Practical Synthesis of Sultams via Sulfonamide Dianion Alkylation: Application to the Synthesis of Chiral Sultams

Convenient Approach to Bicyclic Sultams

A method for the synthesis of aminomethyl-substituted five-membered sultams has been developed. The aminomethyl sultams were synthesized from the corresponding iodomethyl derivatives by nucleophilic substitution of the iodine atom with sodium azide followed by reduction on Pd/C. This method was further expanded to side-chain-substituted sultams, starting from amino acid esters, to obtain aminomethyl-containing bicycles. The simple practical procedure and available starting amino acid esters, including chiral examples, make various bicyclic sultams readily available.

Chemistry of Substituted Thiazinanes and Their Derivatives

Thiazinanes and its isomeric forms represent one of the most important heterocyclic compounds, and their derivatives represented a highly potent drug in disease treatment such as, 1,1-dioxido-1,2-thiazinan-1,6-naphthyridine, which has been shown to have anti-HIV activity by a mechanism that should work as anti-AIDS treatment, while (Z)-methyl 3-(naphthalen-1-ylimino)- 2-thia-4-azaspiro[5 5]undecane-4-carbodithioate showed analgesic activity, cephradine was used as antibiotic and chlormezanone was utilized as anticoagulants. All publications were interested in the chemistry of thiazine (partially or fully unsaturated heterocyclic six-membered ring containing nitrogen and sulfur), but no one was dealing with thiazinane itself which encouraged us to shed new light on these interesting heterocycles. This review was focused on the synthetic approaches of thiazinane derivatives and their chemical reactivity.

Synthesis of 3-Iodomethyl Sultams

A method for the synthesis of iodomethyl-substituted five-membered sultams has been developed. The sultams were synthesized by intramolecular iodoamination of alkenyl sulfamides. The method allows synthesis of N- and C-substituted sultams. NH-Sultams were prepared by acidic cleavage of the corresponding tert-butyl sultams that are readily available. Varying the length of alkenyl substituent at sulfamide it was shown that only five- and six-membered sultams could be prepared by this method. Neither four- nor seven-membered sultams were detected. The simple practical procedure and available starting materials make the variously substituted sultams readily available.

Palladium-catalyzed annulation of N-alkoxy benzsulfonamides with arynes by C–H functionalization: access to dibenzosultams

Palladium-catalyzed C–H/N–H functionalization of N-alkoxy benzsulfonamides with arynes provides dibenzosultams via C–C/C–N bond formation, accompanied by an unexpected N–O bond cleavage.

A visible-light photocatalytic N-radical cascade of hydrazones for the synthesis of dihydropyrazole-fused benzosultams

An efficient N-centred radical 5-exo cyclization/addition/aromatization cascade by cooperative visible light photoredox and cobalt catalysis is described, giving dihydropyrazole-fused benzosultams in satisfactory yields.

Discovery of 1-{4-[3-fluoro-4-((3s,6r)-3-methyl-1,1-dioxo-6-phenyl-[1,2]thiazinan-2-ylmethyl)-phenyl]-piperazin-1-yl}-ethanone (GNE-3500): a potent, selective, and orally bioavailable retinoic acid receptor-related orphan receptor C (RORc or RORγ) inverse agonist

Retinoic acid receptor-related orphan receptor C (RORc, RORγ, or NR1F3) is a nuclear receptor that plays a major role in the production of interleukin (IL)-17. Considerable efforts have been directed toward the discovery of selective RORc inverse agonists as potential treatments of inflammatory diseases such as psoriasis and rheumatoid arthritis. Using the previously reported tertiary sulfonamide 1 as a starting point, we engineered structural modifications that significantly improved human and rat metabolic stabilities while maintaining a potent and highly selective RORc inverse agonist profile. The most advanced δ-sultam compound, GNE-3500 (27, 1-{4-[3-fluoro-4-((3S,6R)-3-methyl-1,1-dioxo-6-phenyl-[1,2]thiazinan-2-ylmethyl)-phenyl]-piperazin-1-yl}-ethanone), possessed favorable RORc cellular potency with 75-fold selectivity for RORc over other ROR family members and >200-fold selectivity over 25 additional nuclear receptors in a cell assay panel. The favorable potency, selectivity, in vitro ADME properties, in vivo PK, and dose-dependent inhibition of IL-17 in a PK/PD model support the evaluation of 27 in preclinical studies.

