BACKGROUND Appendicitis, the inflammation of the appendix, is the most common abdominal surgical emergency requiring expedient surgical intervention. Extendedspectrum beta-lactamases(ESBLs) are bacterial enzymes that ...BACKGROUND Appendicitis, the inflammation of the appendix, is the most common abdominal surgical emergency requiring expedient surgical intervention. Extendedspectrum beta-lactamases(ESBLs) are bacterial enzymes that catalyse the degradation of the betalactam ring of penicillins and cephalosporins(but without carbapenemase activity), leading to resistance of these bacteria to beta-lactam antibiotics. Recent increases in incidence of ESBL-producing bacteria have caused alarm worldwide. Proportion estimates of ESBLEnterobacteriaceae hover around 46% in China, 42% in East Africa, 12% in Germany, and 8% in the United States.CASE SUMMARY The impact of ESBL-producing bacteria on appendiceal abscesses and consequent pelvic abscesses are yet to be examined in depth. A literature review using the search words "appendiceal abscesses" and "ESBL Escherichia coli(E. coli)" revealed very few cases involving ESBL E. coli in any capacity in the context of appendiceal abscesses. This report describes the clinical aspects of a patient with appendicitis whodeveloped a postoperative pelvic abscess infected with ESBL-producing E. coli. In this report, we discuss the risk factors for contracting ESBL E. coli infection in appendicitis and post-appendectomy pelvis abscesses. We also discuss our management approach for postappendectomy ESBL E. coli pelvic abscesses, including drainage, pathogen identification, and pathogen characterisation. When ESBL E. coli is confirmed, carbapenem antibiotics should be promptly administered, as was done efficaciously with this patient. Our report is the first one in a developed country involving ESBL E. coli related surgical complications in association with a routine laparoscopic appendectomy.CONCLUSION Our report is the first involving ESBL E. coli and appendiceal abscesses, and that too consequent to laparoscopic appendectomy.展开更多
Background: β lactamase is a plasmid-encoded enzyme that hydrolyzes β lactam ring of β lactam antibiotics rendering them ineffective. These enzymes, produced by Staphylococcus aureus along with many other organisms...Background: β lactamase is a plasmid-encoded enzyme that hydrolyzes β lactam ring of β lactam antibiotics rendering them ineffective. These enzymes, produced by Staphylococcus aureus along with many other organisms, have hindered the use of many useful and once life-saving β lactam antibiotics from clinical practice. Methods: This study was aimed to compare three test methods-chromogenic, acidimetric and iodometric-for the detection of β lactamase enzyme produced by 404 nosocomial induced S. aureus isolated from two Nepali hospitals, Kathmandu based hospital (KBH) and Lalitpur based Hospital (LBH). The study was carried out following standard methodology during November 2007 to June 2009 in the Department of Microbiology, Institute of Medicine, Kathmandu, Nepal. Sensitivity, specificity, efficiency, positive predictive value, and negative predictive values of the tests were calculated taking penicillin resistance and sensitivity as the standard. Results: Chromogenic method was found to be the most sensitive (98.93%) and efficient (98.51%) test and had a high positive predictive value (99.46%). Sensitivity (98.4%) and efficiency (98.27%) of iodometric method was found to be comparable to chromogenic test;its specificity (96.55 %) and positive predictive value (99.73%) were the highest among the 3 tests. Acidimetric test was the least sensitive (97.33%) and efficient (96.78%). Of note, the sensitivity and specificity of these test methods have been compromised due to the negativity of few penicillin resistant isolates and positivity of some penicillin sensitive isolates, respectively. Conclusion: Chromogenic method was found comparatively to be the best test method for the detection of β lactamase production. However, in contrast to the other two test methods whose reagents can be locally and economically prepared, chromogenic test’s use has been impeded by its cost and unavailability in the local Nepali market.展开更多
