BioHio-2 reacts with aqueous hydroxylamine-O-sulfonic acid to give 2-BioHgNHa-(I) and 2,4-, 2,3-, and 2,7(8)-Bi0H8(NH3)2 (II). Under similar conditions B12Hi2-2 gives Bi2HuNH3-(III) and 1,2-, 1,7-, and 1,12-B12H,o(NH3)2 (IV). The high basicity of amino derivatives of BioHio-2 and Bi2Hi2-2 is reflected in their ready formation of conjugate acid, even under alkaline conditions. Amination of l-BioHgS(CH3)2-and Bi2HnN-(CH3)3gives, respectively, 1,6-(CH3)2SBi0H3NH3 and (CH3)3NBi2Hi0NH3 (predominantly 1,7-isomer). Methylation of I with dimethyl sulfate in alkaline solution can be controlled to give either 2-BioH3NH(CH3)2or 2-BioH3N(CH3)3-. Methylation of II giyes 2,4-, 2,3-, and 2,7(8)-Bi0Hs[N(CH3)3]2. Predominant equatorial amination of BioHio-2 is demonstrated with the aid of B* 11 magnetic resonance spectroscopy.
When the proportion was increased to 6, the yield was 20%. Generation of the somewhat unstable sulfinic acid in situ from three proportions of the salt with equivalent concentrated HC1, with reaction at 60 °C, gave 22 in 35% yield.(b) Preparation of 23 from 22. Solutions were prepared by adding 0.90 mL of 1 N NaOH (0.9 mmol), and then 5 mL of EtOH, to 0.31 g (0.90 mmol) of 22 and also to 0.11 g (0.89 mmol) of -toluenethiol (19). The solution of the resulting thiolate of 19 then was added to that (cloudy) of 22. The solution, which then became clear, was stirred at ~25 °C for 2 h more and then was acidified with 10% aqueous HC1 to pH 1. When the cloudy solution was kept at ~0 °C for 2 h, 0.12 g of the disulfide 23 precipitated: yield 43%; mp 152-153 °C. The melting point, mixture melting point, TLC, IR spectrum, and NMR spectrum were identical with those of 23 prepared from 18. disulfide after ~12 h and no apparent further change in these three spots after ~15 h.
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