32 research outputs found
Preparations of N- and P-substituted acetylenes under metal-free conditions
<p>An efficient strategy towards triazole- or phosphine-oxide-substituted alkynes with the assistance of strong base LiHMDS is described. The facile and practical reaction took place from easily prepared substrates in a one-pot manner without participation of any transition metal catalysts or ligands, exhibiting good functional groups tolerance (up to 37 examples) and high efficiency (up to 90% yields). The isolation of the key intermediate proved the hypothesis of the proposed mechanism of the one-pot preparation.</p
Photoredox catalyst-mediated direct regioselective phosphonylation of indoles
<p>An efficient hetero-cross-dehydrogenative-coupling (hetero-CDC) reaction between <i>N</i>-protected indoles and phosphites to 2-indolyphosphites is described. The regioselective methodology took place in the presence of photo redox catalyst Ru(bpy)<sub>3</sub>(PF<sub>6</sub>)<sub>2</sub> combined with oxygen as an clean oxidant when exposed to visible light, furnishing the 2-indolyphosphites as the exclusive products in moderate to good yields with good functional group tolerance. Moreover, the phosphonylation protocol was proved by the control reaction to proceed through the radical pathway.</p
Copper-Catalyzed Oxidative Alkylation (Methylation) of Phosphonamides and Phosphinamides Using Dicumyl Peroxide
An effective and
practical CuI-catalyzed methodology toward <i>N</i>-alkyl
or <i>N</i>-methyl phosphonamides and
phosphinamides was herein demonstrated. The transformation took place
readily under the oxidative conditions, and plenty of <i>N</i>-alkylated (methylated) amides (30 examples) were successfully furnished
in high efficiency (up to 92% yields). Dicumyl peroxide was considered
to act either as the oxidant for the alkylation reaction or as methyl
donator for the methylation protocol
Rh<sup>III</sup>-catalyzed annulation of <i>N</i>-methoxyindozamides with heterobicyclic alkenes towards indolo[3,2-<i>c</i>]heteroarenes
<p>A rhodium-catalyzed annulation protocol towards indolo[3,2-<i>c</i>]-1-azaanthraenes and successive treatment with different acids, which offered diverse indolo[3,2-<i>c</i>]-heteroarenes, were herein demonstrated. The transition metal-mediated system offered a direct and facile approach towards the heterocyclic compounds of great significance, enjoying high efficiency and good functional groups compatibility.</p> <p>An annulation reaction between <i>N</i>-methoxyindozamides and heterobicyclic alkenes was herein disclosed. The Rh-Ag-cocatalyzed system offered a direct approach towards various indolo[3,2-<i>c</i>]-1-azaanthraenes in high efficiency and good functional group tolerance. Successive treatment of acids gave different products of great importance.</p
Table_1_A comparative study on photosynthetic characteristics and flavonoid metabolism between Camellia petelotii (Merr.) Sealy and Camellia impressinervis Chang &Liang.xls
Camellia petelotii (Merr.) Sealy and Camellia impressinervis Chang & Liang belong to the golden subgroup of Camellia (Theaceae). This subgroup contains the yellow-flowering species of the genus, which have high medicinal and ornamental value and a narrow geographical distribution. These species differ in their tolerance to high light intensity. This study aimed to explore the differences in their light-stress responses and light damage repair processes, and the effect of these networks on secondary metabolite synthesis. Two-year-old plants of both species grown at 300 碌mol路m-2路s-1 photosynthetically active radiation (PAR) were shifted to 700 碌mol路m-2路s-1 PAR for 5 days shifting back to 300 碌mol路m-2路s-1 PAR for recovery for 5 days. Leaf samples were collected at the start of the experiment and 2 days after each shift. Data analysis included measuring photosynthetic indicators, differential transcriptome expression, and quantifying plant hormones, pigments, and flavonoids. Camellia impressinervis showed a weak ability to recover from photodamage that occurred at 700 碌mol路m-2路s-1 compared with C. petelotii. Photodamage led to decreased photosynthesis, as shown by repressed transcript abundance for photosystem II genes psbA, B, C, O, and Q, photosystem I genes psaB, D, E, H, and N, electron transfer genes petE and F, and ATP synthesis genes ATPF1A and ATPF1B. High-light stress caused more severe damage to C. impressinervis, which showed a stronger response to reactive oxygen species than C. petelotii. In addition, high-light stress promoted the growth and development of high zeatin signalling and increased transcript abundance of adenylate dimethylallyl transferase (IPT) and histidine-containing phosphotransferase (AHP). The identification of transcriptional differences in the regulatory networks that respond to high-light stress and activate recovery of light damage in these two rare species adds to the resources available to conserve them and improve their value through molecular breeding. </p
