Colored indicators for simple direct titration of magnesium and lithium reagents

Watson, S. C.; Eastham, Jerome F.

doi:10.1016/s0022-328x(00)92418-5

Cited by 702 publications

(308 citation statements)

References 13 publications

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“…CH 3 MgBr was titrated using 1M sec-butyl alcohol in dry xylene in the presence of phenanthroline as an indicator. 161 PhMgBr was freshly prepared from bromobenzene using a known procedure by Braun et al 162 and was titrated similar to CH 3 MgBr. 161 All experiments involving air-and/or moisture-sensitive compounds were conducted in an oven dried round-bottom flask capped with a rubber septum, and noted, all reported compounds were homogeneous by thin layer chromatography (TLC) and by 1 H NMR.…”

Section: Discussionmentioning

confidence: 99%

Total Synthesis of Depsilairdin

Ward

Pardeshi

2010

J. Org. Chem.

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The total synthesis of depsilairdin, a host-selective phytotoxin isolated from Leptosphaeria maculans (the causal agent of blackleg disease of oilseed Brassicas), has been achieved by N-terminal extension of a suitably protected derivative of the hitherto unknown amino acid (2S,3S,4R)-3,4-dihydroxy-3-methyl-proline (Dhmp) followed by esterification with lairdinol A. The latter esterification, complicated by the sterically hindered nature of the carboxyl group, was accomplished by a novel method involving reaction of the 1-hydroxybenzotriazole (HOBt) derived active ester with the bromomagnesium alkoxide of lairdinol A. Three depsilairdin analogues were also prepared by replacing the Dhmp residue with L-proline and cis-and trans-4-hydroxy-L-proline. Phytotoxicity assays showed that the analogues were nontoxic to both blackleg-susceptible (brown mustard) and -resistant (canola) plants, suggesting that the presence of the Dhmp residue in depsilairdin is important for its host-selective toxicity toward brown mustard.

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Section: Discussionmentioning

confidence: 99%

Total Synthesis of Depsilairdin

Ward

Pardeshi

2010

J. Org. Chem.

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“…Commercially available n-butyllithium was titrated with a 1M solution of sec-butanol in xylene using 1,10-phenanthroline as indicator. 22 Commercially available toluene (Merck) and anhydrous THF (99.9%, water content ≤ 0.006%, Acros) were used as solvents in the reactions. All glassware was dried in an oven at 100ºC and cooled to room temperature under Ar before use.…”

Section: Methodsmentioning

confidence: 99%

Reductive removal of the Boc protecting group via a DTBB-catalysed lithiation reaction

Almansa¹,

Behloul²,

Guijarro³

et al. 2006

Arkivoc

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The DTBB-catalysed lithiation of Boc-protected alcohols, amines and thiols in THF at 0ºC led, after quenching with methanol or water, to the recovery of the free alcohols, amines and thiols in short reaction times and in moderate to very good yields. The procedure has been applied to primary, secondary and tertiary alcohols, phenols, secondary amines and primary, secondary and aromatic thiols. This method represents a reasonable alternative to the previously reported deprotection procedures.

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“…38 n-BuLi reagent was titrated using 1,10-phenanthroline as indicator prior to use. 39 Tellurium metal (200 mesh) was obtained from Aldrich Chemical Co. and dried overnight in an oven at 100°C. Palladium dichloride and copper(I) iodide were purchased from Aldrich Chemical Co. and dried in a desiccator containing CaCl2 and P2O5 under vacuum.…”

Section: Methodsmentioning

confidence: 99%

Coupling of Vinylic Tellurides with Alkynes Catalyzed by Palladium Dichloride: Evaluation of Synthetic and Mechanistic Details.

et al. 2004

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Under palladium dichloride catalysis, vinylic tellurides couple efficiently with alkynes with retention of the double-bond geometry. Herein we show that the amount of the PdCl 2 catalyst can be reduced from 40 mol % to 10 mol % by using copper(II) chloride as an oxidizing agent. Under these conditions, an inert atmosphere is no longer required and the reaction occurs quite efficiently in the presence of air, leading to the enynes in 40-82% isolated yields. Mass and tandem mass spectrometric experiments using electrospray ionization were performed, and Pd-Te cationic intermediates were, for the first time, intercepted and transferred to the gas phase for structural characterization. An expanded catalytic cycle for this important method for enyne synthesis is proposed.

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Colored indicators for simple direct titration of magnesium and lithium reagents

Cited by 702 publications

References 13 publications

Total Synthesis of Depsilairdin

Total Synthesis of Depsilairdin

Reductive removal of the Boc protecting group via a DTBB-catalysed lithiation reaction

Coupling of Vinylic Tellurides with Alkynes Catalyzed by Palladium Dichloride: Evaluation of Synthetic and Mechanistic Details.

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