Collision Cross Section Calculations Using HPCCS.

A technical overview of the High Performance Collision Cross Section (HPCCS) software for accurate and efficient calculations of collision cross sections for molecular ions ranging from small organic molecules to large protein complexes is presented. The program uses helium or nitrogen as buffer gas with considerable gains in computer time compared to publicly available codes under the Trajectory Method approximation. HPCCS is freely available under the Academic Use License at https://github.

Structure-Based Molecular Networking for the Target Discovery of Oxahomoaporphine and 8-Oxohomoaporphine Alkaloids from .

In addition to seven known alkaloids (, -) and 1,2,4-trimethoxybenzene (), three isoquinoline-derived alkaloids (-), namely, duguetinine (), a compound based on an unprecedented oxahomoaporphine scaffold, and two new 8-oxohomoaporphine alkaloids, duguesuramine () and 11-methoxyduguesuramine (), and a new asarone-derived phenylpropanoid () were isolated from the bark of . The isolation workflow was guided by HPLC-HRESIMS/MS and molecular networking-based analyses. Twenty-four known alkaloids were dereplicated from the alkaloid-rich fraction network and were assigned by manual MS/MS interpretation.

Enantioselective, Noncovalent, Substrate-Directable Heck-Matsuda and Oxidative Heck Arylations of Unactivated Five-Membered Carbocyclic Olefins.

Highly diastereo- and enantioselective, noncovalent, substrate-directable Heck desymmetrizations of cyclopentenyl olefins containing hydroxymethyl and carboxylate functional groups are presented. These conformationally unbiased cyclic olefins underwent effective arylations in yields of up to 97 %, diastereoselectivity up to >20:1, and enantiomeric excesses of up to 99 %. Noncovalent directing effects were shown to be prevalent in both Heck-Matsuda and oxidative Heck reactions, allowing the preferential formation of cis-substituted aryl cyclopentenes containing two stereocenters, including quaternary stereocenters.

High performance collision cross section calculation-HPCCS.

Since the commercial introduction of Ion Mobility coupled with Mass Spectrometry (IM-MS) devices in 2003, a large number of research laboratories have embraced the technique. IM-MS is a fairly rapid experiment used as a molecular separation tool and to obtain structural information. The interpretation of IM-MS data is still challenging and relies heavily on theoretical calculations of the molecule's collision cross section (CCS) against a buffer gas.

Guaianolide sesquiterpene lactones and aporphine alkaloids from the stem bark of Guatteria friesiana.

Three guaianolide sesquiterpenes, denoted guatterfriesols A-C, and four aporphine alkaloid derivatives were isolated from the stem bark of the Amazonian plant Guatteria friesiana. Thus far, sesquiterpene lactones have not been described in Annonaceae. Structures of the previously undescribed compounds were established by using 1D and 2D NMR spectroscopy in combination with MS.

Photoisomerization induced scission of rod-like micelles unravelled with multiscale modeling.

Hypothesis: In photorheological fluids, subtle molecular changes caused by light lead to abrupt macroscopic alterations. Upon UV irradiation of an aqueous cetyltrimethylammonium bromide (CTAB) and trans-ortho-methoxycinnamic acid (trans-OMCA) solution, for instance, the viscosity drops over orders of magnitude. Multiscale modeling allows to elucidate the mechanisms behind these photorheological effects.

Noncovalent Substrate-Directed Enantioselective Heck Reactions: Synthesis of S- and P-Stereogenic Heterocycles.

S- and P-Stereogenic heterocycles were synthesized by a remarkably simple enantioselective Heck desymmetrization reaction based on the unprecedented noncovalent directing effect of S=O and P=O functionalities. Selected prochiral symmetric substrates were efficiently arylated using the recently disclosed chiral PyraBOx ligand under mild and open-flask reaction conditions. Several five-membered aryl- sulfones, sulfoxides, and phosphine oxides were synthesized in good to excellent yields, in good to high diastereoselectivity, and enantiomeric ratios up to 98:2.

Separation of glycosidic catiomers by TWIM-MS using CO2 as a drift gas.

Traveling wave ion mobility mass spectrometry (TWIM-MS) is shown to be able to separate and characterize several isomeric forms of diterpene glycosides stevioside (Stv) and rebaudioside A (RebA) that are cationized by Na(+) and K(+) at different sites. Determination and characterization of these coexisting isomeric species, herein termed catiomers, arising from cationization at different and highly competitive coordinating sites, is particularly challenging for glycosides. To achieve this goal, the advantage of using CO2 as a more massive and polarizable drift gas, over N2, was demonstrated.

Molecular variations in aromatic cosolutes: critical role in the rheology of cationic wormlike micelles.

Wormlike micelles formed by the addition to cetyltrimethylammonium bromide (CTAB) of a range of aromatic cosolutes with small molecular variations in their structure were systematically studied. Phenol and derivatives of benzoate and cinnamate were used, and the resulting mixtures were studied by oscillatory, steady-shear rheology, and the microstructure was probed by small-angle neutron scattering. The lengthening of the micelles and their entanglement result in remarkable viscoelastic properties, making rheology a useful tool to assess the effect of structural variations of the cosolutes on wormlike micelle formation.