Penicillin-binding proteins(PBPs) are the target of β-lactam antibiotics(the major treatment for Streptococcus pneumoniae infections),and mutations in PBPs are considered as a primary mechanism for the developmen...Penicillin-binding proteins(PBPs) are the target of β-lactam antibiotics(the major treatment for Streptococcus pneumoniae infections),and mutations in PBPs are considered as a primary mechanism for the development of β-lactam resistance in S.pneumoniae.This study was conducted to investigate the mutations in the PBPs of clinical S.pneumoniae isolates in Hangzhou,China,in correlation with β-lactam resistance.Results showed that 19 F was the predominant serotype(7/27) and 14 of the S.pneumoniae isolates were resistant to both penicillin G and cephalosporin.Genotyping results suggested that β-lactam-resistant isolates primarily exhibited single-site mutations in both the STMK and SRNVP motifs of pbp1 a in combination with double-site mutations in the STMK motif of pbp2 x,which might be the primary mechanisms underlying the β-lactam resistance of the isolates in this study.展开更多
The mechanism of the formation of a key tricyclic lactam intermediate 3 was studied. It was found that the E-form compound 3 was transformed from the Z-form compound 4. The formation of 4 was a kinetically controlle...The mechanism of the formation of a key tricyclic lactam intermediate 3 was studied. It was found that the E-form compound 3 was transformed from the Z-form compound 4. The formation of 4 was a kinetically controlled process while the formation of 3 was a thermodynamically favorable one. A possible mechanism was given in this paper.展开更多
Three new limonoid-type triterpenoids,namely toonasins A–C(1–3)with a rare lactam E ring,along with six known compounds(4–9)were isolated from the barks of Toona sinensis.The structures of new compounds were elucid...Three new limonoid-type triterpenoids,namely toonasins A–C(1–3)with a rare lactam E ring,along with six known compounds(4–9)were isolated from the barks of Toona sinensis.The structures of new compounds were elucidated by interpretation of spectroscopic data,and the relative configuration of compound 1 was further characterized by X-ray crystallographic analyses.The isolated compounds were evaluated for their cytotoxic activities against five human tumor cell lines(HL-60,SMMC-7721,A-549,MCF-7 and SW480),and compounds 3 and 5 showed weak cytotoxicities.展开更多
The crystal of the title compound C, C 30 H 30 N 2O 3S has been prepared by reaction of 1,5 benzothiazepine with N protected glycine and determined by X ray single crystal diffraction. Crystal data:...The crystal of the title compound C, C 30 H 30 N 2O 3S has been prepared by reaction of 1,5 benzothiazepine with N protected glycine and determined by X ray single crystal diffraction. Crystal data: M r =498.62, triclinic with P 1 space group, a=10.880(2), b=13.955(3), c=9.537(2), α=99.34(3)°, β=110.43(3)°, γ=88 56(3)°, V=1338.2(5) 3, F(000)=528, λ (Mo Kα)=0.71073, Z=2, D c =1 237g/cm 3, μ =0.154mm -1 . Final R=0.0453, wR =0.1256 for 3491 observed reflections 〔 I>2σ(I) 〕. Structure analysis reveals that the substituents at C(23) and C(7) in four membered ring are located on the same side. The conformation of seven membered ring is chair like.展开更多
The Beckmann rearrangement of cyclohexanone oxime was achieved by the combined use of cobalt salt and Lewis acids co-catalysts (each 10 mol%). Various combinations of cobalt salts and Lewis acids gave lactams in a sat...The Beckmann rearrangement of cyclohexanone oxime was achieved by the combined use of cobalt salt and Lewis acids co-catalysts (each 10 mol%). Various combinations of cobalt salts and Lewis acids gave lactams in a satisfactory yield under mild conditions. This method makes it possible to reduce undesirable byproducts.展开更多
This paper reports the primary results of the study on β-lactam derivatives of 2,4-diaryl-2, 3-di hydro-1, 5 -benzothiazepines. Five titie compounds have been synthesized, and their configUration and conformation wer...This paper reports the primary results of the study on β-lactam derivatives of 2,4-diaryl-2, 3-di hydro-1, 5 -benzothiazepines. Five titie compounds have been synthesized, and their configUration and conformation were detendned by X-ray crystallographic analysis.展开更多
