A simplified and scalable synthesis of artesunate

Abstract

An efficient and economically viable approach for the large-scale conversion of artemisinin into the antimalarial frontline drug artesunate was developed. This advanced synthesis includes an NaBH4-induced reduction, followed by an esterification with succinic anhydride under basic conditions. The entire conversion follows the principles of green chemistry, i.e., application of reusable solvents.Graphical abstract

Enantioselective Synthesis of SpirothiazolonesviaCooperative Catalysis

“…For example, the aldehyde 4 e can be readily converted to ester 7 e via Pinnick oxidation, [9] followed by esterification with TMS‐diazomethane [12] . Compound 7 e was prepared in high yield (79%) without loss of optical purity.…”

Ruthenium‐Catalyzed Dehydrogenation of Alcohols with Carbodiimide via a Hydrogen Transfer Mechanism

“…Alcohols 1a , 1r , 1t , 1u , 1v , 1w , 3a – 3e , 3h and 3i were purchased from Aldrich Co., Kanto Kagaku Reagent Division, Tokyo Kasei Kogyo Co., and Wako Pure Chemical Industries. Other alcohols ( 1b , 1c , 1d , 1e , 1f , 1g , 1h , 1i , 1j , 1k , 1l , 1m , 1n , 1o , 1p , 1q , 1s , 1v , 1x , 1y , 1a‐D , 3f , 3g ) and diol 5 were prepared according to the literature methods. NMR spectra were recorded on JEOL JNM‐AL400 FT‐NMR spectrometer (400 MHz for 1 H NMR and 100 MHz for 13 C NMR) and JEOL ECZ‐500 (500 MHz for 1 H NMR, 125 MHz for 13 C NMR and 470 MHz for 19 F NMR).…”

The Preparation of Tetramethyl 1,1′,3,3′-Ruthenocenetetra­carboxylate and Tetramethyl 1,1′,3,3′-Osmocenetetracarboxylate, and a Simplified Synthesis for Tetramethyl 1,1′,3,3′-Ferrocene­tetracarboxylate

“…The combined yields of substituted osmocene are significantly lower (66%) compared to similar reactions using ferrocene (92%) or ruthenocene (88%). Following the protocol, which was successful for the tetra-functionalization of ferrocene, the reactions of the carboxylic acids of ruthenocene or osmocene with trimethylsilyldiazomethane [Me 3 SiCHN 2 ] 26 were achieved in a mixture of toluene and methanol and produced the corresponding esters of ruthenocene [RuC 10 H 6 (COOMe) 4 (5 4 ); RuC 10 H 7 (COOMe) 3 (5 3 ); RuC 10 H 8 (COOMe) 2 (5 2 )] and osmocene [OsC 10 H 6 (COOMe) 4 (6 4 ), OsC 10 H 7 (COOMe) 3 (6 3 ); OsC 10 H 8 (COOMe) 2 (6 2 )] (Scheme 4). The tetra-esters 5 4 or 6 4 were isolated as poorly soluble crystalline off-white solids by filtration, the corresponding crystalline tri-and diesters 5 3 /5 2 and 6 3 /6 2 were separated by column chromatography.…”