Excess molar volumes (V^E_m) of binary mixtures of2-methyl-3-buten-3-ol [CH_3C(OH)(CH_3)CHCG_2] with four 1-alcohols:methanol, ethanol, 1-propanol and l-butanol at 298.15 K andatmospheric pressure are derived from den...Excess molar volumes (V^E_m) of binary mixtures of2-methyl-3-buten-3-ol [CH_3C(OH)(CH_3)CHCG_2] with four 1-alcohols:methanol, ethanol, 1-propanol and l-butanol at 298.15 K andatmospheric pressure are derived from density measurements with avibrating-tube densimeter. All the excess volumes are negative in thesystems over the entire composition range. The results are correlatedwith the Redlich-Kister equation. The effects of chain length ofl-alcohols on V^E_m are discussed. The apparent molar volumes of2-methyl-3-ol and l-alcohols are calculated respectively.展开更多
The photoionization and dissociation of 2-methyl-2-propen-1-ol(MPO)have been investigated by using molecular beam experimental apparatus with tunable vacuum ultraviolet synchrotron radiation in the photon energy regio...The photoionization and dissociation of 2-methyl-2-propen-1-ol(MPO)have been investigated by using molecular beam experimental apparatus with tunable vacuum ultraviolet synchrotron radiation in the photon energy region of 8.0-15.5 eV.The photoionization efficiency(PIE)curves for molecule ion and fragment ions:C4H8O^+,C4H7O^+,C3H5O^+,C4H7^+,C4H6^+,C4H5^+,C2H4O^+,C2H3O+,C3H6^+,C3H5^+,C3H3^+,CH3O^+,CHO^+have been measured,and the ionization energy(IE)and the appearance energies(AEs)of the fragment ions have been obtained.The stable species and the first order saddle points have been calculated on the CCSD(T)/cc-pvTZ//B3LYP/6-31+G(d,p)level.With combination of theoretical and experimental results,the dissociative photoionization pathways of 2-methyl-2-propen-1-ol are proposed.Hydrogen migrations within the molecule are the dominant processes in most of the fragmentation pathways of MPO.展开更多
BACKGROUND Chloracne is a rare skin condition that is caused by systemic exposure to halogenated aromatic compounds.The main characteristic of chloracne is blackhead,and in severe cases,it can be accompanied by system...BACKGROUND Chloracne is a rare skin condition that is caused by systemic exposure to halogenated aromatic compounds.The main characteristic of chloracne is blackhead,and in severe cases,it can be accompanied by systemic symptoms.Sodium 3,5,6-trichloropyridin-2-ol(STCP)is a necessary precursor compound for the production of chlorpyrifos and triclopyr,which are extensively used as a pesticide and herbicide,respectively.STCP is also a chlorophenol that has been associated with chloracne.STCP poisoning could induce mild myelin sheath damage.We herein report three cases with chloracne due to exposure to STCP.CASE SUMMARY Three young men,aged 29,33,and 26 years,respectively,in the same workplace had polymorphic skin lesions,characterized mainly by comedones and cysts,and one of them also had acne like lesions in the genital area.These clinical manifestations appeared when they were exposed to STCP for 3 d,1 wk,and 2 wk,respectively.Among them,polyneuropathy and liver damage occurred.We performed dermoscopy and clinical and laboratory tests on these patients.Additionally,histopathology was used for further diagnosis in the serious patient.These patients were diagnosed with chloracne and separated from STCP.The patients were prescribed oral viaminate capsules,topical adapalene gel,and regular hematologic follow-up for aspartate transaminase and lipids.They are still under follow-up.There was no new lesions and the laboratory tests returned to normal in two patients.Pigmentation and shallow scars remained in the original areas of papules.However,in the most serious patient,new papules still appeared intermittently.All these remind us that the treatment of chloracne caused by STCP is difficult,and we should attach great importance to this new compound related with the neuropathy and chloracne.CONCLUSION STCP is becoming a new chemical product to induce chloracne,which should attract the attention of all medical professionals,especially dermatologists.Due to the lack of knowledge on the new chemical,the diagnosis of chloracne cannot be made in time.Chloracne still deserves our attention.展开更多
