Azaneylylidene-based tetradentate Schiff base as a new "ON-OFF" fluorescent probe for the detection of Cu(II) ion: Synthesis, characterization and real sample analysis

Herein we describe the synthesis of Cu²⁺ sensor, 2,2'-((1E,1'E)-((4-chloro-1,2-phenylene)bis(azaneylylidene))bis(methane-ylylidene))bis(4-bromophenol) (CPMB) and characterization using various spectral and analytical techniques. CPMB exhibited high selectivity towards Cu²⁺ ions via fluorescence quenching mechanism, which combined the character of high selectivity towards Cu²⁺ assay even in the presence of other common metal ions such as Cu²⁺, Al³⁺, Co²⁺, Ni²⁺, Mn²⁺, Zn²⁺ Pb²⁺ Cd²⁺, Fe²⁺, Hg²⁺, Mg²⁺ and Fe³⁺ (30 μM) ethanol-water (1:9 v/v) system. Upon the addition of the solution of Cu²⁺ ions to CPMB, the complexation of Cu²⁺ with CPMB leads to the immediate formation of light green color, indicating that CPMB can act as simple colorimetric sensor, particularly for Cu²⁺ in the presence of most interfering metal ions in ethanol-water medium. More interestingly, the ability of sensing behavior of CPMB for Cu²⁺ ion in the real water samples (tap water and lake water samples) was also investigated. Further, Job's plot confirmed that the complexation occurred in 1:1 ratio (ligand:metal). Furthermore, the fluorescence inhibiting factor showed a good linear relationship with the concentration of Cu²⁺ with detection limit of 0.302 μM. The electronic transitions of the complex in ethanol were studied using DFT calculations.

Predictors of mortality in patients with severe COVID-19 pneumonia - a retrospective study

INTRODUCTION

The novel coronavirus pandemic has caused significant mortality throughout the world. This study was done as there is scarce data on mortality predictors in severe COVID-19 pneumonia patients admitted to ICU in the Indian population.

MATERIAL AND METHODS

A retrospective study was conducted on COVID-19 pneumonia patients admitted to tertiary care center during June-October 2020. The records of patients admitted to ICU were collected and data included demography, symptoms, comorbidites and vital parameters. Laboratory parameters included complete hemogram, random blood sugar, S.Ferritin, S.LDH, renal function test, liver function test. Treatment-associated information such as the use of remdesivir, timing of initiating rem-desivir after the symptom onset, the use of steroids, use of anticoagulants, use of HFNC, NIV, ventilator were collected. 30 days mortality data post-discharge was collected via telephonic interview.

RESULTS

4,012 confirmed cases of COVID-19 were admitted to hospital, of which 560 (13.95%) with severe pneumonia were included in the study. Mean age was 57.75 ± 13.96 years. The mortality rates were 54.64% among severe COVID-19 cases and 5% among mild to moderate COVID-19 cases. The Cox multinominal regression analysis identified SpO2/FiO2 < 400, age > 50 years, duration of symptom > 4 days, serum ferritin > 450 µg/L, respiratory rate > 23/min, the presence of comorbidities and non-usage of remdesivir were independently associated with increased mortality. Mortality rate at 30 days was 56.60%.

CONCLUSION

Severe COVID-19 pneumonia is associated with very high mortality, especially in a resource-constrained setting. The use of remdesivir may have to be considered early in the course of disease to prevent excess mortality related to COVID-19.

Factors influencing severity of community-acquired pneumonia

INTRODUCTION

Community-acquired pneumonia (CAP) is a common cause of morbidity and mortality in India. There is a need to understand the risk factors associated with severity of CAP in our population. This study was part of the international global initiative for methicillin-resistant Staphylococcus aureus (MRSA) pneumonia study to evaluate MRSA.

METHODS

A total of 100 consecutive cases of pneumonia admitted to the Department of Pulmonary Medicine in a tertiary care hospital were recruited in the study during March-July 2015. The severity of pneumonia was assessed based on the CURB-65 score. Individuals with pneumonia and CURB-65 score >2 were compared with subjects with CURB-65 score ≤2. Individuals were also evaluated for the causative organism and its resistance pattern with specific reference to the presence of MRSA.

