Nitrogen transfer reactions with sodium

Figure 11. Nitrogen transfer reactions with sodium aziridinylborohydrides.

Bennett and Thomas (1964) have developed a useful technique for studying the reactions of sodium atoms with organic halides. Beams of sodium vapour and the organic reactant are directed onto opposite sides of the exterior surface of a rapidly rotating stainless steel drum which contains liquid nitrogen. Each reactant condenses on a freshly formed surface of the other, and radicals which may result from this interaction are embedded and preserved in a matrix a sample of the deposit is then transferred to the cavity of the spectrometer. In this way, for example, the spectra of alkyl and aryl radicals have been obtained (Bennett and Thomas, 1964 Bennett, Mile and Thomas, 1965) ... 

Store the solutions at 0-5°C. Warm 1 mLof each solution to about 25°C over 15 min and use 50 pL of each solution (corresponding to about 25 nanokatals) for each titration. Carry out the titration in an atmosphere of nitrogen. Transfer 10.0 mL of 0.01 M calcium chloride solution R to the reaction vessel and, while stirring, add 0.35 mL of 0.2 M acetyltyrosine ethyl ester solution R. When the temperature is steady at 25.0 0.1 °C (after about 5 min) adjust the pH to exactly 8.0 with 0.02 N sodium hydroxide. Add 50 pL of the test solution (equivalent to about 5 ig of the substance to be examined) and start a timer. Maintain pH at 8.0 by the addition of 0.02 N sodium hydroxide, noting the volume added every 30 s. Calculate the volume of 0.02 N sodium hydroxide used per second between 30 and 210 s. Carry out a titration in the same manner using the reference solution and calculate the volume of 0.02 N sodium hydroxide used per second. 

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