- Liquid chromatographic assays for barbiturate injections
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Precise, rugged, stability-indicating HPLC assays were developed for phenobarbital, pentobarbital, and secobarbital sodium injections. Degradation products of the three barbiturates were prepared and chromatographed to demonstrate method specificity. The degradation products were also used to demonstrate specificity of official GC methods for pentobarbital and secobarbital sodium capsules. The acetylurea degradation products of pentobarbital and secobarbital were characterized following the separation of their diastereoisomers by HPLC.
- Reif,Kaufmann,DeAngelis,Frankhouser
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Read Online
- Base-controlled chemoselectivity: direct coupling of alcohols and acetonitriles to synthesise α-alkylated arylacetonitriles or acetamides
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We achieved chemoselective synthesis of α-alkylated arylacetonitriles and acetamides by combining Ir complex-catalysed direct coupling of alcohols and nitriles by a simple adjustment of the base. Methanol and ethanol performed well as the alkylating reagents. This method of acetonitrile alkylation provided a novel approach for carbon chain extension.
- Bai, Liang,Ge, Min-Tong,Li, Chen,Qiu, Yuan-Rui,Wang, Ying,Xia, Ai-Bao,Xu, Dan-Qian
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supporting information
p. 15200 - 15204
(2021/09/06)
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- Gold Activation of Nitriles: Catalytic Hydration to Amides
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A gold-based catalytic system that efficiently mediates the hydration of a broad spectrum of nitriles, including aromatic, heteroaromatic and aliphatic examples and efficiently catalyze the hydration of a range of organonitriles has been reported. Nitriles are considered inert in the context gold catalysis and have only been used as reaction solvent or as throw-away ligands in well-defined cationic gold catalysis. The obtained product was purified by flash chromatography using a gradient of pentane/ethyl acetate and compound 1 was isolated as a colorless solid. Aromatic substrates bearing two nitrile groups as in rn-benzenedinitrile and p-benzenedinitrile underwent double nitrile hydration and afforded excellent yields in the corresponding diamides. There is high relevance for the use of cationic gold complexes bearing such ligands and should have important implications in catalysis.
- Ramon, Ruben S.,Marion, Nicolas,Nolan, Steven P.
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supporting information; experimental part
p. 8695 - 8697
(2010/03/24)
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- Lithium/DTBB-induced reduction of N-alkoxyamides and acyl azides
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A series of N-alkoxyamides and N-methoxy-N-methylamides (Weinreb amides) have been subjected to dealkoxylation by reductive cleavage of the N-O bond with lithium powder and a catalytic amount of DTBB (10 mol%) at room temperature, leading to the corresponding amides. When the reaction is performed under reflux conditions, the corresponding alkanes, resulting from a formal deaminocarbonylation process, are obtained. This methodology applied to acyl azides furnished the corresponding primary amides.
- Yus, Miguel,Radivoy, Gabriel,Alonso, Francisco
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p. 914 - 918
(2007/10/03)
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- Biosynthesis of porphyrins and related macrocycles. Part 52.1'2 Synthesis of 1-SH11-4Hjporphobilinogen and the (11R)enantiomer for stereochemical studies on hydroxymethylbilane synthase (porphobilinogen deaminase)
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A synthetic route is devised for the synthesis of (115)-[11-2H,]porphobilinogen la and of the (1 lβ)-enantiomer Ib. Their absolute configurations and enantiomeric purity are established by degradation to a derivative of [2-2H,]glycine of known stereochemistry. Methods are then developed, based on the synthesis of chiral imidate esters, for determination of the configuration of [2H1]-labelled aminomethylpyrroles by converting them into [2H,]-labelled amidines followed by analysis using 'H-NMR. The labelled samples of PEG la and Ib serve as substrates for hydroxymethylbilane synthase and the products are trapped as [2H1]-labelIed aminomethylbilanes 7c and 7d. Their configurations are determined by the NMR assay to demonstrate that as PBG 1 is enzymically converted into the aminomethylbilane 7, there is overall retention of configuration at the aminomethyl carbon. The Royal Society of Chemistry 1999.
- Neidhart, Werner L.,Anderson, Paul C.,Hart, Graham J.,Battersby, Alan R.
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p. 2677 - 2689
(2007/10/03)
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- Stereoselective Hydrolysis of Nitriles and Amides Under Mild Conditions Using a Whole Cell Catalyst
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An immobilised whole cell Rhodococcus sp. (SP 361) has been shown to be an effective catalyst for the stereoselective hydrolysis of both racemic and prochiral nitrile containing compounds. 2-Alkyl-arylacetonitriles 6a-8a were hydrolysed to (S)-acids and (R)-amides whereas the closely related substrate 9a gave the (R)-acid.A series of prochiral dinitriles 10a-13a were hydrolysed to the corresponding (S)-acids with e.e.'s 22-84percent.Models to account for the stereoselectivity of the enzymic hydrolyses have been proposed.
- Beard, Timothy,Cohen, Mark A.,Parratt, Julian S.,Turner, Nicholas J.,Crosby, John,Moilliet, Jock
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p. 1085 - 1104
(2007/10/02)
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