RESULTS

Mean age of patients was 54.03 years, 66% were men. Patients were managed either in the intensive care unit (42%) or wards/high dependency unit (58%), 22% needed noninvasive ventilation and 18% needed mechanical ventilation within 24 h of admission. On multivariate analysis, prior respiratory infection (within last 1 year), obesity (body mass index >30), and alcoholism, old age (>60 years) were independently associated risk factors for severe pneumonia. There were no cases of MRSA. In 34% of cases, organisms could be identified. Most common organisms were Klebsiella (8%), influenza (8%), and Pseudomonas (5%).

CONCLUSION

Prior respiratory infection, obesity, alcoholism, and old age (>60 years) were observed to be important risk factors for severe CAP. Prospective studies should evaluate effect of weight reduction and cessation of alcohol consumption on recurrences of pneumonia in this population and on the severity of pneumonia.

Antibiotic Prescription, Organisms and its Resistance Pattern in Patients Admitted to Respiratory ICU with Respiratory Infection in Mysuru

Aim of Study:

Respiratory infections account for significant morbidity, mortality and expenses to patients getting admitted to ICU. Antibiotic resistance is a major worldwide concern in ICU, including India. It is important to know the antibiotic prescribing pattern in ICU, organisms and its resistance pattern as there is sparse data on Indian ICUs.

Materials and Methods:

We conducted a prospective study from August 2015 to February 2016. All patients getting admitted to RICU with respiratory infection who were treated with antibiotics were included into study. Demographic details, comorbidities, Clinco-pathological score (CPI) on day1 and 2 of admission, duration of ICU admission, number of antibiotics used, antibiotic prescription, antimicrobial resistance pattern of patients were collected using APRISE questionnaire.

Results:

During study period 352 patients were screened and 303 patients were included into study. Mean age was 56.05±16.37 and 190 (62.70%) were men. Most common diagnosis was Pneumonia (66%). Piperacillin-tazobactam was most common empirical antibiotic used. We found 60% resistance to piperacillin-tazobactam. Acinetobacter baumanii was the most common organism isolated (29.2%) and was highly resistant to Carbapenem (60%). Klebsiella pneumoniae was resistant to Amikacin (45%), piperacillin (55%) and Ceftazidime (50%).

Conclusion:

Piperacillin-tazobactam was the most common antibiotic prescribed to patients with respiratory infection admitted to ICU. More than half of patients (60%) had resistance to the empirical antibiotic used in our ICU, highlighting the need for antibiogram for each ICU. Thirty six percent of patient had prior antibiotic use and had mainly gram negative organisms with high resistance to commonly used antibiotics.

Functional Outcome of Isolated Hoffa Fractures Treated with Cannulated Cancellous Screw

Introduction: Isolated Hoffa fracture is an infrequent injury and little research has been done on this subject. The purpose of this study was to evaluate the functional outcome and complications of surgically managed Hoffa fractures with cannulated cancellous screw.

Materials and Methods: Between 2011 and 2014, eight isolated Hoffa fractures in seven adult patients with mean age 39.8±11.9 years (range 25-60 years) were managed with cannulated cancellous screw of 6.5mm diameter applied in anterior to posterior direction using swashbuckler and medial parapatellar approach for lateral and medial Hoffa fractures respectively. All patients were evaluated using knee evaluation score after two years or longer. Mean follow up was 28±3.8 months (range 24-36 months).

Results: All fractures in the eight patients healed clinicoradiologically by the 16th week with excellent result in 87.5% cases and good in 12.5% cases. By the end of union, the range of motion (ROM) of the knee was 0° to 110° except in two patients. One patient had ROM 10°-100° and other had 15°-90°. Mean knee evaluation score was 87.5±10.4. There was no incidence of non-union, infection or avascular changes in the patients or loss of reduction till final follow up.

