The isolated hydrophilic black alder(Alnus glutinosa)bark extractives were characterized in terms of component and functional composition and converted at 150℃-170℃ into liquid green polyols using solvent-free and l...The isolated hydrophilic black alder(Alnus glutinosa)bark extractives were characterized in terms of component and functional composition and converted at 150℃-170℃ into liquid green polyols using solvent-free and lowtoxic base-catalyzed modification with propylene carbonate(PC).FTIR spectroscopy,HP-LC,GC,GPC,and wet chemistry methods were used to characterize the starting constituents,intermediate and final products of the reaction and to monitor the different pathways of PC conversion.The reaction of extractives as well as the model compounds,including catechol,xylose,PEG 400,and benzoic acid,with PC indicated the ability of OH groups of different origins present in the extractives to condense with equivalent amounts of PC.The polyols obtained consist of a copolymer fraction with one oxypropyl unit grafted per OH functionality of extractive components on average and oligo oxypropyl diols with a small number of carbonate linkages in the chain,obtained as a result of remaining PC homopolymerization.The domination of the oxypropylation mechanism vs.transcarbonation for PC ring opening was observed for both copolymerization and homopolymerization processes,making the process of oxypropylation with PC similar to that of conventional oxypropylation.At optimal reaction conditions,including a PC/OH ratio of 3.0 and a 24-h duration at 150°C,uniform polyols with low viscosity of~900 mPa·s^(-1),a biomass content of~27%,and an OHV of~500 mg KOH·g^(-1) were obtained.Increasing the temperature of modification allows shortening the process but drastically increases the polyol viscosity.At fixed temperature values,increasing the PC/OH ratio not only decreases the biomass content but also strongly prolongs the processing.The significantly increased duration of the process using PC as an alternative oxyalkylation agent compared to that of oxyalkylation with propylene oxide is a reasonable trade-off for using a safer and more environmentally friendly technology.展开更多
Late-stage functionalization is an attractive strategy that allows chemists to bypass lengthy synthetic processes,facilitating the rapid generation of drug analogs with potentially enhanced pharmacokinetic and pharmac...Late-stage functionalization is an attractive strategy that allows chemists to bypass lengthy synthetic processes,facilitating the rapid generation of drug analogs with potentially enhanced pharmacokinetic and pharmacological properties.This study describes a novel approach for cross-dehydrogenative oxyalkylation,leveraging a unique g-ray-enabled photoredox process to generate oxyalkyl radicals,followed by a Minisci-type addition in an aqueous solution.The metal-and oxidant-free aqueous conditions,coupled with excellent functional group compatibility,establish this method as a versatile protocol for the late-stage oxyalkylation of unprotected,structurally complex drug molecules.Notably,this method demonstrated improved pharmacokinetics in hydroxymethylated fibroblast activation protein inhibitor(FAPI)molecules,highlighting its potential to accelerate drug discovery efforts.展开更多
A new visible-light-promoted oxidative coupling of vinylarenes with cyclic ethers has been developed using rose bengal as photocatalyst and tert-butyl hydrogenperoxide(TBHP)as oxidant under ambient air at room tempera...A new visible-light-promoted oxidative coupling of vinylarenes with cyclic ethers has been developed using rose bengal as photocatalyst and tert-butyl hydrogenperoxide(TBHP)as oxidant under ambient air at room temperature.A library ofα-oxyalkylated ketones with broad functionalities has been synthesized in moderate to good yields.A radical mechanism is suggested for the present protocol.展开更多
基金financial support from the Latvian Council of Science,Project No.lzp-2021/1-0207.
文摘The isolated hydrophilic black alder(Alnus glutinosa)bark extractives were characterized in terms of component and functional composition and converted at 150℃-170℃ into liquid green polyols using solvent-free and lowtoxic base-catalyzed modification with propylene carbonate(PC).FTIR spectroscopy,HP-LC,GC,GPC,and wet chemistry methods were used to characterize the starting constituents,intermediate and final products of the reaction and to monitor the different pathways of PC conversion.The reaction of extractives as well as the model compounds,including catechol,xylose,PEG 400,and benzoic acid,with PC indicated the ability of OH groups of different origins present in the extractives to condense with equivalent amounts of PC.The polyols obtained consist of a copolymer fraction with one oxypropyl unit grafted per OH functionality of extractive components on average and oligo oxypropyl diols with a small number of carbonate linkages in the chain,obtained as a result of remaining PC homopolymerization.The domination of the oxypropylation mechanism vs.transcarbonation for PC ring opening was observed for both copolymerization and homopolymerization processes,making the process of oxypropylation with PC similar to that of conventional oxypropylation.At optimal reaction conditions,including a PC/OH ratio of 3.0 and a 24-h duration at 150°C,uniform polyols with low viscosity of~900 mPa·s^(-1),a biomass content of~27%,and an OHV of~500 mg KOH·g^(-1) were obtained.Increasing the temperature of modification allows shortening the process but drastically increases the polyol viscosity.At fixed temperature values,increasing the PC/OH ratio not only decreases the biomass content but also strongly prolongs the processing.The significantly increased duration of the process using PC as an alternative oxyalkylation agent compared to that of oxyalkylation with propylene oxide is a reasonable trade-off for using a safer and more environmentally friendly technology.
基金funded by the Ministry of Science and Technology of the People’s Republic of China(2021YFA1601400)the National Natural Science Foundation of China(22225603 and 22441051)the New Cornerstone Science Foundation(The XPLORER PRIZE)and Changping Laboratory to Z.L.,and the National Nature Science Foundation of China(22306005)to B.-S.M.
文摘Late-stage functionalization is an attractive strategy that allows chemists to bypass lengthy synthetic processes,facilitating the rapid generation of drug analogs with potentially enhanced pharmacokinetic and pharmacological properties.This study describes a novel approach for cross-dehydrogenative oxyalkylation,leveraging a unique g-ray-enabled photoredox process to generate oxyalkyl radicals,followed by a Minisci-type addition in an aqueous solution.The metal-and oxidant-free aqueous conditions,coupled with excellent functional group compatibility,establish this method as a versatile protocol for the late-stage oxyalkylation of unprotected,structurally complex drug molecules.Notably,this method demonstrated improved pharmacokinetics in hydroxymethylated fibroblast activation protein inhibitor(FAPI)molecules,highlighting its potential to accelerate drug discovery efforts.
基金supported by Council of Scientific and Industrial Research(CSIR)and New Delhi(02(0307)/17/EMR-II)University Grants Commission(UGC)(DSK)for his fellowship
文摘A new visible-light-promoted oxidative coupling of vinylarenes with cyclic ethers has been developed using rose bengal as photocatalyst and tert-butyl hydrogenperoxide(TBHP)as oxidant under ambient air at room temperature.A library ofα-oxyalkylated ketones with broad functionalities has been synthesized in moderate to good yields.A radical mechanism is suggested for the present protocol.
