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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.
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.
Synthesis and Biological Properties of Luotonin A Derivatives
A. F. M. Motiur Rahman,Dong Hyeon Kim,Jing Lu Liang,이응석,나영화,전규연,권영주,장영동 대한화학회 2008 Bulletin of the Korean Chemical Society Vol.29 No.10
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, 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.
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>
8-아릴옥시카페인의 합성과 그 Topoisomerase II 저해활성
A.F.M. 모튜어 라만,장영동,Rahman, A.F.M. Motiur,Jahng, Yurng-Dong 대한약학회 2011 약학회지 Vol.55 No.6
A series of 8-(substituted)aryloxy- and 8-alkyloxy-caffenines were prepared from 8-bromocaffeine and (substituted) phenols as well as alkanols by Ullmann reaction and their inhibitory activities on topoisomerase II were evaluated. A compound, 8-(quinolin-2-yl)oxycaffeine showed the strongest inhibitory activity against topoisomerase II.
Kadi, Adnan A.,Al-Shakliah, Nasser S.,Motiur Rahman, A. F. M. Korean Society for Mass Spectrometry 2015 Mass spectrometry letters Vol.6 No.3
N-Alkyl/benzyl substituted isatin derivatives are intermediates and synthetic precursors for the preparation of biological active heterocycles. N-alkyl/benzyl isatins have showed various biological activities, such as cytotoxicity, antiviral, caspase inhibition, cannabinoid receptor 2 agonists for the treatment of neuropathic pain, etc. In this study, N-alkyl/benzyl isatin derivatives were synthesized from isatin and alkyl/benzyl halides in presence of K<sub>2</sub>CO<sub>3</sub> in DMF and excellent to quantitative yields (~95%) were obtained. Isatins and benzyl-isatins were condensed with fluorescein hydrazide to form fluorescein hydrazone. All the compounds were subjected to their fragmentation behavior study using LC/MS<sup>n</sup>. N-Alkyl substituted isatin derivatives fragmented at nitrogen-carbon (N-C) bond, hence gave daughter ion as [RN+H]<sup>+</sup>. Whereas, N-benzyl substituted isatin derivatives fragmented at carbon-carbon (C-C) bond of alkyl chain which linked with nitrogen molecules, therefore gave N-methyl fragments [RNCH<sub>2</sub>]<sup>+</sup>. This study demonstrated that, isatin moiety present in a small/large molecule or in a matrix of reaction mixture with/without N-alkyl/benzyl substituents can be identified by mass spectroscopic fragmentation behavior study.
Fragmentation Behavior Studies of Chalcones Employing Direct Analysis in Real Time (DART)
( A. F. M. Motiur Rahman ),( Mohamed W. Attwa ),( Pervez Ahmad ),( Mohammad Baseeruddin ),( Adnan A. Kadi ) 한국질량분석학회 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].+ corresponding to the structures. Multistage mass spectral data MSn (MS2 and MS3) 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.) by radical initiated α-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.). 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>