Tricyclic heterocycles as precursors to functionalized spirocyclic oximes

An efficient synthesis of functionalized spirocyclic oximes from tricyclic heterocycles is reported. This novel method accomplishes high diastereoselectivity via an intramolecular 1,3-dipolar cycloaddition with a regenerating Michael linker strategy. Ring opening of the tricyclic N-(trimethylsilyloxy)pyrrolo[3,4-c]isoxazolidine framework was found to be essential for successful N-alkylation of the tertiary amine on the polymer support. β-Elimination of the quaternary salt releases the spirocyclic oximes from the solid support in overall yields of 45–60%.     

Natural product extracts of the Canadian prairie plant,Thermopsis rhombifolia,have anti-cancer activity in phenotypic cell-based assays

Many plant species within the terrestrial ecological zones of Canada have not yet been investigated for anti-cancer activity. We examined the scientific literature describing the endemic flora from the prairie ecological zone and selected the species, Thermopsis rhombifolia, locally known as the buffalo bean, for investigation of its anti-cancer potential. We tested it in cell-based assays using phenotypic screens that feature some of the hallmarks of cancer. An ethanolic extract prepared from T. rhombifolia was cytotoxic to HT-29 (colon) and SH-SY5Y (brain) cancer cell lines, and showed little cytotoxicity to a normal human cell line (WI-38). In phenotypic assays, we identified activities in the extracts that target cell death, cell cycle and cell adhesion. These data highlight the anti-cancer potential of previously untested plants found in northern ecological zones and the feasibility of using pertinent phenotypic assays to examine the anti-cancer potential of natural product extracts.     

Ambient generation of fatty acid methyl ester ions from bacterial whole cells by direct analysis in real time (DART) mass spectrometry

Direct analysis in real time (DART) is implemented on a time-of-flight (TOF) mass spectrometer, and used for the generation of fatty acid methyl esters (FAMEs) ions from whole bacterial cells.     

Asymmetric halo-Mannich-type reaction provides access to pyrrolidines and beta-proline derivatives

[reaction: see text] A new halo-Mannich-type reaction is reported using cyclopropyl carbonyl-derived enolates and sulfonyl-protected imines. Chiral oxazolidinones auxiliaries were found to be effective for completely controlling the stereochemistry of the products. Variations in the oxazolidinone, protecting group, and imine components show this to be a quite general reaction. The initial iodo-Mannich products were found to be readily cyclized in the presence of triethylamine to afford the resulting protected pyrrolidines, which could be readily deprotected under standard conditions.     

Resolution-Enhanced Kendrick Mass Defect Analysis of Polycyclic Aromatic Hydrocarbons and Fullerenes in the Diffusion Flame from a Butane Torch

A modified Kendrick Mass Defect (KMD) analysis was applied to the analysis of polycyclic aromatic hydrocarbons (PAHs) and fullerenes in the diffusion flame from a handheld butane torch.

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Crystal structure of two lipophilic antifolates: 2,4-diamino-5-(n-hexyl)-6-methylpyrimidine and 2,4-diamino-5-(n-heptyl)-6-methylpyrimidine ethanesulfonate

The 5-hexyl (I) and the 5-heptyl (II) analogs of 2,4-diamino-6-methylpyrimidine both crystallize in the space groupP2₁/c withZ=4. Unit cell parameters of I are C₁₁H₂₀N₄·H₂O,a=17.204(3),b=4.609(9),c=16.765(2)Å,= 91.53(2)°; those of II are C₁₂H₂₃N₄ ⁺·C₂H₅SO₃ ^–,a=12.489(1),b=16.702(2),c=8.9558(7)Å,=99.208(8)°. The molecular packing of I contains one water, while II forms a salt with ethanesulfonic acid. The alkyl chain of I adopts an alltrans conformation; in contrast, II has onegauche orientation between carbons 2 and 3 of heptyl. These are the first structural data on two alkyl lipophilic antifolates with antineoplastic activity.