A series of 2-acyl-β-lactam-2-carboxamides was prepared through a tandem Ugi 4 CC/SN cyclization of bromoacetic acid, primary amine, arylglyoxal, and isocyanide. All of them were characterized by NMR, IR, MS and elem...A series of 2-acyl-β-lactam-2-carboxamides was prepared through a tandem Ugi 4 CC/SN cyclization of bromoacetic acid, primary amine, arylglyoxal, and isocyanide. All of them were characterized by NMR, IR, MS and elemental analysis. Meanwhile, the single crystal of compound 5 a, C_(19)H_(25)ClN_2 O_3, was also obtained and determined by X-ray crystallography. Crystal data: triclinic system, space group P_1, a = 8.1318(15), b = 11.931(2), c = 12.027(2) ?, α = 67.361(3)°, β = 73.009(3)°, γ = 85.663(3)°, V = 1029.1(3) ?3, Z = 2, F(000) = 388, Dc = 1.178 g/cm3, μ = 0.204 mm^(-1), R = 0.0786 and w R = 0.2212 for 3585 independent reflections(Rint = 0.0214) and 2960 observed ones(I > 2σ(I)). Intermolecular N–H···O stacking interactions contributed to the stability of the structure. The antitumor abilities of 5 were analyzed with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazo-liumbromide(MTT) standard method; 5 c stood out as the most potent showing an IC_(50) of 1.70 μmol/L against human tumor cell lines(HepG2).展开更多
A series of spiro, β-Lactams, and thiazolidinones incorporating compounds 4 have been synthesized by cycloaddition reaction of, chloroacetyl chloride and mercaptoacetic acid with the synthesized Shiff,s bases 5a-c to...A series of spiro, β-Lactams, and thiazolidinones incorporating compounds 4 have been synthesized by cycloaddition reaction of, chloroacetyl chloride and mercaptoacetic acid with the synthesized Shiff,s bases 5a-c to give new spiro β- Lactam 6a-c and spiro thiazolidinone 7a-c the cycloaddition were characterized by spectral data including HNMR, 13C-NMR, IR and elemental analysis.展开更多
A novel method for the enantioselective synthesis of β-lactams is described in this study. 2,3-Dihydrobenzooxazin-4-one derived from salicylamide and L-menthone was used as the chiral auxiliary, which reacted with a-...A novel method for the enantioselective synthesis of β-lactams is described in this study. 2,3-Dihydrobenzooxazin-4-one derived from salicylamide and L-menthone was used as the chiral auxiliary, which reacted with a-bromo-acyl bromides in the presence of pyridine to give carboximides 2. The stereo-controlled Reformatsky-type reactions of carboximides with imines yielded the corresponding trans β-lactams with high enantioselectivities(e.e. 75%-86%) and high chemical yields(63%-85%), meanwhile, the chiral auxiliary dihydrobenzooxazin-4-one was released and recovered.展开更多
Objective: Describe resistance to beta lactam antibiotics of Pseudomonas aeruginosa in community infection within HIV-1 infected persons. Methods: We have studied prospectively from June 15th to December 31st 2013 int...Objective: Describe resistance to beta lactam antibiotics of Pseudomonas aeruginosa in community infection within HIV-1 infected persons. Methods: We have studied prospectively from June 15th to December 31st 2013 inthe Clinic Hotel-Dieu and NGO VISA of Lomé, adult HIV-1 infected patients under anti retroviral therapy combining tenofovir, lamivudine and efavirenz for at least one year. The technique of agar diffusion susceptibility using discs of Ticarcillin + clavulanic acid is used to study the β-lactamase production. The diagnosis of species was performed by the chloroform test and the test for sensitivity to kanamycin and colistin. Results: Thirty five strains of Pseudomonas aeruginosa were obtained. The T-lymphocytes CD4 mediane was 575 cells/mm3 of blood. Urine represented 15 cases, skin abscesses 11 cases, externa suppurate otitis 7 cases and vaginal swab for 2 cases. The phenotypes were: wild phenotypes 23 cases (65.7%), resistant phenotypes 12 cases. Among resistant phenotypes, 4 were complex phenotype;5 were ESBL phenotypes;2 were hyper productive cephalosporinases phenotypes and 1 was a specific phenotype with impermeability to imipenem. Conclusion: The acquisition of resistance of Pseudomonas aeruginosa to beta lactam antibiotics in community infections among HIV-1 infected person incentives controls and promotes the rational use of antibiotics.展开更多