Iron-catalyzed deoxygenation and 2-sulfonylation of quinoline <i>N</i>-oxides by sodium sulfinates towards 2-sulfonyl quinolines
<p>An iron(III)-catalyzed protocol towards 2-sulfonyl quinolines from quinoline <i>N</i>-oxides and sodium sulfinates was herein illustrated. The general and direct option featured for high efficiency (up to 91% yields) and good functional compatibilities (27 examples) in the Fe(III)-catalysis. Moreover, free radical mechanism was proposed for the one-pot deoxygenation and sulfonylation reaction based on the results of the control reactions.</p> <p>An novel reaction between quinoline N-oxides and sodium sulfinates for the synthesis of 2-sulfonyl quinolines was herein achieved by an iron(III)-catalyzed system. The general and direct transformation exhibited high efficiency (up to 91% yields) and good functional-groups compatibilities (27 examples). Moreover, free radical mechanism was proposed for the one-pot deoxygenation and sulfonylation reaction based on the results of the control reactions.</p
Copper-Promoted Desulfitative <i>N</i>鈥慉rylation of Sulfonamides and Sulfoximines with Sodium Arylsulfinates
A general
and direct <i>N</i>-arylation of sulfonamides
and NH-sulfoximines by sodium arylsulfinates through a desulfitative
pathway was herein demonstrated. The reaction proceeded with catalytic
loadings of Cu颅(II)-catalysts without any external ligands. And the
novel arylation protocol featured for high efficiency (up to 93% yields)
and good substituent tolerance (up to 53 examples). Moreover, a plausible
reaction mechanism was also discussed
Table_2_A comparative study on photosynthetic characteristics and flavonoid metabolism between Camellia petelotii (Merr.) Sealy and Camellia impressinervis Chang &Liang.xls
Camellia petelotii (Merr.) Sealy and Camellia impressinervis Chang & Liang belong to the golden subgroup of Camellia (Theaceae). This subgroup contains the yellow-flowering species of the genus, which have high medicinal and ornamental value and a narrow geographical distribution. These species differ in their tolerance to high light intensity. This study aimed to explore the differences in their light-stress responses and light damage repair processes, and the effect of these networks on secondary metabolite synthesis. Two-year-old plants of both species grown at 300 碌mol路m-2路s-1 photosynthetically active radiation (PAR) were shifted to 700 碌mol路m-2路s-1 PAR for 5 days shifting back to 300 碌mol路m-2路s-1 PAR for recovery for 5 days. Leaf samples were collected at the start of the experiment and 2 days after each shift. Data analysis included measuring photosynthetic indicators, differential transcriptome expression, and quantifying plant hormones, pigments, and flavonoids. Camellia impressinervis showed a weak ability to recover from photodamage that occurred at 700 碌mol路m-2路s-1 compared with C. petelotii. Photodamage led to decreased photosynthesis, as shown by repressed transcript abundance for photosystem II genes psbA, B, C, O, and Q, photosystem I genes psaB, D, E, H, and N, electron transfer genes petE and F, and ATP synthesis genes ATPF1A and ATPF1B. High-light stress caused more severe damage to C. impressinervis, which showed a stronger response to reactive oxygen species than C. petelotii. In addition, high-light stress promoted the growth and development of high zeatin signalling and increased transcript abundance of adenylate dimethylallyl transferase (IPT) and histidine-containing phosphotransferase (AHP). The identification of transcriptional differences in the regulatory networks that respond to high-light stress and activate recovery of light damage in these two rare species adds to the resources available to conserve them and improve their value through molecular breeding. </p
