Abstract: The invention relates to methods of reducing Schiff bases and making chelator conjugates by treating with borane-pyridine complex.

Abstract: A device for screening unwanted telephone calls is connectable at a station etween a telephone set and a wall outlet plug. In response to ringing current received at the station and signaling an incoming call, the device delays audible ringing at the station for a 2.5 second period. During such period, the call's sender transmits to the station a # dial signal only if the call is in a special category as, say one undertaken to try to make a sale. If such # signal is received during such period, the device transmits back to the sender a return signal acknowledging that the call has been received and rejected at the station, and the device then hangs up call at the station without any audible ringing taking place there. If no such # signal is so received, audible ringing occurs at the line upon expiration of such period, and the call continues in its normal sequence.