Grigg method

The molybdenum content of the flora is determined by the amount of this element in the soil and its bioavaUability, which can be estimated by a variety of methods. The Grigg method (extraction with ammonium... 

Several soil-test methods to determine Mo availability and to predict yield responses on a variety of soils have met with little success. The Grigg method and the method of anion-exchange resin can predict Mo uptake to some extent, but they are less accurate at predicting yield. Extraction tests must take into account Fe as well as Mo, because it has been found that the amount of Fe and the degree of crystallinity of Fe can influence Mo availability. Currently, there is no method available that would be a practical soil-test method and could be easily applied by soil-test laboratories. Because of these problems, the recommendations for addition of Mo must be based on soil PH, soil type, and the crop to be grown. 

An exhaustive series of reports by Grigg et al. (28) outlined two basic methods for the generation of azomethine ylides proceeding via either a 1,2-prototropic shift, or by a decarboxylative approach (29). The decarboxylative route to azomethine ylides can be exemplified by the condensation of benzaldehyde with the cyclic amino acid tetrahydroisoquinoline (108) (30), in DMF at 120 °C, to generate the intermediate awfi-dipole 109, which underwent subsequent cycloaddition with N-methyl maleimide to furnish a 1 1 endo/exo mixture of adducts 110 (R = Ph), in 82% yield (Scheme 3.30). 

For other methods of converting certain alcohols to secondary and tertiary amines, see Murahashi Kondo Hakata Tetrahedron Lett. 1982, 23. 229 Baiker Richarz Tetrahedron Lett. 1977, 1937. Heh. Chim. Acta 1978, 61, 1169, Synth. Common 1978,8. 27 Grigg Mitchell Sutthivaiyakit Tongpenyai 7 Chem. Soc., Chem. Commun 1981, 611 Arcelli Bui-The-Khai Porzi J. Organomel. Chem. 1982,235, 93 Kelly Eskcw Evans 7. Org. Chem. 1986, 51. 95 Huh Tsuji Kobayashi Okuda Watanabc Chem. Lett. 1988, 449. 

For some other methods, see Jones J, Org. Chem. 1967, 32, 1667 Semmelhack Hclquist Gorzynski J. Am. Chem. Soc. 1972, 94, 9234 Wcllmann Steckhan Synthesis 1978,901 Miyahara Shiraishi Inazu Yoshino Bull. Chem. Soc. Jpn. 1979, 52, 953 Grigg Stevenson Worakun J. Chem. Soc., Chem. Common. 1985, 971, Vandercsse Fort Becker Caubere Tetrahedron Lett. 1986, 27, 3517. 

Williams Klinglcr Allen Lichtenthaler Tetrahedron Lett. 1988, 29, 5087 A1 Ncirabeyeh Pujol Tetrahedron Lett. 1990, 31. 2273. For other methods, see Sundararaman Walker Djerassi Tetrahedron Lett. 1978, 1627 Grigg Mitchell Sulthivaiyakit Tetrahedron 1981, 37, 4313 Massoui Beaupdre Nadjo Uzan J. Organornet. Chem. 1983, 259, 345 O Connor Just Tetrahedron Lett. 1987, 28, 3235 McDonald Holcomb Kennedy Kirkpatrick Leathers Vanemon J. Org. Chem. 1989, 54, 1212. For a list of reagents, with references, see Ref. 21, pp. 840-841. 

Schuhknecht (SI) produced a greatly simplified instrument by substituting a filter for the monochromator used by Lundegardh, and this type of apparatus is probably the most widely used today. But for the outbreak of war in 1939 this simple method would certainly have been rapidly adopted by clinical chemists, but it was not until the work of Barnes and associates (Bl) and Domingo and Klyne (D2) after earlier work by Ells and Marshall (E2), Ells (El), Griggs et al. (G2), and Cholak and Hubbard (C2) that the method became widely adopted. 

Cox and Kamprath (1972) reviewed several other methods for testing soils. They cited several researchers who had investigated the method of water-extractable Mo in soil. Water-extractable Mo was found to be proportional to plant Mo concentration, but only within a certain pH range (4.7-7.5). A method for hot-water-extractable Mo was found to be better correlated with plant-tissue Mo concentration than was the traditional method of oxalate-extractable Mo (Grigg s method). Other researchers have used neutral 1-N ammonium acetate, 0.1-N NaOH, 0.03-N NH4F, and 0.1-N HCl + 0.03-N NH4F, with mixed results. A good soil-test method to adequately predict crop yields still eludes us today. 

Griggs, F.E., ed. (1991). Randolph. A biographical dictionary of American civil engineers 2 93. Randolph, I. (1895). Modem methods of canal excavation. Engng. Record 33(Oct. 12) 348-360. Randolph, I. (1895). The Chicago Sanitary District. Journal of the Association of Engineering Societies Boston 14(3), 1-9. 

In 1939 Griggs " and Ells and MarshalE introduced Lundegardh s method into the United States. In 1945 Barnes et al reported on a simple filter photometer for alkali metal determinations. The Perkin-Elmer Corporation apparently was the first American corporation to market such an instrument, which was similar to that developed by Barnes. In 1948 Beckman Instruments, Inc. made a flame excitation attachment available for their spectrophotometer. 

Following on from the pioneering works of Grigg, Watanabe, and Tsuji, there has been an intense period of research focused on the a-methylation of arylnitriles using methanol with a transfer hydrogenation method [150-162]. 

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