Arylsulfonyl Hydrazides Research Articles

Synthesis of N-Acyl-N′-Sulfonyl Hydrazides from Sulfonyl Hydrazides and Activated Amides

AbstractA methodology was developed for synthesizing N-acyl-N'-sulfonyl hydrazides through acyl substitution reactions between activated amides and arylsulfonyl hydrazides. Optimization of the reaction conditions revealed that using Cs₂CO₃ as a base and 1,4-dioxane as a solvent at 25 °C for 12 hours produced the highest yields. Among various amides tested, N-benzoylsuccinimide was found to be the most reactive, with reduced reactivity observed for N-mesityl-, N-tosyl-, and N-Boc-substituted tertiary benzoyl amides. Cross-reactions between a diverse range of N-benzoylsuccinimides and arylsulfonyl hydrazides successfully produced the corresponding N-acyl-N′-sulfonyl hydrazides with yields ranging from 63% to 94%.

Iodine-Promoted Disproportionate Coupling Reaction of Arylsulfonyl Hydrazides: A Simple and Green Access to Thiosulfonates

AbstractAn environmentally friendly iodine-promoted disproportionate coupling reaction of arylsulfonyl hydrazides is reported. This strategy can synthesize thiosulfonates with medium to excellent yields, and features a green system, wide applicability of substrates, and easy availability of raw materials. The preliminary mechanistic study reveals that iodine plays an important role in the radical reaction process.

Electrocatalytic Annulation–Iodosulfonylation of Indole‐Tethered 1,6‐Enynes to Access Pyrrolo[1,2‐a]indoles

AbstractWe present the first example of electrocatalytic three‐component annulation–iodosulfonylation of indole‐tethered 1,6‐enynes with arylsulfonyl hydrazides and KI for accessing various iodosulfonated pyrrolo[1,2‐a]indoles in moderate to excellent yields with high stereospecificity. This electrosynthesis opens new avenues for the construction of pyrrolo[1,2‐a]indoles skeleton with good functional group compatibility under environmentally benign condition. Based on the control experiments and cyclic voltammetry data, we suggested the plausible reaction mechanism which included anodic oxidation, homolysis of arylsulfonyl iodide, arylsulfonyl radical addition, 5‐exo‐dig cyclization, radical coupling or nucleophilic attack of iodide ions cascade.

Neutral nickel-catalyzed dehydrosulfonylation of unactivated allylic alcohols under mild conditions.

Allyl sulfones are important sulfur-containing compounds that have widespread applications in organic synthesis, medicinal chemistry and materials science. Herein, nickel-catalysed dehydrosulfonylation of unactivated allyl alcohols with aryl sulfonyl hydrazides without additional active agents under mild conditions was developed. A variety of functional allyl sulfones could be efficiently synthesized in the presence of air-stable Ni(acac)2 as the catalyst and 1,1'-bis(diphenylphosphino)ferrocene (DPPF) as the ligand.

Rongalite induced metal-free C(sp2)-H functionalization of indoles: direct access to 3-(sulfonylmethyl) indoles.

A rongalite-induced C(sp2)-H functionalization reaction has been developed for the synthesis of 3-(phenylsulfonylmethyl) indole derivatives from indole and arylsulfonyl hydrazides. This regioselective C-H functionalization provides a wide range of C-3 sulfonylmethyl indoles with upto 90% yields. Here, rongalite functions as a C1 unit source and a single electron donor. The use of inexpensive rongalite (ca. $0.03 per 1 g), mild reaction conditions and gram-scale synthesis are some of the key features of this methodology.

Electrochemical synthesis of sulfinic and sulfonic esters from sulfonyl hydrazides.

An electrochemical synthetic method for the synthesis of sulfinic esters and sulfonic esters from sulfonyl hydrazides was developed. Alkyl sulfinic esters were synthesized by treating sulfonyl hydrazides with trialkyl orthoformate in a DMF solvent at a constant current of 5 mA and then optimizing the reaction conditions. Conversely, alkyl sulfonic esters were exclusively obtained when the reaction was conducted in alkyl alcohol solvents at a constant current of 15 mA. The various substituted arylsulfonyl hydrazides afforded moderate to good yields of the desired sulfinic esters and sulfonic esters. Mechanistic investigations revealed that sulfonyl radicals were formed through electrochemical oxidation and that they react with alkyl radicals or alkoxy radicals to generate the respective ester products.

