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SYNTHESIS AND BIOLOGICAL ACTIVITY EVALUATION OF C-9154 ANTIBIOTIC DERIVATIVES FROM VANILLIN
Full text linkThis research was conducted in order to synthesize two derivatives of C-9154 antibiotic from vanillin and to evaluate their biological activities. The synthesis of these C-9154 derivatives was performed through alkylation of vanillin, preparation of the corresponding benzaldoxim, reduction of this benzaldoxim, treatment of the resulting substituted benzilamine with maleic anhydride and esterification of this C-9154 antibiotic derivative. The alkylation of vanillin was carried out using diethylsulfate and NaOH as the base to give 89% yield of ethyl vanillin. The oxim synthesis from ethyl vanillin was performed using hydroxylamine hydrochloride under alkaline condition at 50oC for 2 hours to yield 89% 4-ethoxy-3-methoxybenzaldoxim. Reduction of this benzaldoxim with metallic Na in absolute ethanol afforded 82% yield of 4-ethoxy-3-methoxybenzylamine. This benzylamine derivative was then reacted with maleic anhydride in benzene to give the acid-form of C-9154 antibiotic derivative (6) in 74% yield. Esterification of this acid conducted Jumina using absolute ethanol in the presence of concentrated sulfuric acid at reflux for 4 hours gave the ethyl ester-form of C-9154 antibiotic derivative (7) in 87% yield. Antimicrobial activity evaluation was conducted using Staphyllococcus aureus and Eschericia coli. Based on the minimum inhibition concentration (MIC) data determined using aqueous methanol as the reference, it was observed that the acid-form (6) and the ethyl ester-form (7) of C-9154 antibiotic derivative obtained respectively gave MIC values of 2000-3000 g/ml and 500-1000 g/ml respectively either towards Staphyllococcus aureus or Eschericia coli.Key words: antibiotics, vanillin, oxim, benzylamine, C-9154 derivative, antimicrobe
Antibiotic potential of some synthesized derivatives of C-9154 antibiotic
No full textStructural modification of the C-9154 antibiotic in an attempt to simultaneously improve its activity and lower its toxicity led to the synthesis of an analogue of the C-9154 antibiotic and six derivatives of this analogue. The significant reduction of the polarity of the synthesized analogue in the derivatives to increase permeability across cell membranes was achieved by conversion of the highly polar carboxylic group to the nonpolar ester functional groups. The compounds were synthesized by condensation of 4-nitroaniline with maleic anhydride and then conversion of the terminal carboxylic acid functional group to an ester functional group using a thionyl chloride-mediated esterification. The in vitro biological activity using gram positive bacteria (MRSA, S. pyogenes, B. subtilis, and C. ulcerans), gram negative bacteria (E. coli, P. mirabilis, P. aeruginosa, S. typhii, S. dysenteriae, and K. pneumonia and some fungi (C. albicans, A. nigre and T. rubrum), showed that the derivatives were more active than their respective analogue and significantly better than the standard antibiotics (Sparfloxacin and Fluconazole) used for comparison, establishing their potential or use as antibiotics. The derivatives exhibited activity at concentrations as low as 0.625μg/mL while the analogue was active at 2.5μg/mL. These values were higher than results obtained for the standard drugs which showed activity at concentrations of 5 μg/mL. The derivatives however did not show activity against A. nigre whereas the analogue was active against it.
Keywords: C-9154 Antibiotic, Bioactivity, Fumaramidmycin, antibacterial, antifunga
Sintesis dan Uji Aktivitas Antimikroba Beberapa Turunan antibiotik C-9154 dari Minyak Dann Cengkeh
Full text linkPalam rangka meningkatkan days guns salah satu sumber alam Indonesia yang sangat melimpah yailu minyak daun cengkeh, dan sejalan dengan usaha penyediaan senyawa antbookk berkhasiat tinggi namun dengan harga yang reanf murah, make dalam per elikan ini akan dilakukan sebuah modifikasi terhadap struktur senyawa anlibiotik C-9154 khususnya tumnan mai N-alkilfumarat dengan memanfaatkan sumber slam yang cukup melimpah yaitu minyak deun cengkeh. Senyawa (unman antibiotik C-9154 khususnya turunan meld N-alkilfumaramat dalam hal ini adalah meth N-benzillumaramat (2) telah dilapoilan memberikan khasiat antimikroba yang sangat memuaskan dengan MIC sebesar 25 m./mli terhadap Staphylococcus auteus dan Escheria (Jumina dkk, 2001). Harga MIC demikian bukan saja sebanding dengan harga MIC senyawa induk antibiotik C-0145 (1 ), namun bin dikatakan identik dengan harga MIC (10-150 ng/m1) beberapa jenis anlbiolik yang lazim digunakan dewasa ini sepedi penisilin, amfisilin, kemisihn dan eritromisin (Martin, 1992; Ganelln dkk, 1993).
