The reaction of an aromatic heterocycle with a proton is called a protonation. One of articles about this theory is 《Silylated Sulfuric Acid: Preparation of a Tris(trimethylsilyl)oxosulfonium [(Me3Si-O)3SO]+ Salt》. Authors are Blasing, Kevin; Labbow, Rene; Schulz, Axel; Villinger, Alexander.The article about the compound:Trimethylphosphineoxidecas:676-96-0,SMILESS:CP(C)(C)=O).COA of Formula: C3H9OP. Through the article, more information about this compound (cas:676-96-0) is conveyed.
The chem. of silylated sulfuric acid, O2S(OSiMe3)2 (T2SO4, T=Me3Si; also known as bis(trimethylsilyl) sulfate), has been studied in detail with the aim of synthesizing the formal autosilylation products of silylated sulfuric acid, [T3SO4]+ and [TSO4]-, in analogy to the known protonated species, [H3SO4]+ and [HSO4]-. The synthesis of the [TSO4]- ion only succeeds when a base, such as OPMe3 that forms a weakly coordinating cation upon silylation, is reacted with T2SO4, resulting in the formation of [Me3POT]+[TSO4]-. [T3SO4]+ salts could be isolated starting from T2SO4 in the reaction with [T-H-T]+[B(C6F5)4]- or T+[CHB11Br6H5]- when a weakly coordinating anion is used as counterion. All silylated compounds could be crystallized and structurally characterized.
The article 《Silylated Sulfuric Acid: Preparation of a Tris(trimethylsilyl)oxosulfonium [(Me3Si-O)3SO]+ Salt》 also mentions many details about this compound(676-96-0)COA of Formula: C3H9OP, you can pay attention to it, because details determine success or failure
Reference:
Isoxazole – Wikipedia,
Isoxazole | C3H3NO – PubChem