Thermische und photochemische Umwandlungen von Hetero-1,3,5-hexatrienen in fünfgliedrige Ringe mögliche pericyclische Reaktionen

George, M. V.; Mitra, Anik; Sukumaran, Kutikat B.

doi:10.1002/ange.19800921205

Cited by 18 publications

(2 citation statements)

References 80 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Assisted by the C6 methyl group, the diene can assume an s‐ cis conformation, which allows for an intramolecular [ π 4 a + π 2 a ] cycloaddition 5a. 15 The highest occupied molecular orbital (HOMO) of the diene and the lowest unoccupied molecular orbital (LUMO) of the dienophile are oriented more or less perpendicular to each other and overlap in such a way that bond formation occurs in an antarafacial sense with respect to both components. Coordination of a Lewis acid to the carbonyl group decreases the energy level of the LUMO, enabling this reaction to compete effectively with a 6π electrocyclization.…”

Section: Methodsmentioning

confidence: 99%

P087: Volume contrast imaging: a new approach to identify fetal lungs in cases with thoracic malformations

Ruano

Benachi

Dommergues

2003

Ultrasound Obstet Gynecol

View full text Add to dashboard Cite

Objective:The most common indication for neonatal renal ultrasound is the antenatal finding of pyelectasis followed by suspected renal anomaly. Some of the latter have a characteristic appearance suggesting the diagnosis. This 5-year audit of 778 neonates reviewed the outcome of those with persisting pyelectasis and renal anomalies and suggested protocols for investigation. Method: The Mercy Hospital for Women is a tertiary referral obstetric and gynaecology hospital with a level-3 neonatal intensive care unit and approximately 5000 deliveries a year. A computer search of neonatal renal scans for the years 1996-2000 was made.Neonates with persisting pyelectasis and renal anomalies were reviewed. A micturating cystourethrogram (MCU) was requested in a number of infants. Vesicoureteric reflux (VUR) was classified according to the International Classification of Reflux. The results of investigations and outcome are reported. Results: In the 5 years, 25,204 babies were born at the Mercy Hospital for Women, 778 neonates (3%) were referred for renal ultrasound. The results were classified according to the postnatal diagnosis. Of 592 (76%) with normal postnatal scans, 49 had an MCU and 19 had VUR. There were 120 (15%) with persisting pyelectasis, 15 (13%) with VUR, not always ipsilateral. There were 7 with unilateral renal obstruction. There were 59 (8%) with structural anomalies including multicystic dysplastic kidney (MCDK), anatomic variants, ureterocoeles, reflux nephropathy, polycystic kidney disease and urethral obstruction. Conclusion: In this consecutive series, there were 100 (13%) neonates with significant abnormalities, structural anomalies, unilateral renal obstruction and VUR affecting clinical management. Protocols for investigation of neonates with persisting pyelectasis, severe hydronephrosis and renal anomalies are suggested. P086 Hôpital Necker-Enfants Malades, Paris, FranceObjective: The aim of this study is to present the three-dimensional Doppler-ultrasound contribution to the prenatal diagnosis of lung sequestration. Methods: Prenatal three-dimensional angiosonography was used to image pulmonary blood supply in 20 normal controls and to screen for an abnormal pulmonary blood supply in 6 fetuses with hyperechogenic lung lesions. Post natally (n = 5) or post mortem (n = 1), these lesions turned to be an isolated lung sequestration (n = 2), a type III congenital adenomatoid malformation (n = 2), a type I + III congenital adenomatoid malformation (n = 1), or a complex malformation in which a left congenital diaphragmatic hernia was associated with both lung sequestration and type III adenomatoid malformation (n = 1, termination of pregnancy). Results: Three-dimensional angiosonography demonstrated clearly an abnormal blood supply before 20 weeks of gestation in the three cases that turned to be lung sequestrations, and in none of the other cases. In 2 of the three cases with pulmonary sequestration, 2D ultrasound initially failed to identify the feeding vessel. Conclusion: Three-dimensional ultrasoun...

show abstract

Section: Methodsmentioning

confidence: 99%

P087: Volume contrast imaging: a new approach to identify fetal lungs in cases with thoracic malformations

Ruano

Benachi

Dommergues

2003

Ultrasound Obstet Gynecol

View full text Add to dashboard Cite

show abstract

“…Crystal data for 1¥2 Cl ([Cu 28 L 20 (OAc) 10 Cl 6 (MeOH) 11 10 Cl 6 (MeOH) 15 (1) photodeoxytridachione (2) crispatene (6) dented. We present herein the development of a Lewis acid catalyzed cyclization of hexatrienes to bicyclo[3.1.0]hexenes and the application of this novel reaction toward the total synthesis of 2.…”

mentioning

confidence: 99%

Total Synthesis of (.+‐.)‐Photodeoxytridachione Through a Lewis Acid Catalyzed Cyclization.

Miller

Trauner

2003

ChemInform

View full text Add to dashboard Cite

show abstract

3,6-Bis(p-dimethylaminophenyl)-1,2-dithiin versus 3,4-Bis(p-dimethylaminophenyl)-1,2-dithiete – A Mechanistic Probe for the Photoinduced Behavior of the 1,2-Dithiin System©

Schroth¹,

Spitzner

Bruhn

1998

Eur. J. Org. Chem.

View full text Add to dashboard Cite

Whereas 3,4‐bis(p‐dimethylaminophenyl)‐1,2‐dithiete (18) is in equilibrium with its ring‐opened valence isomer 19/19′, which can also exist as a solid, the analogously disubstituted 1,2‐dithiin 20 is stable when protected from light, but on exposure to light undergoes immediate ring transformation to 2,5‐bis(p‐dimethylaminophenyl)thiophene‐3‐thiol (30). To a lesser extent, it also undergoes sulfur extrusion to form 2,5‐bis(p‐dimethylaminophenyl)thiophene (29). The ring‐opened valence isomer 21/21′ and dihydrothiophene episulfide 28 are suggested as key intermediates. X‐ray crystallography of the disulfide 31 obtained from the main product 30 unequivocally confirms the structure. The synthesis of 20 is based on the nucleophilic addition of 1,1‐dimethylethanethiol to 1,4‐bis(p‐dimethylaminophenyl)butadiyne (23a) with ensuing functional group conversion. An efficient variant of this method using ethoxycarbonylsulfenyl chloride as a deprotecting reagent is described, leading to the synthesis of 3,6‐diphenyl‐1,2‐dithiin (27).

show abstract

Thermische und photochemische Umwandlungen von Hetero-1,3,5-hexatrienen in fünfgliedrige Ringe mögliche pericyclische Reaktionen

Cited by 18 publications

References 80 publications

P087: Volume contrast imaging: a new approach to identify fetal lungs in cases with thoracic malformations

P087: Volume contrast imaging: a new approach to identify fetal lungs in cases with thoracic malformations

Total Synthesis of (.+‐.)‐Photodeoxytridachione Through a Lewis Acid Catalyzed Cyclization.

3,6-Bis(p-dimethylaminophenyl)-1,2-dithiin versus 3,4-Bis(p-dimethylaminophenyl)-1,2-dithiete – A Mechanistic Probe for the Photoinduced Behavior of the 1,2-Dithiin System©

Contact Info

Product

Resources

About