Berdasarkan struktur anfibiotik C-9154 (1) clan turunannya (2) dengan akfiyitas yang tinggi, maka dad segi sintesis kimia organik maupun pertimbangan ekonomi dapat ditawarkan sebuah alternatif yang sweat menjanjikan untuk memproduksi beberapa (unman senyawa (2) dengan memanfaatkan minyak daun cengkeh.
Hal tersebut cukup beralasan karena. walaupun senyawa (2) mempunya; khasiat yang cukup tinge, namun dad sagi sintesis pedu dipartimbangkan Imre rendemennya (40-60 %) yang belum cukup memuaskan (Jumma, 1999). Untuk mencapai Inman inl, make diusulkan stain melocle sintesis senyawa turunan antibiotik C-9154 menggunakan bahan awal minyak daun cengkeh
Sacara berurutan tahap dalam sintesis turunan antibiobk C-9154 mahout, 'soles' minyak cengkeh clan daun cengkeh, isolasi eugenol dari minyak cengkeh, metilisasi eugenol menjadi meal eugenol, hidroborasi meth eugenol menjadi 3-(3,4-dimetoksiterfil)-1-propanol, aminasi secara lidak langung terbadap 3-(3,4-dimetoksifenI)-1-propanol menghasilkan beberapa derivat 3-(3,4-dmetoksifanin-1-propanarnina Pada tahap roil dengan pertimbangan bahwa aminasi terhadap alkohol ficlak direkomendasikan secara sintesis, untuk itu suatu langkah yang perlu dikemukakan sin' adalah bahwa aminasi dilakukan melalui 4 tahap yaitu: oksidasi alkohol menjadi aldehida, transformasi Queue aldehida menjadi oxim, reduksi oxim menjadi senyawa amina
Essensial oil is one of natural resources inourmous amount jr Indonesia. Some of its component are used as new materials of chemist product, one of its component is clove leaves oil that contains eugenoll until 75 — 79 %. Based to get ready of antibiotic with high activity, reversly with low cost, so in this research are to modicate of antibiotic C-9154 derivatives structure especially N-akylfumaric acid (2) derivatives with clove leaves oil as starling materials.
Derivatives of N-alkylfumaric acid (2) have been reported as antimycrobial with high activity that Indicated with 25 ug/ml MIC value to Staphylococcus aureus and Esthetic coil (Amine et. ab 2001), this MIC value close to MIC value of antibiotic C-9145 standart (1). Present, some kind of antibiotics that usually oonsurnming are pentyline, amphicyline, kemisilin den eritromisin (Martin, 1952, Ganelin et. al, 1993).
economilly aspect can be proposed a smooth strategy to synthesis of C¬9154 denvatives (2) with clove leaves oil as starling materials. This proposal is a smooth ideas beCause C-9154 derivatives (2) have high activity, but from synthetically aspect indicated good performance not yet caused its low rendemen (40-60 %) (Jumina, 1999).
Synthesis of anfibyac C-9154 derivatives have been prepared as follows: Isolation of essensials oil from dove leaves, IsoIasi eugenol from essensials oil from clove leaves, methylation eugenol to methyil eugenol, hrdroboration methyl eugenol to 3-(3,4-dLmetoxyphenyI)-1-propanol, amination indinecly 3-(3,4dimethoxyphenyI)-1-propanol to afford some 3- (3,4-dimethoxyphany1)-1-pronanamine derivates. Amination in this research have conducted as followas: orydation of alcohol to aldehyde, transformation aldehyde to oxime, reduction oxime to amine
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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