Cyclization of arylhydrazones of cross-conjugated enynones: synthesis of luminescent styryl-1-pyrazoles and propenyl-1-pyrazoles.

Condensation of 1,5-disubstituted pent-1-en-4-yn-1-ones with arylhydrazines in acidified alcohol results mainly in the formation of the corresponding arylhydrazones with traces of the side products of cyclization at the double bond - 1,5-diaryl-3-(arylethynyl)-4,5-dihydro-1-pyrazoles (pyrazolines). Arylhydrazones are cyclized only by refluxing in high-boiling polar solvents (DMF and ethylene glycol), with the selective formation of 1,5-disubstituted 3-styrylpyrazoles in up to 77-95% yields. Thermodynamically, the cyclization of arylhydrazones at the triple bond is the most preferable pathway, as shown by DFT calculations and preparative synthesis experiments.

Ketone Derivatives of Propargylamines as Synthetic Equivalents of Conjugated 2,4,1-Enynones in the Synthesis of Acetylenic 2-Pyrazolines and Pyrazoles.

An interaction of 1,5-diaryl-3-X-pent-4-yn-1-ones (where X stands for piperidin-1-yl, morpholin-4-yl, 4-methylpiperazin-1-yl) with arylhydrazines proceeds at room temperature and results in 3-aryl-5-arylethynyl-1-phenyl-4,5-dihydro-1-pyrazoles with up to 57-73% yields. Under similar conditions, the cyclocondensation of conjugated 2,4,1-enynones with arylhydrazine proceeds only in the presence of cyclic amines. 1,5-Diaryl-3-X-pent-4-yn-1-ones are reported as synthetic equivalents of conjugated 2,4,1-enynones in reactions with arylhydrazines.

Reactivity of Cross-Conjugated Enynones in Cyclocondensations with Hydrazines: Synthesis of Pyrazoles and Pyrazolines.

The cyclocondensation of cross-conjugated enynones, dienynones, and trienynones (easily available due to low-cost starting compounds) with arylhydrazines leads to the regioselective synthesis of pyrazole derivatives (dihetaryl-substituted ethens, buta-1,3-diens, and hexa-1,3,5-triens) or results in 4,5-dihydro-1-pyrazoles in good yield. The reaction path is controlled by the character of the substituent in enynone: the pyrazoles are obtained from the reaction of substrates that contain five-membered heteroaromatic substituents with arylhydrazines, and the 4,5-dihydro-1-pyrazoles are obtained from the reaction of 1,5-diphenylpent-1-en-4-yn-3-one with arylhydrazines consistently. Despite the presence of a substituent, cyclocondensation of 2-hydrazinylpyridine with all of examined cross-conjugated enynones leads to the formation of pyrazoles.

Crystal structures of ()-5-(4-methyl-phen-yl)-1-(pyridin-2-yl)pent-2-en-4-yn-1-one and [3,4-bis(phenyl-ethyn-yl)cyclo-butane-1,2-di-yl]bis-(pyridin-2-yl-methanone).

Recrystallization of ()-5-phenyl-1-(pyridin-2-yl)pent-2-en-4-yn-1-one at room temperature from ethyl-ene glycol in daylight afforded [3,4-bis-(phenyl-ethyn-yl)cyclo-butane-1,2-di-yl)bis-(pyridin-2-yl-methanone], CHNO (), while ()-5-(4-methyl-phen-yl)-1-(pyridin-2-yl)pent-2-en-4-yn-1-one, CHNO (), remained photoinert. This is the first experimental evidence that pentenynones can be photoreactive when fixed in nearly coplanar parallel positions. During the photoreaction, the bond lengths and angles along the pentenyne chain changed significantly, while the disposition of the pyridyl ring towards the keto group was almost unchanged.

Peculiarities of supramolecular organization of cyclic ketones with vinylacetylene fragments.

1,5-Diaryl(heteroaryl)pentenynones show a tendency to crystallize in acentric space groups due to their inclination to form C-H...

Crystal structure of (2E,4E)-5-[bis-(2-hy-droxy-eth-yl)amino]-1-(4-chloro-phen-yl)-5-phenyl-penta-2,4-dien-1-one.

