bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Chiral Diamine Mediated Asymmetric Baylis–Hillman Reaction
Authors: Hayashi Yujiro , Tamura Tomohiro , Shoji Mitsuru 
Published: September 2004

AbstractA chiral diamine, easily prepared from proline, is an effective, asymmetric organic catalyst for the Baylis–Hillman reaction of aldehydes and methyl vinyl ketone, affording adducts with enantioselectivities up to 75%.
Esterolytic Peptide Dendrimers with a Hydrophobic Core and Catalytic Residues at the Surface
Authors: Clouet Anthony , Darbre Tamis , Reymond Jean‐Louis 
Published: September 2004

Abstract(3S)‐4‐(9‐Fluorenylmethoxycarbonylamino)‐3‐methyl(allyloxycarbonyl)aminoethyloxyacetic acid (1) was prepared from (R)‐3‐aminopropane‐1,2‐diol and used as branching unit for the synthesis of second generation peptide dendrimers with six individually addressable variable amino acid positions. Three pairs of diastereomeric dendrimers were prepared bearing a common hydrophobic core and permutations of the catalytic triad amino acids aspartate, histidine and serine at the surface. Dendrimers with two surface histidine residues catalyzed the hydrolysis of fluorogenic 8‐acyloxypyrene‐1,3,6‐trisulfonates in aqueous buffer pH 6.0 with rate enhancement kcat/kuncat in the 103 range and Michaelis‐Menten constants KM in the 10−4 M range. Substrate recognition involves electrostatic interactions, as shown by competitive inhibition of catalysis observed with pyrene‐1,3,6,8‐tetrasulfonate. The 4‐fold to 7‐fold lowering in KM between the butyryl and nonanoyl esters in the most active dendrimers provides evidence for a hydrophobic component in substrate binding, which is absent in a closely related, less active diastereomeric peptide dendrimer.
Functionalization of Alkynes Catalyzed byt‐Bu‐P4 Base
Authors: Imahori Tatsushi , Hori Chieko , Kondo Yoshinori 
Published: September 2004

AbstractThe addition of O‐ and N‐nucleophiles to alkynes catalyzed by a phosphazene base,t‐Bu‐P4 base, was investigated. Alkynes were easily transformed to enol ethers and enamines in DMSO by the addition of nucleophiles. When phenylacetylene was reacted with diisopropylamine, a unique head‐to‐head dimerization of phenylacetylene was observed to give the enyne derivative. Terminal proton of phenylacetylene was also catalytically activated byt‐Bu‐P4 base to generate the acetylide anion which was reacted with carbonyl compounds to give phenylpropargylic alcohol derivatives.
Aza‐Baylis–Hillman Reactions of N‐(Arylmethylene)diphenylphosphinamides with Activated Olefins in the Presence of Various Lewis Bases
Authors: Shi Min , Zhao Gui‐Ling 
Published: September 2004

AbstractThe aza‐Baylis–Hillman reactions of N‐(arylmethylene)diphenylphosphinamides with methyl vinyl ketone (MVK), methyl acrylate, acrylonitrile, ethyl vinyl ketone (EVK), phenyl vinyl ketone (PVK), phenyl acrylate, 2‐cyclopenten‐1‐one, 2‐cyclohexen‐1‐one have been systemically investigated in the presence of various Lewis bases. The Lewis base and solvent effects in these reactions have been discussed. A new class of double aza‐Baylis–Hillman reactions (in some cases exclusively) and their further transformations including catalytic, asymmetric version in the presence of chiral nitrogen and phosphine Lewis bases have been disclosed in this paper.
Direct Organocatalytic Ring‐Opening Polymerizations of Lactones
Authors: Casas Jesús , Persson Per Valdemar , Iversen Tommy , Córdova Armando 
Published: September 2004