The geometric parameters for D-Ala-D-Ala are optimized by MM, the most and next two stable conformations are obtained. According to the interaction model with target emzyme suggested by us, the traingle-relationship o...The geometric parameters for D-Ala-D-Ala are optimized by MM, the most and next two stable conformations are obtained. According to the interaction model with target emzyme suggested by us, the traingle-relationship of it is obtained. This triangle-relationship could be found in the pharmaceuticals belong to different classes of β-actams also.展开更多
A series of trans-3-chloro-β-lactams was synthesized stereospecifically from imines and chloroacetyl chloride or a mixture of chloroacetyl chloride and nitroacetyl chloride, prepared from vinylidene chloride and a mi...A series of trans-3-chloro-β-lactams was synthesized stereospecifically from imines and chloroacetyl chloride or a mixture of chloroacetyl chloride and nitroacetyl chloride, prepared from vinylidene chloride and a mixture of concentrated nitric acid and sulfuric acid, in the presence of triethylamine. The reaction of vinylidene chloride and the mixed acid was investigated. The formation mechanism of chloroacetyl chloride and nitroacetyl chloride and their reaction process with imines were proposed.展开更多
The title compound -(N-protected amino)--lactam (C36H33N2O5ClS), derivative of 1,5-benzothiazepine, was prepared by the reaction of 1,5-benzothiazepine 1 with (4R)- phenyloxazolidylacetyl chloride and characteized by ...The title compound -(N-protected amino)--lactam (C36H33N2O5ClS), derivative of 1,5-benzothiazepine, was prepared by the reaction of 1,5-benzothiazepine 1 with (4R)- phenyloxazolidylacetyl chloride and characteized by X-ray diffraction analysis. The title compound crystallizes in orthorhombic system, space group P212121 with a=12.293(2), b=26.026(5), c=10.146(2)? V=3246.1?, Z=4, Dc=1.312g/cm3, Mr=641.15, F(000)=1344, μ= 0.228 mm1. The final R=0.0597 and wR=0.1165 for 3226 observed reflections with I ≥ 2?I). The crystal structure shows that the 4-phenyloxazolidyl and phenyl attached to C(8) and C(9) are in cis positions, and no trans product was discovered. So the cyclization to -lactam is stereospecific.展开更多
Reaction of 1,5-benzothiazepine with N-protected glycine gives new a-amino-β-lactamderivatives of 1.5-benzothiazepine. The configuration and conformation of the products wereconfirmed by x-ray diffraction. The resu...Reaction of 1,5-benzothiazepine with N-protected glycine gives new a-amino-β-lactamderivatives of 1.5-benzothiazepine. The configuration and conformation of the products wereconfirmed by x-ray diffraction. The result further reveals that the reaction of 1.5-benzothiazepineswith derivatives of carboxylic acid stereospecific.展开更多
1, 5-Benzothiazepines 1 react with phenylacetyl chloride to give the title compounds.The structures of these new compounds were confirmed by elemental analysis, ~1H NMR, ^(13)C NMRand MS spectroscopy, and their config...1, 5-Benzothiazepines 1 react with phenylacetyl chloride to give the title compounds.The structures of these new compounds were confirmed by elemental analysis, ~1H NMR, ^(13)C NMRand MS spectroscopy, and their configuration (the mutual positions of the substituents relative to theβ-lactam ring) and conformation of the compounds were determined by X-ray crystal analysis.展开更多
A 61-year-old female with past medical history of maculopapular rash reaction to ciprofloxacin and amoxicillin being treated for diverticulitis develops the same rash with administration of piperacillin/tazobactam and...A 61-year-old female with past medical history of maculopapular rash reaction to ciprofloxacin and amoxicillin being treated for diverticulitis develops the same rash with administration of piperacillin/tazobactam and aztreonam. A diffuse maculopapular rash developed after the administration of piperacillin. It resolved with discontinuation of the drug and the patient was switched to aztreonam and a very similar rash developed subsequently. In a review of the literature, there are no documented cases of a patient with an allergy to both aztreonam and piperacillin/tazobactam despite in vivo cross-reactivity. Unfortunately, there are no standardized allergy tests for aztreonam or piperacillin. This case, however, does offer the possibility that aztreonam may not always be the right alternative to persons with beta-lactam antibiotic allergies.展开更多
