• Elastomers and Composites
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• v.59 no.3
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• pp.91-96
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• 2024

A novel aromatic polyimide containing the 4-tert-butyl group was prepared from 4-tert-butyl-1,2-phenylene bis(4-aminobenzoate) and 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA). 4-tert-Butyl-1,2-phenylene bis(4-aminobenzoate) was synthesized from 4-tert-butyl catechol and 4-nitrobenzoyl chloride. The poly(amic acid) was transformed into a polyimide via chemical imidization. The polyimide was soluble in N-methyl-2-pyrrolidone (NMP) and could be cast into a flexible and transparent film. The thermal stability of the polyimide was decreased slightly due to the pendant tertbutyl group.

• Journal of the Korean Chemical Society
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• v.8 no.4
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• pp.153-157
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• 1964

The syntheses of substituted tert.-butyl ${\beta}$-(o-tolyl)- perpropionates via intermediates obtained by chloromethylation, malonic syntheses and decarboxylation is described. The intermediates substituted with a group possessing moderate substituent effect such as bromo, chloro, and methyl group were obtained in good yields. The nitro-substituted intermediat was obtained in poor yield. The chloromethylation of toluenes containing electron donating groups resulted in polymerization.

• Journal of the Korean Chemical Society
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• v.30 no.3
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• pp.265-272
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• 1986

Kinetic studies for the methanolysis of tert-butyl halides (t-BuCl, t-BuBr, t-BuI) were carried out in MeOH-1,1,2,2-tetrachloroethane mixtures. The solvatochromic comparison method was used with six indicators to analyze solvent effects on the ionizations of tert-butyl halides. It was shown that the cooperative effect of solvent polarity-polarizability was the most important factor influenced on the methanolysis rates of tert-butyl halides, but the electrophilic assistance for halide leaving group and the nucleophilic assistance for tert-butylium ion were considerably influential, too. And it was found that the electrophilic assistance caused by hydrogen bonding and the nucleophilic assistance for carbon center were stronger for more basic leaving group ($I^-) and more polarizable leaving group(t-BuCl

• Journal of the Korean Chemical Society
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• v.31 no.1
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• pp.25-30
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• 1987

Solvolysis of tert-butyl halides and 1-adamantyl tosylate in methanol-acetone mixtures and solvolysis of tert-butyl bromide in methanol-chloroform mixtures have been studied. Solvent ionizing power of methanol-acetone mixtures were calculated by the Grunwald-Winstein equation and discussed the Y value variation caused by substrate changes. Y values based on 1-adamantyl tosylate is superion to others since it varies in wide range for methanol-acetone mixtures. It was found that the order of electrophilic assistance to leaving group is OTs > Cl > Br > I.

• Archives of Pharmacal Research
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• v.19 no.4
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• pp.286-291
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• 1996

Phenolic compounds are prevalent as toxins or environmental pollutants, but they are also widely used as drugs for various purpose including anticancer agent. A novel biphenolic compound, bis(2-hydroxy-3-tert-butyl-5-methylphenyl)methane (GERI-BPO02-A) was isolated from the fermentation broth of Aspergillus fumigatus F93 previously, and it has revealed cytotoxicity against human solid tumor cells. Its effective doses that cause 50% inhibition of cell growth in vitro against non-small cell lung cancer cell A549, ovarian cancer cell SK-OV-3, skin cancer cell SK-MEL-2 and central nerve system cancer cell XF498 were 8.24, 10.60, 8.83, $9.85\mug/ml$ respectively. GERI-BPO02-A has also revealed cytotoxicity against P-glycoproteinexpressed human colon cancer cell HCT15 and its multidrug-resistant subline HCT15/CL02, and its cytotoxicity was not affected by P-glycoprotein. We have also tested cytotoxicities of structurally related compounds of GERI-BPO02-A such as diphenylmethane, 1,1-bis(3,4dimethylphenyl)ethane, 2,2-diphenylpropane, 2-benzylpyridine, 3-benzylpyridine, $4,4^I-di-tert-butylphenyl$, bibenzyl, $2,2^I-dimethylbibenzyl$, cis-stilbene, trans-stilbene, 3-tert-butyl-4-hydroxy-5-methylphenyisulfide, sulfadiazine and sulfisomidine for studying of structure and activity relationship, and from these data we could suppose that hydroxyl group of GERI-BPO02A conducted important role in its cytotoxicity.

• Korean Journal of Crystallography
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• v.4 no.1
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• pp.25-35
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• 1993

Tetra-tert-butyl-tetrapropionycalix (4) arena (C56H7208) is Triclinic, space group Pl, with a=13.664(5), b=17.585(5), c=12.863(2)A, a=109.33(2), B=111.97(2), γ=76.45(3) ˚, Z=2, V=2684.08A3, D, =1.152g/cm3, Dm=1.15g/cm3. The intensity data were collected on an Enraf-Nonius CAD-4 Diffractometer with a graphite monochromated Mo-Ka radiation. The structure was solved by direct methods and refined by leastsquares methods. The final R factor was 0.084 for 2561 observed reflections. The configuration of the molecule from the X-ray crystallographic investigation has the partial cone conformation, three tort-butylphenyls are down and a tort-butylphenyl is up. Three propionyloxy groups direct toward the exterior of the macrocycle cavity.

