• Journal of the Korean Chemical Society
• /
• v.9 no.1
• /
• pp.29-32
• /
• 1965

A new conventional method for the preparation of 5-iodo-, chloro-and bromouracil by Sandmeyer reaction was described. According to this procedure, 5-halouracils have been prepared in high yields(up to 75%) without any difficulties to remove of impurities. No appreciable competing reaction was observed.

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

• Proceedings of the Korea Concrete Institute Conference
• /
• 2010.05a
• /
• pp.383-384
• /
• 2010

This study was investigated freezing temperature measurement method and freezing temperature properties of anti-freeze agency in the domestic. Anti-freeze agency kinds were intended for nitrous acid. Anti-freeze agency with water dilution ratio was showed range of $-4.9{\sim}-6.3^{\circ}C$ in case of 1:3, $-3.3{\sim}-4.2^{\circ}C$ in case of 1:5, $-2.1{\sim}-3.3^{\circ}C$ in case of 1:7.

• Journal of the Korean Chemical Society
• /
• v.55 no.6
• /
• pp.988-993
• /
• 2011

Cyclodehydration of 6-amino-5-cyano pyrimidine derivative (2) afforded pyrimidoisoindole derivatives (3). Compound (3) reacted with carbethoxymethylene derivative to give pyridopyrimidine derivatives (5a,b). Compound (3) was also reacted with formamide to give the corresponding pyrimidopyrimdine derivatives (6) that condensed with benzaldehyde to give Schiff's base (7). Refluxing of compound (3) with triethyl orthoformate afforded compound (8) that cyclized with ammonium hydroxide giving the same compound (6). Compound (8) cyclized with hydrazine hydrate giving compound (9) which also cyclized with triethyl orthoformate affording compound (10). Diazotization of compound (3) led to the formation of triazinopyrimidine derivative (11). Cyclization of compound (11) upon treatment with hydrazine hydrate afforded compound (12). Compound (15) was prepared from reaction of compound (3) and ethylenediamine in presence of carbon disulfide. The behaviour of compound (15) toward benzoyl chloride, triethyl orthoformate, nitrous acid and/or carbon disulfide was also described. All proposed structures were supported by elemental analyses, spectroscopic data and some of the new products showed antimicrobial activity.

• Bulletin of the Korean Chemical Society
• /
• v.5 no.5
• /
• pp.179-182
• /
• 1984

MINDO/3 theoretical studies were carried out on sigmatropic hydrogen rearrangements in systems with central nitrogen atom; three systems studied being (1) N-methylformaldimine, (2) nitrous acid, and (3) formaldoxime-nitrosomethane systems. It was found that in system (1), 1,3-H shift is preferred whereas in systems (2) and (3), 1,2-H shifts are favored. The relative order of reactivity for the three systems was found to be (2) < (3) < (1), which is exactly the opposite to that found for the corresponding systems with central carbon atom.

• Bulletin of the Korean Chemical Society
• /
• v.20 no.3
• /
• pp.329-332
• /
• 1999

An automated method is developed for simultaneous determination of water soluble gases at parts per trillion level in the environmental air. The method involves temperature-humidity control of sample air using a thermostated humidifier, collection of analyte gases by condenser-type effluent diffusion denuder and subsequent effluent analysis by ion chromatography. The detection limits (3(σ) of the method for CH3COOH, HNO2 and SO2 gases are 0.022, 0.019 and 0.009 ppbv, respectively. The precisions range from 0.3 to 3.0% RSD. The method has been successfully applied to urban air analysis and some results for nitrous acid and SOx, in Seoul air are presented.

• The Korean Journal of Mycology
• /
• v.16 no.1
• /
• pp.1-8
• /
• 1988

Effect of suppression for zoosporangial germination and mycelial growth of Phyto­phthora capsici causing red pepper fruit rot, was carried out in vitro test by using $NH_4OH$ and $KNO_2$, as ammonium/ammonia, nitrite/nitrous acid and $CaCl_2$, as calcium ion. Results of in vitro tests with $NH_4OH$, $KNO_2$, and $CaCl_2$, mol solutions demonstrated that zoosporangial germination of P. capsici was inhibited about 15 to 50% compared with control, according to $NH_3$, HNO as nonionized form and $Ca^{+2}$ ions. Ammonia concentration$(NH_3)$ was proportionally increased by high pH level and mol concentration, whereas low pH and high mol concentration showed rather higher concentration of $HNO_2$. Ammonia were more toxic at pH 8 than at pH 7 under the same concentration, while nitrous acid$(HNO_2)$ was more toxic than at pH 8. The zoosporangial germination inhibition in the ammonium/ammonia and nitrite/nitrous acid solutions demonstrated that $NN_3$, and $HNO_2$, were primarily responsible for the inhibition at lower concentration and mor" toxic by increasing concentration. $Ca^{+2}$ ions showed that zoosporangial germination was inhibitory by high pH level and increasing mol concentration in comparison with buffer conlrol. pH levels affected to mycelial growth of the fungus, and especially, high pH caused rather retardation of mycelial growth. There was no definite inhibitory response of mycelial growth at various degree concentrations of the toxicant solutions.