Conclusion: Open reduction and fixation with two 6.5 mm cannulated cancellous screws with early mobilization yielded good functional outcome in isolated Hoffa fractures.

Evaluation for airway obstruction in adult patients with stable ischemic heart disease

Background

Ischemic heart disease (IHD) and chronic airway disease (COPD and Asthma) are major epidemics accounting for significant mortality and morbidity. The combination presents many diagnostic challenges. Clinical symptoms and signs frequently overlap. There is a need for airway evaluation in these patients to plan appropriate management.

Methods

Consecutive stable IHD patients attending the cardiology OPD in a tertiary care centre were interviewed for collecting basic demographic information, brief medical, occupational, personal history and risk factors for coronary artery disease and airway disease, modified medical research centre (MMRC) grade for dyspnea, quality of life-St. George respiratory questionnaire (SGRQ), spirometry and six-min walk tests. Patients with chronic airway obstruction were treated as per guidelines and were followed up at 3rd month with spirometry, six-minute walk test and SGRQ.

Results

One hundred fourteen consecutive patients with stable cardiac disease were included (Males-88, Females-26). Mean age was 58.89 ± 12.24 years, 53.50% were smokers, 31.56% were alcoholics, 40.35% diabetics, 47.36% hypertensive. Twenty five patients had airway obstruction on spirometry (COPD-13 and Asthma-12) and none were on treatment. Thirty-one patients had cough and 48 patients had dyspnea. Patients with abnormal spirometry had higher symptoms, lower exercise tolerance and quality of life. Treatment with appropriate respiratory medications resulted in increase in lung function, quality of life and exercise tolerance at 3rd month.

Conclusion

Chronic respiratory disease in patients with stable IHD is frequent but often missed due to overlap of symptoms. Spirometry is a simple tool to recognize the underlying pulmonary condition and patients respond favorably with appropriate treatment

5-[(Benzo[d][1,3]dioxol-5-yl)methyl]-3-[4-(pyridin-2-yl)phenyl]-4,5-dihydroisoxazole

In the molecule of the title compound C22H18N2O3, the benzodioxole and dihydroisoxazole rings are bridgedviaa methylene (CH2) group. The linkage is disordered over two positions with a occupancy factors of 0.887 (5) and 0.113 (5). The dihydroisoxazole and pyridine rings exhibitsyn-clinalandanti-periplanarconformations with respect to the benzodioxole and benzene ring groups, as quantified by the torsion angle values of 70.7 (3) and 157.00 (17)°. Aside from van der Waals contacts, there are no significant intermolecular interactions.

2-(2-Chlorobenzoyl)-1-(3,4-dimethoxyphenyl)-3-iodoquinolin-4(1H)-one

In the title compound C24H17ClINO4, the iodoquinolinyl moiety (r.m.s. deviation = 0.044 Å) makes dihedral angles of 87.44 (10) and 88.64 (10)° with the chloro- and methoxy-substituted benzene rings, respectively. The methoxy groups are present in synperiplanar and antiperiplanar conformations with respect to the benzene ring they are bound to, as indicated by the C—C—O—C torsion angle values of −16.2 (3) and 177.6 (2)°, respectively. The crystal structure features relatively strong methoxybenzene-C—H...O(quinolinyl) hydrogen bonds, leading to helical supramolecular chains along thea-axis direction. Additional C—H...O interactions along with π-stacking [inter-centroid distance = 3.6070 (16) Å between quinolyl-NC5and C6rings] consolidate the three-dimensional molecular packing.

2-(4-Methylphenyl)-2-oxoethyl 3,4-dimethoxybenzoate

In the title compound, C18H18O5, the dihedral angle between the mean planes of the two aromatic rings is 66.55 (8)°. The crystal packing features by intermolecular C—H...O contacts.

