Synthesis of novel room temperature chiral ionic liquids. application as reaction media for the heck arylation of aza-endocyclic acrylates.

New achiral and chiral RTILs were prepared using novel and/or optimized synthetic routes. These new series of imidazolinium, imidazolium, pyridinium and nicotine-derived ionic liquids were fully characterized including differential scanning calorimetry (DSC) analysis. The performance of these achiral and chiral room temperature ionic liquids (RTILs) was demonstrated by means of the Heck arylation of endocyclic acrylates employing arenediazonium salts and aryl iodides. The Heck arylations performed in the presence of these ionic entities, either as a solvent or as an additive, were effective leading to complete conversion of the substrate and good to excellent yield of the Heck adduct. In spite of the good performances, no asymmetric induction was observed in any of the cases studied. Two new diastereoisomeric NHC-palladium complexes were prepared in good yields from a chiral imidazolium salt and their structure characterized by X-ray diffraction. Overall, the Heck arylations employing arenediazonium tetrafluoroborates in RTILs were more effective than the traditional protocols employing aryl iodides in terms of reactivity and yields

Reductive decarboxylation of bicyclic prolinic systems: a new approach to the enantioselective synthesis of the Geissman-Waiss lactone. X-ray structure determination of a key lactone intermediate

Two concise and enantioselective syntheses of the necine base precursors (1R,5R)-N-Cbz and N-Boc-2-oxa-6-azabicyclo[3.3.0]octan-3-ones (Geissman-Waiss lactones) were carried out from two enantiomerically pure endocyclic five-membered enecarbamates with overall yields of 23% and 26%, respectively. The synthetic strategy made use of a highly effective and stereoselective [2+2]cycloaddition of enantiomerically pure endocyclic enecarbamates with dichloroketene, as well as an efficient decarboxylation step of a bicyclic alpha-amino acid employing Boger's acyl selenide protocol employing tributyltin hydride. Interesting aspects concerning the regiochemical outcome of Baeyer-Villiger oxidations of bicyclic cyclobutanones are also reported, in which the usual stereoelectronic bias of Baeyer-Villiger oxidation seems to be counterbalanced by steric effects on the putative Criegee intermediate.Duas sínteses do conhecido precursor de bases necínicas, (1R,5R)-N-Cbz e N-Boc 2-oxa-6-azabiciclo[3.3.0]octan-3-onas (lactonas de Geissman-Waiss) foram realizadas com rendimentos globais de 23% e 26%, em seis e cinco etapas respectivamente, a partir de enecarbamatos endocíclicos de cinco membros enantiomericamente puros. A estratégia sintética adotada está fundamentada em uma reação de cicloadição [2+2] eficiente e altamente estereosseletiva de enecarbamatos de cinco membros com diclorocetenos, assim como em uma eficaz descarboxilação de alfa-amino ácidos bicíclicos pelo método de Boger, que utiliza a redução de selenetos de acila por hidretos de estanho. Aspectos relativos a regiosseletividade da reação de oxidação de azabiciclo ciclobutanonas pelo método de Baeyer-Villiger são também descritos, com destaque para um potencial controle regioquímico advindo de aspectos estéreos em contraposição a aspectos estereoeletrônicos.2738Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Systematisation of seismic retrofitting in vernacular architecture

This paper aims to identify and to systematize the data obtained during the working process of the research project 'SEISMIC-V –Vernacular Seismic Culture in Portugal' in terms of seismic- retrofitting elements earthquake -resistant reinforcement implemented in vernacular buildings. The data will be distinguished based on the structural seismic strengthening and according to the following criteria: strengthening elements, perimeter seismic-resistant elements, arches reinforcing elements, and combined reinforcing elements.Portuguese Science and Technology Foundation (FCT) to the research project ‘SEISMIC - V – Vernacular Seismic Culture in Portu gal’ (PTDC/ATP - AQI/ 3934/2012

Systematisation of seismic mitigation planning at urban scale

This chapter explores the relation between the seismic mitigation planning that was developed to contribute to minimise effects at urban scale, which arise within the seismic impact. In this sense, it deepens the notion that interdependence, solidarity and cohesion of the different morphological constituents promote a better prepared built fabric, when facing catastrophic phenomena of seismic origin. Preventive approaches and reactive measures arising from the testimony of earthquake-resistant culture in Portugal are also mentioned. From the recognition of the importance of local know-how, infers a set of logical that evidence conditions to transcend the respective vernacular context, making it possible to generically systematize them.Portuguese Science and Technology Foundation (FCT) to the research project ‘SEISMIC-V – Vernacular Seismic Culture in Portugal’ (PTDC/ATPAQI/ 3934/2012

Twenty five years of strategies, methodologies and reactions in organic chemistry