The crystals of the title compound C19H16N2O3 were synthesized by thereaction of 4, 4-dicyano-1-phenyl-3-(3', 4'-methylenedioxyphenyl)-l-butan withlow-valent titanium reagent. It belongs to the orthorhombic sy...The crystals of the title compound C19H16N2O3 were synthesized by thereaction of 4, 4-dicyano-1-phenyl-3-(3', 4'-methylenedioxyphenyl)-l-butan withlow-valent titanium reagent. It belongs to the orthorhombic system, space group Pea21with a=11. 547(2), b=13. 168(4), c=10. 645(3) A, V=1618. 4(8) A3, Dc=1.315 g/cm3, Z=4, Mr=320.35. A=0. 71069 A, u(MoKa) =0. 90 cm-1, F(000)=672. The structure was refined to R=0. 036, Rw=0. 044 for 962 observed reflections(I＞3(I) ). X-ray analysis reveals that in the five membered ring the C(11) -C(12)bond is longer than normal double C=C bond while the C(11) -N (1) bond is shorterthan normal C(sp)2-N bond.展开更多
The crystal of title compound C18H16N2O was obtained by recrystal-lizing from ethanol solution. It belongs to orthorhombic system, space group Pbca witha=23. 229(2), b=11. 880(3), c=10. 733(3) A, V=2961 (0) A3, Mr=276...The crystal of title compound C18H16N2O was obtained by recrystal-lizing from ethanol solution. It belongs to orthorhombic system, space group Pbca witha=23. 229(2), b=11. 880(3), c=10. 733(3) A, V=2961 (0) A3, Mr=276. 34, Dc=1. 239 g/cm3, Z=8, A(MoKa)=0. 78 cm-1, F(000) =1168. 00. The structurewas refined to R=0. 049 and Rw=0. 046 for 1102 observed reflections (I＞2d(I) ).The bond lengths of C(3) -C(4) and C(3) -N(1) are 1. 349(5) A and 1. 340(6) A,respectively. The bond angles of N (1) -C(3) -C(2), AN (1) -C(3) -C(4), AC(2) -C(3) -C(4) and C(3) -C(4) -C(5) are 121. 1 (4), 128. 4(4), 110. 5(4)and 113. 1 (4), respectively. The dihedral angle between two phenyl rings is 29. 29.展开更多
We compared two different strategies to increase the catches oflps typographus （L.）, particularly males, in pheromone-baited traps. The first of these strategies, the barrier approach, used alternating pheromone ble...We compared two different strategies to increase the catches oflps typographus （L.）, particularly males, in pheromone-baited traps. The first of these strategies, the barrier approach, used alternating pheromone blends, targeting males and females respectively, in closely-spaced traps forming a barrier around forest stands. The second strategy, the single trap approach, used widely-spaced traps that were all baited with the same lure and intended to trap the highest possible numbers of males without compromising trapping of females. In the blend used for the barrier traps targeting primarily males, with a lower percentage of （4S）-cis-verbenol （cV）, the （-）-α-pinene was replaced step wise with （＋）-limonene at rates of 0%, 1%, 10%, 35%, 60% and 90%. This replacement had no significant effect on the numbers of responding 1. typographus males, but there was a slight effect on the percentage of males caught. In the attractant blend for the barrier traps targeting females, with a higher percentage of cV, the 2-methyl-3-buten-2-ol （MB） was replaced with 1-methoxy-2-propanol （MP） in a similar fashion as for the male-specific blends. The replacement did not significantly affect the catch of females. Thus, it is pos- sible to use the MP in the blend with cV and ipsdienol without significant change in catch efficacy. In the blends for single traps, the （-）-α- pinene was replaced with （＋）-limonene and MB with MP. The replacement of （-）-α-pinene had only a slight effect on the percentage of males, but the results suggest that replacing MB with MP in the blend will not significantly reduce trapping efficacy.展开更多
