A stereocontrolled construction of the side chain of brassinclide and homobrassinolide has been achieved via the tandem vicinal dialkylation of the pyranone moiety as a key step.
Title compounds 2′,2′-dimethylcholesta-2,4-dien[3,2-b]-pyran-4′-one （3）, 2′,2′-dimethyl-3β-substituted cholesta-4,6-dien[7,6- b]-pyran-4′-one （6a,b） and （6c） were prepared by the cyclization of 2-acetylch...Title compounds 2′,2′-dimethylcholesta-2,4-dien[3,2-b]-pyran-4′-one （3）, 2′,2′-dimethyl-3β-substituted cholesta-4,6-dien[7,6- b]-pyran-4′-one （6a,b） and （6c） were prepared by the cyclization of 2-acetylcholesta-2,4-dien-3-ol （2）, 6-acetyl-3β-substituted- cholesta-4,6-dien-7-ol （Sa,b） and （5c） respectively, with pyrrolidine, dry benzene and dry acetone using Dean Stark separator through conventional heating. Furthermore, compounds were also found to be active against Mycobacterium tuberculosis.展开更多
A stereocontrolled construction of the side chain of brassinosteroid was developed via the separated dialkylation and the tandem dialkylation of the pyranone moiety as the key step.
The crystal structure of the title compound （C19H13BrOs） has been detemlined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group P21/c, with a = 10.508（4）, b = 11.354（4）, c = 14.522（5...The crystal structure of the title compound （C19H13BrOs） has been detemlined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group P21/c, with a = 10.508（4）, b = 11.354（4）, c = 14.522（5）A, β = 106.255（4）°, V = 1663.4（10）A3, Mr = 401.20, Z = 4, Do = 1.602 g/cm^3, λ = 0.71073A, F（000） = 808,μ= 2.498 mm^-1, R = 0.0337 and wR = 0.0837 for 2200 observed reflections （1 〉 2σ（Ⅰ））. X-ray analysis reveals that the dihedral angles between planes 1 and 2, 1 and 3, 1 and 4, 2 and 3, 2 and 4, and 3 and 4 are 78.6, 82.5, 87.4, 5.6, 9.5 and 4.9°, respectively. There exists a conjugated system in the molecular structure.展开更多
4-Acetyl-N, N-diethylbenzenesulfonamide (1) was condensed with dimethylformamide dimethy-lacetal (DMF-DMA) to yield the enaminone, which reacts readily with different reagents to give the corresponding pyrazoles, tria...4-Acetyl-N, N-diethylbenzenesulfonamide (1) was condensed with dimethylformamide dimethy-lacetal (DMF-DMA) to yield the enaminone, which reacts readily with different reagents to give the corresponding pyrazoles, triazolopyrimidine, imidazopyridine, pyrimidopyrimidine, pyrazolopyrimidine, benzofuran, pyranone, pyridine, pyrimidine and pyrazolopyridazine derivatives. These compounds were designed to comply with the general features of sulfonamide pharmacophore which act as Cyclooxygenase (COX-2) inhibitors. Virtual screening using molecular docking studies of the synthesized compounds was performed by (MOE), the molecular docking results indicate that, some synthesized compounds suitable inhibitor against (COX-2) with further modification.展开更多
Nucleophilic phosphine and amine catalyst-switched chemodivergent[4+1]and[3+3]annulations of allenyl imides andβ,γ-enones have been developed,furnishing highly substituted 2-cyclopentenone and 2-pyranone derivatives...Nucleophilic phosphine and amine catalyst-switched chemodivergent[4+1]and[3+3]annulations of allenyl imides andβ,γ-enones have been developed,furnishing highly substituted 2-cyclopentenone and 2-pyranone derivatives in moderate to excellent yields.Two plausible reaction mechanisms involving two different ketene intermediates have been proposed to explain the observed chemoselectivity.Moreover,by virtue of theα,β-enone substructure of the[4+1]adducts,1,3-dipolar cycloaddition of nitrile imines has been studied in one-pot to provide various fused pyrazoline derivatives.展开更多
A new synthesis of 2-phenylpyrano[3,2-b]phenothiazin-4（6H）-one derivatives was reported. First 2,10-diacetyl-3-hydroxyphenothiazine （2） was converted into their benzoyloxy esters （3a--3j） using different aro- ma...A new synthesis of 2-phenylpyrano[3,2-b]phenothiazin-4（6H）-one derivatives was reported. First 2,10-diacetyl-3-hydroxyphenothiazine （2） was converted into their benzoyloxy esters （3a--3j） using different aro- matic carboxylic acids in the presence of phosphorous oxychloride in pyridine. Benzoyloxy esters were converted into their 1,3-diones （4a--4j） by using dry KOH in pyridine via Baker-Venkataraman transformation reaction. The 1,3-diones thus obtained were cyclised to pyranophenothiazines （Sa--Sj） by refluxing in an acetic acid/HCl mixture.展开更多
文摘A stereocontrolled construction of the side chain of brassinclide and homobrassinolide has been achieved via the tandem vicinal dialkylation of the pyranone moiety as a key step.
