Fusion of the (+)-amhe (8) with phthalic anhydride provided (+) -2-benzylo~y-N-phthaloyl[l-~H,] ethylamine (9), which was debenzylated quantitatively to (+) -2-hydroxy-N-phthaloyl[1-2Hl]ethylamine (10) by hydrogenolysis over palladium black or 50% palladiumcharcoal in alcoholic solution. Oxidation of the amine (10) to (+)-N-phthal0yl[2-~H,lglycine (1 1) was also studied in detail and the best yields were obtained with potassium permanganate in aqueous 2.5~-sulphuric acid
The optical rotations of fourteen L-a-amino acids dissolved in aqueous potassium carbonate became more positive with time, eventually reaching limiting values, with optical activity enhancements ranging from <1 to >50 fold.The l H n.m.r. signals from the a-protons showed a concomitant down-field shift. These changes are explained by the formation of carbamate (N-carboxy-) salts. The 13C n.m.r. spectra also altered with time, showing the gradual appearance of a signal assigned to the carbamate carbon atom.
Ausgehend von (+)‐(S)‐O‐Benzyl‐serin (Ia) (durch Racemattrennung) wird über die Stufen (Ib) [aus (Ia) mit HNO,/HBr; keine Reinisolierung], (Ic) [aus (Ib) mit Li‐triäthylbordeuterid], (IIa), (IIb) [aus (IIa) mit NaOCl/NaOH] , (Ilc), (III), (IVa) und (IVb) durch Hydrolyse von (IVb) mit Hydrazinacetat/Methanol und weitere Hydrolyse mit HCl das chiral reine deuterierte (S)‐Glycin (IVc) synthetisiert.
Durch Cyclisierung des Pyridins (I) mit Methylamin wird das Dihydro‐1H‐diazainden (II) erhalten, das mit Dichlordicyanbenzochinon (DCC) zu (III) dehydriert wird.
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