• Bulletin of the Korean Chemical Society
• /
• v.34 no.1
• /
• pp.121-127
• /
• 2013

New types of monocyclic ${\beta}$-lactams constitute an important class of compounds due to their unique structures and natures. Here, the design and synthesis of new 4-alkylthio monocyclic ${\beta}$-lactams 2a and 3a are reported. Significantly, compounds 2a and 3a, while keeping a monocyclic system, were designed to contain all of the substructures provided by the cleavage of C(2)-C(3) bond in penicillins. Efficient synthetic pathways for compounds 2a and 3a were established based on two different strategies. Compound 2a was synthesized from raw materials, using 4-acetoxyazetidin-2-one as a key intermediate, through a ten-step synthetic sequence in 3% overall yield. Compound 3a was synthesized from potassium salt of penicillin G (17), using the degraded product 20 as a key intermediate, through a six-step synthetic sequence in 11% overall yield. 4-Alkylthioazetidin-2-one derivatives, introduced in this study, could serve as valuable intermediates for the development of new monocyclic ${\beta}$-lactams.

• Bulletin of the Korean Chemical Society
• /
• v.22 no.5
• /
• pp.493-498
• /
• 2001

An efficient and eco-friendly approach to N-unsubstituted ${\beta}-lactams$ has been developed using mostly water as the reaction medium. This methodology was applied to the synthesis of N-unsubstituted 3-hydroxy-4-phenyl-2-azetidinone derivatives (inclu ding 15N-labeled version) which are suitable precursors for the C-13 side chain of taxol and its analogs.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.10
• /
• pp.2990-2994
• /
• 2014

The studies on design and synthesis of new monocyclic ${\beta}$-lactam esters 4(R/S)-(1'-methoxycarbonylpropyl- 2'(R/S)-thio)-3(R)-phenylacetamidoazetidin-2-one (3a) and 4(R/S)-(1'-methoxycarbonyl-2'-methylpropyl-2'- thio)-3(R)-phenylacetamidoazetidin-2-one (3b) were described. Compounds 3a and 3b were specifically designed to retain all penicillin substructures except the bicyclic system, which would be conceived by cleaving the C(3)-N(4) bond of penicillin G. Compounds 3a and 3b are of particular interest in the context of the structural elucidation of monocyclic ${\beta}$-lactams originated from penicillin. Key intermediates, ${\beta}$-mercapto esters 6a and 6b, were synthesized from conjugate acids 4a and 4b using three-step synthetic sequences, respectively, and 4(S)-acetoxy-3(S)-phenylacetamidoazetidin-2-one (7) was obtained from the degradation of penicillin G. Reactions of 6a and 6b with 7, thus obtained, provided the target compounds 3a and 3b, respectively.

• Korean Journal of Veterinary Service
• /
• v.27 no.3
• /
• pp.265-272
• /
• 2004

It was carried out to compare the residual materials by EEC 4-plate, Charm II and HPLC method in the muscles of cattle and pigs from slaughter-houses in Seoul from 2000 to 2003. Residual materials were detected from $1.10\%$(73/6,623) samples by EEC 4-plate method, and $10.93\%$(55/503) samples by Charm II method. The highest residual concentration(ppm) of oxytetracycline, tetracycline, chloramphenicol, chlortetracycline, sulfamethazine, sulfamerazine, sulfadimethoxine, penicillin and sulfamonomethoxine were 25.5, 3.46, 3.26, 1.5, 0.3, 0.2, 0.2, 0.14, and 0.07, respectively. Eighty nine samples were classified as 58($65.17\%$) only tetracyclines, 20($22.47\%$) only sulfonamides, 3($3.37\%$) only ${\beta}$-lactams, 2($2.25\%$) only chloramphenicol, 4($4.49\%$) tetracyclines and sulfonamides simultaneously, 1($1.12\%$) chloramphenicol and sulfonamides simultaneously, and 1($1.12\%$) chloramphenicol, sulfonamides and tetracyclines simultaneously.

• Bulletin of the Korean Chemical Society
• /
• v.10 no.5
• /
• pp.474-475
• /
• 1989

• Bulletin of the Korean Chemical Society
• /
• v.12 no.5
• /
• pp.589-589
• /
• 1991

• Bulletin of the Korean Chemical Society
• /
• v.11 no.5
• /
• pp.365-366
• /
• 1990

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.48 no.2
• /
• pp.158-167
• /
• 2015

A lateral flow immunoassay kit based on antigen-antibody interactions was developed to detect residues of beta-lactams, quinolones, tetracyclines, and sulfonamides in farmed fish. Group-specific antibodies showing cross-reactivity with other antibiotics in the same group were produced in rabbits. The rabbits were immunized eight times to obtain the maximum titers. Antibodies were extracted from the antisera collected from the immunized rabbits and produced group-specific reactions with antibiotics from the four groups. A kit was prepared that optimize conditions for the antigen-antibody reaction, using colloidal gold conjugated antibodies, and was designed to detect the four groups of antibiotics simultaneously. The kit enabled the detection of antibiotics in the four groups at below maximum residue limits (MRLs), which were $200{\mu}g/kg$ for tetracyclines, $100{\mu}g/kg$ for sulfonamides, $50{\mu}g/kg$ for beta-lactams, and $100{\mu}g/kg$ for quinolones. The cross-reactivity of the antibodies ranged from 10-80% for the sulfonamides, 20-100% for tetracyclines, 38-100% for quinolones, and 20-100% for the beta-lactams, confirming that the antibodies were group specific. The test kit was used 30 times to examine spiked antibiotics at the limits of detection (LODs) and all produced positive results, indicating high sensitivity. The LODs for the assay ranged from 4-20 ng/mL for beta-lactams, 25-50 ng/mL for sulfonamides, 20-100 ng/mL for tetracyclines, and 30-80 ng/mL for quinolones, and there were no false negative reactions at above these LODs. In addition, all of the LODs of the developed kit were correlated with high-performance liquid chromatography (HPLC) data. Our lateral flow immunoassay kit can simultaneously detect antibiotic residues from a large number of fish samples rapidly, strengthening the safety of domestic farmed and imported fish.

• Analytical Science and Technology
• /
• v.23 no.2
• /
• pp.119-127
• /
• 2010

An effective method for the simultaneous analysis of ${\beta}$-lactams from surface water was established. After solid-phase extraction with HLB (Hydrophilic Lipohilic Balance) cartridge at pH 2, seven ${\beta}$-lactams (amoxicillin, ampicillin, penicillin G, cefaclor, cefadroxil, cefatrizine and cephradine) were determined using LC/ESI-MS/MS. In this newly established method, correlation coefficients ($r^2$) of calibration curves for seven ${\beta}$-lactams in blank surface water appeared to be 0.9911~0.9995 in the concentration range of 0.01~1.0 ng/mL. The limits of detection (LODs) and the limits of quantificaiton (LOQs) in spiked surface water were shown to be 0.0003~0.0234 ng/mL and 0.0046~0.0778 ng/mL, respectively. The developed method is believed to serve as a rapid and reliable method for the qualitative and quantitative analysis of residual ${\beta}$-lactam antibiotics from aquatic environment.

• Bulletin of the Korean Chemical Society
• /
• v.12 no.6
• /
• pp.710-711
• /
• 1991