32 research outputs found
Svjetlom do heteropolicikličkih spojeva; Reakcije supstituiranih furostilbena
Synthetic organic photochemistry, the chemistry of excited states of a molecule, differs from the ground state chemistry and provides a simple pathway to complicated structures, heavily obtainable by a classic synthetic approach. In this paper the polycyclic structures with oxygen, prepared by photochemical methodology of new o-substituted furan heterostilbenes are reviewed. The photochemistry of β-(2-furyl)-substituted-o-divinylbenzenes <b>6,13,15</b>, β,β-di(2-furyl)-substituted o-divinylbenzenes <b>18-20</b>, aryl and heteroaryl analogues of 2,3-distyrylfurans 33-36 is described. Due to steric reasons, on irradiation of β-(3-substituted-2-furyl)-o-divinylbenzenes 6, the preferred photoreaction was the intramolecular [2+2]-cycloaddition and formation of the bicyclo[2.1.1]hexenes <b>10</b> along with the formation of the corresponding phenanthrenes 12. On the other hand, furan analogues 6 and 13 give bicyclo[3.2.1]octadiene structures in very good yield. Di-substituted o-divinylbenzene derivatives <b>18-20</b> (with a hexatriene system as part of the aromatic ring) give bicyclo[3.2.1]octadiene derivatives <b>21-23</b> by intramolecular photocycloaddition and cyclophane derivatives <b>24-26</b> by intermolecular [2+2] two-fold photoaddition reaction. Compound 20 is the most selective of these o-divinylbenzenes yielding only the exo-bicyclo[3.2.1]octadiene derivative <b>23</b> at low concentrations, and only the cyclophane derivative 26 at high concentrations. This reaction to <b>23</b> and <b>26</b> is due - intra- or intermolecular complexation. Contrary to these results, on the irradiation of the aryl and heteroaryl analogues of 2,3-distyrylfurans <b>33-36</b> (with a hexatriene system as part of the heteroaromatic ring) different intra- and intermolecular processes have been observed. By intramolecular [2+2]-cycloaddition, this hexatriene system gives the phototransposition products. Also observed are stilbenes and phenanthrenes as secondary products obtained from the primary formed intermolecular cyclobutane adducts
To Hetero-polycyclic Compounds by Light; Reactions of Substituted Furostilbenes
Sintetska organska fotokemija, kemija pobuđenih stanja molekula, razlikuje se od kemije u osnovnom stanju i omogućuje jednostavan pristup kompliciranim strukturama do kojih se često vrlo teško dolazi klasičnim sintetskim putem. U svome radu koristimo fotokemijsku metodologiju u sintezi hetero-policikličkih spojeva, potencijalno biološki aktivnih spojeva. Tako je priređeno niz novih konjugiranih polienskih sustava s heterocikličkom jezgrom (furan, tiofen, pirol, oksazol, sidnon i sl.) koji se osvjetljavanjem u određenim uvjetima prevode u hetero-policikličke derivate.
U ovom pregledu dan je naglasak na fotokemijsku sintezu policikličkih struktura s kisikom polazeći iz o-supstituiranih furanskih heterostilbenaSynthetic organic photochemistry, the chemistry of excited states of a molecule, differs from the ground state chemistry and provides a simple pathway to complicated structures, heavily obtainable by a classic synthetic approach. In this paper the polycyclic structures with oxygen, prepared by photochemical methodology of new o-substituted furan heterostilbenes are reviewed. The photochemistry of β-(2-furyl)-substituted-o-divinylbenzenes 6,13,15, β,β\u27-di(2-furyl)-substituted o-divinylbenzenes 18-20, aryl and heteroaryl analogues of 2,3-distyrylfurans 33-36 is described. Due to steric reasons, on irradiation of β-(3-substituted-2-furyl)-o-divinylbenzenes 6, the preferred photoreaction was the intramolecular [2+2]-cycloaddition and formation of the bicyclo[2.1.1]hexenes 10 along with the formation of the corresponding phenanthrenes 12. On the other hand, furan analogues 6 and 13 give bicyclo[3.2.1]octadiene structures in very good yield. Di-substituted o-divinylbenzene derivatives 18-20 (with a hexatriene system as part of the aromatic ring) give bicyclo[3.2.1]octadiene derivatives 21-23 by intramolecular photocycloaddition and cyclophane derivatives 24-26 by intermolecular [2+2] two-fold photoaddition reaction. Compound 20 is the most selective of these o-divinylbenzenes yielding only the exo-bicyclo[3.2.1]octadiene derivative 23 at low concentrations, and only the cyclophane derivative 26 at high concentrations. This reaction to 23 and 26 is due - intra- or intermolecular complexation. Contrary to these results, on the irradiation of the aryl and heteroaryl analogues of 2,3-distyrylfurans 33-36 (with a hexatriene system as part of the heteroaromatic ring) different intra- and intermolecular processes have been observed. By intramolecular [2+2]-cycloaddition, this hexatriene system gives the phototransposition products. Also observed are stilbenes and phenanthrenes as secondary products obtained from the primary formed intermolecular cyclobutane adducts
To Hetero-polycyclic Compounds by Light; Reactions of Substituted Furostilbenes
Sintetska organska fotokemija, kemija pobuđenih stanja molekula, razlikuje se od kemije u osnovnom stanju i omogućuje jednostavan pristup kompliciranim strukturama do kojih se često vrlo teško dolazi klasičnim sintetskim putem. U svome radu koristimo fotokemijsku metodologiju u sintezi hetero-policikličkih spojeva, potencijalno biološki aktivnih spojeva. Tako je priređeno niz novih konjugiranih polienskih sustava s heterocikličkom jezgrom (furan, tiofen, pirol, oksazol, sidnon i sl.) koji se osvjetljavanjem u određenim uvjetima prevode u hetero-policikličke derivate.