AbstractWe have developed a novel organocatalytic, direct synthesis of aliphatic polyesters. The synthesis was based on a novel direct organic acid‐catalyzed living ring‐opening polymerization (ROP) of ε‐caprolactone and δ‐valerolactone with benzyl alcohol as the initiator. The organic acid‐catalyzed ROPs were performed without solvent and the catalyst was recovered by precipitation of the polyester products. In addition, they were operationally simple, inexpensive and environmentally benign. Organic acid catalysis provides a new entry for the synthesis of valuable biodegradable materials as well as polyesters for biomedical applications.
Product‐Catalyzed Aldol Reaction between Trimethylsilyl Enolates and Aldehydes
Authors: Fujisawa Hidehiko , Nakagawa Takashi , Mukaiyama Teruaki 
Published: September 2004

AbstractAldol reactions between trimethylsilyl ketene acetals and aldehydes by using a catalytic amount of alkoxide anion proceeded smoothly to afford the corresponding aldols in DMF, indicating that the initially‐formed aldolate anion effectively worked to catalyze the reaction. The “product‐catalyzed aldol reaction”, a new class Lewis base‐catalyzed aldol reaction, between trimethylsilyl ketene acetals and aldehydes was performed successfully by the use of aldolate anion as a Lewis base catalyst.
Nucleophilic Phosphine Organocatalysis
Authors: Methot Joey L. , Roush William R. 
Published: September 2004

AbstractPhosphines have recently become popular choices as nucleophilic catalysts in organic synthesis. The unique reactivity of phosphines compared to amines has allowed the discovery of new nucleophilic addition reactions at the α‐ and γ‐positions of unsaturated carbonyl compounds, as well as novel [3+2] and [4+2] cycloaddition reactions of activated alkynes and alkenes. The accessibility of chiral phosphines has rendered several of these transformations enantioselective and has made possible the kinetic resolution of racemic secondary alcohols by phosphine‐catalyzed acylation. This mini‐review presents recent advances in nucleophilic phosphine organocatalysis for carbon‐carbon bond formation.
First Synthesis of a Highly Basic Dendrimer and its Catalytic Application in Organic Methodology
Authors: Sarkar Arunkanti , Ilankumaran Palanichamy , Kisanga Philip , Verkade John G. 
Published: September 2004

AbstractSixteen OCH2CH2N3P(i‐BuNCH2CH2)3N substituents (A) containing the highly basic bicyclic azido‐phosphine moiety shown, have been incorporated into the dendrimer [CH2CH2N[(CH2)3N[(CH2)3NHC(O)‐3,5‐bis‐(A)‐C6H3]2]2]2 in five steps from commercially available starting materials with an overall yield of 22.5%. Also presented are examples of Michael additions, nitroaldol reactions and aryl isocyanate trimerizations that are efficiently catalyzed by the dendrimer.
Thiazolium Ylide‐Catalyzed Intramolecular Aldehyde$\rm{-}$Ketone Benzoin‐Forming Reactions: Substrate Scope
Authors: Hachisu Yoshifumi , Bode Jeffrey W. , Suzuki Keisuke 
Published: September 2004

AbstractThe scope and limitations of intramolecular benzoin‐forming reactions of aldehydes and ketones catalyzed by the combination of a thiazolium salt and a base are described. After optimization of the reaction conditions, five‐ and six‐membered cyclic acyloins were obtained in good to excellent yields and competing reactions such as intramolecular aldol reactions were suppressed. The analogous closure of seven‐membered rings proved difficult.
Bredereck's Reagent Revisited: Latent Anionic Ring‐Opening Polymerization and Transesterification Reactions
Authors: Csihony Szilárd , Beaudette Tristan T. , Sentman Alan C. , Nyce Gregory W. , Waymouth Robert M. , Hedrick James L. 
Published: September 2004

AbstractThe ring‐opening polymerization of lactide with commercially available Bredereck‐type reagents in the presence or absence of alcohol initiators was carried out affording polylactide with controlled molecular weight and narrow polydispersities. An anionic mechanism involving heterolytic cleavage to alkoxides is proposed, where these reagents function as latent anionic initiators for the ring‐opening polymerization of lactide.
N‐Arenesulfonyl‐2‐aminomethylpyrrolidines $\rm{-}$ Novel Modular Ligands and Organocatalysts for Asymmetric Catalysis
Authors: Dahlin Nils , Bøgevig Anders , Adolfsson Hans 
Published: September 2004

