Synthesis of 4,5-Seco-Derivatives of Allobetulin

4,5-Seco-19,28-epoxy-18-olean-3,5-dione wasprepared by ozonation of 19,28-epoxy-18-olean-3(5)-ene. The structures of the synthesized compounds were confirmed using spectral data.     

Allobetulin and its derivatives: synthesis and biological activity

This review covers the chemistry of allobetulin analogs, including their formation by rearrangement from betulin derivatives, their further derivatisation, their fusion with heterocyclic rings, and any further rearrangements of allobetulin compounds including ring opening, ring contraction and ring expansion reactions. In the last part, the most important biological activities of allobetulin derivatives are listed. One hundred and fifteen references are cited and the relevant literature is covered, starting in 1922 up to the end of 2010.     

莰烯醛缩氨基硫脲类化合物的合成及抗菌活性

用莰烯醛为原料,分别与氨基硫脲、4-苯基-3-氨基硫脲、4-甲基-3-氨基硫脲反应,合成了3种莰烯醛缩氨基硫脲类化合物:莰烯醛缩氨基硫脲(3a)、莰烯醛缩-4-苯基氨基硫脲(3b)、莰烯醛缩-4-甲基氨基硫脲(3c).3个化合物的结构通过核磁共振、红外光谱和质谱分析进行了表征;并且采用菌丝生长法对10种植物病原菌的生长...     

Synthesis and antimicrobial activity of N-analogous corollosporines

Corollosporine is an antimicrobial metabolite, which was isolated from the marine fungus Corollospora maritima. Owing to its basic 4-hydroxyphthalic acid anhydride structure, it has become an attractive target for a structure/activity relationship modelling of derived compounds with potential antibiotic activity. In this regard we report on the straightforward synthesis of hetero analogous corollosporines, which were easily prepared by a three-step reaction sequence, taking advantage of a novel multicomponent reaction (AAD-reaction) and a subsequent aromatization/Grignard reaction protocol. Furthermore, the obtained products were tested in several biological assays to evaluate their antimicrobial activity.     

Synthesis and antimicrobial activity of tris phosphonates

Syntheses of novel [{(3‐dialkoxy‐phosphoryl)‐(substituted‐phenyl‐methyl)‐2‐oxo‐2‐phenyl‐2,3‐dihydro‐2λ⁵–benzo [1,3,2] diazaphosphol‐1‐yl}‐(substituted‐phenyl)‐methyl]‐phosphonic acid diethyl/dimethyl esters ( 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h , 3i , 3j ) were conveniently accomplished by cyclocondensation of [(2‐{(dimethoxy‐phosphoryl)‐phenyl‐methyl)‐amino}‐phenyl amino)‐phenyl‐methyl]phosphonic acid diethyl/dimethyl esters ( 2a , 2b , 2c , 2d , 2e , 2f , 2g , 2h , 2i , 2j ) with phenyl phosphonic dichloride in dry toluene in the presence of triethylamine at 40°C. The title compounds were characterized by physicospectral techniques. All the synthesized compounds were found to possess antimicrobial properties. J. Heterocyclic Chem., 2011.     

Synthesis and antimicrobial activity of novel chalcone derivatives

A series of novel 3-[N, N-bis(2-hydroxyethyl)-amino]-chalcone derivatives 3a–3j were synthesized by the aldol condensation of [N, N-bis(2-hydroethyl)-3-amino]-acetophenone 2 with aromatic aldehydes. Their structures were further confirmed by ESI-HRMS, ¹H NMR, IR and elemental analysis. X-ray analysis reveals crystal 3b is a monoclinic system with P2₁/n space group. The antimicrobial activities of the newly synthesized chalcones in vitro were evaluated and the results indicated that most compounds presented moderate to good antimicrobial activities, especially the antifungal capability. Compounds 3a, 3d, 3f and 3g revealed obvious potency against Candida albicans with MIC values of 32 μg/mL, which were better compared with others.     

Synthesis and antimicrobial activity of quinoline-based 2-pyrazolines

A series of 2-pyrazolines was prepared in a reaction of quinolinylchalcones with phenyl hydrazine under both conventional and microwave-induced heating. Structures of the synthesized compounds were characterized by spectroscopic data and CHN analyses. All prepared compounds were tested for antimicrobial activity against bacterial strains, viz. Staphylococcus aureus, Salmonella typhii, Escherichia coli, and Shigella dysentery. Almost all synthesized compounds have shown antimicrobial activity; however, compounds with a chloro group as a substituent have been found to be more effective.     

Synthesis and antimicrobial activity of some netropsin analogues

Nine novel lexitropsins were synthesized by linking two netropsin-like moieties through three different dicarboxylic acids; 9,10-dihydro-2,7-phenanthrenedicarboxylic acid; [(3-[[(carboxymethyl)amino]carbonyl]benzoyl)amino]acetic acid and indole-2,5-dicarboxylic acid. The netropsin residues were modified by the use of N-isopentylpyrrole, 5-methylthiophene or 5-isopropylthiazole heterocyclic building blocks in place of the usual N-methylpyrrole. The compounds were tested against five gram-positive bacteria: Staphylococcus aureus, Streptomyces faecalis, methicillin resistant Staphylococcus aureus, Enterobacter cloacae, Mycobacterium fortuitum, three gram-negative bacteria: Klebsiella aerogenes, Proteus vulgaris, Escherichia coli and three fungi: Aspergillus niger, Candida albicans and Aspergillus nidulans. Some of the compounds showed significant inhibitory effects on the growth of the microorganisms.     