A series of half-titanocene chloride 2-（benzimidazol-2-yl）quinolin-8-olates C1-C6 were synthesized by treating the lithium salts of the ligand with CpTiCI3. All the complexes were characterized by 1H-NMR, 13C-NMR an...A series of half-titanocene chloride 2-（benzimidazol-2-yl）quinolin-8-olates C1-C6 were synthesized by treating the lithium salts of the ligand with CpTiCI3. All the complexes were characterized by 1H-NMR, 13C-NMR and elemental analyses, and the crystal structure of C3 and C6 was measured by X-ray. These half-titanocene complexes showed moderate catalytic activities toward ethylene polymerization （up to 1840 kg·mol-1（Ti）·h-1） when activated with MMAO, affording the high molecular weight polymers. And they also exhibited good activity for copolymerization of ethylene and a-olefin with low content of co-monomer.展开更多
Naphthalene-2-ol is a typical biologically recalcitrant pollutant in dye wastewater.Solvent extraction of naphthalene-2-ol from aqueous solutions using mixed solvents was investigated.Various extractants and diluents ...Naphthalene-2-ol is a typical biologically recalcitrant pollutant in dye wastewater.Solvent extraction of naphthalene-2-ol from aqueous solutions using mixed solvents was investigated.Various extractants and diluents were evaluated,and the effects of volume ratio of extractant to diluent,initial p H,initial concentration of naphthalene-2-ol in aqueous solution,extraction time,temperature,volume ratio of organic phase to aqueous phase（O/A）,stirring rate and extraction stages,on extraction efficiency were examined separately.Regeneration and reuse of the spent extractant were also investigated.Results showed that tributyl phosphate（TBP） achieved 98% extraction efficiency for naphthalene-2-ol in a single stage extraction,the highest among the 12 extractants evaluated.Extraction efficiency was optimized when cyclohexane and n-octane were used as diluents.The solvent combination of 20% TBP,20% n-octanol and 60% cyclohexane（V/V） obtained the maximum extraction efficiency for naphthalene-2-ol,99.3%,within 20 min using three cross-current extraction stages under the following extraction conditions：O/A ratio of 1：1,initial p H of 3,25°C and stirring rate of 150 r/min.Recovery of mixed solvents was achieved by using 15%（W/W） Na OH solution at an O：A ratio of 1：1 and a contact time of 15 min.The mixed solvents achieved an extraction capacity for naphthalene-2-ol stably higher than90% during five cycles after regeneration.展开更多
Because of multiple potential reaction sites and variable oxidation depths,oxidation of cyclohexene can lead to a mixture of products with different oxidation states and functional groups,such as 7-oxabicyclo[4.1.0]he...Because of multiple potential reaction sites and variable oxidation depths,oxidation of cyclohexene can lead to a mixture of products with different oxidation states and functional groups,such as 7-oxabicyclo[4.1.0]heptane,trans/cis-cyclohexane-1,2-diol,cyclohex-2-en-1-ol,cyclohex-2-en-1-one,and even adipic acid.These products are broadly and abundantly used intermediates in the chemical industry;therefore,controllable oxidation reactions for cyclohexene that can selectively afford the targeted products are synthetically valuable for applications in both the academy and industry,thus becoming the aim of synthetic and catalytic chemists in the field.Many reports on selective oxidation of cyclohexene have recently appeared in the literature because of its significance.This short review summarizes the recent advances on this subject,and the contents are mainly classified based on the chosen oxidants.We hope that this review can provide a useful guide for controllable and selective catalytic oxidation of cyclohexene for interested readers from both the academy and industry.展开更多