An overview of the developments that occurred in the field of organic chemistry in Brazil in the last 25 years is presented. These developments are briefly compared to those observed worldwide, including some modern trends. The main source of information was the annual meeting of the Brazilian Chemical Society (RASBQ) covering the period 1979-2001 and the biennial Brazilian Meeting on Organic Synthesis (BMOS). All the contributions presented at these two meetings were classified according to six main indicatives, to permit a discussion about the past, present and future activities of Organic Chemistry in Brazil.748

3-Hydroxy-2-phenyl-2,3,3a,7a-tetrahydro-1H,5H-pyrano[3,2-b]pyrrol-5-one: crystal structure and Hirshfeld surface analysis

The title isoaltholactone derivative, C13H13NO3, has an NH group in place of the ether-O atom in the five-membered ring of the natural product. The five-membered ring is twisted about the N—C bond linking it to the six-membered ring, which has a half-chair conformation with the O atom connected to the ether-O atom lying above the plane defined by the remaining atoms. The dihedral angle between the mean planes of the rings comprising the fused-ring system is 75.10 (8)°. In the crystal, hydroxy-O—H...N(amine) hydrogen bonding sustains linear supramolecular chains along the a axis. Chains are linked into a three-dimensional architecture via amine-N—H...π(phenyl) and phenyl-C—H...O(hydroxy) interactions. The influence of the amine-N—H...π(phenyl) contact on the molecular packing is revealed by an analysis of the Hirshfeld surface

Ethyl 2-(4-methoxyphenyl)-6-oxa-3-azabicyclo[3.1.0]hexane-3-carboxylate: crystal structure and Hirshfeld analysis

The title compound, C14H17NO4, features an epoxide-O atom fused to a pyrrolidyl ring, the latter having an envelope conformation with the N atom being the flap. The 4-methoxyphenyl group is orthogonal to [dihedral angle = 85.02 (6)°] and lies to the opposite side of the five-membered ring to the epoxide O atom, while the N-bound ethyl ester group (r.m.s. deviation of the five fitted atoms = 0.0187 Å) is twisted with respect to the ring [dihedral angle = 17.23 (9)°]. The most prominent interactions in the crystal are of the type methine-C—H...O(carbonyl) and these lead to the formation of linear supramolecular chains along the c axis; weak benzene-C—H...O(epoxide) and methine-C—H...O(methoxy) interactions connect these into a three-dimensional architecture. The analysis of the Hirshfeld surface confirms the presence of C—H...O interactions in the crystal, but also the dominance of H...H dispersion contacts.</jats:p

The statistics of atmospheric turbulence at Maunakea measured by RAVEN

Prior statistical knowledge of the turbulence such as turbulence strength, layer altitudes and the outer scale is essential for atmospheric tomography in adaptive-optics (AO). These atmospheric parameters can be estimated from measurements of multiple Shack-Hartmann wave-front sensors (SH-WFSs) by the SLOpe Detection And Ranging (SLODAR). In this paper, we present the statistics of the vertical CN^2 and the outer scale L_0 at Maunakea in Hawaii estimated from 60 hours telemetry data in total from multiple SH-WFSs of RAVEN, which is an on-sky multi-object AO demonstrator tested on the Subaru telescope. The mean seeing during the RAVEN on-sky observations is 0.475 arcsec, and 55% turbulence is below 1.5 km. The vertical profile of CN^2 from the RAVEN SLODAR is consistent with the profiles from CFHT DIMM and MASS, and TMT site characterization

Short chain U(600) di-urea cross-linked poly(oxyethylene)/siloxane ormolytes doped with lanthanum triflate salt

Promising La3+-doped electrolytes based on a hybrid poly(oxyethylene)/siliceous host matrix, U(600), have been produced. The organic and inorganic components of the hybrid structure are covalently bonded through urea linkages. The low molecular weight of the polyether segments of U(600) is thought to be responsible for the total amorphous character and high conductivity at room temperature (1.1×10−4 S cm−1) of these ormolytes.Fundação para a Ciência e a Tecnologia (FCT

(1R,2S,5R)-5-Methyl-2-[2-(4-nitrophenyl)propan-2-yl]cyclohexyl 2-(4-methoxyphenyl)-2,5-dihydro-1H-pyrrole-1-carboxylate: crystal structure and Hirshfeld analysis

In the title compound, C28H34N2O5, the adjacent ester and nitrobenzene substituents are connected via an intramolecular methylene-C—H. ...(nitrobenzene) interaction and the molecule approximates to a U-shape. The dihydropyrrole ring (r.m.s. deviation = 0.003 A ˚ ) is almost co-planar with the carboxylate residue [Cm—N—C1—Oc (m = methine, c = carboxyl) torsion angle = 1.8 (4).] but is orthogonal to the 4-methoxybenzene ring [dihedral angle = 84.34 (17).]. In the crystal, methylene-C—H. ...O(carbonyl) interactions lead to linear supramolecular chains along the b-axis direction, which pack without directional interactions between them. The analysis of the calculated Hirshfeld surface points to the importance of weak interatomic H. . .H, O. . .H/H. . .O and C. . .H/H. . .C contacts in the crystal