Synthesis and determination of the absolute stereochemistry of the enantiomers of adrafinil and modafinil

Rhodium-catalyzed enantioselective C-H alkynylation of sulfoxides in diverse patterns: desymmetrization, kinetic resolution, and parallel kinetic resolution

Rhodium-catalyzed enantioselective C-H alkynylation of achiral and racemic sulfoxides is disclosed with alkynyl bromide as the alkynylating reagent. A wide range of chiral sulfoxides have been constructed in good yield and excellent enantioselectivity (up to 99% ee, s-factor up to > 500) via desymmetrization, kinetic resolution, and parallel kinetic resolution under mild reaction conditions. The high enantioselectivity was rendered by the chiral cyclopentadienyl rhodium(iii) catalyst paired with a chiral carboxamide additive. The interactions between the chiral catalyst, the sulfoxide, and the chiral carboxylic amide during the C-H bond cleavage offer the asymmetric induction, which is validated by DFT calculations. The chiral carboxamide functions as a base to promote C-H activation and offers an additional chiral environment during the C-H cleavage.

Synthesis of Chiral Sulfoxides via Pd(II)-Catalyzed Enantioselective C-H Alkynylation/Kinetic Resolution of 2-(Arylsulfinyl)pyridines

A Pd(II)-catalyzed enantioselective C-H alkynylation of 2-(arylsulfinyl)pyridines via kinetic resolution using cheap and commercially available l-pGlu-OH as a chiral ligand is reported. A wide range of 2-(arylsulfinyl)pyridines were compatible with this protocol, giving the alkynylation products and recovered sulfoxides in high yields with high enantioselectivities (up to 99% ee). Furthermore, the enantioenriched products can be easily transformed to several other types of chiral sulfoxide scaffolds with the retention of enantiopurity.

Sulfur stereogenic centers in transition-metal-catalyzed asymmetric C-H functionalization: generation and utilization

Transition-metal-catalyzed enantioselective C–H functionalization has emerged as a powerful tool for the synthesis of enantioenriched compounds in chemical and pharmaceutical industries. Sulfur-based functionalities are ubiquitous in many of the biologically active compounds, medicinal agents, functional materials, chiral auxiliaries and ligands. This perspective highlights recent advances in sulfur functional group enabled transition-metal-catalyzed enantioselective C–H functionalization for the construction of sulfur stereogenic centers, as well as the utilization of chiral sulfoxides to realize stereoselective C–H functionalization.

This perspective highlights sulfur functional groups enabled enantioselective C–H functionalization for the construction of sulfur stereogenic centers, and the utilization of chiral sulfoxide to realize stereoselective C–H functionalization.

Spectroscopic and structural investigations on modafinil by FT-IR, FT-Raman, NMR, UV-Vis and DFT methods

Chiral sulfoxide based smart drug modafinil were studied experimentally and theoretically. Vibrational spectra were recorded in the mid IR region and electronic spectra were recorded in UV-Visible region. The molecular geometry, vibrational spectra, magnetic spectra and electronic spectra were simulated using Density Functional Theory (DFT) employed with B3LYP/6-311++G(d,p) basis set. The molecular geometry optimization, vibrational frequencies, chemical shifts and solvent effect on electronic properties were reported. The intermolecular interactions have been studied by Hirshfeld surface analysis. There is good agreement was found between calculated and observed values, thereby to confirm the molecular structure of modafinil.

Synthesis of (R)-Modafinil via Organocatalyzed and Non-Heme Iron-Catalyzed Sulfoxidation Using H2O2 as an Environmentally Benign Oxidant

The first organocatalyzed sulfoxidation reaction towards enantioenriched (R)-modafinil (Armodafinil®), a drug against narcolepsy, is reported here. A series of chiral organocatalysts, e.g., different chiral BINOL-phosphates, or a fructose-derived N-substituted oxazolidinone ketone (Shi catalyst) were applied for the sulfoxidation reaction with environmentally friendly H2O2 as a convenient oxygen transferring agent. Furthermore, the potential of a biomimetic catalytic system consisting of FeCl3 and a dipeptide-based chiral ligand was demonstrated, which constitutes the most successful asymmetric non-heme iron-catalyzed synthesis of (R)-modafinil so far.

Simple synthesis of modafinil derivatives and their anti-inflammatory activity

Simple synthesis of modafinil derivatives and their biological activity are described. The key synthetic strategies involve substitution and coupling reactions. We determined the anti-inflammatory effects of modafinil derivatives in cultured BV2 cells by measuring the inhibition of nitrite production and expression of iNOS and COX-2 after LPS stimulation. It was found that for sulfide analogues introduction of aliphatic groups on the amide part (compounds 11a–d) resulted in lower anti-inflammatory activity compared with cyclic or aromatic moieties (compounds 11e–k). However, for the sulfoxide analogues, introduction of aliphatic moieties (compounds 12a–d) showed higher anti-inflammatory activity than cyclic or aromatic fragments (compounds 12e–k) in BV-2 microglia cells.

Convenient synthesis and biological evaluation of modafinil derivatives: benzhydrylsulfanyl and benzhydrylsulfinyl [1,2,3]triazol-4-yl-methyl esters

Simple synthesis and biological activities of modafinil derivatives are described. The key reactions include condensation of acid and propargyl alcohol, subsequent 1,3-dipolar cycloaddition reaction of alkynes and (3-azido-propyl)cyclohexane or (4-azido-butyl)benzene in the presence of sodium ascorbate and CuSO₄·5H₂O in excellent yield. They were then evaluated for the suppression of LPS-induced NO generation in vitro. It was found that all compounds showed moderate effects for suppression of LPS-induced NO generation.

Indene-based thiazolidinethione chiral auxiliary for propionate and acetate aldol additions

An indene-based thiazolidinethione chiral auxiliary was prepared in two steps from trans-1-amino-2-indanol. Chlorotitanium enolates of this chiral auxiliary delivered excellent diastereoselectivities in propionate and acetate aldol additions. The chiral auxiliary was easily removed to deliver several valuable functionalities.