Presentation_1_A comparative study on photosynthetic characteristics and flavonoid metabolism between Camellia petelotii (Merr.) Sealy and Camellia impressinervis Chang &Liang.pdf
Camellia petelotii (Merr.) Sealy and Camellia impressinervis Chang & Liang belong to the golden subgroup of Camellia (Theaceae). This subgroup contains the yellow-flowering species of the genus, which have high medicinal and ornamental value and a narrow geographical distribution. These species differ in their tolerance to high light intensity. This study aimed to explore the differences in their light-stress responses and light damage repair processes, and the effect of these networks on secondary metabolite synthesis. Two-year-old plants of both species grown at 300 碌mol路m-2路s-1 photosynthetically active radiation (PAR) were shifted to 700 碌mol路m-2路s-1 PAR for 5 days shifting back to 300 碌mol路m-2路s-1 PAR for recovery for 5 days. Leaf samples were collected at the start of the experiment and 2 days after each shift. Data analysis included measuring photosynthetic indicators, differential transcriptome expression, and quantifying plant hormones, pigments, and flavonoids. Camellia impressinervis showed a weak ability to recover from photodamage that occurred at 700 碌mol路m-2路s-1 compared with C. petelotii. Photodamage led to decreased photosynthesis, as shown by repressed transcript abundance for photosystem II genes psbA, B, C, O, and Q, photosystem I genes psaB, D, E, H, and N, electron transfer genes petE and F, and ATP synthesis genes ATPF1A and ATPF1B. High-light stress caused more severe damage to C. impressinervis, which showed a stronger response to reactive oxygen species than C. petelotii. In addition, high-light stress promoted the growth and development of high zeatin signalling and increased transcript abundance of adenylate dimethylallyl transferase (IPT) and histidine-containing phosphotransferase (AHP). The identification of transcriptional differences in the regulatory networks that respond to high-light stress and activate recovery of light damage in these two rare species adds to the resources available to conserve them and improve their value through molecular breeding. </p
Table_4_A comparative study on photosynthetic characteristics and flavonoid metabolism between Camellia petelotii (Merr.) Sealy and Camellia impressinervis Chang &Liang.xls
Camellia petelotii (Merr.) Sealy and Camellia impressinervis Chang & Liang belong to the golden subgroup of Camellia (Theaceae). This subgroup contains the yellow-flowering species of the genus, which have high medicinal and ornamental value and a narrow geographical distribution. These species differ in their tolerance to high light intensity. This study aimed to explore the differences in their light-stress responses and light damage repair processes, and the effect of these networks on secondary metabolite synthesis. Two-year-old plants of both species grown at 300 碌mol路m-2路s-1 photosynthetically active radiation (PAR) were shifted to 700 碌mol路m-2路s-1 PAR for 5 days shifting back to 300 碌mol路m-2路s-1 PAR for recovery for 5 days. Leaf samples were collected at the start of the experiment and 2 days after each shift. Data analysis included measuring photosynthetic indicators, differential transcriptome expression, and quantifying plant hormones, pigments, and flavonoids. Camellia impressinervis showed a weak ability to recover from photodamage that occurred at 700 碌mol路m-2路s-1 compared with C. petelotii. Photodamage led to decreased photosynthesis, as shown by repressed transcript abundance for photosystem II genes psbA, B, C, O, and Q, photosystem I genes psaB, D, E, H, and N, electron transfer genes petE and F, and ATP synthesis genes ATPF1A and ATPF1B. High-light stress caused more severe damage to C. impressinervis, which showed a stronger response to reactive oxygen species than C. petelotii. In addition, high-light stress promoted the growth and development of high zeatin signalling and increased transcript abundance of adenylate dimethylallyl transferase (IPT) and histidine-containing phosphotransferase (AHP). The identification of transcriptional differences in the regulatory networks that respond to high-light stress and activate recovery of light damage in these two rare species adds to the resources available to conserve them and improve their value through molecular breeding. </p