Sulfonamide Products Research Articles

Asymmetric Radical Addition of Ethers to Enantiopure N-p-Toluenesulfinyl Aldimines, Mediated by Dimethylzinc−Air

Asymmetric radical addition of ethers to enantiopure aromatic N-p-toluenesulfinyl aldimines has been achieved. The requisite radicals were generated by dimethylzinc-air. Lewis acid activation of the N-p-toluenesulfinyl aldimines followed by radical addition gives a mixture of sulfinamide and sulfonamide products. Subsequent treatment of the mixture with dry m-CPBA affords the sulfonamide product in enantiomerically enriched form. [reaction: see text]

A Convenient Preparation of Heteroaryl Sulfonamides and Sulfonyl Fluorides from Heteroaryl Thiols

Heteroaromatic thiols may be oxidized to the sulfonyl chloride at low temperature (-25 degrees C) by using 3.3 equiv of aqueous sodium hypochlorite. The reaction is rapid, avoids the use of chlorine gas, and succeeds with substrates that have previously been found to afford little or none of the sulfonamide product with other procedures. The method allows the preparation of the sulfonyl fluorides, which are stable enough to be purified and stored, making them potentially useful monomers in parallel chemistry efforts.

Synthesis of Functionalised Sulfonamides via Microwave Assisted Displacement of PFP‐Sulfonates with Amines

AbstractA convenient microwave assisted synthesis of sulfonamides from PFP‐sulfonates is described. Reaction of various commercially available amines with pentafluorophenyl (PFP) sulfonate esters under microwave irradiation led to the corresponding sulfonamide products in good yields and without the requirement for chromatographic purification. The data shows that a number of functional groups are tolerated in both the amine and sulfonate ester and that the method can be extended to heterocyclic sulfonamides of potential biological interest.

Expedient synthesis of secondary amines bound to indole resin and cleavage of resin-bound urea, amide and sulfonamide under mild conditions

Highly efficient, new protocols for the attachment of primary amines to indole aldehyde resin using Ti(O i Pr) 4–NaBH 4 and CH(OMe) 3–NaBH 3CN–HOAc are reported. Mild cleavage conditions for the release of urea, amide and sulfonamide products from the solid support using 1% trifluoroacetic acid (TFA) are developed.

Synthesis of functionalized sulfonamides via 1,3-dipolar cycloaddition of pentafluorophenyl vinylsulfonate.

[reaction: see text] An efficient intermolecular 1,3-dipolar cycloaddition of a variety of nitrones to pentafluorophenyl (PFP) vinylsulfonate is described. The transformation produces stable "reversed" cycloadducts of unprecedented stereo- and regioselectivity. Subsequent amine displacement of the PFP moiety furnished functionalized sulfonamide products in good yields.

Selective ortho and benzylic functionalization of secondary and tertiary p-tolylsulfonamides. Ipso-bromo desilylation and Suzuki cross-coupling reactions.

Kinetic vs thermodynamic deprotonation studies on secondary and tertiary sulfonamides 1 and 2 using n-BuLi have been carried out. While both 1 and 2 show kinetic ortho-metalation, thermodynamic conditions lead to ortho and benzylic deprotonation, respectively (Figures 1 and 2). Metalation of 1 using the n-BuLi/KOtBu superbase led to regioselective benzylic metalation (Figure 4); LDA deprotonation was also briefly explored. Application of the developed conditions allows the synthesis of diverse sulfonamide products 5a-e, 6a-e, 7a,b, and 8a-e. Ipso-bromo desilylation reactions afford sulfonamides 9a,b while Suzuki cross-coupling reactions furnish biaryl sulfonamides 11a-c.

Kinetics and mechanism of hydrolysis of N-amidomethylsulfonamides

The kinetics of the hydrolyses of secondary and tertiary N-amidomethylsulfonamides were studied at 50 °C. Both types of N-amidomethylsulfonamide hydrolyse through acid- and base-catalysed processes, as indicated by the pH–rate profiles. The order of reactivity for the acid-catalysed pathway implies a mechanism involving protonation of the amide followed by expulsion of a neutral amide and formation of a sulfonyliminium ion. In the base-catalysed region, compound 5c, which is substituted at both amide and sulfonamide nitrogen atoms, hydrolyses by nucleophilic attack of hydroxide ion at the amide carbonyl carbon atom to form benzoic acid and a sulfonamide. In contrast, compound 5b, which contains a sulfonamide NH group, hydrolyses to benzamide and sulfonamide products by an E1cbrev mechanism involving ionisation of the sulfonamide. Compound 5a, which contains an amide NH, also hydrolyses to sulfonamide and amide products, probably by an E2 mechanism.

Mineral oil deterioration : C. Balsbaugh, A. G. Assaf, and W. W. Pendleton. ( Industrial and Engineering Chemistry, Vol. 33, No. 10)

The synthesis, characterization, surface activity and applications of nonionic surfactants derived from the asphalt components (maltenes M) are presented. These compounds were synthesized by the sulfonation of (maltene), then the prepared maltene sulfonic acid (MS) was reacted with hexadecylamine giving maltene sulfonamide product (A) which undergoes an alkali-catalyzed ethoxylation at (135–150 °C). Several surfactants (M-10 to M-40) were formed with different ethylene oxide units (from 10 up to 40) and were characterized by molecular weight determinations, elemental analyses and FTIR analysis. Surface tension, as a function of concentration of the surfactants in the aqueous media, was measured at 25 °C. From these measurements, the critical micelle concentration (CMC), the maximum surface excess concentration (Гmax), Minimum area per molecule (Amin), effectiveness of surface reduction (ПCMC) and the efficiency (pC20) were calculated. The prepared surfactants were applied as emulsifying agents for making asphalt emulsions. Storage stability, (Saybolt Furol) viscosity, settlement (water content difference %), coating ability and water resistance were measured. The results indicated that M-20 (maltene sulfonamide ethoxylated with 20 units of ethylene oxides) gives a maximum stability.