Masanori Morita

The chemistry of zerumbone. Part 5: Structural transformation of the dimethylamine derivatives

Abstract Zerumbone ( 1 ) and its 6,7-epoxide ( 2 ) react with ammonia and dimethylamine regio- and stereospecifically, affording monoamines 3 , 4 , 7 and 8 . All adducts have the same relative configuration at C2 and C3. The conjugate amination is thermodynamically controlled to arrive at a single diastereomer. At 15°C 7 reacts with cyanide to give aminonitrile 10 as the single product, while at 30°C, acyclic aminonitrile 11 is also formed. The reaction with 8 affords at 0°C bicyclic aminonitrile 12 of the asteriscane skeleton, while at 30°C or higher temperature, mixtures of 12 and tricyclic nitriles 13 and 13′ are obtained. Refluxing of 7 , 8 and 10 in aqueous acetonitrile promotes scission of the zerumbone ring by retro-Mannich reaction to provide acyclic aldehydes 16–18 , respectively. The dimethylamino group of 7 , 8 and 10 is eliminated stereospecifically by Cope- and base-catalyzed eliminations to regenerate the zerumbone skeleton in the products 1 , 2 and 21 . Cope elimination of 12 results in a mixture of 13 and 13′ by deaminative transannular etherification.

Determination of the presence of ceramide aminoethylphosphonate and ceramide N-methylaminoethylphosphonate in marine animals by fast atom bombardment mass spectrometry

Phosphonosphingolipids from 15 kinds of shellfish were analyzed by fast atom bombardment mass spectrometry to determine the contents of ceramide aminoethylphosphonate (CAEPn) and ceramide N-methylaminoethylphosphonate (CMAEPn). Two pairs of ions, at m/z 126 and 140 in the positive ion mode and at m/z 124 and 138 in the negative ion mode, were used to distinguish between aminoethylphosphonic acid and N-methylaminoethylphosphonic acid in CAEPn and CMAEPn. Interestingly, mollusca in the early stage of evolution have both CAEPn and CMAEPn, while most in the middle stage have only CMAEPn and those in the highest stage have only CAEPn.

Isolation and characterization of new limonoid glycosides from Citrus unshiu peels.

Three limonoid glycosides were isolated from Citrus unshiu peels, and their structures were determined based on MS and NMR spectroscopic data as nomilinic acid 17-O-beta-D-glucopyranoside (1), methyl nomilinate 17-O-beta-D-glucopyranoside (2), and obacunone 17-O-beta-D-glucopyranoside (3). In particular, the location of the sugar moiety was clearly determined by the B/E constant linked scan FABMS method. No limonoid glycosides obtained here were found to have antitumor activity in NCI-H292 and EL-4 cell lines.

Fast atom bombardment mass spectrometry and linked scan analyses at constant B/E in the structural characterization of new polyisoprenepolyols isolated from an edible mushroom (Hypsizigus marmoreus)

Fast atom bombardment (FAB) mass spectrometry is a powerful tool for analyzing the structure of polyisoprenepolyols. Analyses in the positive and negative ion mode are complementary in that the former provides data on the number of hydroxy groups present while the latter provides data on the isoprenoid sequence. Some of this information is already available from routine FAB mass spectra. More detailed information is contained in the linked scan spectra.

Lactone formation of N-acetylneuraminic acid oligomers and polymers as examined by capillary electrophoresis.

We examined lactone‐formation reaction of oligomers and polymers of N‐acetylneuraminic acid in diluted hydrochloric acid solution and found that the time course of the lactonization reaction was easily traced by capillary electrophoresis. The reaction proceeded more rapidly with increasing the molecular mass of oligomers because the conformation of inner units became rigid and more favorable for the formation of lactone linkage. Present results obtained using capillary electrophoresis will be useful in understanding of physical and chemical properties of oligo/polysialic acids.

Investigation of functional molecules in African Celosia argentea L.

Abstract Five glycosides were isolated from the leaves of Celosia argentea L. and their structures were determined based on UV, MS, 1 H NMR and 13 C NMR spectroscopic data as 1-(4- O -β-glucopyranosyl-3-methoxyphenyl) propane-2-ene (citrusin C, 1 ), 3- O -β-glucopyranosyl-1 H -indole (indican, 2 ), (3 Z )-hexenyl-(1- O -α-rhamnopyranosyl-β-glucopyranoside) ( 3 ), (3 Z )-hexenyl-1- O -β-glucopyranoside ( 4 ), and (7 E )-6,9-dihydromegastigma-7-ene-3-one-9- O -[β-glucopyranoside ( 5 ). On bioassay on the germination of lettuce, compound 1 , the aglycone of 1 ( 1a ), and the aglycone of 3 (3a) exhibited growth inhibitory activity, whereas compound 2 and 3 exhibited growth promotive activity. Compounds 1 –5 were detected in the leaves of Celosia argentea L. for the first time in this study.

Structural Elucidation of Complex Lipids by FAB/MS.

As a part of our search for functional natural molecules we have been investigating the extract of an edible fungi (bunashimeji). In this manuscript we describe structural elucidation of complex lipids and polyisoprenepolyols isolated from the mushroom bunashimeji by FAB mass spectrometry.