Stephen method

F. Montgomery, S. Montgomery, and P. Stephens. Method of controlling porosity of well fluid blocking layers and corresponding acid soluble mineral fiber well facing product. Patent US 5222558, 1993. 

The complex hydride reductions of nitriles to aldehydes compare favorably with the classical Stephen reduction which consists of treatment of a nitrile with anhydrous stannous chloride and gaseous hydrogen chloride in ether or diethylene glycol and applies to both aliphatic and aromatic nitriles [183,285, 1152]. An advantage of the Stephen method is its applicability to polyfunctional compounds containing reducible groups such as carbonyl that is reduced by hydrides but not by stannous chloride [1153]. 

Several reduction methods are available to convert nitriles (Stephen reaction) or acyl chlorides (Rosenmund reduction) or amides to aldehydes. The use of lithium aluminum hydride at low temperatures or lithium triethoxyaluminum hydride appears to be a more effective means of reduction than the stannous chloride-HCl used in the Stephen method or palladium and hydrogen used in the Rosenmund reduction. 

The Stephen s method allows the reduction of nitriles by stannous chloride in acid medium. If the amine chlorhydrate initially formed is hydrolyzed, the corresponding aldehyde is obtained (37, 91). Harington and Moggridge (37) have reduced 4-methyl-5-cyanothiazole by this method (Scheme 23). However, Robba and Le Guen (91) did not obtain the expected products with 4.5-dicyanothiazole and 2-methyl-4,5-dicyanothiazole. These compounds have been reduced with diisobutyl-aluminium hydride with very low yields (3 to 6%) (Scheme 24). In other conditions the reaction gives a thiazole nitrile aldehyde with the same yield as that of the dialdehyde. 

As mentioned previously, aldehydes can be prepared by Stephen s method of reduction of nitriles by stannous chloride (37, 91). Polaro-graphic reduction of thiazolecarboxylic acids and their derivatives gives lower yields of aldehydes (58). Ozonolysis of styrylthiazoles, for example, 2-styryl-4-methylthiazole, followed by catalytic reduction gives aldehyde with 47% yield of crude product (30). 

Sun, 1994. Jinjun Sun, Benjamin Liu, Peter McMurry, and Stephen Greenwood, A Method to Increase Control Efficiencies for Wet Scrubbers for Submicron Particles and Particulate Metals, J. Air Waste Management Association, 44 2, February 1994. 

Adopting Auwers original method, Milton and Stephen prepared 2-chloroflavonol 16 from 4-chlorocoumaran-2-one 13 in 3 steps in 70% overall yield. 4-Chloroflavonol was synthesized via the same sequence. The same group also carried out the bromination of 2-benzylidenedihydro-b-naphthafurano-l-one (17) and subsequently treated the dibromide with aqueous potassium hydroxide to give 5,6-benzflavonol 18. However,... 

Die Stephen-Reduktion von Nitrilen mit Tetrachlor-zinn(ll)-saure fiihrt zu Aldimin-Komplexen bzw. nach Hydrolyse zu Aldehyden (s. Bd. VII/1, S. 299ff. und Lit.1). Die Methode ist fur viele aliphatische Nitrile ungeeignet, da bei ihnen die primar entstehenden Nitriliumsalze ein zweites Molekiil Nitril addieren. In einzelnen Fallen bil-den sich bei der Stephen-Reduktion auch Amine (s. Bd. XI/1, S. 546). 

There are two principal methods for the reduction of nitriles to aldehydes. In one of these, known as the Stephen reduction, the nitrile is treated with HCl to form... 

This is redueed with anhydrous SnCl2 to RCH=NH, which precipitates as a complex with SnC and is then hydrolyzed (16-2) to the aldehyde. The Stephen reduction is most successful when R is aromatic, but it can be done for aliphatic R up to about six carbons. It is also possible to prepare 21 in a different way, by treating ArCONHPh with PCI5, which can then be converted to the aldehyde. This is known as the Sonn-Muller method. 

Molecular Luminescence Spectroscopy Methods and Applications in three parts). Edited by Stephen G. Schulman... 

G. S. Penny, R. S. Stephens, and A. R. Winslow. Method of supporting fractures in geologic formations and hydraulic fluid composition for same. Patent US 5009797, 1991. 

M. Stephens. Low density well cement compositions and method of use. Patent US 6176314, 2001. 

The coupling of terminal alkynes with organic halides, known as the Castro-Stephens-Sonogashira reaction, has wide applications in synthesis. The most widely used method is the Sonogashira coupling, using a combination of palladium and copper as the catalyst.13 Recently,... 

Photothermal Spectroscopy Methods for Chemical Analysis. By Stephen E. Bialkowski Element Speclatlon in Bioinorganic Chemistry. Edited by Sergio Caroli Laser-Enhanced Ionization Spectrometry. Edited by John C. Travis and Gregory C. Turk Fluorescence Imaging Spectroscopy and Microscopy. Edited by Xue Feng Wang and Brian Herman... 

This benefit comes at a cost, which arises from significantly reduced S/N and some interpretive difficulty as compared to IR. Developments on the latter front are bringing the theoretical prediction capability of VCD for small molecules to a level demonstrably superior to that for ECD (Freedman and Nafie, 1994 Stephens et al., 1994 Stephens and Devlin, 2000), especially for peptide spectra (Kubelka et al., 2002). Most previous protein applications of VCD used empirically based analyses (Keiderling, 1996, 2000). Theoretical methods are limited when applied to large molecules such as proteins however, a hybrid approach using ab initio determination of spectral parameters with modest-sized molecules for transfer to large peptides has made simulation of spectra for large peptides possible (Bour et al., 1997 Kubelka et al., 2002). Theoretical techniques for simulation of small-molecule VCD are the focus of several previous reviews (Stephens and Lowe, 1985 Freedman and Nafie,... 

Stephens M, Smith N, Donnelly P. A new statistical method for haplotype reconstruction from population data. Am J Hum Genet 2001 68 978-989. 

In one of the earliest reports of the use of clean evaporated alloy films in surface studies, Stephens described the preparation and characterization of Pd-Au films and presented some results for the adsorption of oxygen on them 46). Films of pure Pd and 60% Au were evaporated directly from wires, while films of 80% Au and pure Au were evaporated from a pre-outgassed tungsten support wire. The films were evaporated in a UHV system and the pressure was kept below PC8 Torr during evaporation. After evaporation, the films were stabilized by cycling between —195° and 30°C four times. They w ere characterized by X-ray diffraction and chemical analysis surface areas were measured by the BET method using krypton adsorption. 

Most of the methods for preparation of /3-naphthaldehyde have been given previously.2 A recent procedure describes the preparation of /3-naphthaldehyde from 2-bromomethylnaphthalene and hexamethylenetetramine in boiling acetic acid.3 The method of reduction of nitriles by stannous chloride was discovered by Stephen.4... 

Hatayama, H. K., Chen, J. J., de Vera, E. R., Stephens, R. D. Storm, D. L. 1980. A Method for Determining the Compatibility of Hazardous Wastes. EPA-600/2-80-076. Cincinnati United States Environmental Protection Agency, Center for Environmental Research Information. 

Optical Fiber Splices and Connectors Theory and Methods, Calvin M. Miller with Stephen C. Mettler and Ian A. White... 

Cramer, Stephen P. and Hodgson, Keith O., X-Ray Absorption Spectroscopy A New Structural Method and Its Applications to Bioinorganic Chemistry. .. 25 1... 

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