AbstractA novel series of (S)‐N‐arenesulfonyl‐2‐aminomethylpyrrolidines were prepared in high overall yield starting from N‐Boc‐L‐proline. The mono‐sulfonyldiamines were evaluated as organocatalysts in the asymmetric α‐amination of propanal using diethyl azadicarboxylate (DEAD) as the amine source. The initially formed α‐aminated aldehyde was reduced in situ to the corresponding N‐aminooxazolidinone, which was obtained in moderate to high yield in up to 87% ee.
Neutral Coordinate‐Organocatalysts in Organic Synthesis: Allylation of Acylhydrazones with Allyltrichlorosilanes
Authors: Kobayashi Shū , Sugiura Masaharu , Ogawa Chikako 
Published: September 2004

AbstractN,N‐Dimethylformamide (DMF), sulfoxides, and phosphine oxides, etc., which are neutral, uncharged molecules and coordinate to silicon atoms of organosilicon reagents to activate nucleophilic addition, are defined as neutral coordinate‐organocatalysts (NCOs). In the presence of NCOs, allylation reactions of acylhydrazones, useful imine surrogates, using allyltrichlorosilanes proceed smoothly to afford the synthetically useful racemic and non‐racemic homoallylic amine derivatives in high yields with high diastereoselectivities.
Theoretical Explorations of Enantioselective Alkylation Reactions of Pyrroles and Indoles Organocatalyzed by Chiral Imidazolidinones
Authors: Gordillo Ruth , Carter Jennifer , Houk K. N. 
Published: September 2004

AbstractThe transition structures for MacMillan's alkylations of N‐methylpyrrole by aldehydes catalyzed by chiral amine salts were explored with B3LYP/6‐31G(d) density functional theory. These results provide an explanation of the enantioselectivities observed with these two catalysts.
The Scope of the Direct Proline‐Catalyzed Asymmetric Addition of Ketones to Imines
Authors: Notz Wolfgang , Watanabe Shin‐ichi , Chowdari Naidu S. , Zhong Guofu , Betancort Juan M. , Tanaka Fujie , Barbas Carlos F. 
Published: September 2004

AbstractA full account of catalytic direct asymmetric Mannich‐type reactions is presented describing the scope of amino acid‐catalyzed additions of unmodified ketones to a large variety of imines. These reactions are performed under very mild, operationally simple, and environmentally friendly and benign conditions employing a one‐pot, three‐component protocol as well as preformed imines. Typically, products were obtained with high regio‐ and diastereoselectivities and excellent enantioselectivities. The methodology developed was applied as a powerful approach toward the synthesis of enantiomerically pure functionalized α‐amino acids, γ‐lactones, oxime‐functionalized amino acids as well as pharmacologically important targets such as (R)‐cyclohexylglycine.
Molecular cytogenetic characterization of ring chromosome 15 in three unrelated patients
Authors: Tümer Z. , Harboe T.L. , Blennow E. , Kalscheuer V.M. , Tommerup N. , Brøndum‐Nielsen K. 
Published: September 2004

