青蒿砜—氨基二硫代甲酸酯类化合物的合成

以双氢青蒿素(DHA)为原料,与草酰氯发生酰化反应,然后经硫代吗啉取代反应、双氧水氧化反应得到青蒿砜1,由1经过烷基化反应、脱硅保护基和碘代反应得到青蒿砜-碘代物2α;以三乙胺为催化剂,2α与哌嗪类化合物、CS_2在"一锅煮"条件下得到青蒿砜-氨基二硫代甲酸酯化合物(3a~3d)。所有目标化合物的结构均经~1H NMR、~(13)C NMR、IR和HR-ESI-MS得到确证。     

竹红菌乙素与巯基乙酸、正辛硫醇的反应

本文研究了竹红菌乙素与巯基乙酸、正辛硫醇的反应。在室温下,在含氨水的二甲基亚砜溶液中,乙素同巯基乙酸或正辛硫醇迅速反应,主要产物为乙素母核上5位或/和8位氢被巯基化合物取代的衍生物。有氧参加反应时,还得到乙素母核氢被羟基取代的产物。这些取代产物的吸收光谱都比乙素本身明显地红移。乙素和巯基乙酸的反应产物有较好的水溶性,且保持了乙素所具有的光化学活性。文中还用UV和ESR谱,猝灭实验探讨了反应机制。     

青蒿素及其一类物结构和合成的研究——Ⅺ.环氧青蒿酸的分离和鉴定

青蒿亦称黄花蒿(Artemisia annua L.),为菊科植物,我国民间用于治疗疟疾。据报道,该植物的主要成分为挥发油、烯炔和倍半萜内酯。倍半萜内酯有青蒿素、青蒿甲素、青蒿乙素及青蒿丙素(脱氧青蒿素)。此外,还有青蒿酸、香豆素及黄酮等。我们由山东七、八月所产青蒿提取物中分到青蒿素、青蒿甲素、青蒿乙素、青蒿丙     

青蒿素及其一类物的结构和合成 XXIII: 脱氧青蒿素碱降解产物内酯构型的测定

本文根据具有双氢青蒿乙素这类结构的化合物, 其内酯构型和内酯羰基α-位氢的化学位移间存在的经验性规律, 推定了脱氧青蒿素碱降解产物的内酯构型应为β-顺式内酯构型2, 并通过合成此降解产物加以证实, 同时讨论了降解产物形成的机理。     

青蒿素及其一类物的结构和合成 XXIII: 脱氧青蒿素碱降解产物内酯构型的测定

本文根据具有双氢青蒿乙素这类结构的化合物,其内酯构型和内酯羰基α-位氢的化学位移间存在的经验性规律,推定了脱氧青蒿素碱降解产物的内酯构型应为β-顺式内酯构型2,并通过合成此降解产物加以证实。同时讨论了降解产物形成的机理。     

青蒿素及其一类物的结构和合成XI.青蒿乙素及异青蒿乙素的立体选择性合成

本文报道以青蒿酸为原料合成青蒿乙素(1)及其6β-异构体4. 并根据红外光谱丶核磁共振谱丶圆二色散以及有关的化学反应确定了究们的结构和构型.     

青蒿素及其一类物的结构和合成——Ⅺ.青蒿乙素及异青蒿乙素的立体选择性合成

本文报道以青蒿酸为原料合成青蒿乙素(1)及其6β-异构体4.并根据红外光谱、核磁共振谱、圆二色散以及有关的化学反应确定了它们的结构和构型.     

青蒿素及其一类物结构和合成的研究Ⅶ.异青蒿乙素的全合成

异青蒿乙素(A)可用R(+)-香草醛为原料,通过十步合成3(亦能从2降解而得),然后由3经5得到6,最后用二苯二硒脱氢和间氯过苯甲酸环氧化而成.环氧的构型经~1H NMR及双竖键破环反应证明.α-次甲基γ-内酯的构型用圆二色散测定. 结构和内酯构型最后经X射线衍射确证。     

青蒿素及其一类物结构和合成的研究XV. 青蒿酸A,B环的构型

青蒿酸甲酯4环氧化所得的化合物5和6经三氟化硼重排生成的7及其表异构物8在圆二色谱294nm 附近分别出现负的和正的Cotton 效应. 因而推定青蒿酸的A,B环为顺式稠合. 用双氢青蒿酸甲酯也得到相同的CD结果.     