2-[3,5-Di-O-β-D-glucosyl-4-(3-methylbut-2-enyl)phenyl]benzofuran-6-ol,a new prenylated arylbenzofuran derivative was isolated from Morus alba L.Its structure was elucidated by various spectroscopic methods including ...2-[3,5-Di-O-β-D-glucosyl-4-(3-methylbut-2-enyl)phenyl]benzofuran-6-ol,a new prenylated arylbenzofuran derivative was isolated from Morus alba L.Its structure was elucidated by various spectroscopic methods including MS,~1H NMR,^(13)C NMR,DEPT,~1H-~1HCOSY,HMQC and HMBC.展开更多
An inexpensive synthesis of 6-ethynylbipyridine has been accomplished using Sonogashira coupling of 2-bromo-6-iodopyridine with 2-methyl-3-butyn-2-ol. Subsequent Stille coupling with 2-(trimethylstannanyl) pyridine an...An inexpensive synthesis of 6-ethynylbipyridine has been accomplished using Sonogashira coupling of 2-bromo-6-iodopyridine with 2-methyl-3-butyn-2-ol. Subsequent Stille coupling with 2-(trimethylstannanyl) pyridine and hydrolysis provided the target compound in an overall high yield.展开更多
The discovery of novel flavonoids and elucidation of their biosynthesis are fundamental to understanding their roles in plants and their benefits for human and animal health.Here,we report a new pathway for polymeriza...The discovery of novel flavonoids and elucidation of their biosynthesis are fundamental to understanding their roles in plants and their benefits for human and animal health.Here,we report a new pathway for polymerization of a group of novel oligomeric flavonoids in plants.We engineered red cells for discovering genes of interest involved in the flavonoid pathway and identified a gene encoding a novel flavanol polymerase(FP)localized in the central vacuole.FP catalyzes the polymerization of flavanols,such as epicatechin and catechin,to produce yellowish dimers or oligomers.Structural elucidation shows that these compounds feature a novel oligomeric flaven–flavan(FF)skeleton linked by interflavan–flaven and interflaven bonds,distinguishing them from proanthocyanidins and dehydrodicatechins.Detailed chemical and physical characterizations further confirmed the novel FFs as flavonoids.Mechanistic investigations demonstrated that FP polymerizes flavan-3-ols and flav-2-en-3-ol carbocation,forming dimeric or oligomeric flaven-4→8-flavans,which we term“papanridins.”Data from transgenic experiments,mutant analysis,metabolic profiling,and phylogenetic analyses show that the biosynthesis of papanridins is prevalent in cacao,grape,blueberry,corn,rice,Arabidopsis,and other species in the plant kingdom.In summary,our study discoveries a group of novel oligomeric flavonoids,namely papanridins,and reveals that a novel FP-mediated polymerization mechanism for the biosynthesis of papanridins in plants.展开更多
基金Supported by the National Natural Science Foundation of China (No. 29976035).
文摘Excess molar volumes (V^E_m) of binary mixtures of2-methyl-3-buten-3-ol [CH_3C(OH)(CH_3)CHCG_2] with four 1-alcohols:methanol, ethanol, 1-propanol and l-butanol at 298.15 K andatmospheric pressure are derived from density measurements with avibrating-tube densimeter. All the excess volumes are negative in thesystems over the entire composition range. The results are correlatedwith the Redlich-Kister equation. The effects of chain length ofl-alcohols on V^E_m are discussed. The apparent molar volumes of2-methyl-3-ol and l-alcohols are calculated respectively.