文摘BACKGROUND Appendicitis, the inflammation of the appendix, is the most common abdominal surgical emergency requiring expedient surgical intervention. Extendedspectrum beta-lactamases(ESBLs) are bacterial enzymes that catalyse the degradation of the betalactam ring of penicillins and cephalosporins(but without carbapenemase activity), leading to resistance of these bacteria to beta-lactam antibiotics. Recent increases in incidence of ESBL-producing bacteria have caused alarm worldwide. Proportion estimates of ESBLEnterobacteriaceae hover around 46% in China, 42% in East Africa, 12% in Germany, and 8% in the United States.CASE SUMMARY The impact of ESBL-producing bacteria on appendiceal abscesses and consequent pelvic abscesses are yet to be examined in depth. A literature review using the search words "appendiceal abscesses" and "ESBL Escherichia coli(E. coli)" revealed very few cases involving ESBL E. coli in any capacity in the context of appendiceal abscesses. This report describes the clinical aspects of a patient with appendicitis whodeveloped a postoperative pelvic abscess infected with ESBL-producing E. coli. In this report, we discuss the risk factors for contracting ESBL E. coli infection in appendicitis and post-appendectomy pelvis abscesses. We also discuss our management approach for postappendectomy ESBL E. coli pelvic abscesses, including drainage, pathogen identification, and pathogen characterisation. When ESBL E. coli is confirmed, carbapenem antibiotics should be promptly administered, as was done efficaciously with this patient. Our report is the first one in a developed country involving ESBL E. coli related surgical complications in association with a routine laparoscopic appendectomy.CONCLUSION Our report is the first involving ESBL E. coli and appendiceal abscesses, and that too consequent to laparoscopic appendectomy.
文摘Background: β lactamase is a plasmid-encoded enzyme that hydrolyzes β lactam ring of β lactam antibiotics rendering them ineffective. These enzymes, produced by Staphylococcus aureus along with many other organisms, have hindered the use of many useful and once life-saving β lactam antibiotics from clinical practice. Methods: This study was aimed to compare three test methods-chromogenic, acidimetric and iodometric-for the detection of β lactamase enzyme produced by 404 nosocomial induced S. aureus isolated from two Nepali hospitals, Kathmandu based hospital (KBH) and Lalitpur based Hospital (LBH). The study was carried out following standard methodology during November 2007 to June 2009 in the Department of Microbiology, Institute of Medicine, Kathmandu, Nepal. Sensitivity, specificity, efficiency, positive predictive value, and negative predictive values of the tests were calculated taking penicillin resistance and sensitivity as the standard. Results: Chromogenic method was found to be the most sensitive (98.93%) and efficient (98.51%) test and had a high positive predictive value (99.46%). Sensitivity (98.4%) and efficiency (98.27%) of iodometric method was found to be comparable to chromogenic test;its specificity (96.55 %) and positive predictive value (99.73%) were the highest among the 3 tests. Acidimetric test was the least sensitive (97.33%) and efficient (96.78%). Of note, the sensitivity and specificity of these test methods have been compromised due to the negativity of few penicillin resistant isolates and positivity of some penicillin sensitive isolates, respectively. Conclusion: Chromogenic method was found comparatively to be the best test method for the detection of β lactamase production. However, in contrast to the other two test methods whose reagents can be locally and economically prepared, chromogenic test’s use has been impeded by its cost and unavailability in the local Nepali market.