(6-Fluoro-2-oxo-2H-chromen-4-yl)methyl diethylcarbamodithioate

The title compound, C15H16FNO2S2, crystallizes with two independent molecules (AandB) in the asymmetric unit. They differ essentially in the orientation of the ethyl groups. The chromene rings are planar (r.m.s. deviations = 0.013 Å for both molecules), with the maximum deviation from the ring planes being 0.014 (2) and 0.018 (2) Å for atoms C9Aand C9B, respectively. The mean plane of the chromene ring makes dihedral angles of 80.01 (7) and 76.97 (8)° with the carbamodithioate moiety [(N—C(=S)—S] of moleculesAandB, respectively. In the crystal, the two molecules are linked by C—H...S hydrogen bonds, forming a ladder-like arrangement propagating along thea-axis direction. Within the ladders there are offset π–π interactions involving the coumarins rings of theBmolecules [intercentroid distances vary from 3.705 (2) to 3.860 (1) Å]. Neighbouring ladders are linkedviaoffset π–π interactions involving the coumarins rings of theAmolecules [intercentroid distances vary from 3.539 (1) to 3.601 (1) Å]. These latter interactions lead to the formation of layers parallel to theacplane.

4-[(4-Hydroxymethyl-2H-1,2,3-triazol-2-yl)methyl]-6,8-dimethyl-2H-chromen-2-one. Corrigendum

In the paper by El-Khatatneh et al. [IUCrData (2016), 1, x161644], the scheme and chemical name in the title are corrected.

6-tert-Butyl-4-[(4-hydroxymethyl-2H-1,2,3-triazol-2-yl)methyl]-2H-chromen-2-one. Corrigendum

In the paper by El-Khatatneh et al. [IUCrData (2016), 1, x161618], the scheme and chemical name in the title are corrected.

4-[(4-Hydroxymethyl-2H-1,2,3-triazol-2-yl)methyl]-6-isopropyl-2H-chromen-2-one

In the title compound, C16H17N3O3, the chromene ring is planar, with a maximum deviation of 0.017 (4) Å for the ring O atom. The triazole and the chromene rings, bridged by a methylene C atom, are inclined to one another by 78.3 (2)°. In the crystal, methylene–triazole C—H...N hydrogen bonds lead to the formation of helical supramolecular chains along thebaxis. The sample was refined as an inversion twin. The terminal methylhydroxy group is disordered over two sets of sites [site occupancy = 0.610 (13) for the major component].

6-tert-Butyl-4-[(4-hydroxymethyl-2H-1,2,3-triazol-2-yl)methyl]-2H-chromen-2-one

In the title compound, C17H19N3O3, the triazole ring and the chromene ring system [maximum deviation = 0.018 (2) Å for the O atom] bridged via a methylene C atom, are inclined to one another by 73.2 (1)°. In the crystal, molecules are linked by O—H...N hydrogen bonds, forming zigzag chains along [001]. The chains are linked by C—H...O hydrogen bonds, forming layers parallel to (010), and these layers are linked by C—H...π and π–π interactions [intercentroid distance = 3.557 (1) Å], forming a three-dimensional newwork. The hydroxymethyl group at the 4-position of the triazole ring is disordered over two sets of sites, with a refined occupancy ratio of 0.418 (11):0.584 (11).

4-[(4-Hydroxymethyl-2H-1,2,3-triazol-2-yl)methyl]-6,8-dimethyl-2H-chromen-2-one

In the title compound, C15H15N3O3, the dihedral angle between the triazole ring and coumarin ring system [r.m.s. deviation = 0.040 Å] is 77.40 (6)°. The O atom of the hydroxymethyl group deviates from the triazole ring plane by 1.345 (1) Å. In the crystal, inversion dimers linked by pairs of O—H...O hydrogen bonds generate R 2 2(22) loops; C—H...O and C—H...N interactions link the dimers into a three-dimensional network.

Methyl 2-(benzoyloxy)benzoate

In the title compound, C15H12O4, the dihedral angle between the two aryl rings is 68.19 (9)°. In the crystal, molecules are linked by C—H...π interactions forming chains along theb-axis direction. The chains are linked by offset π–π interactions [intercentroid distance = 3.6806 (14) Å], forming sheets lying parallel to (10-1).