基金supported by the National Natural Science Foundation of China(No.91544105,No.U1532137,No.275127,No.U1232130,No.U1232209,and No.U11575178)the Supercomputing Center of USTC is also acknowledged
文摘The photoionization and dissociation of 2-methyl-2-propen-1-ol(MPO)have been investigated by using molecular beam experimental apparatus with tunable vacuum ultraviolet synchrotron radiation in the photon energy region of 8.0-15.5 eV.The photoionization efficiency(PIE)curves for molecule ion and fragment ions:C4H8O^+,C4H7O^+,C3H5O^+,C4H7^+,C4H6^+,C4H5^+,C2H4O^+,C2H3O+,C3H6^+,C3H5^+,C3H3^+,CH3O^+,CHO^+have been measured,and the ionization energy(IE)and the appearance energies(AEs)of the fragment ions have been obtained.The stable species and the first order saddle points have been calculated on the CCSD(T)/cc-pvTZ//B3LYP/6-31+G(d,p)level.With combination of theoretical and experimental results,the dissociative photoionization pathways of 2-methyl-2-propen-1-ol are proposed.Hydrogen migrations within the molecule are the dominant processes in most of the fragmentation pathways of MPO.
文摘BACKGROUND Chloracne is a rare skin condition that is caused by systemic exposure to halogenated aromatic compounds.The main characteristic of chloracne is blackhead,and in severe cases,it can be accompanied by systemic symptoms.Sodium 3,5,6-trichloropyridin-2-ol(STCP)is a necessary precursor compound for the production of chlorpyrifos and triclopyr,which are extensively used as a pesticide and herbicide,respectively.STCP is also a chlorophenol that has been associated with chloracne.STCP poisoning could induce mild myelin sheath damage.We herein report three cases with chloracne due to exposure to STCP.CASE SUMMARY Three young men,aged 29,33,and 26 years,respectively,in the same workplace had polymorphic skin lesions,characterized mainly by comedones and cysts,and one of them also had acne like lesions in the genital area.These clinical manifestations appeared when they were exposed to STCP for 3 d,1 wk,and 2 wk,respectively.Among them,polyneuropathy and liver damage occurred.We performed dermoscopy and clinical and laboratory tests on these patients.Additionally,histopathology was used for further diagnosis in the serious patient.These patients were diagnosed with chloracne and separated from STCP.The patients were prescribed oral viaminate capsules,topical adapalene gel,and regular hematologic follow-up for aspartate transaminase and lipids.They are still under follow-up.There was no new lesions and the laboratory tests returned to normal in two patients.Pigmentation and shallow scars remained in the original areas of papules.However,in the most serious patient,new papules still appeared intermittently.All these remind us that the treatment of chloracne caused by STCP is difficult,and we should attach great importance to this new compound related with the neuropathy and chloracne.CONCLUSION STCP is becoming a new chemical product to induce chloracne,which should attract the attention of all medical professionals,especially dermatologists.Due to the lack of knowledge on the new chemical,the diagnosis of chloracne cannot be made in time.Chloracne still deserves our attention.
文摘The crystals of the title compound C19H16N2O3 were synthesized by thereaction of 4, 4-dicyano-1-phenyl-3-(3', 4'-methylenedioxyphenyl)-l-butan withlow-valent titanium reagent. It belongs to the orthorhombic system, space group Pea21with a=11. 547(2), b=13. 168(4), c=10. 645(3) A, V=1618. 4(8) A3, Dc=1.315 g/cm3, Z=4, Mr=320.35. A=0. 71069 A, u(MoKa) =0. 90 cm-1, F(000)=672. The structure was refined to R=0. 036, Rw=0. 044 for 962 observed reflections(I＞3(I) ). X-ray analysis reveals that in the five membered ring the C(11) -C(12)bond is longer than normal double C=C bond while the C(11) -N (1) bond is shorterthan normal C(sp)2-N bond.
