Subject(s)
Congenital Abnormalities/physiopathology , Hemangioma/drug therapy , Hemangioma/physiopathology , Laryngeal Neoplasms/drug therapy , Laryngostenosis/etiology , Larynx/abnormalities , Respiratory Sounds/physiopathology , Female , Humans , Infant, Newborn , Laryngostenosis/physiopathology , Larynx/physiopathology , Treatment OutcomeABSTRACT
A rapid and stereodefined synthesis of MIDA-boryl vinylsilanes has been achieved through the hydrosilylation of an alkynylboronic ester. The E products which contain a silyl and boryl group can be selectively cross-coupled in a two-step bidirectional sequence to provide a rapid and high-yielding synthesis of complex styrenes.
Subject(s)
Silanes/chemistry , Stilbenes/chemical synthesis , Styrenes/chemical synthesis , Vinyl Compounds/chemistry , Boronic Acids/chemistry , Esters , Molecular Structure , Stereoisomerism , Stilbenes/chemistry , Styrenes/chemistryABSTRACT
Two base-mediated cascade rearrangement reactions of diallyl ethers were developed leading to selective [2,3]-Wittig-oxy-Cope and isomerization-Claisen rearrangements. Both diaryl and arylsilyl-substituted 1,3-substituted propenyl substrates were examined, and each exhibits unique reactivity and different reaction pathways. Detailed mechanistic and computational analysis was conducted, which demonstrated that the role of the base and solvent was key to the reactivity and selectivity observed. Crossover experiments also suggest that these reactions proceed with a certain degree of dissociation, and the mechanistic pathway is highly complex with multiple competing routes.
Subject(s)
Ethers/chemistry , Propane/analogs & derivatives , Propane/chemistry , Silanes/chemistry , Catalysis , Isomerism , Molecular StructureABSTRACT
A rhenium-catalyzed N-selective allylic amination reaction of N-hydroxycarbamates has been developed. This reaction occurs with excellent N/O selectivity and with complete carbon selectivity on the allylic system. The reaction is tolerant of many functional groups and also proceeds with N-hydroxysulfonamides and hydroxamic acids.
ABSTRACT
A facile and user-friendly protocol has been developed for the selective synthesis of E-vinyl silanes derived from propargylic alcohols using a PtCl2/XPhos catalyst system. The reaction is generally high yielding and provides a single regioisomer at the ß-position with E-alkene geometry. The reaction is extremely tolerant of functionality and has a wide scope of reactivity both in terms of alkynes and silanes used. The catalyst loading has been investigated and it is found that good reactivity is observed at extremely low catalyst loadings. This methodology has also been extended to a one-pot hydrosilylation Denmark-Hiyama coupling.
Subject(s)
Alkynes/chemistry , Platinum/chemistry , Propanols/chemistry , Silanes/chemical synthesis , Alkenes/chemistry , Catalysis , Silanes/chemistry , StereoisomerismABSTRACT
Guidelines on making do not resuscitate (DNR) decisions have changed in recent years in keeping with changing attitudes and legislation. Decisions should now be discussed with all competent patients, and nursing staff should be involved in the process. The views of nursing staff in 1989 and 2003 were compared, focusing on what factors they thought were important in coming to a DNR decision and any implications it had for other treatment. A patient's wishes, their previous quality of life and the chances of successful resuscitation were rated highly in both studies. Advanced age was rated as important less often in 2003 but was still thought to be an important factor by 61% respondents. In 2003 nurses were significantly more likely to state that active treatment, such as admission to an intensive care unit or surgical intervention, could be appropriate for patients with DNR orders. However, the number of respondents who considered intravenous fluids (18%) or antibiotics (26%) inappropriate for patients not for resuscitation was concerning.