U ovom pregledu dan je naglasak na fotokemijsku sintezu policikličkih struktura s kisikom polazeći iz o-supstituiranih furanskih heterostilbenaSynthetic organic photochemistry, the chemistry of excited states of a molecule, differs from the ground state chemistry and provides a simple pathway to complicated structures, heavily obtainable by a classic synthetic approach. In this paper the polycyclic structures with oxygen, prepared by photochemical methodology of new o-substituted furan heterostilbenes are reviewed. The photochemistry of β-(2-furyl)-substituted-o-divinylbenzenes 6,13,15, β,β\u27-di(2-furyl)-substituted o-divinylbenzenes 18-20, aryl and heteroaryl analogues of 2,3-distyrylfurans 33-36 is described. Due to steric reasons, on irradiation of β-(3-substituted-2-furyl)-o-divinylbenzenes 6, the preferred photoreaction was the intramolecular [2+2]-cycloaddition and formation of the bicyclo[2.1.1]hexenes 10 along with the formation of the corresponding phenanthrenes 12. On the other hand, furan analogues 6 and 13 give bicyclo[3.2.1]octadiene structures in very good yield. Di-substituted o-divinylbenzene derivatives 18-20 (with a hexatriene system as part of the aromatic ring) give bicyclo[3.2.1]octadiene derivatives 21-23 by intramolecular photocycloaddition and cyclophane derivatives 24-26 by intermolecular [2+2] two-fold photoaddition reaction. Compound 20 is the most selective of these o-divinylbenzenes yielding only the exo-bicyclo[3.2.1]octadiene derivative 23 at low concentrations, and only the cyclophane derivative 26 at high concentrations. This reaction to 23 and 26 is due - intra- or intermolecular complexation. Contrary to these results, on the irradiation of the aryl and heteroaryl analogues of 2,3-distyrylfurans 33-36 (with a hexatriene system as part of the heteroaromatic ring) different intra- and intermolecular processes have been observed. By intramolecular [2+2]-cycloaddition, this hexatriene system gives the phototransposition products. Also observed are stilbenes and phenanthrenes as secondary products obtained from the primary formed intermolecular cyclobutane adducts
Greater Expectations?
Physically Unclonable Functions (PUFs) are key tools in the construction of lightweight authentication and key exchange protocols. So far, all existing PUF-based authentication protocols follow the same paradigm: A resource-constrained prover, holding a PUF, wants to authenticate to a resource-rich verifier, who has access to a database of pre-measured PUF challenge-response pairs (CRPs). In this paper we consider application scenarios where all previous PUF-based authentication schemes fail to work: The verifier is resource-constrained (and holds a PUF), while the prover is resource-rich (and holds a CRP-database). We construct the first and efficient PUF-based authentication protocol for this setting, which we call converse PUF-based authentication. We provide an extensive security analysis against passive adversaries, show that a minor modification also allows for authenticated key exchange and propose a concrete instantiation using controlled Arbiter PUFs
Super universality of the quantum Hall effect and the "large picture" of the angle
It is shown that the "massless chiral edge excitations" are an integral and
universal aspect of the low energy dynamics of the vacuum that has
historically gone unnoticed. Within the
non-linear sigma model we introduce an effective theory of "edge excitations"
that fundamentally explains the quantum Hall effect. In sharp contrast to the
common beliefs in the field our results indicate that this macroscopic
quantization phenomenon is, in fact, a {\em super universal} strong coupling
feature of the angle with the replica limit only playing a
role of secondary importance. To demonstrate super universality we revisit the
large expansion of the model. We obtain, for the first time,
explicit scaling results for the quantum Hall effect including quantum
criticality of the quantum Hall plateau transition. Consequently a scaling
diagram is obtained describing the cross-over between the weak coupling
"instanton phase" and the strong coupling "quantum Hall phase" of the large
theory. Our results are in accordance with the "instanton picture" of the
angle but fundamentally invalidate all the ideas, expectations and
conjectures that are based on the historical "large picture."Comment: 40 pages, 9 figure
Oleic acid variation and marker-assisted detection of Pervenets mutation in high- and low-oleic sunflower cross
High-oleic sunflower oil is in high demand on the market due to its heart-healthy properties and richness in monounsaturated fatty acids that makes it more stable in processing than standard sunflower oil. Consequently, one of sunflower breeder's tasks is to develop stable high-oleic sunflower genotypes that will produce high quality oil. We analyzed variability and inheritance of oleic acid content (OAC) in sunflower, developed at the Institute of Field and Vegetable Crops, by analyzing F-1 and F-2 progeny obtained by crossing a standard linoleic and high-oleic inbred line. F-2 individuals were classified in two groups: low-oleic with OAC of 15.24-31.28% and high-oleic with OAC of 62.49-93.82%. Monogenic dominant inheritance was observed. Additionally, several molecular markers were tested for the use in marker-assisted selection in order to shorten the period of detecting high-oleic genotypes. Marker F4-R1 was proven to be the most efficient in detection of genotypes with Pervenets (high-oleic acid) mutation
