Stephen E. Johnson

Management of the Urethra in Patients Undergoing Radical Cystectomy for Bladder Carcinoma

Computerized data on 174 male patients who underwent radical cystectomy for bladder carcinoma were studied in relationship to the incidence of urethral involvement. Simultaneous or delayed urethrectomies were done on 32 patients, 7 of whom had overt urethral carcinoma (4 per cent of the total number of male patients) and 10 of whom had carcinoma in situ (5.7 per cent of the total number of male patients). The low incidence of these 2 phenomena leads us to the conclusion that routine urethrectomy need not be done on patients undergoing radical cystectomy unless overt urethral carcinoma or positive margins are found at cystectomy. We believe that the use of urethral cytologies is crucial to the routine followup of patients who have undergone radical cystectomy for bladder cancer and should be combined with clinical followup to establish the indication for urethrectomy.

Carbon monoxide substitution of anionic and neutral (η5-dicarbollyl)Rh(CO)2 with phosphines and phosphites: a kinetic and mechanistic study of ring slippage as compared to (η5-C5H5)Rh(CO)2☆

Abstract Anionic rhodacarborane isomers of the type [closo-3,3-(CO)2-3,1,2-Rh(η5-C2B9H11)]− (1), [closo-3,3-(CO)2-3,1,7-Rh(η5-C2B9H11)]− (2), and the charge-compensated derivative closo-3,3-(CO)2-4-(C5H5N)-3,1,2-Rh(η5-C2B9H10) (3) are described. Their CO substitution reactions with phosphorus ligands were found to follow a second-order rate law. The relative rates for the reactions decrease in the order 3 ⪢ 1 > 2 , with activation parameters of ΔH# = 10.2, 11.6, 16.5 kcal mol−1 and ΔS# = −31, −36, −26 cal mol−1 K−1, respectively. These reactions are believed to occur by associative pathways similar to the η5→η3→η5 ring-slippage mechanism proposed for CO substitution of (η5-C5H5)Rh(CO)2 with the relative rates of reaction decreasing in the order 3 >(η 5 - C 5 H 5 ) Rh ( CO ) 2 > 1 . Detailed kinetic data are presented and mechanisms of reaction are discussed.

Rings Compounds of Boron and Phosphorus

Abstract The synthesis and characterization of some ring systems of phosphorus and boron are described. Ring systems of boron such as boroxines, silylboranes, and diborabenzenes are considered. The structural and spectroscopic data for the ring derivatives support varying degrees of electron delocalization, depending on the size of the ring. Ring systems of phosphorus such as phosphenium ions and diphosphorus cations are outlined. The importance of P-C π-bonding interactions and the heterocyclic frameworks in the stabilization of these compounds are highlighted. Finally, new heterocyclic organoboranes are reported, which result from reductions of RBX2 and with alkalai metals. All the rings and their respective derivatives have been characterized spectroscopically and the solid-state structures of some representative members were determined by X-ray crystallography. The degree of delocalization in the pertinent ring complexes are compared with theoretical models.