Synthese von γ,γ'-Dihydroxysulfonen und γ-Hydroxy-γ'-ketosulfonen

Syntheses of γ,γ'-Dihydroxysulfones and γ-Hydroxy-γ'-ketosulfones Reduction of γ,γ'-diketosulfones 1 with dimethylaminoborane leads to γ,γ'-dihydroxysulfones 3 via γ-hydroxy-γ'-ketosulfones 2 . The influence of substituents on the ratio of the yields of 2 and 3 is investigated.     

Analysis of γβ, βγ, γγ, ββ multiple turns in proteins

Abstract: The number of γ‐turns in a representative protein dataset selected from the current Protein Data Bank has increased almost seven times during the past decade. Eighty percent classic γ‐turns and 57% inverse γ‐turns are associated as multiple turns with either another γ‐turn or a β‐turn. We refer to these as multiple turns of the (γβ)_1,2,3 or (βγ)_1,2,3 type, depending upon whether the γ‐turn is before or after the β‐turn along the protein chain, respectively. However, for multiple turns involving only γ‐turns, we follow the nomenclature analogous to that proposed earlier for the multiple (or double) β‐turns. Fifty‐eight per cent β‐turns are associated as multiple turns with another β‐turn. We extracted multiple turns from the protein dataset and classified them on the basis of individual γ‐ or β‐turn types and the number of overlapping residues. Furthermore, we evaluated the amino acid positional potentials and determined the statistically significant amino acid preferences, hydrogen bond/side‐chain interaction preferences in the multiple turns and secondary structure preferences for residues immediately flanking these turns. The results of our analysis would be useful in the modeling, prediction or design of multiple turns in proteins. The amino acid sequence corresponding to the multiple turn, position in the protein chain, PDB Code/chain in which multiple turn is present and the individual turn types constituting the multiple turns are available from our website and this information would also be integrated in our Database of Structural Motifs in Proteins ( http://www.cdfd.org.in/dsmp.html ).     

Analysis of γβ, βγ, γγ, ββ continuous turns in proteins

Abstract: We report the observation of continuous turns in proteins which comprise individual γ‐turns or β‐turns or both that are situated immediately one after the other along the polypeptide chain. The continuous turns were identified from a representative data set of three‐dimensional protein crystal structures. The γβ/βγ, γγ and ββ continuous turns represent peptides of varying amino acid residue lengths and conformations. The continuous turns frequently observed in proteins were: γβ, between a coil and a strand; βγ, between a helix and a strand; γγ, between coils; and ββ, either between a strand and a coil or between strands or coils. We determined the statistically significant amino acid residue preferences at individual positions in the turn, calculated amino acid positional potentials and analyzed main chain hydrogen bonds and side‐chain interactions likely to stabilize the continuous turns. The data on continuous turns have been integrated in the database of structural motifs in proteins (DSMP) on our web server at ( http://www.cdfd.org.in/dsmp.html ). This is useful to make queries on sequences compatible with different continuous turns.     

3-O-demethyl-2,3-di-epi-fortimicins and 3-O-demethyl-3-epi-fortimicins

Syntheses of the 3-O-demethyl-2,3-di-epi-fortimicins A and B and the 3-O-demethyl-3-epi-fortimicins A and B have been accomplished in processes the key steps of which were solvolyses of 4-N-acetyl-3-O-demethyl-3-O-methanesulfonylfortimicin derivatives. Antibacterial activities of the new antibiotics are reported.     

3',3'-Difluoro-3'-deoxythymidine: comparison of anti-HIV activity to 3'-fluoro-3'-deoxythymidine.

3',3'-Difluoro-3'-deoxythymidine (3) has been synthesized in four steps from thymidine, and characterized by 1H NMR and NOE experiments. The JHF coupling constants support a conformation in solution that is predominantly 2'-endo (S). Although conformationally and sterically nucleoside 3 may resemble other thymidine analogs which are active against HIV-1, 3 is virtually inactive.     

Cyanolyse von γ-Hydroxy-γ'-ketosulfonen: ein neuer Weg zur Darstellung von γ-Sultinen

Cyanolysis of γ-Hydroxy-γ'-ketosulfones: A New Approach to γ-Sultines Cleavage of γ-hydroxy-γ'-ketosulfones 3 with cyanide leads to γ-ketonitriles 4 and γ-hydroxysulfinic acids 5 . Compounds 5 by cyclisation yield γ-sultines 6 .     

Lactone, 10. Mitt. Zur Synthese N-heterocyclisch substituierter γ,γ-Diphenyl-γ-butyrolactone

Lactones, X: Synthesis of γ,γ-Diphenyl-γ-butyrolactones Substituted by N-Heterocycles Starting from 3 and 16 , syntheses of γ,γ-diphenyl-γ-butyrolactones with N-heterocycles at the α-position are described. Scope and limitation of the syntheses, tautomerism and stereochemistry of the products as well as spectroscopic results which are inconsistent with data from the literature are discussed.     

