Reaction Route and Mechanism of the Direct N-Alkylation of Sulfonamides on Acidic Mesoporous Zeolite β-Catalyst

Abstract

Development of highly active heterogeneous catalysts with strong acidity and mesoporous structure is a highly attractive strategy for organic synthesis. In this study, a mesoporous zeolite beta (HBeta-M) with bulky particle size and strong acidity was synthesized and used in the direct N-alkylation of sulfonamides with alcohols. The strongly acidic HBeta-M had a higher intrinsic activity with initial turnover frequency of 11 × 10–2 s–1 than those of H-form mordenite nanosheets (3.3 × 10–2 s–1) and montmorillonite (4.0 × 10–2 s–1) catalysts. The experiment and characterization results demonstrate that there are two parallel reaction routes on the acidic catalysts. One route is the reaction of benzhydrol with p-toluenesulfonamide (route I). Another route is the reaction of dibenzhydryl ether, arising from route I, with p-toluenesulfonamide (route II), which is found in this work. The reaction rate of route I (13 × 10–3 mol kg–1 s–1) was higher than that of route II (9.8 × 10–3 mol kg–1 s–1) on HBeta-M, but route II predominantly contributed to the formation of the target product with high selectivity. Hereby, a complete reaction mechanism is proposed in this work.

Highly Efficient and Selective N-Alkylation of Amines with Alcohols Catalyzed by in Situ Rehydrated Titanium Hydroxide

“…The product yield for the ammonolysis reaction dramatically decreased from 86 % to nearly 0 as the pretreatment temperature increased from 180 to 400 o C (inset of Figure 9b). It indicates that the ammonolysis of dibenzyl ether requires acid sites as well, which is consistent with the previous report [65]. However, the reaction is less sensitive to amount of acid sites in comparison with dehydration of alcohol to ether.…”

Boron-Catalyzed N-Alkylation of Arylamines and Arylamides with Benzylic Alcohols

“…In particular, N -alkyl sulfonamides, a subclass of amide, are commonly employed as the cannabinoid receptor 2 inverse agonist, inhibitors of Mycobacterium tuberculosis, and secreted frizzled-related protein-1 (sFRP-1) inhibitors (Figure b) . Due to the several limitations of the classical approaches for the synthesis of N -alkyl sulfonamides, the widely accepted methodologies involve borrowing hydrogen catalysis in the presence of transition-metal- and Lewis- or Brønsted-acid-catalyzed direct substitution of alcohol by nitrogen nucleophiles. Despite the development of these remarkable atom-economical processes, often their green credentials are somehow limited due to the use of (i) toxic noble metals, (ii) capricious ligands and bases, (iii) high reaction temperature, (iv) excess amines or alcohols, and (v) highly reactive and nonrenewable feedstock.…”

Acidic mesoporous Beta zeolite assembled Fe catalyst with good catalytic performance in the carboazidation of N‐arylacrylamides

“…These catalysts show high activity and selectivity in the seleno-functionalization of alkenes, decarboxylative coupling of cinnamic acids with alcohols, and N-alkylation of sulfonamides and knoevenagel reaction. [21][22][23][24] As a continuous work to develop highly efficient heterogeneous catalyst applied in organic reactions, in this work, acidic mesoporous Beta zeolite (Beta-M) assembled Fe catalyst was prepared and applied in the carboazidation of N-arylacrylamides with azide trimethylsilane (TMSN 3 ). The obtained catalyst showed higher activity and good product selectivity than the homogeneous FeCl 3 catalyst, acid mesoporous ZSM-5 (ZSM-5-M) supported Fe catalysts.…”