• Journal of Korean Society for Atmospheric Environment
• /
• v.24 no.1
• /
• pp.16-29
• /
• 2008

Nitrous acid (HONO) can be produced by heterogenous reactions of nitrogen dioxide on surface materials and direct emission from combustion sources. However, a little is known of indoor HONO levels or the relationship between residential HONO, NO, and $NO_2$ concentrations in occupied houses. Therefore, we measured simultaneously NO, $NO_2$, and HONO concentrations in living room of an apartment using continuous analyzers to study the production of HONO (June $22{\sim}30$, 2006). The 4-min average concentrations of indoor NO, $NO_2$, and HONO were 4.3 (range: $0.4{\sim}214.3$), 10.3 ($2.0{\sim}87.3$), and 1.8 ppb ($0.3{\sim}7.7$), respectively. Peak levels of HONO up to 7.7 ppb and 24-hr averages as high as 1.7 ppb were measured. In agreement with previous studies, indoor HONO concentrations increased during operation of an unvented gas range. Examination of the observed kinetics suggests that the secondary production of indoor HONO, possibly as a result of heterogeneous reactions involving $NO_2$ and $H_2O$ is associated with $[NO_2]^2[H_2O]\;(r^2=0.88)$ rather than with $[NO][NO_2][H_2O]\;(r^2=0.75)$. Three combustion experiments at nighttime were also carried out to investigate the effects of vented combustion on the HONO, NO, and $NO_2$ concentrations. It was found to release HONO for $10{\sim}15$ minutes after NO and $NO_2$ source was turned off, and peak values were finally attained. Compared to unvented combustion, peak $NO_2$ and HONO concentrations were 3.2 and 2.0 times lower at weak vented combustion (air flow: $340\;m^3/hr$) and 4.9 and 2.4 times lower at strong vented combustion (air flow: $540\;m^3/hr$), respectively, emphasizing importance of operating ventilation hood fan during combustion to improve indoor air quality.

• Journal of Dairy Science and Biotechnology
• /
• v.33 no.2
• /
• pp.93-102
• /
• 2015

The aim of this study was to investigate the physiological characteristics and immunomodulatory activity of Lactobacillus fermentum 450 isolated from raw milk. L. fermentum 450 showed optimum growth at $40^{\circ}C$ and exhibited immunomodulatory effects on $interleukin-1{\alpha}$, tumor necrosis $factor-{\alpha}$, and nitrous oxide at concentrations of >2,500 pg/mL, >2,000 pg/mL, and $11.55{\pm}2.95{\mu}M$, respectively. Of the 16 antibiotics tested, L. fermentum 450 exhibited the highest sensitivity to rifampicin, followed by penicillin-G, and the highest resistance to kanamycin, followed by neomycin and polymyxin B. The strain showed high acid phosphatase activity and was comparatively tolerant to bile juice and acid. Moreover, the strain displayed high resistance to Salmonella Typhimurium (63.86%). These results demonstrate that L. fermentum 450 has potential for use as a probiotic with immunomodulatory activity.

• Journal of Korean Society on Water Environment
• /
• v.34 no.1
• /
• pp.96-108
• /
• 2018

Large efforts have recently been made on research and development of sustainable and energy-efficient short-cut nitrogen removal processes owing to strong attention to the energy neutral/positive wastewater treatment system. Anaerobic ammonium oxidizing bacteria (anammox bacteria) have been highlighted since 1990's due to their unique advantages including 60% less energy consumption, nearly 100% reduction for carbon source requirement, and 80% less sludge production. Side-stream short-cut nitrogen removal using anammox bacteria and partial nitritation anammox (PN/A) has been well established, whereas substantial challenges remain to be addressed mainly due to undesired main-stream conditions for anammox bacteria. These include low temperature, low concentrations of ammonia, nitrite, free ammonia, free nitrous acid or a combination of those. In addition, an anammox side-stream nitrogen management is insufficient to reduce overall energy consumption for energy-neutral or energy positive water resource recovery facility (WRRF) and at the same time to comply with nitrogen discharge regulation. This implies the development of the successful main-stream anammox based technology will accelerate a conversion of current wastewater treatment plants to sustainable water and energy recovery facility. This study discusses the status of the research, key mechanisms & interactions of the protagonists in the main-stream PN/A, and control parameters and major challenges in process development.