5-{[1-(2,4-Dichlorophenyl)-1H-1,2,3-triazol-4-yl]methyl}-5H-dibenz[b,f]azepine

In the molecule of the title compound, C23H16Cl2N4, the dihedral angle between the benzene rings fused to the azepine ring is 52.00 (6)°. The plane of the triazole ring makes dihedral angles of 74.40 (5), 25.56 (8) and 44.78 (6)° with the planes of the benzene rings of the dibenzoazepine moiety and the dichlorophenyl ring, respectively. The azepine ring adopts a boat conformation. There are no classical hydrogen bonds in the crystal.

1-[(4-Methoxyphenyl)sulfonyl]-1H-indole-3-carbaldehyde

In the molecule of the title compound, C16H13NO4S, the mean plane of the indole ring system and that of the methoxyphenyl ring, which are bridged by a sulfonyl group, are inclined at a dihedral angle of 88.98 (9)°. The crystal structure is stabilized by intermolecular C—H...O hydrogen bonds.

(7, 8-Dimethyl-2-oxo-2H-chromen-4-yl)methyl morpholine-4-carbodithioate

In the title compound, C17H19NO3S2, the chromene unit makes a dihedral angle of 88.48 (5)° with the best plane through the morpholine ring. The carbodithioate group is present in an antiperiplanar conformation with respect to the morpholine ring, as indicated by the S—C—N—C torsion angle of −171.64 (8)°. The morpholine moiety adopts the usual chair conformation. The crystal structure features C—H...O and C—H...S hydrogen bonds and C—H...π interactions.

Crystal structure of 10-[(3-oxo-3H-benzo[f]chromen-1-yl)meth-yl]-2-tri-fluoro-methyl-9a,10-di-hydro-benz[4,5]imidazo[1,2-a]pyrimidin-4(5aH)-one

In the title compound, C₂₅H₁₄F₃N₃O₃, the dihedral angle between the planes of the benz[4,5]imidazo[1,2-a]pyrimidine unit (r.m.s. deviation = 0.035 Å) and the benzochromene ring system (r.m.s. deviation = 0.106 Å) is 72.82 (5)°. In the crystal, mol­ecules are linked by C—H⋯O inter­actions, generating [010] C(9) chains. A weak aromatic π–π stacking inter­action [centroid–centroid separation = 3.5376 (15) Å] is also observed.

Crystal structure of 4-azido-methyl-6-tert-butyl-2H-chromen-2-one

In the title compound, C14H15N3O2, one of the methyl C atoms of the tert-butyl group lies almost in the plane of the chromene ring system [deviation = -0.097 (2) Å], one lies above and one lies below [deviations = 1.460 (3) and 1.006 (3) Å, respectively]. The C-C-N-N torsion angle is 142.33 (17)°. In the crystal, moelcules are linked by weak C-H⋯O hydrogen bonds to generate C(6) chains propagating in the [010] direction.

FT-IR, Laser-Raman spectra and computational analysis of 5-Methyl-3-phenylisoxazole-4-carboxylic acid

In this study the experimental and theoretical vibrational frequencies of a newly synthesized anti-tumor, antiviral, hypoglycemic, antifungal and anti-HIV agent namely, 5-Methyl-3-phenylisoxazole-4-carboxylic acid has been investigated. The experimental FT-IR (4000-400 cm(-1)) and Laser-Raman spectra (4000-100 cm(-1)) of the molecule in solid phase have been recorded. The theoretical vibrational frequencies and optimized geometric parameters (bond lengths, bond angles and torsion angles) have been calculated by using density functional theory (DFT/B3LYP: Becke, 3-parameter, Lee-Yang-Parr and DFT/M06-2X: highly parametrized, empirical exchange correlation function) with 6-311++G(d,p) basis set by Gaussian 09W software, for the first time. The assignments of the vibrational frequencies have been done by potential energy distribution (PED) analysis by using VEDA 4 software. The theoretical optimized geometric parameters and vibrational frequencies have been found to be in good agreement with the corresponding experimental data and results in the literature. In addition, the highest occupied molecular orbital (HOMO) energy, the lowest unoccupied molecular orbital (LUMO) energy and the other related molecular energy values of the compound have been investigated by using the same theoretical calculations.