Synthesis of Ibuprofen Conjugates with Betulin,Allobetulin, and Betulinic Acid

Chemistry of Natural Compounds - Syntheses of mono- and diester derivatives of betulin, allobetulin, and betulinic acid with ibuprofen that were based on Steglich condensation or acid-chloride...     

Synthesis and antimicrobial activity of tryptanthrin adducts with ketones

Reactions of tryptanthrin with acetone, cyclopentanone, hexan-2-one, 4-methylpentan-2-one, 4-hydroxy-4-methylpentan-2-one, cyclohexanone, and butan-2-one in the presence of potassium carbonate afforded racemic phaitanthrin A and other addition products to the ketone group of tryptanthrin with high yields. Thermal dissociation, some chemical transformations, and antimicrobial activity of some adducts were studied, and inhibitory effect against gram-positive bacteria was found for particular derivatives.     

Synthesis of novel heterocycles with antimicrobial and surface activity

A new series of anionic surfactants with dual type of activity antimicrobial and surface activity have been synthesized by reaction of 4H‐3,1‐benzoxazinone 3 and quinazolinethione 10 with nitrogen nucleophiles and activated olefinic compounds. The compounds were evaluated for their surface activity as well as their antimicrobial and biodegradability properties.     

氯代苯二酚双苯醚的合成与抑菌活性研究

为了寻求优良的苯醚类新化合物抑菌剂,本文设计合成了邻(对)苯二酚二-(2-氯-4-羟基苯基)醚,其结构均经1HNMR、IR、MS和元素分析证实,并且测试了化合物对大肠杆菌,金黄色葡萄球菌,白色念珠菌,白色葡萄球菌,变形杆菌,卡他双球菌,青枯假单胞菌的抑菌活性,初步研究结果表明:羟基的位置对活性存在较大影响,羟基的个数对试剂的抑菌活性没有明显的影响。     

Synthesis and antimicrobial activity of novel oxysterols from lanosterol

Chemically diverse oxysterols and their synthetic manipulations were carried out from variety of Δ⁸⁽⁹⁾-lanosterol derivatives and evaluated for their in vitro antimicrobial activities. Most of the synthesized oxysterols exhibited significant antifungal activity against the tested strains.     

Synthesis and antimicrobial activity of o- and p-hydroxybenzoic acid thiosemicarbazides

The ortho- and para-hydroxybenzoic acid thiosemicarbazide derivatives which are potentially biologically active substances were obtained by the reaction of the corresponding hydrazides with various isothiocyanates. Their structures were determined using IR, ¹H NMR spectroscopy, and mass spectrometry. Pronounced antimicrobial activity of synthesized derivatives was revealed.     

Synthesis and antimicrobial activity of a perfluoroalkyl-containing quaternary ammonium salt

A novel perfluoroalkyl-containing quaternary ammonium salt 5 was designed and synthesized. Consequently, the antimicrobial activities of compound 5 were measured with Escherichia coli 8099 as a Gram-negative strain and Staphylococcus aureus ATCC 6538 as a Gram-positive strain. Both the minimum inhibitory concentration (MIC, the lowest concentration of compound 5 that inhibits microbial growth) values of quaternary ammonium salt 5 against Escherichia coli 8099 and Staphylococcus aureus ATCC 6538 were 7.8 μg/ml.     

Synthesis and antimicrobial activity of some new sugar-based monocyclic beta-lactams

The syntheses of some new sugar-based monocyclic beta-lactams possessing several other functionalities in addition to the carbohydrate moiety are described. The key step was the Staudinger [2+2] cycloaddition of chiral carbohydrate Schiff base 5 with phthalimidoacetyl chloride to yield the sugar-based monocyclic beta-lactam 6 as a single isomer. Treatment of protected beta-lactams 6 and 8 with methylhydrazine afforded the free amino beta-lactams 9 and 10. Acylation of these free amino beta-lactams with benzoyl, phenoxyacetyl, cinnamoyl and phenylacetyl chloride in the presence of pyridine afforded beta-lactams 11a-d and 12a-d. Some of these novel beta-lactams were found to be active against Staphilococcus citrus, Klebsiella pneumoniae, Escherichia coli and Bacillus subtilis.     

Synthesis, characterization and antimicrobial activity of new 1,2,3-selenadiazoles

The commercially available aromatic polyketones 1a-d were utilized for the synthesis of the multi-arm1,2,3-selenadiazole derivatives 3a-d. The preparation starts with the reaction between compounds 1a-d and p-toluenesulfonyl hydrazide to give the corresponding tosylhydrazones 2a-d. Subsequent reaction with selenium dioxide leads to regiospecific ring closure of the tosylhydrazones to give the target multi-arm 1,2,3-selenadiazole derivatives in high yield. A 1,2,3-selenadiazole derivative 3e containing an epoxide ring was also prepared. The structures of all the synthesized compounds were confirmed on the basis of spectral and analytical data. The compounds were screened in vitro for their antimicrobial activity against various pathogenic bacterial and Candida strains obtained from King Abdullah Hospital in Irbid -Jordan. Compounds 3a, 3c and 3e were found to be highly active against all the selected pathogens. Compound 3e showed an inhibition zone of 13 mm against the highly resistant P. aruginosa.     

Synthesis of Triterpenoid with an Ethylidene Fragment in the E Ring from Allobetulin

Russian Journal of Organic Chemistry - Allobetulin was converted to 3β-acetoxy-21β-acetyl-20β,28-epoxy-18α,19β-ursane, followed by reduction of the acetyl fragment and...