Syntheses and reactions of (trimethylsiloxy)benzoyl chlorides

Abstract

The (trimethylsi1oxy)benzoyl chlorides 1 -7 are easily to obtain under mild conditions from silylated hydroxybenzoic acids by means of thionyl chloride. Whereas these acid chlorides are stable at room temperature, they undergo condensation polymerization at temperatures above 100°C. Reactions with various nucleophils, such as thioalcohols, phenols, amines, N,O-bis(sily1ated) amino acids and N-silylated lactams were investigated. With hexamethyldisilazane and thionyl chloride the (trimethylsi1oxy)benzonitriles 21, 22 are accessible, and by means of trimethylsilyl azide the (trimethylsi1oxy)phenyl isocyanates 23 -25 were obtained. Conversion with phenyl carbazate and subsequent silylation lead to the 2-(trirnethylsiloxy)phenyl-l,3,4-oxadiazol-5-ones 27a -c.

Polycondensation of ‘a − bn’ or ‘a2 + + bn’ Monomers ‐ A Comparison

“…The first synthetic method to allow the preparation of hyperbranched homo-and copolymers was reported by Kricheldorf et al [94,95] on the basis of mono-or trimethylsiloxy benzoyl chlorides (46,47,48), Figure 4. [96,97] This approach was later elaborated by other research groups in more detail. [98][99][100] Like Flory's theory of two dimensional (or linear) polycondensations, his so-called cascade theory is based on the assumption that cyclization reactions are totally absent or at least negligible.…”

Acid chloride‐functionalized hyperbranched polyester for facile and quantitative chain‐end modification: One‐pot synthesis and structure characterization

“…The trimethylsiloxy A group reacts with the acid chloride B group only when activated, and this permits the isolation of the AB 2 monomer. Polycondensation reactions of similar (trimethylsiloxy)benzoyl chlorides in the presence of a catalyst at elevated temperatures to form linear and hyperbranched polyesters were demonstrated by Kricheldorf and coworkers,25–27 Fréchet and coworkers,6, 28, 29 and others 30, 31…”

Macrocycles 14. Polycondensations of Aspirin and Other Monomers of Salicylic Acid

“…Ortho-and meta-trimethylsiloxy benzoyl chloride were prepared as described previously. [7] Silylation of Acetyl Salicylic Acid Aspirin (0.5 mol) and chlorotrimethylsilane (0.52 mol) were heated in dry toluene (1 L) and triethylamine (0.52 mol) was added dropwise with stirring. The reaction mixture was refluxed for 2 h, cooled (finally with ice) filtered under exclusion of moisture and concentrated in vacuo.…”