Vibrational spectroscopy investigation using M06-2X and B3LYP methods analysis on the structure of 2-Trifluoromethyl-10H-benzo[4,5]-imidazo[1,2-a]pyrimidin-4-one

In this study, the experimental and theoretical vibrational frequencies of a newly synthesized bioactive agent namely, 2-Trifluoromethyl-10H-benzo[4,5]-imidazo[1,2-a]pyrimidin-4-one (TIP) have been investigated. The experimental FT-IR (4000-400 cm(-1)) and Laser-Raman spectra (4000-100 cm(-1)) of the molecule in solid phase have been recorded. The theoretical vibrational frequencies and the optimized geometric parameters (bond lengths and bond angles) have been calculated using density functional theory (DFT/B3LYP: Becke, 3-parameter, Lee-Yang-Parr) and M06-2X (the highly parametrized, empirical exchange correlation function) quantum chemical methods with 6-311++G(d,p) basis set by Gaussian 09W software, for the first time. The assignments of the vibrational frequencies have been done by potential energy distribution (PED) analysis using VEDA 4 software. The theoretical optimized geometric parameters and vibrational frequencies have been found to be in good agreement with the corresponding experimental data and results in the literature. In addition, the highest occupied molecular orbital (HOMO) energy, the lowest unoccupied molecular orbital (LUMO) energy and the other related molecular energy values of the compound have been investigated using the same theoretical calculations.

Ethyl 5-oxo-4-phenyl-5,6-di-hydro-4H-1,3,4-oxadiazine-2-carboxyl-ate

The asymmetric unit of title compound, C12H12N2O4, consists of two independent mol-ecules. In each mol-ecule, the oxadiazine ring has a flattened envelope conformation with the methyl-ene C atom as the flap atom, and the eth-oxy-carbonyl unit is in a syn-periplanar conformation with respect to the oxadiazine ring as indicated by O-C-C=O torsion angles of 1.9 (4) and 2.5 (4)°. The dihedral angles between the mean plane of the oxadiazine ring and the phenyl ring are 80.07 (13) and 42.98 (14)°. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds and stacked in a double-column along the a-axis direction.

N'-Benzoyl-5-methyl-1,3-diphenyl-1H-pyrazole-4-carbohydrazide

In the title compound, C24H20N4O2, the pyrazole ring makes dihedral angles of 47.57 (10)° and 30.56 (11)° with its N-bound and C-bound phenyl groups, respectively. The C-N-N-C group that links the two carbonyls has a torsion angle of 81.5 (2)°. The torsion angles between the carbonyl groups and their adjacent pyrazole and phenyl rings are 125.89 (19) and 164.22 (17)°, respectively. In the crystal, pairs of mol-ecules are linked by N-H⋯O hydrogen bonds into R 2 (2)(10) ring motifs, which in turn link to form chains that propagate parallel to the c-axis direction.

5-Methyl-1,3-diphenyl-N-(5-phenyl-1,3,4-thia-diazol-2-yl)-1H-pyrazole-4-carboxamide

The asymmetric unit of the title compound C25H19N5OS, contains two mol-ecules, A and B. In mol-ecule A, the dihedral angles between the pyrazole ring and the C-bound phenyl group, the N-bound phenyl group and the thia-diazole ring are 32.30 (14), 52.25 (14) and 34.94 (12)°, respectively. The corresponding angles in mol-ecule B are 33.32 (14), 50.67 (15), and 70.30 (12)°, respectively. In the crystal, the A and B mol-ecules are linked by pairs of N-H⋯N hydrogen bonds, generating R 2 (2)(8) loops. This dimer linkage is reinforced by two C-H⋯O hydrogen bonds and one C-H⋯N hydrogen bond.

