Amino-de-hydrogenation

The Direct Conversion of Aldehydes to Amides Amination or Amino-de-hydrogenation... 

Recent results have shown that a number of other commercially available ligands can be expected to have industrial potential for the hydrogenation of dehydro a-amino acid derivatives. However, it must be pointed out that in most cases model substrates and not industrially relevant targets have been investigated until now. Chiral Quest has shown that Rh-TangPhos as well as Rh-f-Ke-talPhos (for structures, see Fig. 37.9) were able to hydrogenate a variety of a-de-hydro amino acid derivatives with ee-values of 98->99%, TONs of up to 10000... 

The use of the 6-amino group and N1 nitrogen of the purine base to model the pharmacophore, as seen with staurosporine, is not possible in two other adenine-type inhibitors. Both isopentenyl adenine, a nonspecific inhibitor of protein kinases, and olomoucin, a more specific inhibitor of Ser/Thr protein kinases, are modified only at the 6-amino group position. Thus, bidentate hydrogen-bond formation as seen in the ATP purine base is not possible. Furthermore, there are inhibitors that do not contain the chemical structure of adenine, for example des-chloro-flavopyridol, a potent inhibitor of cdc-2 cell cycle kinase. 

Radiation Biochemistry of Proteins and Amino Acids. Up to the levels of 500 krads the changes in pigment properties of heme proteins are similar to those caused by oxidation or reduction. Changes in the proteins, in addition to deamination and loss of —SH groups, indicate a partial de-naturation similar to that induced by hydrogen ions. This results in some enhancement of reactivity of the heme portion (2). 

Reduction of 8-nitro-9,10-difluoro-7-oxo-2,3-dihydro-7H-pyrido[l,2, 3-cfe][l,4]benzoxazine-6-carboxamides with Na2S204 in aqueous MeOH under reflux for 5 h gave 8-amino derivatives in 51-74% yields (09WOP2009/035634). 8-Amino derivative was obtained from (S)-8-nitro-9-fluoro-10-(l-aminocyclopropyl)-7-oxo-2,3-dihydro-7/T-pyrido[l,2,3-de][l,4]benzoxazine-6-carboxylic acid by catalytic hydrogenation over Pd/C catalyst in AcOH (06MIP1). 

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