Über eine neue Methode zur Darstellung von Aldehyden. 1. Mitteilung

Organic chemistry:

“…The value for the high voltage is the optimal neither for carbon- 14 nor for tritium, but is a compromise that permits (a) satisfactory counting of either isotope separately, and (b) simultaneous counting of the two isotopes in a mixture.…”

“…We have now separated and analyzed the labeled-D-fructose 14 formed from D-mannose -1-C under conditions similar to those used for preparing "a n -D-glucosaccharinic acid. Alkaline degradation of 'the labeled D-fructose to the next lower aldonic acid (D-arabinonic acid) showed 98% of the carbon-l4…”

“…To account for the presence of carbon-l4 at the tertiary 14 carbon atom of the product from D-mannose -1-C , with the new mechanism the attack of the hydroxyl ion must be at C-2, causing migration of the methyl group to C-3; with the Lemieux mechanism,, the attack must be at C-J> 3 causing migration of the CUH 7 CU group to C-2. Table 5 …”

“…Migration of carbon atoms in the formation of "a"-D-glucosaccharinic acid However, a modified Rosenmund reduction [14],, as first used by Cook and Major on fully acetylated aldonyl chlorides [15] synthesis of tritium-labeled as well as carbon-l4-labeled carbohydrates, and (b) techniques for using double-labeled compounds Carbohydrates position-labeled with tritium must be synthesized by methods entirely different from those already described.…”

Recent Development of Palladium-Supported Catalysts for Chemoselective Hydrogenation

“…The first method is the application of adequate catalyst poisons, such as sulfur-or nitrogen-containing compounds, as additives, which causes the appropriate deactivation of persisting palladium catalysts based on their ability to coordinate with palladium species [7][8][9][10][11][12][13][14][15][16][17][18] ; e.g., Lindlar's hydrogenation enables the semihydrogenation of alkynes to the corresponding alkenes using lead acetate and quinoline as catalyst poisons under Pd/CaCO 3 -catalyzed hydrogenation conditions. 7,8) We have also developed Pd/C-ethylenediamine [Pd/C(en) (Wako Pure Chemical Industries, Ltd., Osaka, Japan; 169-21443)] [19][20][21][22][23][24][25][26][27] and Pd/C-diphenylsulfide [Pd/C(Ph 2 S) (N.E.…”