基金supported by Grants from the National Natural Sciences Foundation of China[81772232]Zhejiang Provincial Program for the Cultivation of High-level Innovative Health Talents
文摘Penicillin-binding proteins(PBPs) are the target of β-lactam antibiotics(the major treatment for Streptococcus pneumoniae infections),and mutations in PBPs are considered as a primary mechanism for the development of β-lactam resistance in S.pneumoniae.This study was conducted to investigate the mutations in the PBPs of clinical S.pneumoniae isolates in Hangzhou,China,in correlation with β-lactam resistance.Results showed that 19 F was the predominant serotype(7/27) and 14 of the S.pneumoniae isolates were resistant to both penicillin G and cephalosporin.Genotyping results suggested that β-lactam-resistant isolates primarily exhibited single-site mutations in both the STMK and SRNVP motifs of pbp1 a in combination with double-site mutations in the STMK motif of pbp2 x,which might be the primary mechanisms underlying the β-lactam resistance of the isolates in this study.
文摘The mechanism of the formation of a key tricyclic lactam intermediate 3 was studied. It was found that the E-form compound 3 was transformed from the Z-form compound 4. The formation of 4 was a kinetically controlled process while the formation of 3 was a thermodynamically favorable one. A possible mechanism was given in this paper.
基金the National Knowledge Innovation of CAS(No.KSCX2-YW-G-038)the Foundation of State Key Laboratory of Phytochemistry and Plant Resources in West China(P2015-ZZ09)。
文摘Three new limonoid-type triterpenoids,namely toonasins A–C(1–3)with a rare lactam E ring,along with six known compounds(4–9)were isolated from the barks of Toona sinensis.The structures of new compounds were elucidated by interpretation of spectroscopic data,and the relative configuration of compound 1 was further characterized by X-ray crystallographic analyses.The isolated compounds were evaluated for their cytotoxic activities against five human tumor cell lines(HL-60,SMMC-7721,A-549,MCF-7 and SW480),and compounds 3 and 5 showed weak cytotoxicities.
文摘The crystal of the title compound C, C 30 H 30 N 2O 3S has been prepared by reaction of 1,5 benzothiazepine with N protected glycine and determined by X ray single crystal diffraction. Crystal data: M r =498.62, triclinic with P 1 space group, a=10.880(2), b=13.955(3), c=9.537(2), α=99.34(3)°, β=110.43(3)°, γ=88 56(3)°, V=1338.2(5) 3, F(000)=528, λ (Mo Kα)=0.71073, Z=2, D c =1 237g/cm 3, μ =0.154mm -1 . Final R=0.0453, wR =0.1256 for 3491 observed reflections 〔 I>2σ(I) 〕. Structure analysis reveals that the substituents at C(23) and C(7) in four membered ring are located on the same side. The conformation of seven membered ring is chair like.
文摘The Beckmann rearrangement of cyclohexanone oxime was achieved by the combined use of cobalt salt and Lewis acids co-catalysts (each 10 mol%). Various combinations of cobalt salts and Lewis acids gave lactams in a satisfactory yield under mild conditions. This method makes it possible to reduce undesirable byproducts.
