Staudinger reduction Subject

Ultrasonic waves also bring about a reduction in the viscosity of nitrocellulose. The effect is more marked the higher the initial viscosity, and thus the longer the nitrocellulose chains (Sollner [93] Schmidt and Rommel [94]). For instance, nitrocellulose with a molecular weight of 123,000, estimated by means of Staudinger s viscosity equation, subjected in solution form to the action of ultrasonic waves suffered a degradation to a molecular weight of 70,000-80,000. 

Treatment of enecarbamate 344 with sodium azide and ceric ammonium nitrate (CAN) in acetone furnished azidocarbazole 345. The low yield in this oxidative cychzation reaction is due to formation of the diastereomer consisting of stereochemical inversion at the azide-substituted carbon. At this point, azide reduction employing the Staudinger conditions of triphenyl-phosphine in a mixture of water and THF led to an amine, which was subjected to trichloroacetyl chloride in a solution of dichloromethane and triethylamine to yield amide 346 (Scheme 49). 

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