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Mohammed Mahabubur Rahman1,Md. Motiur Rahman,Mahbubul Alam 강원대학교 산림과학연구소 2010 Journal of Forest Science Vol.26 No.3
A study was conducted for indentifying the floral biodiversity of woody species by calculating four diversity indices using data collected from 4 stands of different age groups and disturbance regimes in two areas of Madhupur tract. Results showed that highest species diversity in the old growth secondary coppice forest (>60 years) under moderate anthropogenic disturbances of Madhupur National Park area (delete (D=0.74, Hʼ=3.36) followed by old growth secondary forest stands (>40 years) under moderate disturbances at Bhawal National Park area (D=0.65, Hʼ=2.81). Plant species diversity of the young enrichment plantations (<20 years and <15 years) under high anthropogenic disturbances in both the areas are much low (D=0.54 and Hʼ=2.16 and D=0.52 and Hʼ=1.92 respectively), which indicate high anthropogenic disturbances coupled with introduction of invasive exotics that are rival for endemic species are detrimental for conservation of biological diversity of tropical moist deciduous forests of Madhupur tract in Bangladesh.
Rahman, A.F.M. Motiur,Liang, Jing Lu,Lee, Seung-Ho,Son, Jong-Keun,Jung, Mi-Ja,Kwon, Young-Joo,Jahng, Yurng-Dong 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.9
The 2,2-dimethyl-2H-pyran-derived alkaloids acronycine and its demethylated congeners were prepared in three steps from anthranilic acid and phloroglucinol. The phenylboronic acid-mediated inter-amolecular cyclization reaction of 1,3-dihydroxyacridone and 3-methylbut-2-enal was employed as a key step, which was also applied to the synthesis of related cytotoxic benzo[b]acronycine. Inhibitory activities of the compounds prepared on topoisomerase I and II as well as their cytotoxicities were evaluated. Cytotoxicity of 2 is closely related to the strong inhibitory activity against topo II at $20{\mu}M$ level.
Fragmentation Behavior Studies of Chalcones Employing Direct Analysis in Real Time (DART)
Motiur Rahman, A.F.M.,Attwa, Mohamed W.,Ahmad, Pervez,Baseeruddin, Mohammad,Kadi, Adnan A. Korean Society for Mass Spectrometry 2013 Mass spectrometry letters Vol.4 No.2
Chalcones are naturally occurring, biologically active molecules generating interest from a wide range of research applications including synthetic methodology development, biological activity investigation and studying fragmentation patterns. In this article, a series of chalcones has been synthesized and their fragmentation behavior was studied using modern ambient ionization technique Direct Analysis in Real Time (DART). DART ion source connected with an ion trap mass spectrometer was used for the fragmentation of various substituted chalcones. The chalcones were introduced to the DART source using a glass capillary without sample preparation step. All the chalcones showed prominent molecular ion peaks $[M]^{{\cdot}+}$ corresponding to the structures. Multistage mass spectral data $MS^n$ ($MS^2$ and $MS^3$) were collected for all the chalcones studied. The chalcones with substitutions at 3, 4 or 5 positions gave product ion peaks with the loss of a phenyl radical ($Ph^{\cdot}$) by radical initiated ${\alpha}$-cleavage, while substitution at 2 position of chalcone in the A-ring gave a product ion peak with the loss of substituted styryl radical (PhCH = $CH^{\cdot}$). In case of the chalcones with the substituent at 4 positions in A and B rings gave both types of fragmentation patterns. In conclusion, chalcones can be easily characterized using modern DART interface in very short time and efficiently without any cumbersome sample pretreatment.
