Insertion of Sulfur Trioxide into the N-Si bond of Anilinotrimethylsilane. An Improved Method for the Preparation of Free Phenylamidosulfuric Acid

Article abstract of DOI:10.1246/bcsj.59.2517

The reaction between anilinotrimethylsilane (1) and a variety of sulfonating agents has been studied.With SO3, 5, or a dioxane-sulfur trioxide complex a sulfur trioxide molecule was inserted selectively into the N-Si bond of 1 to yield trimethylsilyl phenylamidosulfate (2), which on treatment with acetic acid, trifluoroacetic acid, or methanol gave free phenylamidosulfuric acid (3).The reaction of 1 with ClSO3H afforded 3 directly, but the product was contaminated with slight amounts of anilinium hydrogensulfate and anilinium chloride.The reaction of 1 with 10 yielded a mixture containing dianilinium (4-sulfonatophenylamido)sulfate, 4-aminobenzenesulfonic acid, and ethyl phenylamidosulfate as major products (after desilylation).The reaction of 1 with 5 has been found to provide an improved method for preparing 3.