Synthesis of Symmetrical Disulfides by an NIS/PPh3-Mediated Reductive Self-Coupling of Sulfonyl Hydrazides

AbstractThe present study discloses an NIS/PPh3-mediated reductive self-coupling of arylsulfonyl hydrazides to prepare symmetric diaryl disulfides. This methodology has a broad functional-group tolerance and a high scalability. This strategy permits the introduction of sulfonyl hydrazides into the synthesis of symmetrical organic disulfides without the use of a catalyst or base, and symmetrical aromatic disulfides can be prepared in moderate to excellent isolated yields from inexpensive and readily available starting materials.

Dioxygen concentration-dependent selective hydroxysulfonylation of olefins by rose bengal-sensitized photocatalysis.

The synthesis of β-hydroxysulfones selectively in preference to β-ketosulfones by dye-sensitized photocatalysis is demonstrated by employing inexpensive and readily available olefins and sulfonyl hydrazides/N-hydroxy sulfonamides in the presence of oxygen. The facile hydroxysulfonylation reaction, which involves the use of rose bengal (RB) as a photocatalyst and dioxygen as an oxidant, permits access selectively to secondary and tertiary β-hydroxysulfones in good to excellent isolated yields at rt and is compatible with aryl, heteroaryl and alkyl sulfonyl hydrazides. Mechanistically, sulfonyl radicals are generated by a cascade of redox reactions, set off by the photocatalyst RB, between sulfonyl hydrazide and dioxygen. Attack of the sulfonyl radicals on olefins followed by oxygenation of the radical intermediates leads to hydroxysulfonylation products selectively without the requirement of a metal catalyst/additive/reductant/base, conforming to the tenets of sustainable chemistry. It is shown that the formations of β-hydroxysulfones and β-ketosulfones proceed concurrently through two different routes and that the outcome is crucially dependent on oxygen concentration with the former being formed predominantly under an oxygen atmosphere, a feature that is heretofore unprecedented to the best of our knowledge.

Divergent Reaction of Allenoates: Synthesis of Polysubstituted Pyrazoles and N‐Alkylated Hydrazones

AbstractA strategy for the divergent synthesis of polysubstituted pyrazoles and N‐alkylated hydrazone derivatives through three‐component reaction of aromatic aldehydes, aryl sulfonyl hydrazides, and allenoates under the mild reaction conditions is described. Both products can be obtained by changing the reaction base.magnified image

Synthesis of Thiosulfonates by I2/TBHP‐mediated the Ring‐opening/coupling Reaction of Benzothiazole

AbstractA novel I2/TBHP (tert‐Butyl hydroperoxide)‐mediated the ring‐opening/coupling reaction of benzothiazole with sulfonyl hydrazides is disclosed. Various aryl, heteraryl and alkyl sulfonyl hydrazides are applied for the reaction and the corresponding thiosulfonates are obtained in moderate to good yields. It provides a mild and convenient way for the synthesis of thiosulfonates.

C4-Sulfenylation of 4-iodine-1H-pyrazole-5-amine with arylsulfonyl hydrazide in water

A C4-sulfenylation of 4-iodine-1H-pyrazole-5-amine with arylsulfonyl hydrazide in water was developed. A series of C4-sulfenylated products were obtained in moderate to excellent yields. This protocol features green reaction conditions (metal-free, water as the solvent, in the air), odorless and easily available sulfur reagent, broad substrate scope as well as gram-scale synthesis. Mechanistic studies showed that the in-situ formation of iodine from 4-iodine-1H-pyrazole-5-amine in the presence of aryl sulfonyl hydrazides was the key to the C4-Sulfenylation.

Ligand-Enabled Gold-Catalyzed C(sp2)-S Cross-Coupling Reactions.

Herein we report C(sp2)-S cross-coupling reactions of aryl iodides and arylsulfonyl hydrazides under ligand-enabled, Au(I)/Au(III) redox catalysis. This strategy operates under mild reaction conditions, requires no prefunctionalized aryl coupling partner, and works across several aryl iodides. The utility of this protocol is highlighted through the synthesis of various medicinally relevant biaryl sulfones. The reaction mechanism is supported with control experiments, mass spectrometry, and NMR studies.

Synthesis of Isoquinoline-1,3(2H,4H)-diones by Visible-Light-Mediated Cyclization of Acryloylbenzamides with Alkylboronic Acids, Arylsulfonyl Hydrazides and Oxime Esters

AbstractAn efficient visible-light-mediated tandem reaction of acryl­oylbenzamides with alkylboronic acids, arylsulfonyl hydrazides and oxime esters has been developed. The reaction proceeds via radical addition and cyclization to give various isoquinoline-1,3(2H,4H)-diones in satisfactory yields under mild conditions, which provides a good opportunity to discover new meaningful bioactive compounds.