In the title compound, C21H22ClNO3, the penta-diene unit is nearly planar [maximum deviation = 0.023 (1) Å], but the carbonyl O atom deviates significantly [by 0.304 (1) Å] from its mean plane, which is twisted with respect to the phenyl and chloro-benzene rings by 71.

[Conservative management of placenta percreta invading the bladder: be patient].

We report a case of placenta percreta with bladder invasion in a multiparous woman with five previous cesarean sections. At 25 weeks of gestation, because of severe hematuria, antenatal diagnosis was easy. A multidisciplinary management was carried out with conservative treatment.

[Pulmonary aspiration: epidemiology and risk factors].

Objective: To determine the epidemiology and risk factors for gastric aspiration in a French university hospital.

Methods: Files were prospectively selected from a computer database of rare and severe complications between January 2002 et April 2007. Medical files were then analyzed according to a predetermined list of specific items.

[Labour epidural analgesia for a woman with a factor XI deficiency: an illconsidered risk?].

Inherited bleeding disorders contraindicate epidural analgesia because of the risk of epidural haematoma. However, there is no consensus about a minimal rate of factor XI required for its performance. We report here a case of epidural analgesia in a pregnant woman with a moderate and symptomatic factor XI deficiency, despite this theoretical contraindication.

Induction of anaesthesia: a guide to drug choice.

In developed countries, the choice of an anaesthetic agent for induction of anaesthesia remains based mainly on its pharmacodynamic properties. Until now, cardiovascular effects were the main factor in this decision. However, other factors, such as the depth of anaesthesia and effects on cortisol synthesis, can modify this simplistic view.

[What are the changes in paediatric anaesthesia practice afforded by new anaesthetic ventilators?].

Because of specific paediatric respiratory physiology (mainly decreased compliance and functional residual capacity, increased O2 demand and CO2 production), ventilators for paediatric anaesthesia need to be powerful and able to deliver small volumes at a high rate without compression volume loss. The compensation of compliance now available on every anaesthesia machine, compensates for the volume of gas lost by compression in the circuit tubing allowing the tidal volume to reach preset commands, even for bellow in box respirators. Preset tidal volume is then totally delivered to the lung by volume-controlled ventilation because it becomes independent of total pulmonary compliance and fresh gas flow.

Low flow and economics of inhalational anaesthesia.

Even when anaesthesia does not represent a major part of the expense of a given surgical operation, reducing costs is not negligible because the large number of patients passing through a department of anaesthesia accounts for a huge annual budget. Volatile anaesthetics contribute 20% of the drug expenses in anaesthesia, coming just behind the myorelaxants; however, the cost of halogenated agents has potential for savings because a significant part of the delivered amount is wasted when a non- or partial-rebreathing system is used. The cost of inhaled agents is related to more than the amount taken up; it also depends on their market prices, their relative potencies, the amount of vapour released per millilitre of liquid, and last but not least the fresh-gas flow rate (FGF) delivered to the vaporizer--the most important factor determining the cost of anaesthesia.

[Analgesic effect of continuous intravenous nefopam after urological surgery].

Objectives: To evaluate the efficacy of continuous infusion of nefopam. Indeed this analgesic is commonly used by continuous infusion by many anaesthetists to reduce its adverse effects. However whether the analgesic effect of an intermittent administration of nefopam has been proven, the efficacy of continuous infusion has not been established.

[Postoperative nausea and vomiting: cost and therapeutic algorithm. Part II: high-risk patients and late PONV].

Objectives: To evaluate in high-risk patients and in usual clinical conditions, the efficiency of treatments based on an algorithm on late (24 h) postoperative nausea and vomiting (PONV).

Study Design: Prospective and descriptive.

Methods: The nature and efficiency of prophylactic and curative PONV treatments was evaluated 24 h after surgery under general anesthesia in patients at high risk of PONV, one and 15 month after the introduction of a clinical and therapeutic algorithm.

[Postoperative nausea and vomiting: cost and advantage induced by a quality insurance programme. Part I: post anaesthesia care unit].

Objectives: To report the efficiency and direct cost induced by a quality insurance programme (QIP) aimed to reduce the incidence of post-operative nausea and vomiting (PONV) in the post-anaesthesia care unit.

Type Of Study: Prospective and descriptive study.

Methods: The occurrence and treatment of PONV were prospectively recorded in the post-anaesthesia care unit in a standardised file before and following therapeutic recommendations made by volunteers component of a QIP.