Synthesis of Derivatives of 2,6-Dideoxy-2,2-Difluoro-3-O-Methyl-l-Arabinopyranose (2,2-Difluorooleandrose)

Abstract

L-Oleandrose is the carbohydrate constituent of the potent anthelmintic agents the avermectins. Diethylaminosulfur tri-fluoride treatment of appropriate uloses did not give gem-difluoro sugars. Trifluorofluoroxymethane or xenon difluoride addition to the double bond of 4-O-benzoyl-6-deoxy-2-fluoro-3-O-methyl-L-glucal produced protected 2,2-difluorooleandrose derivatives activated at their anomeric center and ready for glycosidation.     

Synthesis of Aminomethyl Derivatives of 2,6-Dihydroxynaphthalene

Russian Journal of Organic Chemistry - Mono- and bis-aminomethyl derivatives of 2,6-dihydroxynaphthalene containing cyclic amine residues have been synthesized, and the formation of a strong...     

Synthesis of Novel 3,7-Dihydro-purine-2,6-dione Derivatives

Forty-six novel 3,7-dihydro-purine-2,6-dione derivatives (substituted xanthines) with great structural diversity were synthesized for biological activity screening. Three series of substituted xanthine analogs have been prepared in moderate to excellent yields.     

嘌呤6位含氟基团取代衍生物的合成

以6-氯嘌呤衍生物和6-溴嘌呤衍生物为原料, 通过卤素交换反应制得6-氟嘌呤衍生物; 通过烷氧基化反应制得6-三氟乙氧基嘌呤衍生物, 通过三氟甲基化反应制得6-三氟甲基嘌呤衍生物, 所有化合物的结构均经过1H NMR, MS和元素分析表征. 分析了所得化合物对稻草芽孢杆菌、黑曲酶和热带假丝酵姆的抑菌活性, 结果表明: 化合物2b, 4b对稻草芽孢杆菌(Bacillus subtillis)有比较好的杀菌效果, 化合物4a, 4b对黑曲酶(Aspergillus niger)有比较好的杀菌效果, 化合物3b, 4b对热带假丝酵姆(Cardida tropicals)有比较好的杀菌效果.     

6-硝基苯并咪唑杂环衍生物的合成

以６－硝基苯并咪唑－１－乙酰肼和５－（６－硝基苯并咪唑－１－亚甲基）－３－巯基－４－氨基－１,２,４－三唑为原料,在不同条件下合成了一系列新的均三唑〔３,４－ｂ〕－１,３,４－噻二唑,１,２,４－三唑和１,３,４－恶二唑衍生物。化合物的结构均经元素分析、＾１Ｈ ＮＭＲ、ＩＲ和ＭＳ确证,并对其波谱性质进行了讨论。     

2,6-吡啶二甲酰双吡唑衍生物的合成

合成了4个吡唑及其衍生物,其结构经元素分析,IR,1^HNMR和^13CNMR等表征。     

新型2,6-二取代嘌呤衍生物的合成及其抗肿瘤活性

以2,6-二氯嘌呤为原料,对其2-位和6-位进行结构修饰,合成了8个新型2,6-二胺嘌呤类衍生物(3a~3h),其结构经¹H NMR, IR和MS（ESI）表征。采用MTT法研究了3a~3h对人胃癌SGC-7901细胞的体外抗肿瘤活性。结果表明: 3a, 3b, 3c, 3g具有良好的抗肿瘤活性,其中3c（IC₅₀ 65.01 μmol·L^-1）对人胃癌细胞SGC-7901的抑制作用最强。     

An Efficient and Convenient Synthesis of 2-Thio[1,2,4]triazolo[1,5-c]quinazoline and its Derivatives

Summary. 4-Hydrazinoquinazoline with carbon disulfide underwent a recyclization reaction. The title compound 2-thio[1,2,4]triazolo[1,5-c]quinazoline was obtained after treatment of 4-hydrazinoquinazoline with potassium ethylxanthogenate via a facile in situ Dimroth-like rearrangement of the expected [4,3-c] system. Its structure was established by X-ray diffraction study and confirmed by an independent synthesis, starting from o-aminobenzonitrile.     

