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1.
Brindaban Roy Rajendra Narayan De Somjit Hazra 《Monatshefte für Chemie / Chemical Monthly》2012,41(8):119-125
Abstract
A concise synthesis of pyrrolo[1,2-f]phenanthridine-annulated polycyclic heterocycles has been achieved in good yields by palladium-catalyzed intramolecular direct arylation reaction. 相似文献2.
Supichar Chokpaiboon Panida Unagul Sutichai Nithithanasilp Somjit Komwijit Wiwat Somyong Thanawut Ratiarpakul 《Natural product research》2018,32(2):149-153
Two salicylaldehyde derivatives (1 and 2), a hydroxymethylphenol (3), five dihydroisobenzofuran (4–8) derivatives, and a 5-chloro-3-deoxyisoochracinic acid (9), together with a known 3-deoxyisoochracinic acid (10) were isolated from the marine fungus Zopfiella marina BCC 18240 (or NBRC 30420). The structures of these compounds were elucidated by extensive spectroscopic analysis. Compound 1 showed weak antituberculous activity against Mycobacterium tuberculosis H37Ra, and antibacterial activity against Bacillus cereus with MIC values of 25 and 12.5 μg/mL, respectively. 相似文献
3.
We show that the only orthogonal polynomials satisfying a q-difference equation of the form π(x)D
q
P
n
(x) = (α
n
x + β
n
)P
n
(x) + γ
n
P
n−1(x) where π(x) is a polynomial of degree 2, are the Al-Salam Carlitz 1, little and big q-Laguerre, the little and big q-Jacobi, and the q-Bessel polynomials. This is a q-analog of the work carried out in [1].
2000 Mathematics Subject Classification Primary—33C45, 33D45 相似文献
4.
Jittra Kornsakulkarn Siriporn SaepuaSomjit Komwijit Pranee RachtaweeChawanee Thongpanchang 《Tetrahedron》2014
Five new compounds, phthalide 1, dihydroisocoumarin 2, and 3, pyrone 4, and benzophenone 5, together with nine known compounds, 3,4-dihydro-4,5,8-trihydroxy-3-methylisocoumarin, sclerotinin A, methyl-8-hydroxy-6-methylxanthone-1-carboxylate, sydowinin A, conioxanthone A, 1,3,8-trihydroxy-6-methylxanthone, 1,8-dihydroxy-3-methoxy-6-methylxanthone, coniochaetone B, and xylaranol B, were isolated from the fungus Astrocystis sp. BCC 22166. Structures of these compounds were elucidated using NMR spectroscopic and MS spectrometric analyses. Compound 1 exhibited antibacterial activity against Bacillus cereus (IC50=12.5 μg/mL) while compound 2 showed cytotoxicity to KB and Vero cells (IC50=22.6 and 48.2 μg/mL). 相似文献
5.
Chakapong Intaraudom Aibrohim DramaeSumalee Supothina Somjit KomwijitPattama Pittayakhajonwut 《Tetrahedron》2014
Eight new compounds including 9′-[2-amino-3-(4″-O-methyl-α-rhamnopyranosyloxy) phenyl]nonanoic acid (1), 9′-[2-amino-3-(4″-O-methyl-α-ribopyranosyloxy)phenyl] nonanoic acid (2), 11′-[2-amino-3-(4″-O-methyl-α-rhamnopyranosyloxy)phenyl]undecanoic acid (3), 11′-[2-amino-3-(4″-O-methyl-α-ribopyranosyloxy)phenyl]undecanoic acid (4), 8-(4′-O-methyl-α-rhamnopyranosyloxy)-3,4-dihydroquinolin-2(1H)-one (5), 8-(4′-O-methyl-α-ribopyranosyloxy)-3,4-dihydroquinolin-2(1H)-one (6), 8-(4′-O-methyl-α-rhamnopyranosyloxy)-2-methyquinoline (7), and 8-(4′-O-methyl-α-ribopyranosyloxy)-2-methylquinoline (8) were isolated from Actinomadura sp. BCC27169. The chemical structures of these compounds were determined based on NMR and high-resolution mass spectroscopy. The absolute configurations of these monosaccharides were revealed by the hydrolysis of compounds 7 and 8. Compounds 3 and 8 exhibited antitubercular activity at MIC 50 μg/mL. Only compound 3 showed cytotoxicity against KB cell at IC50 18.63 μg/mL, while other isolated compounds were inactive at tested maximum concentration (50 μg/mL). 相似文献
6.
Masahiko Isaka Somporn PalasarnSomjit Komwijit Sayanh SomrithipolSujinda Sommai 《Tetrahedron letters》2014
Cyclodepsipeptides SCH 217048 (1), SCH 218157 (2), and a new analog, pleosporin A (3), were isolated from cultures of an unidentified elephant dung fungus of the family Pleosporaceae. The structure of 3 was elucidated on the basis of detailed spectroscopic interpretation. The absolute configurations of 1–3 were determined by chiral column HPLC analysis and Marfey’s method. Cyclodepsipeptides 1–3 exhibited antimalarial activity against Plasmodium falciparum K1 with respective IC50 values of 1.6, 6.4, and 1.6 μg/mL, while they did not show cytotoxicity against KB, MCF-7 and NCI-H187 cell-lines or non-cancerous Vero cells at 50 μg/mL. 相似文献
7.
Masahiko Isaka Pitchapa Berkaew Kamolphan Intereya Somjit Komwijit Thiptiwa Sathitkunanon 《Tetrahedron》2007,63(29):6855-6860
Four new cyclohexadepsipeptides, pullularins A-D, were isolated from the endophytic fungus Pullularia sp. BCC 8613. Structures of these compounds were elucidated by interpretation of NMR spectroscopic and mass spectrometric data. The absolute configurations of amino acid and hydroxy acid residues were determined by HPLC analysis of depsipeptide acid hydrolyzates using a chiral column and Marfey's method. Pullularin A exhibited activities against the malarial parasite Plasmodium falciparum K1 (IC50 3.6 μg/mL) and herpes simplex virus type 1 (HSV-1; IC50 3.3 μg/mL), whereas it showed weak cytotoxicity to Vero cells (IC50 36 μg/mL). 相似文献
8.
Rachada Haritakun Pranee Rachtawee Somjit Komwijit Sutichai Nithithanasilp Masahiko Isaka 《Helvetica chimica acta》2012,95(2):308-313
Two new ergostane derivatives, 12β,15α,25,26‐tetrahydroxyergosta‐4,6,8(14),22‐tetraen‐3‐one ( 1 ) and 12β,15α,25,28‐tetrahydroxyergosta‐4,6,8(14),22‐tetraen‐3‐one ( 2 ), and a new aranotin‐type diketopiperazine, bisdethiobis(methylsulfanyl)apoaranotin ( 3 ), were isolated from the fungus Aspergillus terreus BCC 4651. The structures of the new compounds were elucidated by means of NMR spectroscopic and MS analyses. 相似文献
9.
A simple high yielding and highly efficient synthesis of oxazoline ring fused with uracil moiety is reported. Hypervalent iodine (PIDA) in the presence of BF3–OEt2 generates an effective electrophile to activate uracil C5–C6 double bond leading to heterocyclization. 相似文献
10.
A CuCl2-catalyzed dehydrogenative C–H activation leading to regioselective synthesis of coumarin, quinolone, and naphthalene fused heterocycles is reported. The reaction has been carried out in one pot under open atmosphere and it offers good to excellent yields of the cyclized products. 相似文献