Adams modification

Zinc cyanide. Solutions of the reactants are prepared by dis solving 100 g. of technical sodium cyanide (97-98 per cent. NaCN) in 125 ml. of water and 150 g. of anhydrous zinc chloride in the minimum volume of 50 per cent, alcohol (1). The sodium cyanide solution is added rapidly, with agitation, to the zinc chloride solution. The precipitated zinc cyanide is filtered off at the pump, drained well, washed with alcohol and then with ether. It is dried in a desiccator or in an air bath at 50°, and preserved in a tightly stoppered bottle. The yield is almost quantitative and the zinc cyanide has a purity of 95-98 per cent. (2). It has been stated that highly purified zinc cyanide does not react in the Adams modification of the Gattermann reaction (compare Section IV,12l). The product, prepared by the above method is, however, highly satisfactory. Commercial zinc cyanide may also be used. 

This reaction, applicable only to the preparation of hydroxy-aldehydee, is alternative to the Gattermann aldehyde reaction (or the Adams modification of it) given under 4. The yields are usually smaller, but a large quantity of the phenol may be recovered. The following mechanism is consistent with the known facts ... 

Adams modification of, 690, 701,702 Gattermann reaction, 593, 606 Gattermann-Koch, reaction 689, 697, 698... 

The yield is almost quantitative and the zinc cyanide has a purity of 95-98 per cent. It has been stated that highly purified zinc cyanide does not react in the Adams modification of the Gattermann reaction (compare Expt 6.113). The product, prepared by the above method, is, however, highly satisfactory. Commercial zinc cyanide may also be used. 

Certain aromatic analogues of natural amino acids can be used as potential fluorescent probes of peptide structure and dynamics in complex environments. The research team of M.L. McLaughlin undertook the gram scale synthesis of racemic 1- and 2-naphthol analogues of tyrosine. The synthesis of the 1-naphthol tyrosine analogue started with the Gattermann formylation of 1-naphthol using the Adams modification to afford the formylated product 4-hydroxy-1-naphthaldehyde in 67% yield. 

Fuson and his co-workers592 further improved the Adams modification they raised the reaction temperature to 70°, using tetrachloroethane as solvent, and thus obtained particularly good yields from aromatic compounds. 

For preparative purposes the Gattermann reaction is much more useful. It was first usedS5 to prepare ethyl 2-formyl-3,5-dimethyl- and ethyl 3-formyl-2,5-dimethyl-pyrrole-4-carboxylate, by means of hydrogen cyanide and hydrogen chloride in ether. Later applications sometimes involved minor changes such as the use of chloroform as solvent, or of Adams modification of the reaction . Formylation generally occurs at an a-position, but if none is open there is usually no difficulty in jS-substitution. Pyrrole-2-aldehyde cannot be made this way, for it reacts further to form dyestuffs, but several 1-alkylpyrroles have been satisfactorily formylated . The initial... 

Color Difference Assessment. Color difference scales include those of Judd-Hunter, Macadam, Adams-Nickerson, ANLAB, and ANLAB40. AH of these have limitations in some way or another they are described in most texts (1 4). Each appHes only to the precise conditions used in thek determination and interconversion is not possible. Modifications of CIELAB in the metric form such as the CMC(1 c) system (14) promise improved performance for the future. 

Lianos (1979) provides an accessible insight into how the multiplier can be located in the reproduction schema. By focusing specifically upon Department 1 he states, it is convenient to assume a one sector economy (ibid. 407). Only information from Department 1 of the example used by Marx (Table 2.2) is included in the Lianos reproduction schema, as shown in Table 2.3. The key modification which enables a translation to Keynesian economic categories is to interpret all value added, variable capital plus surplus value, as net income (T,) for Department 1. Assuming away for the moment the problems associated with Adam Smith s dogma, this income is net of constant capital. The net income of the one-good economy is 2,000, consisting of 1,000 units of variable capital and 1,000 units of surplus value. 

McGregor, A., Murray, J.B., Adams, C.J., Stoddey, P.G. and Connolly, B. A. (1999) Secondary structure mapping of an RNA ligand that has high affinity for tire MeLT repressor protein and interference modification analysis of tlie protein-RNA complex, J. Biol. Chem. 274, 2255-2562. 

With some modifications, such a technique has been used to study the time scale of the effects of 02 and sensitizers on cells in aqueous solution (Adams et al. 1968 Whillans 1982 Whillans and Hunt 1982). The rapid lysis technique works on the same principle. It permits cells to be lysed at a given time after a dose of radiation (Johansen and Boye 1975 Johansen et al. 1975 Sapora et al. 1975,1977 Fox et al. 1976 Millar et al. 1980). This allows the study of repair kinetics at early times. 

In Langmuir s original instrument, and Adam s first modification of it, leakage of the film past the ends of the float was prevented by leaving narrow gaps, closed by jets of air. These are effective if carefully adjusted, but disturb the float slightly so that delicate surface-pressure measurements are not possible. 

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