Common Genetic Variants Contribute to Risk of Transposition of the Great Arteries
Rationale: Dextro-transposition of the great arteries (D-TGA) is a severe congenital heart defect which affects approximately 1 in 4,000 live births. While there are several reports of D-TGA patients with rare variants in individual genes, the majority of D-TGA cases remain genetically elusive. Familial recurrence patterns and the observation that most cases with D-TGA are sporadic suggest a polygenic inheritance for the disorder, yet this remains unexplored. Objective: We sought to study the role of common single nucleotide polymorphisms (SNPs) in risk for D-TGA. Methods and Results: We conducted a genome-wide association study in an international set of 1,237 patients with D-TGA and identified a genome-wide significant susceptibility locus on chromosome 3p14.3, which was subsequently replicated in an independent case-control set (rs56219800, meta-analysis P=8.6x10-10, OR=0.69 per C allele). SNP-based heritability analysis showed that 25% of variance in susceptibility to D-TGA may be explained by common variants. A genome-wide polygenic risk score derived from the discovery set was significantly associated to D-TGA in the replication set (P=4x10-5). The genome-wide significant locus (3p14.3) co-localizes with a putative regulatory element that interacts with the promoter of WNT5A, which encodes the Wnt Family Member 5A protein known for its role in cardiac development in mice. We show that this element drives reporter gene activity in the developing heart of mice and zebrafish and is bound by the developmental transcription factor TBX20. We further demonstrate that TBX20 attenuates Wnt5a expression levels in the developing mouse heart. Conclusions: This work provides support for a polygenic architecture in D-TGA and identifies a susceptibility locus on chromosome 3p14.3 near WNT5A. Genomic and functional data support a causal role of WNT5A at the locus
Common Genetic Variants Contribute to Risk of Transposition of the Great Arteries
RATIONALE: Dextro-transposition of the great arteries (D-TGA) is a severe congenital heart defect which affects approximately 1 in 4,000 live births. While there are several reports of D-TGA patients with rare variants in individual genes, the majority of D-TGA cases remain genetically elusive. Familial recurrence patterns and the observation that most cases with D-TGA are sporadic suggest a polygenic inheritance for the disorder, yet this remains unexplored. OBJECTIVE: We sought to study the role of common single nucleotide polymorphisms (SNPs) in risk for D-TGA. METHODS AND RESULTS: We conducted a genome-wide association study in an international set of 1,237 patients with D-TGA and identified a genome-wide significant susceptibility locus on chromosome 3p14.3, which was subsequently replicated in an independent case-control set (rs56219800, meta-analysis P=8.6x10-10, OR=0.69 per C allele). SNP-based heritability analysis showed that 25% of variance in susceptibility to D-TGA may be explained by common variants. A genome-wide polygenic risk score derived from the discovery set was significantly associated to D-TGA in the replication set (P=4x10-5). The genome-wide significant locus (3p14.3) co-localizes with a putative regulatory element that interacts with the promoter of WNT5A, which encodes the Wnt Family Member 5A protein known for its role in cardiac development in mice. We show that this element drives reporter gene activity in the developing heart of mice and zebrafish and is bound by the developmental transcription factor TBX20. We further demonstrate that TBX20 attenuates Wnt5a expression levels in the developing mouse heart. CONCLUSIONS: This work provides support for a polygenic architecture in D-TGA and identifies a susceptibility locus on chromosome 3p14.3 near WNT5A. Genomic and functional data support a causal role of WNT5A at the locus
Common Genetic Variants Contribute to Risk of Transposition of the Great Arteries.
RATIONALE: Dextro-transposition of the great arteries (D-TGA) is a severe congenital heart defect which affects approximately 1 in 4,000 live births. While there are several reports of D-TGA patients with rare variants in individual genes, the majority of D-TGA cases remain genetically elusive. Familial recurrence patterns and the observation that most cases with D-TGA are sporadic suggest a polygenic inheritance for the disorder, yet this remains unexplored.
OBJECTIVE: We sought to study the role of common single nucleotide polymorphisms (SNPs) in risk for D-TGA.
METHODS AND RESULTS: We conducted a genome-wide association study in an international set of 1,237 patients with D-TGA and identified a genome-wide significant susceptibility locus on chromosome 3p14.3, which was subsequently replicated in an independent case-control set (rs56219800, meta-analysis P=8.6x10
CONCLUSIONS: This work provides support for a polygenic architecture in D-TGA and identifies a susceptibility locus on chromosome 3p14.3 nea