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Biomedical subjects

N Roques

Publications and source records attributed to N Roques.

8 recordsLinked to original sources
PubMed2001

Acylation and related reactions under microwaves. 4. Sulfonylation reactions of aromatics.

Solvent-free sulfonylation of benzene and its activated or deactivated derivatives were carried out under microwave (MW) irradiation and a catalytic amount of iron(III) chloride, which, under these conditions, is more active than other metallic salts. With more reactive and/or nonvolatile reagents (anisole, xylenes, mesitylene) expeditious conditions (short reaction time at constant MW power without control of the temperature) were used. With less reactive and/or low-boiling reagents (benzene, toluene, halobenzenes), the rise in temperature and the increase of reaction time were controlled either by sequential MW irradiation or by a temperature order. It was shown that MWs cause preferential interactions with polar species present in the reaction, especially the aryl sulfone and its FeCl3-complexed form. A MW nonthermal effect was not observed when identical temperature gradients were produced by classical heating and MW irradiation, and if reaction temperature was strictly controlled.

Journal Article↗
PubMed2000

Nucleophilic trifluoromethylation of carbonyl compounds and disulfides with trifluoromethane and silicon-containing bases

Provided that DMF (or another N,N-dialkylformamide) is present in the reaction medium, at least in a catalytic amount, fluoroform trifluoromethylates efficiently carbonyl compounds, even enolizable ones, when opposed to (TMS)(2)N(-) M(+), generated in situ from N(TMS)(3) and M(+) F(-) or RO(-) Na(+). When F(-) is used in a catalytic amount, silylated alpha-(trifluoromethyl)carbinols are obtained: in this case, the four-component system HCF(3)/N(TMS)(3)/catalytic F(-)/catalytic DMF behaves like the Ruppert's reagent, especially as far as nonenolizable carbonyl compounds are concerned (CF(3)SiMe(3) remains more efficient for enolizable carbonyl compounds). This process involves an adduct between DMF and (-)CF(3) which is the true trifluoromethylating agent. In the same way, fluoroform efficiently trifluoromethylates disulfides and diselenides when deprotonated with a strong base selected from t-BuOK or N(SiMe(3))(3)/Me(4)NF (or TBAT). t-BuOK is more adapted to the trifluoromethylation of aryl disulfides whereas N(SiMe(3))(3)/F(-) is well suited to that of aliphatic disulfides.

Journal Article↗
PubMed2000

Design, synthesis, and evaluation of a novel class of enantioselective electrophilic fluorinating agents: N-fluoro ammonium salts of cinchona alkaloids (F-CA-BF(4)).

The first enantiopure N-fluoro quaternary ammonium salts of cinchona alkaloids as enantioselective fluorinating agents are reported. A one-step transfer-fluorination on the naturally occurring cinchona alkaloids gave the fluorinating agents F-CA-BF(4). This new generation of fluorinating agents exhibited asymmetric induction up to 61% on fluorination of enolates and silyl enol ethers of 2-methyl-1-tetralone.

Cinchona Alkaloids↗
PubMed1995

[Initial clinical experiences with the Storz Modulith SL 20 lithotripter: the results 3 months after a single session].

The objective of this study was to evaluate the performances of the Storz Modulith SL20 lithotriptor. Fifty patients with a total of 52 renal (31) or ureteric (21) stones were treated, in a single session, between June and October 1993. The mean stone diameter was 7.9 mm. All patients were reviewed after 3 months. The complete success rate, with radiological cure, was 65% at 3 months. The partial success rate, defined as fragmentation of the stone with persistence of residual fragments less than 3 mm in diameter, not requiring further treatment, was 12% at 3 months. The failure rate at 3 months was 23%. The commonest complication was renal colic in 12 patients (24%). Two patients developed an extrarenal haematoma. The Modulith SL20 possesses a good detection system: firing is well tolerated under minimal analgesia. Our success rates are slightly lower than those obtained by other teams using the same apparatus.

Adolescent↗
PubMed1994

[Percutaneous endopyelotomies. Preliminary results (a series of 16 patients)].

Percutaneous endopyelotomy was performed in 16 patients with ureteropelvic junction obstruction. The procedure was always completed with no intra-operative complication. After a mean follow-up of 18 months (6-30 mos), we report 12 good results (75%), 2 patients with no clinical symptoms but remaining partial radiological obstruction, and 2 failures (12.5%) which required early open surgery. Much care must be given to the ureteral stenting: one of our failures was due to extra-pelvic migration of the stent. Endopyelotomy may be considered as an efficient procedure, but long-term evaluation is still required.

Adolescent↗
PubMed1989

[A study of prescriptions for psychotropic drugs at a French psychiatric hospital].

The prescribing habits were studied in a psychiatric hospital which provides services for one district of Paris. The sample consisted of 175 inpatients. A mean of 2.1 psychotropic drugs was prescribed per patient, and more than two-thirds received two psychotropic drugs or more. Almost one-half had a PRN order. Major tranquilizers were frequently used in patients not having a psychotic disorder and were associated to anticholinergic drugs in 55% of the cases. Factors associated with drug prescriptions were diagnosis, age and unit of treatment. Our results are similar to those of previous studies on excessive polypharmacy. The discussion draws attention on the need to obtain data on the rationale for prescribing and the response to treatment. Emphasis is placed on the potential usefulness of studying drug prescriptions for psychiatric practice.

Adolescent↗