A Cyclic Sulfate Approach to the Synthesis of 1,4-Dideoxy-1,4-imino Derivatives of L-Xylitol,L-Arabinitol and D-Xylitol

Polyhydroxylated pyrrolidines are readily accessible by ring opening of a 1,4-cyclic sulfate function in pentitol derivatives by nitrogen nucleophiles and further processing of the in situ generated charged sulfate group.     

Synthesis and Properties of Functional Derivatives of 2,6-Diisobornylphenol and 2-Isobornyl-6-(1-phenylethyl)phenol

New isobornylphenol derivatives have been produced by introducing allyl, hydroxypropyl, and chloropropyl groups into the para-position of 2,6-diisobornylphenol and 2-isobornyl-6-(1-phenylethyl)phenol. The radical scavenging and antioxidant activity and the membrane-protective properties of the newly-obtained compounds in chemical and biological model systems were studied.     

2,6-二氧杂双环[3.2.1]辛烷类衍生物的串联合成

以2-甲基-4-戊烯-1,2-二醇和芳香醛为原料, 三氯化铟为催化剂, 得到了一系列1,3-二取代2,6-二氧杂双环[3.2.1]辛烷类衍生物. 整个反应采用一锅法, 反应条件简单且产率高. 所有的化合物均用¹H NMR, ¹³C NMR和质谱法进行了表征, 并用NOESY确立了分子的相对构型.     

Synthesis and reactions of 6-chloro-2,2,6-trimethyl- and 2,6-dichloro-2,6-dimethyl-1-oxa-2,6-disilacyclohexanes

6-Chloro-2,2,6-trimethyl- and 2,6-dichloro-2,6-dimethyl-1-oxa-2,6-disilacyclohexanes have been synthesized. Their behavior in alcoholysis, amination, acetoxylation, and reduction reactions has been studied.     

Analogues of Sialic Acids as Potential Sialidase Inhibitors Synthesis of 2-C-Hydroxymethyl Derivatives of N-Acetyl-6-amino-2,6-dideoxy-neuraminic Acid

The intramolecular cycloaddition of the previously described azidoalkene 16 , the related diacetates 7 and 13 , and the monoacetate 8 led diastereoselectivity to the (2R)- and (2S)-configurated hydropyridotriazoles 17 , 9 and 11 , 14 and 15 , and 10 and 12 , respectively (Scheme 1). Thermolysis of 16 gave also the aziridine 18 , its proportion increasing with reaction time. The diastereoselectivity of the cycloaddition- is rationalized on the basis of steric interactions and of H? bonds in the transition state. Photolysis in benzene partially transformed 9 into the aziridine 19 . Treatment of 9 with aqueous AcOH gave 19 and the tetrahydrofuran 20 , with AcOH in benzene 20 and the triacetate 23 , and with aqueous H₂SO₄ in THF, the primary alcohol 22 (room temperature) or 19 and 22 (0°). Deacetylation of 9 followed by reaction with pyridinium hydrochloride led to the tetrahydrofuran 21 and the chloride 24 (Scheme 2). The diacetate 22 and the triacetate 23 gave the tripl 25 which was deprotected to 26 . Reduction of the keto-aziridine 18 (NaBH₄) gave the alcohols 27 and 29 which were acetylated to give 28 and 19 , respectively (Scheme 3). Treatment of the aziridine 28 with AcOH in benzene followed by deacetylation gave 30 and hence 31 . AcOH in benzene transformed the triazoline 15 first into the aziridine 32 and hence into 33 , which was deprotected to give the triol 34 and hence 35 . The 2-(hydroxymethyl)piperidines 26 , 31 , and 35 inhibited Vibrio cholerae sialidase with K₁ = 3.8 · 10^?2 M, 3.4 · 10^?3 M, and 1.5 · 10^?4 M, respectively. The conformation of the glycerol side chain of these compounds and of the unbranched piperidines 2–4 deviates from the one of Neu5Ac (and Neu2en5Ac). This finding is rationalized by an H-bond between OH? C(8) and NH? C(6). The conformations and the K₁ values of 26 , 31 , and 35 correlate with each other.     