文摘This paper reports the primary results of the study on β-lactam derivatives of 2,4-diaryl-2, 3-di hydro-1, 5 -benzothiazepines. Five titie compounds have been synthesized, and their configUration and conformation were detendned by X-ray crystallographic analysis.
基金Financial support from the National Natural Science Foundation of China(No.81773746)the Open Project of Hubei Key Laboratory of Wudang Local Chinese Medicine Research,Hubei University of Medicine(No.WDCM009 and 2011JH-2014CXTT07)+1 种基金the Foundation of Health and Family planning Commission of Hubei Province(No.WJ2015Z113)the Foundation for Innovative Research Team of Hubei University of Medicine(2014CXZ01 and 2014CXZ05)
文摘A series of 2-acyl-β-lactam-2-carboxamides was prepared through a tandem Ugi 4 CC/SN cyclization of bromoacetic acid, primary amine, arylglyoxal, and isocyanide. All of them were characterized by NMR, IR, MS and elemental analysis. Meanwhile, the single crystal of compound 5 a, C_(19)H_(25)ClN_2 O_3, was also obtained and determined by X-ray crystallography. Crystal data: triclinic system, space group P_1, a = 8.1318(15), b = 11.931(2), c = 12.027(2) ?, α = 67.361(3)°, β = 73.009(3)°, γ = 85.663(3)°, V = 1029.1(3) ?3, Z = 2, F(000) = 388, Dc = 1.178 g/cm3, μ = 0.204 mm^(-1), R = 0.0786 and w R = 0.2212 for 3585 independent reflections(Rint = 0.0214) and 2960 observed ones(I > 2σ(I)). Intermolecular N–H···O stacking interactions contributed to the stability of the structure. The antitumor abilities of 5 were analyzed with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazo-liumbromide(MTT) standard method; 5 c stood out as the most potent showing an IC_(50) of 1.70 μmol/L against human tumor cell lines(HepG2).
文摘A series of spiro, β-Lactams, and thiazolidinones incorporating compounds 4 have been synthesized by cycloaddition reaction of, chloroacetyl chloride and mercaptoacetic acid with the synthesized Shiff,s bases 5a-c to give new spiro β- Lactam 6a-c and spiro thiazolidinone 7a-c the cycloaddition were characterized by spectral data including HNMR, 13C-NMR, IR and elemental analysis.
基金This work is supported by the National Natural Science Foundation of China (grant No: 20372056)a Research Fund from the Royal Society of Chemistry. UK.
基金National Natural Science Foundation of China(No. 20272051)Natural Science Foundation of Zhejiang Province, China(No. R404109)
文摘A novel method for the enantioselective synthesis of β-lactams is described in this study. 2,3-Dihydrobenzooxazin-4-one derived from salicylamide and L-menthone was used as the chiral auxiliary, which reacted with a-bromo-acyl bromides in the presence of pyridine to give carboximides 2. The stereo-controlled Reformatsky-type reactions of carboximides with imines yielded the corresponding trans β-lactams with high enantioselectivities(e.e. 75%-86%) and high chemical yields(63%-85%), meanwhile, the chiral auxiliary dihydrobenzooxazin-4-one was released and recovered.
文摘Objective: Describe resistance to beta lactam antibiotics of Pseudomonas aeruginosa in community infection within HIV-1 infected persons. Methods: We have studied prospectively from June 15th to December 31st 2013 inthe Clinic Hotel-Dieu and NGO VISA of Lomé, adult HIV-1 infected patients under anti retroviral therapy combining tenofovir, lamivudine and efavirenz for at least one year. The technique of agar diffusion susceptibility using discs of Ticarcillin + clavulanic acid is used to study the β-lactamase production. The diagnosis of species was performed by the chloroform test and the test for sensitivity to kanamycin and colistin. Results: Thirty five strains of Pseudomonas aeruginosa were obtained. The T-lymphocytes CD4 mediane was 575 cells/mm3 of blood. Urine represented 15 cases, skin abscesses 11 cases, externa suppurate otitis 7 cases and vaginal swab for 2 cases. The phenotypes were: wild phenotypes 23 cases (65.7%), resistant phenotypes 12 cases. Among resistant phenotypes, 4 were complex phenotype;5 were ESBL phenotypes;2 were hyper productive cephalosporinases phenotypes and 1 was a specific phenotype with impermeability to imipenem. Conclusion: The acquisition of resistance of Pseudomonas aeruginosa to beta lactam antibiotics in community infections among HIV-1 infected person incentives controls and promotes the rational use of antibiotics.
