• YAKHAK HOEJI
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• v.32 no.3
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• pp.164-169
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• 1988

$^{13}C$ NMR chemical shifts for 18 ${\alpha}-susbstituted$ toluenes at high dilution in $CCl_4$ solution have been determined. Substituents are as follows: H, Me, Et, n-Pr, iso-Pr, Ph, F, Cl, Br, $NH_2$, NHMe, $NMe_2$, OH, OMe, OCOMe, $CO_2Me$, $CO_2Et$, CN. Those chemical shifts of the methylene carbon of the toluene and the ${\alpha}-carbon$ of the n-butane systems are correlated well. (r=.975, slope=.962)

• Journal of the Korean Chemical Society
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• v.55 no.4
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• pp.590-593
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• 2011

A novel organotin(IV) complex has been prepared from $Bu_2SnCl_2$ and the N, O and S donor ligand, 5-(p-dimethylaminobenzylidene) rodanine (HL). The ligand is deprotonated in the presence of a base and the complex with the general formula $SnBuCl_2L$ is formed. This complex was fully characterized by IR, $^1H$ NMR and $^{119}Sn$ NMR and elemental analysis. Spectroscopic data indicate the ligand is coordinated through the oxygen atom to the tin and the coordination number of four is supported by $^{119}Sn$ NMR data in solution.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.687-692
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• 2011

$^1H$ and $^{13}C$ NMR spectra of series of (E)-1-aryl-(2- and 3-thienyl)-2-propenones, that are aldol condensation products between 2- and 3-thiophenecarbaldehydes and m- and p-substituted acetophenones, were examined to make complete assignments of the chemical shifts. Long range couplings, $^4J$ and $^5J$, are observed in the $^1H-^1H$ COSY of both 2- and 3-thienyl compounds, which makes the elucidation of the conformation in solution possible. In contrast, the 2-furyl analogue shows the long range coupling phenomena, but the 3-furyl and phenyl analogues do not show similar phenomena.

• Natural Product Sciences
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• v.9 no.2
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• pp.49-51
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• 2003

The underground part of Rosa rugosa Thunb. has been used in Korean folk medicine for treating diabetes. The $^{1}H-NMR$ signal of procyanidin B3 isolated from Rosa rugosa was fully assigned by utilizing $^{1}H-^{1}H$ COSY. Procyandin B3 showed a moderate inhibitory activity against HIV-1 protease.

• Analytical Science and Technology
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• v.18 no.1
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• pp.1-4
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• 2005

The stable $Ti(OPr^i)_2(OAc)_2$ sol which reacts with a solution of prehydrolysed $Si(OEt)_4$ was made by addition of acetic acid. The structure evolution of the reaction mixture was monitered by $^1H$, $^{29}Si$ NMR and FT-IR spectroscopy.

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.936-942
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• 2013

Series of (E)-1-aryl-3-(2-pyrrolyl)-2-propenones, that were aldol condensation products between pyrrole-2-carbaldehyde and m- and p-substituted acetophenones, were prepared and their $^1H$ and $^{13}C$ NMR spectra were examined to obtain the information on the conformation of the enone system. Similar studies were carried out with (E)-3-aryl-1-(2-pyrrolyl)-2-propenones that were prepared from 2-acetylpyrrole and m- and p-substituted benzaldehydes. The substituent chemical shifts were studied by applying the Hammett relationship.

• Journal of the Korean Magnetic Resonance Society
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• v.19 no.2
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• pp.88-94
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• 2015

Bub1 is one of the spindle checkpoint proteins and plays a role in recruitment of the related proteins to kinetochore. Here, we studied the structural characteristic of the evolutionarily conserved 160 amino acid region in the N-terminus (hBub1 CD1), using Circular Dichroism (CD) and NMR. Our CD results showed that hBub1 CD1 is a highly helical protein and its structure was affected by pH: as pH was elevated to basic pH, the helical propensity increased. This could be related to the surface charge of the hBub1 CD1. However, the structural change did not largely depend on the salt concentration, though the thermal stability a little increased. The previous NMR analysis revealed that the hBub1 CD1 adopts eight helices, which is consistent with the CD result. Our result would be helpful for evaluating the molecular mechanism of the hBub1 CD1 and protein-protein interactions.

• Journal of the Korean Chemical Society
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• v.53 no.5
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• pp.530-535
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• 2009

Dicyclohexyl telluride was obtained in a high yield by the reaction of cyclohexyl bromide with NaTeH(prepared in situ) in an aqueous ethanolic solution. A series of new organotelluronium salts of the general formula ${(cyclo-C_6H_11)}_2Te(R)X$ (where R = $CH_3$, X = I (1); R = $C_2H_5$, X = Br(2); R = $C_2H_5$, X = I (3); R = C_3H_5$, X = Br (4)) were prepared by the reaction of ${(cyclo-C_6H_11)}_2Te$ with the corresponding alkyl halide. Reaction of 1 with NaBPh4 gave compound 5 ( i.e. R = CH3, X = BPh4 ‒) in 78% yield. Reaction of ${(cyclo-C_6H_11)}_2Te$ with benzyl bromide and 4-bromophenacyl bromide gave unexpectedly dibenzylcyclohexyltelluronium bromide (6) and bis(4-bromophenacyl)cyclohexyltelluronium bromide (7), respectively. Reaction of 6 with NaBPh4 gave the corresponding tetraphenylborate derivative (8) in high yield. $^1H$ NMR studies revealed that in $CDCl_3$solution compound 1 eliminated alkyl halide. Conductivity, IR, $^1H\;and\;^{13}C$ NMR and thermal data for the new compounds are presented and discussed.

• Polymer(Korea)
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• v.35 no.4
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• pp.308-313
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• 2011

The ring-opening isomerization polymerization behavior of 2,5,6,7-tetrahydro-3H-imidazo[2,1-b] [1,3] oxazine(TII) has been studied under various conditions. The present study aimed at improving the low polymerizability of the above monomer (six-membered ring) up to a level comparable to that of 2,5,6-tetrahydroimidazo[2,1-b] [l,3] oxazole(TIO) (five-membered ring). The optimum result could be observed when methyl trifluoromethanesulfonate(MeOTf) and nitrobenzene were used as an initiator and a solvent in the polymerization at $60^{\circ}C$ for 24 h. Polymers were confirmed by$^1H$ NMR과$^{13}C$ NMR, and m measurements. The molecular weight obtained by gel permeation chromatography (GPC) corresponded to the molecular weight theoretically calculated from the feed ratio. The melting temperature ($T_m$) of TII was conspicuously different from that of TIO, because of the difference in the alkyl group.

• Applied Biological Chemistry
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• v.37 no.2
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• pp.100-104
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• 1994

From the 48 hour-cultured mycelial broth of Phellinus linteus, six compounds were isolated by means of ethyl acetate extraction, silica gel column chromatography and preparative thin layer chromatography, consecutively. Compound 1 was identified as a succinic acid by the comparison of its spectral data with authentic sample. Compounds 2 and 3 were identified as p-hydroxyphenyl acetic acid methyl ester and p-hydroxybenzaldehyde by spectroscopic studies, respectively. NMR and MS studies of compound 6 revealed that it was 2,5-dihydroxymethyl furan. Compound 4, which showed similar NMR absorptions and MS fragmentation pattern with those of compound 6 was identified as 2-hydroxymethyl-5-methoxymethylfuran. These structures were verified by the spectral data of the acetate derivatives of the compounds. Compound 5 was supposed to be a N-acetyltyramine from its $^1H-NMR$ and EI-MS data, and its structure was confirmed by a synthesis starting from tyramine.