In the chemical reaction process, reaction time, type of solvent, can easily affect the result of the reaction, thereby determining the yield and properties of the reaction product. An updated downstream synthesis route of 3975-77-7 as follows. Recommanded Product: 3975-77-7
General. 1H NMR studies revealed that?supermesityl bromide? (mes*Br, S1)S7 and n-BuLi coexist in t-BuOMeover more than 18 h at room temperature, while this solvent is very slowlydeprotonated by n-BuLi with formation of isobutene. Similarly, t-BuLideprotonates t-BuOMe, leaving S1intact.When prepared from S1 withn-BuLi, mes*Li (S2)is not stable in a THF solution at ambient temperature. However, its stabilityis greatly enhanced on dilution of the THF with pentane. Moreover, a portion ofS2 will crystallize from pentane/THF(4:1)S8 and may be washedwith dry petroleum ether if pure mes*Li is required.In Et2O atroom temperature, the formation of mes*Li(S2) from S1and n-BuLiwas complete within 10 min; therefore,the traditional long reaction periods of this Br/Li interchange reaction in thesolvent Et2O can be considerably shortened, and the presence of apromoter (such as TMEDA) is unnecessary.This Et2O solution containing S2 and 1-bromobutane was stable for several hours at ambienttemperature and for at least 18 hours under argon gas in a refrigerator. Although S2in Et2O was protonated very slowly by N,N-diisopropylamine atroom temperature, proton transfer fromcyclohexylamine (pKa =41.6) to S2 was fast andquantitative. Procedure. A dry NMR tube (5 mm) was charged with mes*BrS7 (S1,80 mg, 0.24 mmol), pentane (0.40 mL), and anhydrous THF (0.10 mL), then cooled to -70 C during the addition of n-BuLi (0.37 mmol) in hexanes (0.14 mL)and for further 60 min. The colorless precipitate of S2 was washed with pentane (2 ) and then dissolved in anhydrous Et2O(0.50 mL), showing dH = 7.01 ppm for 3-/5-H of S2. The addition of cyclohexylamine (0.027 mL, 0.24 mmol) at -70 C converted S2 completely into 1,3,5-tri-tert-butylbenzene(dH = 7.31 ppm), which was isolated afterquenching with solid CO2 andaqueous workup (no acid S3) as apure, colorless powder (35 mg, 58%). This indicates that pKa> 41.6 for S2. A similar run with N,N-diisopropylamine(ca. 2 equiv, pKa = 34.4)in place of cyclohexylamine disclosed a very slow proton transfer at room temperature (ca. 30% in 10 min).
According to the analysis of related databases, 3975-77-7, the application of this compound in the production field has become more and more popular.
Reference:
Article; Knorr, Rudolf; Rossmann, Eva C.; Knittl, Monika; Boehrer, Petra; Tetrahedron; vol. 70; 34; (2014); p. 5332 – 5338;,
Bromide – Wikipedia,
bromide – Wiktionary