• Archives of Pharmacal Research
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• v.23 no.6
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• pp.564-567
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• 2000

The use of amino acid derivatives as building blocks in peptide synthesis is increasingly being recognized as a potential route for the development of pharmaceutical agents. Side chain protection of polyfunctional amino acids such as Ser, Thr, Tyr is viewed as being particularly important. Although these derivatives are commercially listed, they are expensive and not widely available. We describe here a practical large-scale synthesis of t-butyl introduced D-serine, one of the building blocks of zoladex, a peptide drug.

• Korean Journal of Crystallography
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• v.7 no.2
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• pp.105-112
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• 1996

The structure of the tetra-tert-butyl-dipropionyloxy-dihydroxycalis[4]arene (C50H64O6) has been determined by X-ray diffraction methods. The crystal is monoclinic, space group C2/c, unit cell constant a=16.067(2), b=26.391(17), c=10.335(1)Å, β=94.26(1)°, Z=4, V=4370.2(29)Å3, Dc=1.16, Dm=1.2 gcm-3. The intensity data were collected on an Enraf-Nonius CAD-4 Diffractometer with a graphite monochromated Cu-Kα radiation (λ=1.5418Å). The structure was solved by direct methods and refined by least-squares methods. The final R value was 0.07 for 2354 observed reflections. The molecule has the 1, 3-alternate conformation with own two-fold symmetry axis, : two propionyloxy phenyl groups are up and the other two hydroxy phenyl groups are down.

• Bulletin of the Korean Chemical Society
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• v.24 no.12
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• pp.1809-1813
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• 2003

Monomeric antioxidant 1 was prepared by the reaction of 3,5-di-tert-butyl-4-hydroxybenzyl alcohol with N-[4-(chlorocarbonyl)phenyl]maleimide in the presence of imidazole. Monomeric antioxidant 2, bearing carbamate group, was synthesized from the reaction of 3,5-di-tert-butyl-4-hydroxybenzyl alcohol and azidomaleimide. Antioxidant 3 was prepared by the reaction of N-(4-hydroxyphenyl)maleimide and 3-(3,5-ditert-butyl-4-hydroxyphenyl) propionic chloride in the presence of triethylamine. These reactive antioxidants were grafted onto polypropylene (PP) by melt-processing with free radical initiators in a mini-max moulder. From the infrared spectra of the grafted PP, it was found that the monomeric antioxidants were grafted onto PP. IR spectroscopic methods were used for the quantitative determination of the extent of grafting of monomeric antioxidant. To optimize the reaction conditions, the influences of the concentration of DCP, monomeric antioxidant, reaction time and temperature on the extent of grafting were studied.

• Journal of Acupuncture Research
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• v.17 no.3
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• pp.176-187
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• 2000

Objectives : This study was purposed to investigate the antioxidative effects of Paeoniae radix aqua-acupuncture solution(PR) on culture liver cell system, lipid peroxidation and antioxidative enzyme activities in tert-butyl hydroperoxide(t-BHP) treatmented conditions. Methods : Cultured normal rat liver cell(Ac2F) were prepared and incubated with or without PR(at 2% volume in culture medium). After 16~18hr, cells placed in DMEM medium without serum, and then incubated with 1mM t-BHP for 2hr. Viable cells were detected by MTT assay, and the levels of lipid peroxide(LPO) were measured by TBA method. And catalase activity was measured as the decrease in hydrogen peroxide absorbance at 240nm on spectrophotometer using 30mM hydrogen peroxide. Superoxide dismutase(SOD) were assayed by recording the inhibition of nitro blue tetrazolium reduction with xanthine and xanthine oxidase. Glutathione peroxidase(GPX) activity was determined by the modified coupled assay developed by Paglia and Lawrence. The reaction was started by addition of 2.2mM hydrogen peroxide as substrate. The change in absorbance at 340nm was measured for 1min on spectrophotometer. Glutathione-S-transferase(GST) activity was assayed with CDNB as substrate and enzyme activity of GST towards the glutathione conjugation of CDNB. Results : Cell killing was significantly enhanced by addition of t-BHP compared to those of untreated group. PR pretreated cell resisted the toxic effects of t-BHP. LPO levels of t-BHP treatment group were significantly higher than other groups. This increased level was significandy reduced by PR pretreatment. The t-BHP treatment resulted in a decrease of catalase, GPX and GST activities. By contrast, PR pretreatment markedly increased compare to those of untreated groups. Conclusions : T-BHP which can produce intracellular free radical was used for inducer of the peroxidation of cellular lipids. PR protected the cell death induced by t-BHP and significantly increased cell viabiliry in the normal rat liver cell, and showed effective inhibition of lipid peroxidation, and elevations of catalase, GPX and GST activities. These results suggested that PR might play a protective role in lipid peroxidation by free radicals.