Mass spectrometry of some N-acyldaunosamine derivatives.
Abstract The principal modes of fragmentation subsequent to electron impact of some N -acyl derivatives of daunosamine, the glycoside moiety of the antitumour antibiotics daunomycin and adriamycin, have been studied by using specifically deuterated derivatives and high-resolution measurements. In particular, the elimination of MeOH from methyl β-daunosaminides is shown to occur extensively and stereo-specifically, and involves HO-4. The splitting of the moieties C-1-C-2 and C-5-O-5 affords the fragments D 2 , D ′ 2 , and D ′′ 2 , which are among the most abundant.
Spectrographie de masse en série du bornane—II: Amino‐bornanols et dérivés
Les auteurs ont etudie les spectres de masse d'un grand nombre d'amino-bornanols et derives et leurs oxazolidines. Une etude comparative des fragments obtenus selon la position de l'amine montre que la rupture entre les carbones 2 et 3 porteurs des substituants reste primordiale aussi bien pour les amino-2 que pour les amino -3 bornanols. 
 
 
 
L'etude des spectres des oxazolidines et des amino-alcools, montre que, si dans les premiers la charge semble etre egalement repartie entre les deux heteroatomes, N et 0, il n'en est pas ainsi dans les amino-alcools ou l'azote porte preferentiellement la charge. 
 
 
 
Enfin, si la spectrographie de masse ne semble pas d'une grande utilite pour l'etude de la stereoisomerie, elle se revele un moyen de choix pour preciser l'isomerie deposition dans ce type de compose. 
 
 
 
A study has been made of the fragmentation of amino-bornanols and their oxazolidines derivatives by mass spectroscopy. Different fragmentations were compared according to the 2- or 3-position of the ionized substituent. These results show the importance of cleavage between the two heterosubstituted carbon atoms. Interpretation of the mass spectra of oxazolidines leads to the supposition that the charge is distributed between the oxygen and the nitrogen atoms, whereas in the amino-alcohols only the nitrogen atom was ionized. Some characteristic fragmentations of the bornane skeleton were observed. Mass spectroscopy does not permit the determination of the epimeric nature of the substituents, but on the other hand it does facilitate the determination of positional isomers.
Melanocins A, B and C, new melanin synthesis inhibitors produced by Eupenicillium shearii. I. Taxonomy, fermentation, isolation and biological properties.
New melanin synthesis inhibitors, melanocins A, B and C, were isolated from the fermentation broth and mycelium extract of Eupenicillium shearii F80695. Melanocin A, an isocyanide compound, inhibited mushroom tyrosinase and melanin biosynthesis of B16 melanoma cells with IC50 value of 9.0 nM and MIC value of 0.9 microM, respectively. Melanocin A also inhibited growth of Streptomyces bikiniensis. While, the structurally very related but non-isocyanide compounds melanocins B and C did not show inhibitory activity in these assays. Melanocins A, B and C showed potent antioxidant activity with scavenging activity of DPPH radical and superoxide anion radical.