Simple Synthesis of Geminal Diacetates (Acylals) of Aromatic Aldehydes
Rahman, Motiur A. F. M.,Jahng, Yurngdong Taylor Francis 2006 Synthetic communications Vol.36 No.9
<P> The geminal diacetates of aromatic aldehydes were prepared from corresponding aldehydes by refluxing with acetic anhydride without any catalysts or even any additional solvent.</P>
( Motiur Rahman ),( Roushown Ali ),( Yurngdong Jahng ),( Adnan A Kadi ) 영남대학교 약품개발연구소 2012 영남대학교 약품개발연구소 연구업적집 Vol.22 No.0
Solvent-free Claisen-Schmidt reactions of cycloalkanones with various substituted benzaldehydes (aryl aldehydes) using solid NaOH (20 mol%) and applying a grinding technique were studied. Quantitative yields (96-98%) of α,α`-bis-(substituted-benzylidene)cycloalkanones were obtained. Aliphatic aldehydes also provided α,α`-bis-(substituted-alkylidene)cycloalkanones in very good yields with minor amounts of a-(substituted-alkylidene)cycloalkanones. The catalytic performance of solid NaOH was examined. The molar ratio of NaOH was optimized. The catalytic effect of solid NaOH was also evaluated by comparing it with KOH, NaOAc, and NH(4)OAc and it turns out that 20 mol% of solid NaOH was good enough to catalyze the Claisen-Schmidt reactions of cycloalkanones with various substituted benzaldehydes. Additionally, the regioselectivity of the Claisen-Schmidt reaction of acetone with benzaldehyde was examined. Using the same method, we could synthesize the corresponding bis-benzylidene- and mono-benzylideneacetone separately in 98% and 96% yields, respectively.
Rahman, Mohammed Mahabubur,Rahman, Md. Motiur,Alam, Mahbubul Institute of Forest Science 2010 Journal of Forest Science Vol.26 No.3
A study was conducted for indentifying the floral biodiversity of woody species by calculating four diversity indices using data collected from 4 stands of different age groups and disturbance regimes in two areas of Madhupur tract. Results showed that highest species diversity in the old growth secondary coppice forest (>60 years) under moderate anthropogenic disturbances of Madhupur National Park area (delete (D=0.74, H'=3.36) followed by old growth secondary forest stands (>40 years) under moderate disturbances at Bhawal National Park area (D=0.65, H'=2.81). Plant species diversity of the young enrichment plantations (<20 years and <15 years) under high anthropogenic disturbances in both the areas are much low (D=0.54 and H'=2.16 and D=0.52 and H'=1.92 respectively), which indicate high anthropogenic disturbances coupled with introduction of invasive exotics that are rival for endemic species are detrimental for conservation of biological diversity of tropical moist deciduous forests of Madhupur tract in Bangladesh.
Synthesis and Biological Properties of Luotonin A Derivatives
Rahman, A. F. M. Motiur,Kim, Dong-Hyeon,Liang, Jing-Lu,Lee, Eung-Seok,Na, Young-Hwa,Jun, Kyu-Yeon,Kwon, Young-Joo,Jahng, Yurng-Dong Korean Chemical Society 2008 Bulletin of the Korean Chemical Society Vol.29 No.10
A series of new derivatives on the ring A of luotonin A were prepared by Friedländer condensation of 6,7,8,10- tetrahydropyrrolo[2,1-b]quinazoline-6,10-dione and suitably substituted 2-aminobenzaldehydes and 2- aminoacetophenones. Their inhibitory activities on topoisomerases and cytotoxicities against selected human cancer cell lines were evaluated. Among the compounds tested, 8-fluoroluotonin A showed similar inhibitory activity on topoisomerase I comparable to camptothecin while luotonin A and 9-hydroxyluotonin A showed 1.37 and 0.94 times stronger inhibitory activity, respectively, on topoisomerase II compared to etoposide. Some derivatives of luotonin A showed moderate cytotoxicity. The possible relationship between the inhibitory activity on Topo II and the cytotoxicity of luotonin A and its analogues, thus, cannot be ruled out.
Rahman, Motiur A. F. M.,Jahng, Yurngdong WILEY-VCH Verlag 2007 European Journal of Organic Chemistry Vol. No.
<P>The geminal diacylates of a variety of aldehydes were prepared in good yields without any catalysts or solvent by simply refluxing the aldehydes with aliphatic acid anhydrides. The scope of the reactions and relative reactivities of aldehydes and acid anhydrides were examined. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)</P> <B>Graphic Abstract</B> <P> <img src='wiley_img/1434193X-2007-2007-2-EJOC200600737-fig000.gif' alt='wiley_img/1434193X-2007-2007-2-EJOC200600737-fig000'> </P>