3-二甲胺基-3-苯基丙醇的制备

苯甲醛和丙二酸经Knoevenagel缩合、NaBH4-I2体系还原得3-氨基-3-苯基丙醇，再经Eschweiler-Clark反应制得3-二甲胺基-3-苯基丙醇，总收率29％。     

重症监护室患者呼吸道感染铜绿假单胞菌耐药性变迁分析

研究2008-2010年从重症监护室（ICU）患者分离的铜绿假单胞菌菌株对常用抗菌药物耐药率的变迁。方法回顾性分析2008-2010年本院ICU患者所有分离株,药敏试验采用K-B纸片扩散法。结果ICU患者呼吸道铜绿假单胞菌感染例数从2008年89例上升至2010年113例。对头孢他啶、头孢吡肟、亚胺培南耐药率逐年上升,头孢他啶从2008年的30．50％升至2010年的35．05％、头孢吡肟2010年升至38．94％、亚胺培南2010年升至46.24％;对哌拉西林／他唑巴坦耐药率最稳定,2008-2010年分别为21．15％、18．82％、20．93％。结论铜绿假单胞菌是医院感染常见条件致病菌,临床实验室定期进行耐药监测、指导临床合理用药,对防止院内感染的发生具有重要的意义。     

PTPMeg2抑制NIH3T3/STAT3CA细胞模型STAT3转录活性的研究

目的探讨磷酸酶PTPMeg2对NIH3T3/STAT3CA细胞模型的增殖及STAT3转录活性的影响。方法构建STAT3异常突变的细胞模型NIH3T3/STAT3CA,MTT法和裸鼠异体移植瘤实验分别用于观察PTPMeg2对NIH3T3/STAT3CA细胞体外和体内增殖的影响,免疫共沉淀实验用于PTPMeg2与STAT3CA相互作用的研究,双荧光素酶报告基因法用于转录活性的研究。结果 PTPMeg2对NIH3T3/STAT3CA细胞在体外和体内都具有增殖抑制作用,与对照组比较均具有明显的统计学意义。PTPMeg2对NIH3T3/STAT3CA细胞的转录活性具有抑制作用,而PTPMeg2的突变体(PTPMeg2C515S)和ShPTPMeg2则无效。结论 PTPMeg2对NIH3T3/STAT3CA细胞具有增殖抑制作用,其作用机制可能与抑制STAT3的转录活性有关。     

Mutagenicity of 3-nitrodibenzofuran and 3-aminodibenzofuran

Mutagenicities of 3-nitrodibenzofuran and 3-aminodibenzofuran were examined using Salmonella typhimurium TA98 and TA100. Strong mutagenicity was found in both compounds. The mutagenic potency of 3-nitrodibenzofuran was approximately 3.5-fold stronger in TA98 and twice stronger in TA100 than that of benzo[a]pyrene. Mutagenicity of 3-aminodibenzofuran was observed under metabolic activation and was 10 times stronger in TA98 and about 5 times stronger in TA100 than that of benzo[a]pyrene.     

Synthesis, antitumor activity, and antiviral activity of 3-substituted 3-deazacytidines and 3-substituted 3-deazauridines

Novel 3-substituted analogues of 4-amino-1-beta-D-ribofuranosyl-2(1H)-pyridinone (3-deazacytidine, 3) and 4-hydroxy-1-beta-D-ribofuranosyl-2(1H)-pyridinone (3-deazauridine, 4) have been synthesized and tested for antitumor and antiviral activity. Thus the 3-chloro (9a), 3-bromo (9b), and 3-nitro (9c) analogues of 3 and the 3-chloro (9d), 3-bromo (9e), and 3-nitro (9f) analogues of 4 were prepared by standard glycosylating procedures. Novel requisite heterocycles 4-amino-3-chloro-2(1H)-pyridinone (7a) and 4-amino-3-bromo-2(1H)-pyridinone (7b) were prepared by halogenating 4-amino-2(1H)-pyridinone (5). Requisite heterocycles 4-amino-3-nitro-2(1H)-pyridinone (7c), 3-chloro-4-hydroxy-2(1H)-pyridinone (7d), 3-bromo-4-hydroxy-2(1H)-pyridinone (7e), and 4-hydroxy-3-nitro-2(1H)-pyridinone (7f) were synthesized by known procedures from 4-hydroxy-2(1H)-pyridinone (6). Structure proof of target nucleosides was provided by independent synthesis, 1H NMR, and UV. Compounds 9a-f were devoid of activity against intraperitoneally implanted L1210 leukemia in mice. Compound 9f displayed significant activity against rhinovirus type 34 grown in WISH cells. 4-Amino-3-fluoro-1-beta-D-ribofuranosyl-2(1H)-pyridinone (1) displayed good activity against intraperitoneally implanted P388 leukemia in mice, but it was devoid of activity against M5076 sarcoma, amelanotic (LOX) melanoma xenograft, and subrenal capsule human mammary carcinoma MX-1 xenograft in mice. Compound 1 also displayed significant activity against rhinovirus type 34.