AbstractWe report molecular cytogenetic characterization of ring chromosome 15 in three unrelated male patients with the karyotype 46,XY,r(15). One was a stillborn child with several malformations, and the other two cases showed pre‐ and postnatal growth retardation and developmental delay, common features for ring chromosome 15 syndrome. One of these patients also displayed clinical features resembling Prader–Willi syndrome (PWS). To delineate the extent of the deletion on chromosome 15, we have carried out fluorescence in situ hybridization (FISH) using bacterial artificial chromosomes (BACs) mapping to the distal long arm of chromosome 15. The deletion breakpoints clustered within a 4.5–6.5 Mb region proximal to the 15q telomere. Two deletions involved the same known genes, while the largest deletion observed in the stillborn child involved three additional genes, including the COUP‐TFII gene, which has been suggested to play a role in heart development. The heart malformations, which are observed in this patient, are thus likely to be due to hemizygosity/haploinsufficiency of the COUP‐TFII gene. In all three patients, the insulin‐like growth factor I receptor gene (IGF1R) gene was deleted supporting the association between IGF1R and growth retardation seen in ring chromosome 15 syndrome. © 2004 Wiley‐Liss, Inc.
Genomewide search and association studies in a Finnish celiac disease population: Identification of a novel locus and replication of the HLA and CTLA4 loci
Authors: Rioux John D. , Karinen Hannele , Kocher Kerry , McMahon Sheila Guschwan , Kärkkäinen Päivi , Janatuinen Esko , Heikkinen Markku , Julkunen Risto , Pihlajamäki Jussi , Naukkarinen Anita , Kosma Veli‐Matti , Daly Mark J. , Lander Eric S. , Laakso Markku 
Published: September 2004

AbstractIt has been reported that celiac disease (CD) is strongly associated with the HLA‐DQ2 alleles DQA1*0501 and DQB1*0201. However, this association only accounts for a portion of the genetic component of CD. Several non‐HLA loci and candidate genes that potentially contribute to CD susceptibility have been reported, but have not been confirmed. The aim of this study was to identify loci that contribute to disease susceptibility in a CD population from Finland. We performed a genomewide linkage scan and identified two regions of significant linkage to CD (6p and 2q23‐32) and one region of suggestive linkage (10p). We also performed targeted typing and analyses that replicated the associations of the HLA and CTLA4 loci. © 2004 Wiley‐Liss, Inc.
Maternal and fetal genetic factors account for most of familial aggregation of preeclampsia: A population‐based Swedish cohort study
Authors: Cnattingius Sven , Reilly Marie , Pawitan Yudi , Lichtenstein Paul 
Published: September 2004

AbstractThere is accumulated evidence for genetic influences on preeclampsia. However, no study has been able to separate the effects of maternal and fetal genetic factors from environmental factors, and there are still uncertainties about the origin and magnitude of the genetic effects. We used the population‐based Swedish Birth and Multi‐Generation Registries to identify a cohort of women who gave birth from 1987 through 1997. In order to separate the genetic and environmental contributions to preeclampsia, we analyzed pregnancy outcomes from families joined by full siblings. We included information from 244,564 sibling pairs (62,236 sister pairs, 63,288 brother pairs, and 119,040 sister–brother pairs), who had 701,488 pregnancies. We found that 35% of the variance in liability of preeclampsia was attributable to maternal genetic effects, 20% to fetal genetic effects (with similar contribution of maternal and paternal genetic effects), 13% to the couple effect, less than 1% to shared sibling environment, and 32% to unmeasured factors. Among women and men without a history of preclampsia, partner change reduced the risk of preeclampsia (odds ratio, 0.6; 95 percent confidence interval, 0.4–0.9). Genetic factors account for more than half of the liability of preeclampsia, and maternal genes contribute more than fetal genes. We suggest that the couple effect is due to a genetic interaction between mother and father. © 2004 Wiley‐Liss, Inc.
Monozygotic twins discordant for frontonasal malformation
Authors: Mohammed Shehla N. , Swan Marc C. , Wall Steven A. , Wilkie Andrew O.M. 
Published: September 2004

AbstractFrontonasal malformation (FNM), also known as the median cleft face syndrome, encompasses a spectrum of phenotypes that are believed to result from a single underlying aetiology. Over the course of two decades, the Craniofacial Unit at the Radcliffe Infirmary, Oxford has been involved in the management of six same‐sex twins where only a single twin is affected. With local ethical committee approval, five sets of twins were traced and consented to participation in this study. Monozygosity of all five twin pairs was confirmed, and the clinical features were reviewed. We discuss the mechanistic relationship between FNM and the twinning process and the genetic implications of this association. © 2004 Wiley‐Liss, Inc.
A case of tangier disease with a novel mutation in the c‐terminal region of ATP‐binding cassette transporter A1
Authors: Guan Jing‐Zhi , Tamasawa Naoki , Brunham Liam R. , Matsui Jun , Murakami Hiroshi , Suda Toshihiro , Ochiai Shigeru , Tsutsui Masahiro , Kudou Kenji , Satoh Kei , Hayden Michael R. 
Published: September 2004