An approach for the synthesis of 2-aryl-3-sulfonyl substituted quinolines through an electrochemical cascade annulation pathway

An electrochemical protocol for the synthesis of 2,3-disubstituted quinolines by reacting benzoxazinones with arylsulfonyl hydrazides was established under simple and mild conditions (room temperature and an undivided cell).

Palladium-catalyzed sulfonylative coupling of benzyl(allyl) carbonates with arylsulfonyl hydrazides

An efficient palladium-catalyzed sulfonylative coupling for the synthesis of benzyl(allyl) sulfones from sulfonyl hydrazides and carbonates was developed. The novel methodology employs easily accessible chemical feedstocks including stable and readily available arylsulfonyl hydrazides and benzyl(allyl) carbonates. A variety of benzyl(allyl) sulfones could be obtained in good to excellent yields in the presence of Pd(dppf)Cl2 without additional base under mild conditions.

Tetrabutylammonium Iodide Mediated Sulfenylation of Poly­substituted 1H-Pyrazol-5-amines with Arylsulfonyl Hydrazides

AbstractA TBAI-mediated sulfenylation of N,3-diaryl-1-arylsulfonyl-1H-pyrazol-5-amines with arylsulfonyl hydrazides has been established, and an expanded inventory of N,5-diaryl-4-(arylthio)-1H-pyrazol-3-amines was constructed through C–S bond formation and N–S bond breaking. Mechanistic investigations suggest thiosulfonate as a key intermediate in the sulfenylation, and the detosylation is promoted by the generated arylsulfinic acid. The method is characterized by simple operating conditions, broad substrate range as well as gram-scale reaction.

TBAI-catalyzed ring-opening sulfonylations of benzothiazoles and arylsulfonyl hydrazides

An efficient TBAI-catalyzed ring-opening sulfonylation of benzo[d]thiazole and arylsulfonyl hydrazide has been developed. Various benzo[d]thiazole as good thiol surrogates are compatible with the catalytic conditions, providing diversified unsymmetrical thiosulfonates with good yields. This strategy features mild reaction conditions, broad substrate scope, readily available starting materials, and gram-scale synthesis. Importantly, these products can be readily converted to novel o-amino-substituted diaryl sulfides.

Transition Metal‐Free Synthesis of Sulfonyl‐ and Bromo‐Substituted Indolo[2,1‐α]isoquinoline Derivatives through Electrochemical Radical Cascade Cyclization

AbstractA tunable electrosynthesis of sulfonyl‐ and bromo‐substituted indolo[2,1‐α]isoquinoline derivatives has been disclosed. In this reaction, a variety of easily available 2‐aryl‐N‐acryloyl indoles can readily react with sulfonyl and/or bromine radicals, which are generated from arylsulfonyl hydrazides and potassium bromide respectively, to furnish the valuable sulfonyl‐ and bromo‐substituted benzindolo‐fused polycyclic compounds in moderate to good yields. Control experiment indicated that the reaction proceeds via a radical cascade cyclization pathway. This protocol features broad substrate scope and good functional group tolerance under transition metal‐free and oxidant‐free conditions.magnified image

NIS-promoted three-component reaction of 3-oxo-3-arylpropanenitriles with arylsulfonyl hydrazides.

A new three-component reaction of 3-oxo-3-arylpropanenitriles with arylsulfonyl hydrazides has been established, and an expanded inventory of 3-aryl-4-(arylthio)-1H-pyrazol-5-amines is synthesized by sequential cyclization and sulfenylation reactions under the action of NIS. In addition to the attractive features of multicomponent reactions, the protocol presents broad substrate scope, good functional group tolerance and mild reaction conditions. The utility of this procedure is further established by gram-scale synthesis as well as the diversified transformations of the products to useful compounds.

NaI/TBHP-promoted reaction of indole-2-thiones with arylsulfonyl hydrazides: construction of achiral axial 3,3′-biindole-2,2′-dibenzenesulfonothioate derivatives

A new method for the synthesis of achiral axial 3,3′-biindole-2,2′-dibenzenesulfonothioate derivatives from indole-2-thiones with arylsulfonyl hydrazides promoted by NaI/TBHP is disclosed.