基金Project supported by National Scientific Foundation of China
文摘The geometric parameters for D-Ala-D-Ala are optimized by MM, the most and next two stable conformations are obtained. According to the interaction model with target emzyme suggested by us, the traingle-relationship of it is obtained. This triangle-relationship could be found in the pharmaceuticals belong to different classes of β-actams also.
基金Supported by the National Natural Science Foundation of China(Nos.20772005,20972013)the Beijing Natural Science Foundation,China(No.2092022)the Specialized Research Fund for the Doctoral Program of Higher Education,Ministry of Education of China
文摘A series of trans-3-chloro-β-lactams was synthesized stereospecifically from imines and chloroacetyl chloride or a mixture of chloroacetyl chloride and nitroacetyl chloride, prepared from vinylidene chloride and a mixture of concentrated nitric acid and sulfuric acid, in the presence of triethylamine. The reaction of vinylidene chloride and the mixed acid was investigated. The formation mechanism of chloroacetyl chloride and nitroacetyl chloride and their reaction process with imines were proposed.
基金Supported by the Natural Foundation of Hebei Province
文摘The title compound -(N-protected amino)--lactam (C36H33N2O5ClS), derivative of 1,5-benzothiazepine, was prepared by the reaction of 1,5-benzothiazepine 1 with (4R)- phenyloxazolidylacetyl chloride and characteized by X-ray diffraction analysis. The title compound crystallizes in orthorhombic system, space group P212121 with a=12.293(2), b=26.026(5), c=10.146(2)? V=3246.1?, Z=4, Dc=1.312g/cm3, Mr=641.15, F(000)=1344, μ= 0.228 mm1. The final R=0.0597 and wR=0.1165 for 3226 observed reflections with I ≥ 2?I). The crystal structure shows that the 4-phenyloxazolidyl and phenyl attached to C(8) and C(9) are in cis positions, and no trans product was discovered. So the cyclization to -lactam is stereospecific.
文摘Reaction of 1,5-benzothiazepine with N-protected glycine gives new a-amino-β-lactamderivatives of 1.5-benzothiazepine. The configuration and conformation of the products wereconfirmed by x-ray diffraction. The result further reveals that the reaction of 1.5-benzothiazepineswith derivatives of carboxylic acid stereospecific.
文摘1, 5-Benzothiazepines 1 react with phenylacetyl chloride to give the title compounds.The structures of these new compounds were confirmed by elemental analysis, ~1H NMR, ^(13)C NMRand MS spectroscopy, and their configuration (the mutual positions of the substituents relative to theβ-lactam ring) and conformation of the compounds were determined by X-ray crystal analysis.
文摘A 61-year-old female with past medical history of maculopapular rash reaction to ciprofloxacin and amoxicillin being treated for diverticulitis develops the same rash with administration of piperacillin/tazobactam and aztreonam. A diffuse maculopapular rash developed after the administration of piperacillin. It resolved with discontinuation of the drug and the patient was switched to aztreonam and a very similar rash developed subsequently. In a review of the literature, there are no documented cases of a patient with an allergy to both aztreonam and piperacillin/tazobactam despite in vivo cross-reactivity. Unfortunately, there are no standardized allergy tests for aztreonam or piperacillin. This case, however, does offer the possibility that aztreonam may not always be the right alternative to persons with beta-lactam antibiotic allergies.