反应详情

Quinoid-6,6-Me2PH2 is an intermediate in the synthesis of 6,6-Me2PH4 (see above). It can also be prepared quantitatively by bromine oxidation of 6,6-Me2PH4. The properties of q-6,6-Me2PH2 were determined on material made by the latter route. 6,6-Me2PH4 dihydrochloride, 0.1 mmoles, was dissolved in 3 ml methanol, and 22 mg Br2 (0.14 mmoles) was added. Removal of solvent by rotary evaporation left a dark orange film. The sample was repeatedly redissolved in 3 ml fresh methanol and evaporated to dryness for a total of 6 times, until the film was light yellow and no odor of bromine could be detected. Failure to remove the excess bromine resulted in complex absorbance changes that hindered spectral studies of q-6,6-Me2PH2. The quantitative yield was established by reduction back to 6,6-Me2PH4 using 2-mercaptoethanol, which resulting in full recovery of the original material.

1. customRemoval of solvent
2. customby rotary evaporation
3. waitleft a dark orange film
4. dissolutionThe sample was repeatedly redissolved in 3 ml fresh methanol
5. customevaporated to dryness for a total of 6 times, until the film
6. customFailure to remove the excess bromine
7. customresulted in complex absorbance changes that
8. customresulting in full recovery of the original material