文摘The crystal of title compound C18H16N2O was obtained by recrystal-lizing from ethanol solution. It belongs to orthorhombic system, space group Pbca witha=23. 229(2), b=11. 880(3), c=10. 733(3) A, V=2961 (0) A3, Mr=276. 34, Dc=1. 239 g/cm3, Z=8, A(MoKa)=0. 78 cm-1, F(000) =1168. 00. The structurewas refined to R=0. 049 and Rw=0. 046 for 1102 observed reflections (I＞2d(I) ).The bond lengths of C(3) -C(4) and C(3) -N(1) are 1. 349(5) A and 1. 340(6) A,respectively. The bond angles of N (1) -C(3) -C(2), AN (1) -C(3) -C(4), AC(2) -C(3) -C(4) and C(3) -C(4) -C(5) are 121. 1 (4), 128. 4(4), 110. 5(4)and 113. 1 (4), respectively. The dihedral angle between two phenyl rings is 29. 29.
基金supported by Slovak Research and Development Agency (APVV-51-P06005 and APVV-27-P05205)the Scientific Grant Agency of the Ministry of Education of the Slovak Republic and the Slovak Academy of Sciences (2/6153/26)
文摘We compared two different strategies to increase the catches oflps typographus （L.）, particularly males, in pheromone-baited traps. The first of these strategies, the barrier approach, used alternating pheromone blends, targeting males and females respectively, in closely-spaced traps forming a barrier around forest stands. The second strategy, the single trap approach, used widely-spaced traps that were all baited with the same lure and intended to trap the highest possible numbers of males without compromising trapping of females. In the blend used for the barrier traps targeting primarily males, with a lower percentage of （4S）-cis-verbenol （cV）, the （-）-α-pinene was replaced step wise with （＋）-limonene at rates of 0%, 1%, 10%, 35%, 60% and 90%. This replacement had no significant effect on the numbers of responding 1. typographus males, but there was a slight effect on the percentage of males caught. In the attractant blend for the barrier traps targeting females, with a higher percentage of cV, the 2-methyl-3-buten-2-ol （MB） was replaced with 1-methoxy-2-propanol （MP） in a similar fashion as for the male-specific blends. The replacement did not significantly affect the catch of females. Thus, it is pos- sible to use the MP in the blend with cV and ipsdienol without significant change in catch efficacy. In the blends for single traps, the （-）-α- pinene was replaced with （＋）-limonene and MB with MP. The replacement of （-）-α-pinene had only a slight effect on the percentage of males, but the results suggest that replacing MB with MP in the blend will not significantly reduce trapping efficacy.
基金supported by NSFC (No. 20904059)Key Project of 863 Program of China(No. 2009AA034605)
文摘A series of half-titanocene chloride 2-（benzimidazol-2-yl）quinolin-8-olates C1-C6 were synthesized by treating the lithium salts of the ligand with CpTiCI3. All the complexes were characterized by 1H-NMR, 13C-NMR and elemental analyses, and the crystal structure of C3 and C6 was measured by X-ray. These half-titanocene complexes showed moderate catalytic activities toward ethylene polymerization （up to 1840 kg·mol-1（Ti）·h-1） when activated with MMAO, affording the high molecular weight polymers. And they also exhibited good activity for copolymerization of ethylene and a-olefin with low content of co-monomer.
基金supported by the International S&T Cooperation Program of China(No:2015DFG92750)the National Natural Science Foundation of China(Nos.51478172 and 51278464)the Department of Science and Technology of Hunan Province(No:2014GK1012)
文摘Naphthalene-2-ol is a typical biologically recalcitrant pollutant in dye wastewater.Solvent extraction of naphthalene-2-ol from aqueous solutions using mixed solvents was investigated.Various extractants and diluents were evaluated,and the effects of volume ratio of extractant to diluent,initial p H,initial concentration of naphthalene-2-ol in aqueous solution,extraction time,temperature,volume ratio of organic phase to aqueous phase（O/A）,stirring rate and extraction stages,on extraction efficiency were examined separately.Regeneration and reuse of the spent extractant were also investigated.Results showed that tributyl phosphate（TBP） achieved 98% extraction efficiency for naphthalene-2-ol in a single stage extraction,the highest among the 12 extractants evaluated.Extraction efficiency was optimized when cyclohexane and n-octane were used as diluents.The solvent combination of 20% TBP,20% n-octanol and 60% cyclohexane（V/V） obtained the maximum extraction efficiency for naphthalene-2-ol,99.3%,within 20 min using three cross-current extraction stages under the following extraction conditions：O/A ratio of 1：1,initial p H of 3,25°C and stirring rate of 150 r/min.Recovery of mixed solvents was achieved by using 15%（W/W） Na OH solution at an O：A ratio of 1：1 and a contact time of 15 min.The mixed solvents achieved an extraction capacity for naphthalene-2-ol stably higher than90% during five cycles after regeneration.