AbstractTangier disease (TD), a rare disorder characterized by extremely low levels of high density lipoprotein cholesterol (HDL‐C), is caused by mutations in the ATP‐binding cassette transporter A1 (ABCA1) gene. Here, we describe a new patient with TD. The 42‐year‐old proband had obvious juvenile cataracts, mild hepatosplenomegaly, and an extremely low level of HDL‐C (1 mg/dl), consistent with the diagnosis of TD. The proband was homozygous for a novel CTC6914‐6TT → 2203X mutation in the carboxy terminus of the ABCA1 protein. ApoAI‐mediated cholesterol efflux from patient fibroblasts was markedly decreased compared to control, despite normal levels of protein expression. This indicates that this mutant protein is normally transcribed and exists as a stable product, yet is functionally defective. These results point to a critical role for the intracellular C‐terminal region of the ABCA1 gene product in regulating cholesterol efflux and HDL‐cholesterol levels. © 2004 Wiley‐Liss, Inc.
Clinical variability in KBG syndrome: Report of three unrelated families
Authors: Maegawa Gustavo Henrique Boff , Leite Júlio Cesar Loguercio , Félix Têmis Maria , da Silveira Heraldo Luís Dias , da Silveira Heloísa Emília 
Published: September 2004

AbstractThe KBG syndrome is characterized by short stature, macrodontia, a specific combination of minor anomalies, developmental delay, and/or mental retardation. We reported on four patients from three unrelated families. The most frequent clinical findings were: atypical face, long/flat philtrum, thin upper lip, macrodontia, dental malposition, enamel hypoplasia, and cleft teeth. Skeletal anomalies such as cervical ribs and vertebral abnormalities were also noted. Hand anomalies were observed in three patients. Mental retardation and developmental delay were present in three of the four patients. There is wide clinical variability in the expression of this syndrome. The males are usually more severely affected then the females, suggesting possible X‐linked inheritance in some cases. © 2004 Wiley‐Liss, Inc.
Ocular coloboma and high myopia with Hirschsprung disease associated with a novel ZFHX1B missense mutation and trisomy 21
Authors: Gregory‐Evans C.Y. , Vieira H. , Dalton R. , Adams G.G.W. , Salt A. , Gregory‐Evans K. 
Published: September 2004

AbstractSyndromic Hirschsprung disease has been associated with mutations in ZFHX1B, a Smad‐interacting transcriptional repressor protein. Tissue in situ hybridization has demonstrated strong expression of ZFHX1B in the developing eye, suggesting that some mutations in this gene may cause visual loss. However, none of the reported mutations have been associated with an ocular phenotype. We describe a patient with Down syndrome and Hirschsprung disease with high myopia and ocular coloboma affecting the iris and retina. In addition to trisomy 21, a novel, de novo heterozygous A to G transition in exon 8 of the ZFHX1B gene was identified, which results in a R953G amino acid substitution. This abnormality was not seen in a screen of 200 chromosomes from ethnically matched, normal controls. The arginine residue at position 953 is an extremely conserved amino acid throughout evolution. This is the first report associating Hirschsprung disease and severe eye defects with a specific genetic mutation and is the first report of a mutation in ZFHX1B causing a developmental ocular anomaly. © 2004 Wiley‐Liss, Inc.
Proteomic studies identified a single nucleotide polymorphism in glyoxalase I as autism susceptibility factor
Authors: Junaid Mohammed A. , Kowal Dagmar , Barua Madhabi , Pullarkat Premila S. , Sklower Brooks Susan , Pullarkat Raju K. 
Published: September 2004