新型青蒿砜-酯类衍生物的合成及其抗癌活性研究

以双氢青蒿素为起始原料,经胺化、氧化、烷基化、酯化反应,快速、高效地合成了一系列青蒿砜系列衍生物,目标化合物的结构通过IR、1H NMR、13C NMR和HRMS得到了确证;以四甲基偶氮唑盐比色法(MTT法),研究了该类化合物对人肝癌细胞株SMMC-7721的抗癌活性.初步研究结果表明,该类化合物具有明显地抑制人肝癌细胞增殖、诱导其凋亡的细胞活性,给药72 h,半数抑制浓度IC50最优值为0.06μmol/L.同时采用Annexin/PI流式细胞分析法检测化合物7b对人肝癌细胞SMMC-7721的凋亡情况,结果显示实验组与正常对照组相比人肝癌细胞早期凋亡率和总凋亡率均显著增加.在与青蒿素、双氢青蒿素(DHA)和青蒿砜的对比实验中发现,该类化合物的抗肿瘤活性明显提高,表现出了该类化合物在抗癌药物开发方面具有潜在的应用价值.     

Direct amination of 2-methyl-7-chloroceramidonine with ammonia or sodamide

Treatment of 2-methyl-7-chloroceramidonine with aqueous ammonia gives 2-methyl-6-amino-7-chloro-ceramidonine, while treatment with sodamide gives 2-methyl-7-chloro-8-aminoceramidonine.     

Alkaloid studies. VI. lithium aluminum hydride reduction of apoyohimbine and the synthesis of 3,4,5,6-tetradehydroyohimbane-16-methanols

Catalytic reduction of apoyohimbine ( 1 ), prepared from yohimbine and thionyl chloride in pyridine, gives methyl yohimbane-16α-carboxylate ( 2 ) after equilibration with methoxide. LAH reduction of 2 or β-yohimbine O-tosylate ( 3 ) gives yohimbane-16α-methanol ( 4a ). LAH reduction of 1 affords yohimbane-16α-carboxaldehyde ( 5 ), yohimb-16-ene-16-methanol ( 6a ) and yohimbane-16β-methanol ( 7a ). Structural assignments 6a and 7a are confirmed by mass spectral measurements. Pmr spectra of 4a, 6a and 7a and their O-acetates 4b, 6b and 7b are discussed. LAH reduction of apo-α-yohimbine ( 8 ) affords alloyohimb-16-ene-16-methanol ( 9 ). Dehydrogenation of 4a with palladium black and maleic acid gives 3,5,4,5,6-tetradehydroyohimbane-16α-methanol ( 10 ) iodide, and 7a gives 3,4,5,6-tetradehydroyohimbane-16β-methanol ( 11 ) iodide and picrate. Properties of 10 and 11 differ from those of melinonine E.     

Reaction of 1,2-diamino-4-nitrobenzene with 1,5-diketones. Synthesis and oxidative reactions of nitrobenzimidazoles

Reaction of 1,5-diketones with 1,2-diamino-4-nitrobenzene gave a mixture of the 6- and 7-nitro derivatives of 4a,9-diaza-1,2,4a,9a-tetrahydrofluorene. Oxidation of the 6-nitro derivatives with MnO₂ gives para-quinone imines with elimination of the nitro groups. Oxidation of the 7-nitro derivative and oxidative conjugation of 5-nitro-2,2-pentamethylene-1,2-dihydrobenzimidazole with primary amines in the presence of MnO₂ gives nitro ortho-quinone imines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 927–930, July, 1990.     

Unconventional nucleotide analogues—II Synthesis of the adenyl analogue of willardiine

The Michael addition of adenine (6a), 6-chloropurine (6b) and 2,6-dichloropurine (6c) to methyl -chloroacrylate gives high yields of the corresponding adducts (7a-7c). Hydrolysis and amination of 7a gave the adenyl analogue of Willardiine (2).     

Synthesis and properties of substituted 1-aryl-1,4-dihydro-4-oxopyrido[2,3-d]-pyrimidines

The reaction of 2-arylamno-6-methylnicotinonitriles with acetic anhydride or benzoyl chloride gives N-acyl-2-arylamino-6-methylnicotinonitriles. Upon treatment with hydrogen chloride in anhydrous ethanol, these products are converted to 2-substituted 1-aryl-1,4-dihydro-7-methyl-4-oxopyrido[2,3-d]pyrimidines. Heating amides of 2-aryl-amino-6-methylnicotinic acids or 1-aryl-2,7-dimethyl-1,4-dihydro-4-oxopyrido[2,3-d]-pyrimidines at reflux with acetic anhydride in the presence of anhydrous sodium acetate gives 1-aryl-2-acetonyl-7-methyl-1,4-dihydro-4-oxopyrido[2,3-d]pyrimidines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 114–116, January, 1985.     