Ethyl 1,4-bis-(4-chloro-phen-yl)-2-methyl-1H-pyrrole-3-carboxyl-ate

In the title mol­ecule, C₂₀H₁₇Cl₂NO₂, the pyrrole moiety makes dihedral angles of 63.42 (11) and 70.43 (12)° with the chlorobenzene rings. The eth­oxy­carbonyl unit is present in a synperiplanar conformation with respect to the pyrrole ring, as indicated by the dihedral angle of 14.5 (3)°. In the crystal, mol­ecules are linked into chains parallel to the a-axis direction by weak C—H⋯O hydrogen bonds.

2-(1,3-Benzodioxol-5-yl)-3-phenyl-quinazolin-4(3H)-one

In the mol­ecule of the title compound, C₂₁H₁₄N₂O₃, the quinazoline ring system [maximum deviation = 0.076 (1) Å] makes dihedral angles of 40.57 (9) and 42.31 (11)°, respectively, with the phenyl and 1,3-benzodioxole rings. The dihedral angle between the phenyl ring and the 1,3-benzodioxole ring is 4.34 (10)°. In the crystal, C—H⋯O hydrogen bonds link the mol­ecules into infinite zigzag chains extending along [100].

2-Tri-fluoro-methyl-10H-benzo[4,5]imidazo[1,2-a]pyrimidin-4-one

In the mol-ecule of the title compound, C11H6F3N3O, the three fused rings of the benzo[4,5]imidazo[1,2-a]pyrimidine unit are essentially coplanar, the maximum deviation from the mean plane being 0.096 (2) Å. In the crystal, N-H⋯O hydrogen bonds link the mol-ecules into chains running along the b-axis direction.

Microwave assisted synthesis of dihydrobenzo[4,5]imidazo[1,2-a]pyrimidin-4-ones; synthesis, in vitro antimicrobial and anticancer activities of novel coumarin substituted dihydrobenzo[4,5]imidazo[1,2-a]pyrimidin-4-ones

The present article describes the synthesis of dihydrobenzo[4,5]imidazo[1,2-a]pyrimidin-4-one (2a-h) under microwave irradiation. The product was obtained in excellent yield (74-94%) in a shorter reaction time (2 min). These molecules (2a, b) further reacted with various substituted 4-bromomethylcoumarins (3a-f) to yield a new series of coumarin substituted dihydrobenzo[4,5]imidazo[1,2-a]pyrimidin-4-ones (4a-h). The structure of all the synthesized compounds were confirmed by spectral studies and screened for their in vitro antibacterial activity against three Gram-positive bacteria viz., Staphylococcus aureus, Enterococcus faecalis, Streptococcus mutans and three Gram-negative bacteria viz., Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa and antifungal activity against Candida albicans, Aspergillus niger, Aspergillus fumigatus, Aspergillus flavus, Fusarium oxysporum, Penicillium chrysogenum and anticancer activity against Dalton's Ascitic Lymphoma (DAL) cell line. In general, all the compounds possessed better antifungal properties than antibacterial properties. The coumarin substituted dihydrobenzo[4,5]imidazo[1,2-a]pyrimidin-4-one (4g) (R = i-Pr, R₁ = 6-Cl) was found to be the most potent cytotoxic compound (88%) against Dalton's Ascitic Lymphoma cell line at the concentration of 100 μg/mL.

5-Methyl-3-phenyl-isoxazole-4-carb-oxy-lic acid

In the title compound, C₁₁H₉NO₃, the phenyl and isoxazole rings form a dihedral angle of 56.64 (8)°. The carb­oxy group is almost in the same plane as the isoxazole ring with a C—C—C—O torsion angle of −3.3 (2)°. In the crystal, pairs of O—H⋯O hydrogen bonds link the mol­ecules into head-to-head dimers. C—H⋯N hydrogen bonds and π–π stacking inter­actions between phenyl rings [centroid–centroid distance = 3.9614 (17)Å] link the dimers into a three-dimensional network.