Synthesis and reactions of 6-chloro-2,2,6-trimethyl- and 2,6-dichloro-2,6-dimethyl-1-oxa-2,6-disilacyclohexanes

6-Chloro-2,2,6-trimethyl- and 2,6-dichloro-2,6-dimethyl-1-oxa-2,6-disilacyclohexanes have been synthesized. Their behavior in alcoholysis, amination, acetoxylation, and reduction reactions has been studied.     

Synthesis and Inhibitory Activity Evaluation of 2,6‐Disubstituted Purine Derivatives

A series of novel 2,6‐disubstituted purine derivatives were designed and synthesized from 2,6‐dichloropurine. The structures of target compounds were determined by ¹H‐NMR, ¹³C‐NMR, and HRMS. The synthesized compounds were evaluated for their inhibitory activities against lung cancer cell lines of A549 and liver cancer cell lines of Bel‐7402. 2‐(4‐Benzyloxy‐phenylamino)‐6‐(cyclohexylamino)purine( 3 ), 2‐(4‐chloro‐phenylamino)‐6‐(n‐butylamino)purine ( 5 ), 2‐(4‐morpholinoamino)‐6‐(4‐hydroxy‐phenylamino)purine ( 9 ), and 2‐(4‐O‐galactosyl‐phenylamino)‐6‐(cyclohexylamino)purine ( 12 ) exhibited moderate inhibitory activity.     

The Synthesis of 6-Alkyl-5-Fluorouracil Derivatives

As an antitumor drug, because of its low efficacy and high toxicity, several modifications have been made on 5-fluorouracil (5-Fu). Some compounds have been found to be highly efficient and much less toxic for the treatment of various solid tumors1~4. Among them, deoxyfluridine (Furtulon) has been used clinically for several years. In our previous work, we have prepared several substituted derivatives of 5-Fu and the primary result shows that some of them have certain antitumor activity5,6. …     

Synthesis,Photo-physical Properties and Cell Imaging of Meso-2,6-dichlorophenyl Boron-dipyrromethene Derivatives

The meso-2,6-dichlorophenyl boron-dipyrromethene(BODIPY) derivative 1 was synthesized and characterized by single-crystal X-ray diffraction analysis, 1 H NMR and Esi-HRMS. Compound 1 crystallizes in monoclinic, space group P21/n with a = 8.717(4), b = 20.938(9), c = 12.402(6) ?, β = 98.660(7)°, V = 2237.7(17) ?3, D3 c = 1.333 Mg/cm, F(000) = 936, μ = 0.319 –mm1, Z = 4, the final R = 0.0537 and wR = 0.1556 for 5064 observed reflections with I 2ζ(I). Its photophysical properties were investigated by fluorescence and UV-Vis spectrum. 1 shows high fluorescence quantum yield in different solvents and poor solvent effect. In addition, compound 1 has high values of initial decomposition temperature(298 ℃). Moreover, cell imaging experiments showed 1 is promising for further bioimaging applications.     

Synthesis and Structural Characterization of Pyridine-2,6-dicarboxamide and Furan-2,5-dicarboxamide Derivatives

Derivatives based on pyridine-2-6- and furan-2,5-dicarboxamide scaffolds reveal numerous chemical properties and biological activities. This fact makes them an exciting research topic in supramolecular and coordination chemistry and in discovering new pharmacologically-active compounds. This work aimed to obtain a series of symmetrical pyridine-2-6- and furan-2,5-dicarboxamides through a condensation reaction of the appropriate acyl chlorides and aromatic amides. Successful syntheses were confirmed with NMR spectroscopy. We solved their crystal structures for seven compounds; two pyridine and five furan derivatives. Based on our crystallographic studies, we were able to indicate supramolecular features of the crystals under investigation. Additionally, Hirshfeld surface analysis allowed us to calculate a distribution of intermolecular contacts in the dicarboxamide crystals.     

Derivatives of 2,6-dihydroxy-4,5-dihydropyrimidines

By the catalytic hydrogenation (5% of Rh on Al₂O₃) of orotic acid and its derivatives, DL-4,5-dihydroorotic and DL-1-methyl- and DL-1,3-dimethyldihydroorotic acids have been obtained. A number of salts of DL-4,5-dihydroorotic acid with amines have been synthesized.