Stibonium compounds, quaternary

Quaternary Arsonium and Stibonium Compounds. More recently, experimental work in this laboratory has revealed that quaternairy arsonium compounds (18) are extremely effective as latent accelerators for epoxy-anhydride resius. Surprisingly, it has also been found that quaternary stibonium compounds are very much less effective as accelerators than quaternary arsonium, phosphonium or ammonium compounds. In fact, the order of gelation reactivity of these compounds with epoxy-anhydride resins would appear to be as follows ... 

The quaternary stibonium compounds are formed in reaction (2) and have subsequently to be dealt with according to equation (6). 

The stibonium compounds are the most difficult to prepare and are the least common. These quaternary salts, excepting the hydroxides, which are obtained as sirupy masses, are white crystalline compounds. The tetra-phenyl-phosphonium and -arsonium ions are useful for precipitating large anions such as ReO, CIO and complex anions of metals. Tetraphenyl-stibonium hydroxide has been shown55 to contain tbp molecules, with the OH group in an axial position. 

Crum Brown and Fraser (6) in 1868 attributed curariform activity to the onium ion. Even at that early date, they suggested therapeutic possibilities of synthetic quaternary salts which could be prepared of constant purity and effectiveness. Boehm (7, 8) first showed that the active alkaloids of curare preparations are quaternary ammonium compounds. Since these discoveries, a great many quaternary compounds have been investigated, and even the simplest quaternary ammonium salts, as well as sul-fonium, phosphonium, arsonium, and stibonium salts, exhibit curare activity (9). Quaternary ammonium compounds widely varied in character have been found to exhibit curare activity. Hunt and Renshaw and collaborators (10, 11) have published a series of papers on onium compounds and their effects on the autonomic nervous system. In addition to curare action, they were shown to exhibit muscarinic and nicotinic actions in varying degrees. 

Preparative oxidation of EtjAs and PhjAs or PhjSb in the presence of aromatic or heteroaromatic compounds leads to formation of quaternary arsonium or stibonium salts . The oxidations were carried out in nominally dry MeCN in the presence of an excess of the aromatic compound which, in the case of the arsines, were naphthalene, thiophene, pyridine and furan , and in the case of Ph3Sb were thiophene and toluene . ... 

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