Ethyl 5-methyl-3-phenyl-isoxazole-4-carboxyl-ate

In the title compound, C13H13NO3, the dihedral angle between the phenyl and isoxazole rings is 43.40 (13)°. The eth-oxy-carbonyl group is rotated out of the plane of the isoxazole ring by 16.2 (13)°.

3-(4-Meth-oxy-phen-yl)-5-methylisoxazole-4-carb-oxy-lic acid

In the title compound, C12H11NO4, the dihedral angle between the benzene and isoxazole rings is 42.52 (8)°. The carb-oxy-lic acid group is close to being coplanar with the isoxazole ring [dihedral angle = 5.3 (2)°]. In the crystal, inversion dimers linked by pairs of O-H⋯O hydrogen bonds generate R2(2)(8) loops.

(Z)-4-Benzyl-idene-3-methyl-isoxazol-5(4H)-one

In the title compound C₁₁H₉NO₂, the phenyl and isoxazole rings are almost coplanar, making a dihedral angle of 1.14 (9)°. This planarity is also assisted by an intra­molecular C—H⋯O hydrogen bond between the phenyl ring and the carbonyl O atom. In the crystal, weak C—H⋯O inter­actions generate a layered structure parallel to the ac plane.

(E)-N'-Hy-droxy-1,3-diphenyl-4,5-di-hydro-1H-pyrazole-5-carboximidamide

In the mol-ecule of the title compound, C(16)H(16)N(4)O, the pyrazole ring makes dihedral angles of 8.52 (13) and 9.26 (12)° with the phenyl rings. The dihedral angle between the benzene rings is 1.86 (13)°. In the crystal, mol-ecules are linked into centrosymmetric dimers via pairs of O-H⋯N hydrogen bonds. Weak N-H⋯N inter-actions connect the dimers into a chain along the [100] direction. The pyrazole ring adopts a highly flattened envelope conformation.

1-(3-Bromo-2-thien-yl)ethanone

In the title compound, C(6)H(5)BrOS, the non-H and aromatic H atoms lie on a crystallographic mirror plane. In the crystal, mol-ecules are linked into chains propagating along the c axis by inter-molecular C-H⋯O hydrogen bonds.

4-Nitro-2-phenoxyaniline

In the title compound, C₁₂H₁₀N₂O₃, the oxygen atom bridging the two aromatic rings is in a synperiplanar (+sp) conformation. The dihedral angle between the aromatic rings is 71.40 (12)°. In the crystal, mol­ecules are linked by inter­molecular N—H⋯O hydrogen bonds.

Novel delta2-isoxazolines as group II phospholipase A2 inhibitors

The synthesized imidazolyl substituted delta2-isoxazolines were subjected to Phospholipase A(2) (PLA(2)) enzyme inhibitory activity against snake venom source and their structure-activity relationship with respect to different groups attached to this moiety is reported for the first time. The crystal structure of the compound 2-butyl-5-chloro-3H-imidazolyl-4-carbaldehyde oxime 2, an intermediate for the construction of isoxazolines is reported. These compounds exerted a significant PLA(2) enzyme inhibitory activity against group II PLA(2). The in vivo activity on mice of selected compounds 3bI and 3bIV shows the comparable anti-inflammatory activity with the known standard ursolic acid.

Treatment of acute urinary infection by norfloxacin or nalidixic acid/citrate: a multi-centre comparative study

The efficacy, tolerability and side effects of a 3-day treatment for acute urinary infection in general practice with norfloxacin (400 mg 12 hourly) or nalidixic acid/citrate (1 sachet 8 hourly) were compared in a randomized study. Patient groups had similar demography, symptomatology and initial infecting bacteria. Of the evaluable 55 patients in each treatment group with initial bacteriuria, 53 (96%) had no bacteriuria at immediate follow-up after treatment with norfloxacin and 45 (82%) with nalidixic acid/citrate. The corresponding rates at late follow-up were 40/45 (89%) and 29/43 (67%) (P less than 0.05). Among the bacteriuric patients a significantly greater proportion were recorded as having cured and improved symptoms. The tolerability of norfloxacin seemed to be better than that of nalidixic acid/citrate.