• Bulletin of the Korean Chemical Society
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• v.23 no.3
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• pp.374-380
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• 2002

Several compounds of 3,9-dialkylxanthines were prepared from 1-methyl-6-chlorouracil via nucleophillic reactions with different aliphatic amines, followed by nitrosation, reduction, formaylation and finally dehydrocyclization. On the other hands, a series of 8-aryl-3,9-dimethylxanthines were synthesized by dehydrocyclization of 5-arylamido-1-methyl-6-methylaminouracils either by fussion or oxidation of 5-arylidine-amino-1-methyl-6-methylaminouracils using sodium periodate. Phosphoryl chloride was found to be uneffective reagent for dehydrocyclization that, gave another products from 1,3-oxazolo[5,4-d] pyrimidines.

• YAKHAK HOEJI
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• v.27 no.2
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• pp.177-179
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• 1983

A copper complex of $\epsilon$-N-[(2-chloroethyl)carbamoyl]-L-lysine was prepared by the treatment of the L-lysine copper complex with 2-chloroethyl isocyanate in cold water. Within the L-lysine copper complex molecule, the $\alpha-amino$ and carboxyl groups are bounded to $Cu^{2+}$ but the $\epsilon-amino$ group is free and can react with carbamoylating agents. A potential antitumor agent, $\epsilon-N-[(2-chloroethyl)$ nitrosocarbamoyl]-L-lysine was synthesized by nitrosation of this copper complex with Na $NO_{2}$ in anhydrous formic acid, followed by the passage of $H_{2}$S gas.

• Bulletin of the Korean Chemical Society
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• v.24 no.5
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• pp.638-640
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• 2003

• Archives of Pharmacal Research
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• v.16 no.2
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• pp.94-98
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• 1993

Various hydrazines such as aryl-, carbonyl-, and sulfonyl-hydrazine were reacted with dinitrogen tetroxide to give the corresponding azides in excellent yields under mild ocnditions at low temperature $(-20-40^\circ{C)}$ in acetonitrile. The reaction appears to be initiated by formation of the .betha.-nitroso hydrazine intermediate which converts into the azide product.

• Applied Biological Chemistry
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• v.43 no.2
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• pp.110-115
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• 2000

This study was carried out to investigate the effect of extracts from garlic on the formation of nitrosamine, nitrosomorphorine, the nitrite scavenging ability and the antioxidant activity. The extracts from garlic made the nitrite scavenging ability higher at low pH than at high pH. Especially ethanol extracts from garlic resulted in 89.6% of nitrite scavenging ability at pH 1.2. They were also more effective in the electron donating and antioxidant abilities than water extracts in expressing as the reduction of ${\alpha},{\alpha}-diphenyl-{\beta}-picrylhydrazyl$(DPPH) and peroxide value(POV), respectively. Inhibitory effect of nitrosamine formation by ethanol extract from garlic was excellently more than 80% at pH 1.2 and 3.0, but only 29.9% at pH 6.0. This meant that the inhibition of nitrosamine formation is pH dependent.

• Journal of the Korean Chemical Society
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• v.9 no.1
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• pp.37-40
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• 1965

7-Nitro-8-hydoxyquinoline-5-sulfonate (NHQS) have been synthesized from 8-hydroxyquinoline-5-sulfonic acid by nitrosation in alkaline medium at temperature below $10^{\circ}C$ and the acid dissociation constants of NHQS have been determined by spectrophotometric and potentiometric methods. Almost same values are obtained by both methods but the values are lower than the corresponding 8-hydroxyquinoline. The lower basicity of NHQS is considered as the effect of electron withdrawing groups, especially adjacent nitroso group.

• Archives of Pharmacal Research
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• v.14 no.2
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• pp.118-123
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• 1991

Potentially dangerous nitrosamines have been shown to result from the reaction of sodium nitrogusside with several drugs under physiological conditions (pH 7.3 and $37^\circ{C})$. In each case the products were identical to those produced upon reaction with nitrous acid at much lower pH values. Reaction rates were shown to reflect a first order dependence on both amine and nitroprusside concentrations and to increase at higher pH values, approximately in proportion to concentrations of unprotonated amine. Fast reactions of sodium nitroprusside with reduced glutathione, cysteine, and ascorbate suppress but do not prevent the conversion of amines into N-nitrosamines. These results show sodium nitroprusside to be very potent nitrosating agent under physiological conditions and suggested nitrosamines may be formed during its normal pharmacological administration.

• Preventive Nutrition and Food Science
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• v.1 no.1
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• pp.6-9
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• 1996

A total of 47 beer samples, produced in Korea. Were analyzed for their N-nitrosamine levels by gas chromatography-thermal energy analyzer. N-nitrosodimethyamine(NDMA) was detected in 35 of 47 sam-ples analyzed. The range of levels was 0~7.2$\mu\textrm{g}$/kg while the average was about 0.9mg/kg. The identity of NDMA was confirmed by mass spectrometry. Samples which were found only NDMA before nitrosation were detected to include N-nitrosopyrroidine(45$\mu\textrm{g}$.kg) and N-nitrosomorpholine(4$\mu\textrm{g}$/kg) as well as NDMA(837$\mu\textrm{g}$/kg)

• Journal of the Korean Chemical Society
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• v.35 no.3
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• pp.240-248
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• 1991

The regioselectivity in the nitrosation of seven N-methyl-N'-substituted phenylureas ($CH_3NHCONHC_6H_4-G$; G = H, p-CH$_3$, m-CH$_3$, m-CH$_3$O, p-F, m-F, m-Br) was examined using NaNO$_2$ and 4 different acids (diluted HCl, HCOOH, CH$_3$COOH, CF$_3$COOH). In all cases, the two regioisomeric products, N-nitroso-N-methyl-N'-substituted phenylureas (A) and N'-nitroso-N-methyl-N'-substituted phenylureas (B) were observed to be formed as major products and product ratios were determined by the integration of their methyl peaks in $^1$H-NMR. Electron donating substitutent(G) on phenyl of the ureas generally led to increase the ratio of B to A. The data have revealed that the relative sensitivity of the nitrosonium species (HONO, HCOONO, CH$_3$COONO, CF$_3$COONO) toward the change of electron density on nitrogen with phenyl substitutents are 1.00 : 0.93 : 0.78 : > ∼ 0.7.

• Food Science and Biotechnology
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• v.14 no.1
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• pp.168-170
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• 2005

The myeolchi-jeot samples were divided into different groups with or without the supplementation with biogenic amines. Subsequently, the samples were placed in an oven at $80^{\circ}C$ for 1 hr to allow the chemical reaction to proceed, and then were analyzed for N-nitrosamine contents using GC-TEA. N-nitrosamine was not detected in any of the myeolchi-jeot samples which had been treated with/without sodium nitrite. On the other hand, the yield of N-nitrosopyrrolidine from 1,000 mg/kg of putrescine and spermidine in the myeolchi-jeot samples (treated with 5 mg/kg of sodium nitrite) was 0.002 and 0.014%, respectively. N-nitrosamine was not produced from any other biogenic amines like, histamine, tyramine, cadaverine and spermine. In addition, curing and heating were the factors which influenced the formation of N-nitrosamine during the nitrosation of biogenic polyamines. For the formation of N-nitrosamine in the food systems, treatment with sodium nitrite and heating at appropriate temperature along with the satisfied supplementation of biogenic polyamines are required.