AbstractAutism is a neurodevelopmental disability characterized by deficits in verbal communications, impairments in social interactions, and repetitive behaviors. Several studies have indicated strong involvement of multigenic components in the etiology of autism. Linkage analyses and candidate gene search approaches so far have not identified any reliable susceptibility genes. We are using a proteomic approach to identify protein abnormalities due to aberrant gene expression in autopsied autism brains. In four of eight autism brains, we have found an increase in polarity (more acidic) of glyoxalase I (Glo1) by two‐dimensional gel electrophoresis. To identify the molecular change resulting in the shift of Glo1 polarity, we undertook sequencing of GLO1 gene. Direct sequencing of GLO1 gene/mRNA in these brains, has identified a single nucleotide polymorphism (SNP), C419A. The SNP causes an Ala111Glu change in the protein sequence. Population genetics of GLO1 C419A SNP studied in autism (71 samples) and normal and neurological controls (49 samples) showed significantly higher frequency for the A419 (allele frequency 0.6 in autism and 0.4 in controls, one‐tailed Fisher's test P < 0.0079). Biochemical measurements have revealed a 38% decrease in Glo1 enzyme activity in autism brains (one‐tailed t‐test P < 0.026). Western blot analysis has also shown accumulation of advanced glycation end products (AGE's) in autism brains. These data suggest that homozygosity for A419 GLO1 resulting in Glu111 is a predisposing factor in the etiology of autism. © 2004 Wiley‐Liss, Inc.
Girl with monosomy 1p36 and Angelman syndrome due to unbalanced der(1) transmission of a maternal translocation t(1;15)(p36.3;q13.1)
Authors: Torisu Hiroyuki , Yamamoto Toshiyuki , Fujiwaki Takehisa , Kadota Mitsutaka , Oshimura Mitsuo , Kurosawa Kenji , Akaboshi Shinjiro , Oka Akira 
Published: September 2004

AbstractWe report on a girl with monosomy 1p36.3 and Angelman syndrome due to an unbalanced transmission of a maternal balanced chromosomal translocation. She manifested monosomy 1p36 and Angelman syndrome including generalized hypopigmentation, ataxic movements, intractable seizures with characteristic electroencephalographic (EEG) abnormality compatible with Angelman syndrome, and other minor anomalies, large anterior fontanelle, severe psychomotor retardation, and seizures due to monosomy 1p36. Her karyotype was 45, XX, der(1) t(1;15)(p36.31;q13.1),−15, derived from maternal translocation. Molecular analysis determined a breakpoint of 1p between D1S243 and D1S468, which suggested that most genes contributing to the common phenotype are in the distal region. © 2004 Wiley‐Liss, Inc.
Neither single‐marker nor haplotype analyses support an association between genetic variation near NOTCH4 and bipolar disorder
Authors: Prathikanti Sridhar , Schulze Thomas G. , Chen Yu‐Sheng , Harr Bettina , Akula Nirmala , Hennessy Kathy , Potluri Suneeta , Lyons Jennifer , Nguyen Tu , McMahon Francis J. 
Published: September 2004

AbstractMarkers near the NOTCH4 locus on chromosome 6p21.3 have been reported to be associated with schizophrenia in some studies. Since schizophrenia and bipolar affective disorder (BPAD) may share genetic determinants, we tested markers in and near NOTCH4 in a sample of 153 parent–offspring triads ascertained through a sibling pair with BPAD for evidence of association. This sample would have 80% power to detect an association at or above a genotype relative risk of 2.4 at the 10−7 level of significance. In addition to the two markers previously showing the most significant association with schizophrenia, three additional nearby markers were studied. The five markers were genotyped using validated methods. Both single‐marker and 3‐marker haplotype data was analyzed using family‐based association methods. No genome‐wide significant association was detected between any of the five SNP‐markers and BPAD in this sample. One marker showed nominal evidence of association (P = 0.049), but this evidence was not supported by haplotype analyses including nearby flanking markers or by case‐control analysis using 93 Caucasian controls. These results do not support an association between genetic variation near NOTCH4 and BPAD in this sample. © 2004 Wiley‐Liss, Inc.