (LH) mechanisms [8]. 

The product selectivity was assumed to be markedly different as explained in Section I. The relations between the structures of asym DAMs and their hydrogenolytic behaviors, as well as their reactivities, are the next point for discussion. In our studies, a fixed catalyst was used in order to maintain the same effect on the hydrogenolysis of asym DAMs (53). 

Pyrimidinopyrazines related to folic acid have been investigated in some detail for their antimeta-bolic and antineoplastic activities. A related compound, which lacks one nitrogen atom, has been described as an antiproliferative agent, indicating it too has an effect on cell replication. Aldol condensation of the benzaldehyde 99 with ethyl acetoacetate gives the cinnamate 100. Thi.s is then reduced catalytically to the acetoacetate 101. Reaction of that keto ester with 2,4,6- triami-nopyrimidine gives the product 102 which is subsequently chlorinated (103) and subjected to hydrogenolysi.s. There is thus formed piritrexim (104) [17]. 

Hydrogen is a common reactant in the hydrogenolysis and hydrogenation reactions that show a support effect on the activity. The mode of chemisorption and the bondstrength of hydrogen on the surface of supported Pt particles is studied in chapter 5 and chapter 6. 

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