Diboron → 4,7,13,16-Tetraoxa-21,24-dithia-1,10-diazabicyclo[8.8.8]hexacosane

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Reaction Steps

A solution of 1.6 g. of the bicyclic diamide obtained in Example 30 in 30 ml. anhydrous tetrahydrofuran is slowly added to 20 ml. of the fresh prepared diborane solution (1.5 N) under nitrogen atmosphere and a temperature of 0° C. The mixture is stirred two hours at reflux temperature. The excess reagent is destroyed by adding 5 ml. of water and the solution is evaporated on a rotary evaporator under vacuum. This residue is treated with 50 ml. 6 N hydrochloric acid under heating at reflux for two hours and a solution is obtained. The mixture is evaporated under vacuum on a rotary evaporator (water bath 80°-100° C.). The residue is dissolved in 50 ml. water and the solution is passed through a column of an anion exchange resin (Dowex 1, Trade Mark). The column is washed with water until there is no basic reaction. The water is evaporated. The residue is dried in vacuum (0.1 mm. Hg) and recrystallized from a benzene and heptane mixture, yielding the desired compound.

Provenance & Evidence