Novel Multidimensional Liquid Chromatography Workflow with In-Loop Enzymatic Digests of Multiple Heart-Cuts for Fast and Flexible Characterization of Biotherapeutic Protein Variants.

Multidimensional liquid chromatography (mD-LC) is becoming a powerful tool for complete characterization of individual peaks and protein variants through separation methods such as nondenaturing ion exchange (IEC) or size-exclusion chromatography coupled to reversed-phase (RP) chromatography. The flexibility of commercially available and customized mD-LC systems is still limited in terms of enzymatic peak processing between chromatographic dimensions. In this regard, only a few column-immobilized proteases are available for detailed peak characterization by mD-LC coupled to mass spectrometry (mD-LC-MS).

Aryldiones incorporating a [1,4,5]oxadiazepane ring. Part 2: chemistry and biology of the cereal herbicide pinoxaden.

Background: Pinoxaden is a new cereal herbicide that provides outstanding levels of post-emergence activity against a broad spectrum of grass weed species for worldwide selective use in both wheat and barley.

Results: Factors influencing activity and tolerance to pinoxaden were in part linked to distinct structural parts of the active ingredient. Three complementary contributions that decisively impact upon the herbicidal potency against grasses were identified: a preferred 2,6-diethyl-4-methyl aromatic substitution pattern, a dione area suitable for proherbicide formation and beneficial adjuvant effects.

Automated normal-phase preparative high-performance liquid chromatography as a substitute for flash chromatography in the synthetic research laboratory.

An automated normal-phase preparative HPLC system was developed in order to omit time-consuming flash column chromatography in the synthetic research laboratory. The system is equipped with steel columns packed with spherical 12 microm silica and is able to separate samples in a range of 0.1-10 g depending on the column diameter and chromatographic problem.

5-Azidoimidacloprid and an acyclic analogue as candidate photoaffinity probes for mammalian and insect nicotinic acetylcholine receptors.

The 5-azido analogue of the major insecticide imidacloprid, 1-(5-azido-6-chloropyridin-3-ylmethyl)-2-nitroiminoimidaz olidine (1), and an acyclic analogue, N-(5-azido-6-chloropyridin-3-ylmethyl)-N'-methyl-N' '-nitroguanidine (2), were prepared in good yields as candidate photoaffinity probes for mammalian and insect nicotinic acetylcholine receptors (nAChRs). The essential intermediate was 5-azido-6-chloropyridin-3-ylmethyl chloride (3) prepared in two ways: from 6-chloro-5-nitronicotinic acid by selective reduction and then diazotization, and from N-(6-chloropyridin-3-ylmethyl)morpholine by an electrophilic azide introduction with lithium diisopropylamide followed by chlorine substitution of morpholine with ethyl chloroformate. Coupling of 3 with 2-nitroiminoimidazolidine gave 1.