文摘Because of multiple potential reaction sites and variable oxidation depths,oxidation of cyclohexene can lead to a mixture of products with different oxidation states and functional groups,such as 7-oxabicyclo[4.1.0]heptane,trans/cis-cyclohexane-1,2-diol,cyclohex-2-en-1-ol,cyclohex-2-en-1-one,and even adipic acid.These products are broadly and abundantly used intermediates in the chemical industry;therefore,controllable oxidation reactions for cyclohexene that can selectively afford the targeted products are synthetically valuable for applications in both the academy and industry,thus becoming the aim of synthetic and catalytic chemists in the field.Many reports on selective oxidation of cyclohexene have recently appeared in the literature because of its significance.This short review summarizes the recent advances on this subject,and the contents are mainly classified based on the chosen oxidants.We hope that this review can provide a useful guide for controllable and selective catalytic oxidation of cyclohexene for interested readers from both the academy and industry.
基金supported by the Great Research Project of National Major New Drug Development(No. 2009ZX09102-110)
文摘2-[3,5-Di-O-β-D-glucosyl-4-(3-methylbut-2-enyl)phenyl]benzofuran-6-ol,a new prenylated arylbenzofuran derivative was isolated from Morus alba L.Its structure was elucidated by various spectroscopic methods including MS,~1H NMR,^(13)C NMR,DEPT,~1H-~1HCOSY,HMQC and HMBC.
文摘An inexpensive synthesis of 6-ethynylbipyridine has been accomplished using Sonogashira coupling of 2-bromo-6-iodopyridine with 2-methyl-3-butyn-2-ol. Subsequent Stille coupling with 2-(trimethylstannanyl) pyridine and hydrolysis provided the target compound in an overall high yield.
基金funded by the US Department of Agriculture 526614-09725(D.-Y.X.)in 2006.
文摘The discovery of novel flavonoids and elucidation of their biosynthesis are fundamental to understanding their roles in plants and their benefits for human and animal health.Here,we report a new pathway for polymerization of a group of novel oligomeric flavonoids in plants.We engineered red cells for discovering genes of interest involved in the flavonoid pathway and identified a gene encoding a novel flavanol polymerase(FP)localized in the central vacuole.FP catalyzes the polymerization of flavanols,such as epicatechin and catechin,to produce yellowish dimers or oligomers.Structural elucidation shows that these compounds feature a novel oligomeric flaven–flavan(FF)skeleton linked by interflavan–flaven and interflaven bonds,distinguishing them from proanthocyanidins and dehydrodicatechins.Detailed chemical and physical characterizations further confirmed the novel FFs as flavonoids.Mechanistic investigations demonstrated that FP polymerizes flavan-3-ols and flav-2-en-3-ol carbocation,forming dimeric or oligomeric flaven-4→8-flavans,which we term“papanridins.”Data from transgenic experiments,mutant analysis,metabolic profiling,and phylogenetic analyses show that the biosynthesis of papanridins is prevalent in cacao,grape,blueberry,corn,rice,Arabidopsis,and other species in the plant kingdom.In summary,our study discoveries a group of novel oligomeric flavonoids,namely papanridins,and reveals that a novel FP-mediated polymerization mechanism for the biosynthesis of papanridins in plants.