文摘Title compounds 2′,2′-dimethylcholesta-2,4-dien[3,2-b]-pyran-4′-one （3）, 2′,2′-dimethyl-3β-substituted cholesta-4,6-dien[7,6- b]-pyran-4′-one （6a,b） and （6c） were prepared by the cyclization of 2-acetylcholesta-2,4-dien-3-ol （2）, 6-acetyl-3β-substituted- cholesta-4,6-dien-7-ol （Sa,b） and （5c） respectively, with pyrrolidine, dry benzene and dry acetone using Dean Stark separator through conventional heating. Furthermore, compounds were also found to be active against Mycobacterium tuberculosis.
文摘A stereocontrolled construction of the side chain of brassinosteroid was developed via the separated dialkylation and the tandem dialkylation of the pyranone moiety as the key step.
基金the Science and Technology Foundation of Guangdong Province (No. 031792, 06028565)
文摘The crystal structure of the title compound （C19H13BrOs） has been detemlined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group P21/c, with a = 10.508（4）, b = 11.354（4）, c = 14.522（5）A, β = 106.255（4）°, V = 1663.4（10）A3, Mr = 401.20, Z = 4, Do = 1.602 g/cm^3, λ = 0.71073A, F（000） = 808,μ= 2.498 mm^-1, R = 0.0337 and wR = 0.0837 for 2200 observed reflections （1 〉 2σ（Ⅰ））. X-ray analysis reveals that the dihedral angles between planes 1 and 2, 1 and 3, 1 and 4, 2 and 3, 2 and 4, and 3 and 4 are 78.6, 82.5, 87.4, 5.6, 9.5 and 4.9°, respectively. There exists a conjugated system in the molecular structure.
文摘4-Acetyl-N, N-diethylbenzenesulfonamide (1) was condensed with dimethylformamide dimethy-lacetal (DMF-DMA) to yield the enaminone, which reacts readily with different reagents to give the corresponding pyrazoles, triazolopyrimidine, imidazopyridine, pyrimidopyrimidine, pyrazolopyrimidine, benzofuran, pyranone, pyridine, pyrimidine and pyrazolopyridazine derivatives. These compounds were designed to comply with the general features of sulfonamide pharmacophore which act as Cyclooxygenase (COX-2) inhibitors. Virtual screening using molecular docking studies of the synthesized compounds was performed by (MOE), the molecular docking results indicate that, some synthesized compounds suitable inhibitor against (COX-2) with further modification.
基金the financial support for this investigation from the National Natural Science Foundation of China(No.22072111the Fundamental Research Funds for the Central Universities(No.2023IVA055).
文摘Nucleophilic phosphine and amine catalyst-switched chemodivergent[4+1]and[3+3]annulations of allenyl imides andβ,γ-enones have been developed,furnishing highly substituted 2-cyclopentenone and 2-pyranone derivatives in moderate to excellent yields.Two plausible reaction mechanisms involving two different ketene intermediates have been proposed to explain the observed chemoselectivity.Moreover,by virtue of theα,β-enone substructure of the[4+1]adducts,1,3-dipolar cycloaddition of nitrile imines has been studied in one-pot to provide various fused pyrazoline derivatives.
文摘A new synthesis of 2-phenylpyrano[3,2-b]phenothiazin-4（6H）-one derivatives was reported. First 2,10-diacetyl-3-hydroxyphenothiazine （2） was converted into their benzoyloxy esters （3a--3j） using different aro- matic carboxylic acids in the presence of phosphorous oxychloride in pyridine. Benzoyloxy esters were converted into their 1,3-diones （4a--4j） by using dry KOH in pyridine via Baker-Venkataraman transformation reaction. The 1,3-diones thus obtained were cyclised to pyranophenothiazines （Sa--Sj） by refluxing in an acetic acid/HCl mixture.
