Structure Revision of Protoaculeine B, a Posttranslationally Modified N-Terminal Residue in the Peptide Toxin Aculeine B

2020 ◽  
Author(s):  
Raku Irie ◽  
Kei Miyako ◽  
Satoko Matsunaga ◽  
Ryuichi Sakai ◽  
Masato Oikawa
Keyword(s):  
Mass Spectra ◽  
Chemical Reactivity ◽  
Model Compounds ◽  
Structural Revision ◽  
Structure Revision ◽  
Peptide Toxin ◽  
One Step ◽  
Marine Peptide ◽  
Synthetic Models ◽  
Long Chain

<div>Here, we newly propose the structure of protoaculeine B, an N-terminal moiety of the marine peptide toxin aculeine B, as possessing the cis-disubstituted tetrahydro-beta-carboline framework. We prepared two truncated model compounds that lack long-chain polyamine by one-step Pictet-Spengler reaction of tryptophan, and compared the NMR and mass spectra and chemical reactivity with those of natural protoaculeine B. The synthetic models reproduced the profiles of the natural product well, which was conclusive for the structural revision.</div>

Structure Revision of Protoaculeine B, a Posttranslationally Modified N-Terminal Residue in the Peptide Toxin Aculeine B

2020 ◽  
Author(s):  
Raku Irie ◽  
Kei Miyako ◽  
Satoko Matsunaga ◽  
Ryuichi Sakai ◽  
Masato Oikawa
Keyword(s):  
Mass Spectra ◽  
Chemical Reactivity ◽  
Model Compounds ◽  
Structural Revision ◽  
Structure Revision ◽  
Peptide Toxin ◽  
One Step ◽  
Marine Peptide ◽  
Synthetic Models ◽  
Long Chain

<div>Here, we newly propose the structure of protoaculeine B, an N-terminal moiety of the marine peptide toxin aculeine B, as possessing the cis-disubstituted tetrahydro-beta-carboline framework. We prepared two truncated model compounds that lack long-chain polyamine by one-step Pictet-Spengler reaction of tryptophan, and compared the NMR and mass spectra and chemical reactivity with those of natural protoaculeine B. The synthetic models reproduced the profiles of the natural product well, which was conclusive for the structural revision.</div>

scholarly journals Aliphatic Diacidic Long-Chain C16 Polyesters from 10,16-Dihydroxyhexadecanoic Acid Obtained from Tomato Residual Wastes

Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1524 ◽  
Author(s):  
Arrieta-Baez ◽  
Hernández Ortíz ◽  
Terán ◽  
Torres ◽  
Gómez-Patiño
Keyword(s):  
Mass Spectrometry ◽  
Enzymatic Reaction ◽  
Reaction Conditions ◽  
1H And 13C Nmr ◽  
Force Microscopy ◽  
Langmuir Blodgett ◽  
Atomic Force ◽  
One Step ◽  
Long Chain ◽  
Polyester Film

10,16-dihydroxyhexadecanoic acid obtained from agroresidual tomato waste, was oxidized to produce 7-oxohexadecanedioic acid in good yield (>70%) and purified without oxidation side products in one step. Polycondensation with 1,8-octanediol, yielded the polyester (poly(ω-carboxyl PA-co-OD)) with Mw = 2155.15 and Mn = 1637.27. The best enzymatic reaction conditions to get the polyester were using lipase CAL-B (%-by-wt relative to monomer) in toluene as a solvent for 1 h at 60 °C. The poly(ω-carboxyl PA-co-OD) was characterized by 1H- and 13C-NMR, mass spectrometry (MALDI-TOF) and the polyester film formed with a Langmuir-Blodgett Trough was analyzed by means of spectroscopic ellipsometry and atomic force microscopy.

The Mass Spectra of Some Organophosphorus Pesticide Compounds

1966 ◽  
Vol 49 (5) ◽  
pp. 1027-1045
Author(s):  
Joseph N Damico
Keyword(s):  
Alkyl Group ◽  
Mass Spectra ◽  
Organophosphorus Pesticide ◽  
Ester Group ◽  
Base Peak ◽  
Mass Measurements ◽  
Model Compounds ◽  
Hydrogen Migration ◽  
Accurate Mass Measurements ◽  
Individual Parent

Abstract The mass spectra of 23 pentavalent organophosphorus pesticide esters were investigated. Rearrangements and fragmentation by simple cleavage are postulated from analogy with similar compounds, from the presence of chlorine atoms with their readily-recognizable isotopic distribution when applicable, from elemental compositions determined by accurate mass measurements, and, in a few cases, from model compounds. The compounds are divided into four groups: phosphorodithioates, phosphorothionates, phosphorothiolates, and phosphates. The base peaks are formed by rearrangements and simple cleavage. Rearrangement ions are formed by (I) hydrogen migration from the alkyl ester group to the thiophosphite-oxygen skeleton; (2) migration of hydrogen from the Z moiety (aryl or alkyl group) to the phosphorus-oxygen skeleton; (3) migration of hydrogen from the Z moiety to the thiophosphite-oxygen skeleton; (4) migration of hydrogen from the ester group bonded to phosphorus to the Z moiety; and (5) alkyl migration to the Z moiety. The base peak does not characterize the different groups or compounds within a group. However, beta-cleavage (relative to the Z moiety) producing relatively intense peaks (with the charge on the Z moiety) is characteristic of a given group. These data may be useful in identifying metabolites isolated from crops field sprayed with an individual parent organophosphorus pesticide.

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