Synthesis of substituted pteridines

Conclusions The cyclocondensation of 2,5,6-triamino-4-oxo-3,4-dihydropyrimidine and tetraaminopyrimidine with butylthioacetone and 2-butylthiopropanal gives 7-methylpteridines, while the reaction of these pyrimidine derivatives with 2-phthalimidopropanal, 1,1-dibutoxyacetone, 1,1-dichloroacetone, and 1,1-dibromoacetone gives mixtures of 6- and 7-methylpteridines.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 452–455, February, 1986.     

Hetarylnitrenes V. Reactions of Tetrazolopyrazine Ring Contraction of Nitrenodiazines in Solution. Preliminary communication

Thermolysis of tetrazolopyrazine ( 1 ) in organic solvents gives pyrazinylnitrene ( 2 ) which undergoes ring contraction to 1-cyanoimidazole ( 3 ). 7-Methyl-5-methylthio-tetrazolo[1,5-c]pyrimidine ( 4 ) likewise gives 1-cyano-2-methylthio-4-methyl-imidazole ( 6 ). The two tetrazoles also undergo ring contraction to 1-cyanoimidazoles by gas chromatography, and 1 gives a low yield of 3 by photolysis. Thermolysis of 1 and 4 in cyclohexane gives aminopyrazine ( 7 ) and 6-amino-4-methyl-2-methylthio-pyrimidine ( 8 ), respectively. Tetrazolo[1,5-a]pyrimidines ( 9 ) give only 2-aminopyrimidines ( 10 ). 1-Cyanoimidazole, formed by thermolysis of 1 in acetic acid, reacts further to give 1-acetylimidazole, which with more acetic acid gives imidazole and acetic anhydride. An earlier report [2] of ring expansion of pyrazinylnitrene in acetic acid is discredited. In protic deuteriated solvents (D₃O, CH₃OD), tetrazolopyrazine reacts as an enamine, specifically exchanging H? C(6) for deuterium.     

Über Pterinchemie 67. Mitteilung Zum Verlauf der katalytischen Reduktion von 6, 7-Diphenylpterin

On the pathway of the catalytic reduction of 6,7-diphenylpterin The pathway of the hydrogen addition to the pyrazine ring of 6, 7-diphenylpterin ( 1a ) during acid-catalyzed reduction was elucidated. Initial hydrogenation of the 5, 6-double bond produces 6, 7-diphenyl-5, 6-dihydropterin ( 2a ); this then undergoes a [1, 2]-H-rearrangement, which yields the thermodynamically more stable 6, 7-diphenyl-7, 8-dihydropterin ( 3a ). Subsequent reduction of 3a gives 4 .     

Asymmetric Diels-Alder and Ficini reactions with alkylidene β-ketoesters catalyzed by chiral ruthenium PNNP complexes: mechanistic insight

Hydride abstraction from the β-position of the enolato ligand of the previously reported complex [Ru(3a-H)(PNNP)]PF(6) (5a; 3a-H is the enolate of 2-tert-butoxycarbonylcyclopentanone) with (Ph(3)C)PF(6) gives the dicationic complex [Ru(6a)(PNNP)](2+) (7a) as a single diastereoisomer, which contains the unsaturated β-ketoester 2-tert-butoxycarbonyl-2-cyclopenten-1-one (6a) as a chelating ligand. The methyl analogue 2-methoxycarbonylcyclopentanone (3b) gives [Ru(3b-H)(PNNP)]PF(6) as a mixture of noninterconverting diastereoisomers (ester group of 3b trans to P, 5b; or to N, 5c), which were separated by column chromatography. Hydride abstraction from 5b (or 5c) yields diastereomerically pure [Ru(6b)(PNNP)](2+) (7b or 7c). Complexes 7b and 7c do not interconvert at room temperature in CD(2)Cl(2) and form opposite enantiomers of the Diels-Alder adduct upon reaction with Dane's diene (1 equiv). X-ray studies of 7a, 5b, and 5c give insight into the origin of enantioselection and the sense of asymmetric induction in the previously reported asymmetric Diels-Alder and Ficini cycloaddition reactions with 2,3-disubstituted butadienes and ynamides, respectively. Stoichiometric reactions (substrate coordination, cycloaddition, and product displacement) between [Ru(OEt(2))(2)(PNNP)](2+) (2), 6b (or 6a), and Dane's diene (15, to give estrone derivatives) or N-benzyl-N-(cyclohexylethynyl)-4-methylbenzenesulfonamide (17, to give cyclobutenamides) suggest that product displacement from the catalyst is turnover limiting.     

Products of the reaction of 2-chloro-6-thio-7-methyl-purine with amines

Treatment of 2-chloro-6-thio-7-methylpurine with aniline, piperidine, or morpholine with heating in DMF gives 2-phenylamino(piperidino or morpholino)-6-thio-7-methylpurine. The scheme for the formation of the side products 2,6-dithio-and 2,6-dipiperidino-7-methylpurine is discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 82–84, January, 2000.