Palladium-catalyzed α-arylation of sultams with aryl and heteroaryl iodides

Palladium(0)-catalyzed conditions for the α-arylation of sultams with aryl and heteroaryl iodides have been developed. Arylation of 3-substituted 1,3-propanesultams gave rise to high yields and high diastereomeric ratios, leading to the thermodynamically favored cis product. The arylation was broadly applicable to various electron-rich and electron-poor (hetero)aromatic iodides.

Parallel syntheses of eight-membered ring sultams via two cascade reactions in water

From vinyl sulfonamides as precursors to vinyl sulfonamide epoxides, two cascade reaction protocols were developed to synthesize eight-membered ring sultams in water. These protocols employ intermolecular Michael addition by NaOH or NaHS in water, followed by rapid proton transfer and intramolecular 8-endo-tet epoxide ring-opening to give medium-size sultams selectively in one-pot. Novel core structures and high synthetic efficiency make these cascade reactions highly suitable for sultam library production. Both reactions proceeded well and afforded the respective sultams in good yields under environmentally friendly conditions.

One-pot, three-component, domino Heck-aza-Michael approach to libraries of functionalized 1,1-dioxido-1,2-benzisothiazoline-3-acetic acids

A sequential three-component synthesis of functionalized benzisothiazoline-3-acetic acid 1,1-dioxides utilizing a domino Heck-aza-Michael pathway is reported. This one-pot procedure rapidly assembles functionalized benzylsulfonamides, which undergo a palladium-catalyzed, domino, Heck-aza-Michael transformation in an experimentally straightforward manner. This attractive protocol has been utilized to synthesize three combinatorial sublibraries (I-III) comprising a total of 95 compounds in high purities (> or =95% for 75 compounds), yield and quantities.

Domino Heck-Aza-Michael Reactions: A One-Pot, Sequential Three-Component Approach to 1,1-Dioxido-1,2-benzisothiazoline-3-acetic Acid

The development of a new method for the synthesis of 1,1-dioxido-1,2-benzisothiazoline-3-acetic acid by a domino process is reported whereby a classical Heck reaction is coupled to an intramolecular aza-Michael reaction. Ultimately, this method has been expanded to a one-pot, sequential three-component protocol to generate diverse benzofused γ-sultams from a range of commercially available α-bromobenzenesulfonyl chlorides, amines and Michael acceptors.

An RCM strategy to stereodiverse delta-sultam scaffolds

An asymmetric approach for the synthesis of substituted delta-sultams with multiple synthetic handles is described. This study demonstrates the facile construction of a stereochemically diverse array of substituted delta-sultams, more specifically substituted 3,4,5,6-dihydro 1,2-thiazine 1,1-dioxides. A pivotal Mitsunobu alkylation/RCM sequence is used to assemble key allyl sultam building blocks possessing a C3 stereogenic handle. All subsequent reactions are achieved with high levels of diastereoselectivity to afford enantiopure delta-sultams in good yields.

Highly Enantioselective Pd-Catalyzed Asymmetric Hydrogenation of Activated Imines

Pd/bisphosphines complexes are highly effective catalysts for asymmetric hydrogenation of activated imines in trifluoroethanol. The asymmetric hydrogenation of N-diphenylphosphinyl ketimines 3 with Pd(CF3CO2)/(S)-SegPhos indicated 87-99% ee, and N-tosylimines 5 could gave 88-97% ee with Pd(CF3CO2)/(S)-SynPhos as a catalyst. Cyclic N-sulfonylimines 7 and 11 were hydrogenated to afford the useful chiral sultam derivatives in 79-93% ee, which are important organic synthetic intermediates and structural units of agricultural and pharmaceutical agents.

Thermal and high pressure intramolecular Diels–Alder reaction of vinylsulfonamides

Vinylsulfonamides with a furan, carbocyclic, semicyclic or acyclic 1,3-diene moiety are synthetized via a domino elimination-amidation reaction of 2-chloroethanesulfonyl chloride. Intramolecular Diels-Alder reaction of these vinylsulfonamides with thermal (toluene, 110 degrees C) or high pressure (dichloromethane, 13 kbar) activation provides efficient access to a range of gamma- and delta-sultams following a 2-3 d long synthetic procedure. Enantiopure sultams are readily obtained from N-1-phenylethyl substituted vinylsulfonamides.

Synthesis of α-Fluorosulfonamides by Electrophilic Fluorination

Alpha-fluorosulfonamides were prepared by electrophilic fluorination of tertiary sulfonamides using N-fluorobenzenesulfonimide as fluorinating agent and utilizing the dimethoxybenzyl group (DMB) as a new sulfonamide protecting group. Removal of the DMB group with TFA/CH(2)Cl(2) gave primary and secondary alpha-fluorosulfonamides.