Highly enantioselective catalytic synthesis of chiral pyridines

General methods to prepare chiral pyridine derivatives are greatly sought after due to their significance in medicinal chemistry. Here, we report highly enantioselective catalytic transformations of poorly reactive β-substituted alkenyl pyridines to access a wide range of alkylated chiral pyridines. The simple methodology involves reactivity enhancement via Lewis acid (LA) activation, the use of readily available and highly reactive Grignard reagents, and a copper-chiral diphosphine ligand catalyst. Apart from allowing the introduction of different linear, branched, cyclic, and functionalised alkyl chains at the β-position of alkenyl pyridines, the catalytic system also shows high functional group tolerance.

Chiral pyridines are valuable building blocks in medicinal chemistry applications. Here, the authors report the copper-catalysed Lewis acid-assisted asymmetric alkylation of β-substituted alkenyl pyridines with Grignard reagents affording chiral pyridines with excellent enantioselectivity.

[Gastroesophageal reflux and respiratory pathology]

The prevalence of gastroesophageal reflux (GER) in 86 children with respiratory disease (recurrent pneumonia, chronic cough, bronchial asthma) has been evaluated by mean of prolonged (22-24 hours) esophageal pH-monitoring. The following parameters were evaluated: the total percentage of time pH < 4 and the percent time the esophageal pH was < 4 while sleeping. None of the children had gastrointestinal symptoms suggesting GER and no neurological disorder was noted in any of the studied patients. The mean age was 68.98 +/- 46.46 months (range 14-189); 53 (61.6%) males and 33 (38.4%) females were considered in the study. Atopy was evidenced in 42/86 (48.8%) children (total IgE > 2SD in 42/86 and prick tests positiveness in 32/86. A pH-metry indicating pathological GER was present in 52/86 (60.5%) children: 39/62 (62.9%) patients with bronchial asthma, 5/10 (50%) subjects with chronic cough and 8/14 (57.2%) children with recurrent pneumonia. No significant difference in the diagnosis of GER was recorded between atopic or non-atopic patients. The children with abnormal pH-metric recording were also evaluated by upper gastrointestinal series and/or endoscopy. A conventional barium radiology was performed in 44/52 patients and confirmed GER in 19/44 (43.2%). Esophagitis was evidenced in 21/46 (45.7%) studied patients. The presence of esophagitis was significantly (p = 0.032) related to the total percentage of time pH < 4, but the most significant (p = 0.002) association was with the percent time the esophageal pH was < 4 during sleep.(ABSTRACT TRUNCATED AT 250 WORDS)

[Radiologic examination of the paranasal sinuses in asthmatic children]

We examined the prevalence of abnormalities found by sinus X-Rays in 80 asthmatic children classified into three groups in relation to severity of their symptoms. All the children underwent skin tests and some of them methacholine challenge. 63.7% of asthmatics showed abnormalities in sinus X-Rays. No correlation was found between the severity of asthma, radiographic findings, and atopic status. Bronchial hyperreactivity studied using metacholine challenge according to the method of Chai was the same both in patients with asthma and sinusitis and in those with asthma only. In conclusion, abnormal sinus X-Rays do not seem to be an aggravating factor in asthmatic status.

[Diagnosis by imaging in renal and urinary tract malformations. Comparison of echography and traditional radiological studies]

The diagnostic sensitivity of Ultrasound (US) was studied in 142 children with suspected kidney and urinary tract malformations. According to the clinical tests performed the patients underwent excretory urography (EU) and/or voiding cystouretrography (VCU); the results were compared to US findings. In the 75 patients with malformations, US proved to be extremely sensitive in abdominal renal ectopies, in "horseshoe" kidney, and in congenital obstructions of the ureteropelvic and vesico-ureteral junctions. US showed a higher sensitivity than EU in identifying multicystic kidney and in most cases of hypodysplasia. On the other hand, VCU was more accurate in vesico-ureteral reflux studies; US should thus be used in the follow-up of the patients undergoing medical therapy. EU must however be considered as the most important tool in the evaluation of early renal injuries and their possible development.

[Experience acquired over a 4-year period with the Vichi method in the study of bronchopulmonary changes in cystic fibrosis]

The classification of chest alterations in Cystic Fibrosis (CF) and related score proposed by Chrispin and Norman has been widely adopted in Europe and is still applied (although slightly modified) in most European Centres. Brasfield classification instead has been mostly used in the USA. Lately, however, to revise both classifications, the need has been felt, for a more precise correlation to anatomo-radiological data as well as for inclusion of headings which have not been taken into account so far. In 1980 one of the Authors (Vichi) worked out a new scoring system for the chest alterations of CF. Results are reported from a follow-up of 15 patients with CF carried out at the FC Centre of Meyer Ospedale in Florence from the late 1981 to 1985. The patients underwent periodic checkings including determination of clinical scoring system-according to Shwachman and Kulczychi modified by Doershuk-respiratory function tests, chest X-rays evaluated by three radiologists separately, following both Chrispin and Norman and Vichi scoring systems. The latter system has proved to be well correlated to clinical data and to the ordinary pulmonary function tests but it mainly presents a high observer reproducibility.