GeMs/GSAOI observations of La Serena 94: an old and far open cluster inside the solar circle

Physical properties were derived for the candidate open cluster La Serena 94, recently unveiled by the VVV collaboration. Thanks to the exquisite angular resolution provided by GeMS/GSAOI, we could characterize this system in detail, for the first time, with deep photometry in JHK$_{s}$ - bands. Decontaminated JHK$_{s}$ diagrams reach about 5 mag below the cluster turnoff in H. The locus of red clump giants in the colour - colour diagram, together with an extinction law, was used to obtain an average extinction of $A_V =14.18 \pm 0.71$. The same stars were considered as standard - candles to derive the cluster distance, $8.5 \pm 1.0$ kpc. Isochrones were matched to the cluster colour - magnitude diagrams to determine its age, $\log{t(yr)}=9.12\pm 0.06$, and metallicity, $Z=0.02\pm0.01$. A core radius of $r_{c}=0.51\pm 0.04$ pc was found by fitting King models to the radial density profile. By adding up the visible stellar mass to an extrapolated mass function, the cluster mass was estimated as $M=(2.65\pm0.57) \times 10^3$ M$_{\odot}$, consistent with an integrated magnitude of $M_{K}=-5.82\pm0.16$ and a tidal radius of $r_{t}=17.2\pm2.1$ pc. The overall characteristics of La Serena 94 confirm that it is an old open cluster located in the Crux spiral arm towards the fourth Galactic quadrant and distant $7.30\pm 0.49$ kpc from the Galactic centre. The cluster distorted structure, mass segregation and age indicate that it is a dynamically evolved stellar system.Comment: 16 pages, 24 figures, 2 Tables, accepted by MNRAS; corrected typo

Electrochemical synthesis of diaminodicarboxylic acid derivatives

Diaminoadipic acid derivatives were synthesized in good yields by electrolysis of N,N-diacyidehydroalanines. Cyclic voltammetry measurements on the precursors are presented and interpreted as supporting formation of a nucleophilic intermediate generated by electrochemical reduction. (C) 2003 Elsevier Science Ltd. All rights reserved.- Fundação para a Ciência e a Tecnologia (project no. POCTI/1999/QUI/32689)

Synthesis of 2,3,5-substituted pyrrole derivatives

2,3,5-Substituted pyrrole derivatives are prepared by treatment of 2,3-dihydrofuran derivatives with trifluoroacetic acid. These in turn are obtained by Michael addition of carbon nucleophiles of the beta-dicarbonyl type to N-(4-toluenesulfonyl)-N-(tert-butyloxycarbonyl)-dehydroalanine methyl ester.- Fundação para a Ciência e a Tecnologia(POCTI/1999/QUI/32689

Synthesis of non-proteinogenic amino acids from N-(4-toluenesulfonyl)dehydroamino acid derivatives

By treating N-(4-toluenesulfonyl)-N-(tert-butyloxycarbonyl)-dehydroamino acid derivatives with different reactants under different conditions, a variety of new amino acids are obtained, viz. (i) alpha-alcoxy-alpha-amino acids, (ii) alpha,alpha-diamino acids and (iii) novel beta-substituted dehydroamino acids. (C) 2002 Elsevier Science Ltd. All rights reserved.Fundação para a Ciência e a Tecnologia for financial support (project no. POCTI/ 1999/QUI/32689)

Cyclic voltammetry studies on substituted arenesulfonhydrazides

Additional Z and Boc groups on the vicinal nitrogen of sulfonyl hydrazines have no significant effect on the cathodic potential of the sulfonyl functions as measured by cyclic voltammetry, whereas a Boc group on the geminal nitrogen invariably gives rise to shifts of about 0.2 V to less negative potential similar to those previously observed for derivatives of amines.This work was supported by the Swedish Natural Science Research Council (NFR) and the Fundaçao para a Ciência e a Tecnologia (Portugal)

Efficient synthesis of dehydroamino acid derivatives

By using a DMAP catalysed reaction of P-hydroxyamino acid derivatives with tert-butylpyrocarbonate, the corresponding dehydroamino acid derivatives were obtained in high yields.- (undefined

Juvenile polyposis of infancy in a child with deletion of BMPR1A and PTEN genes: Surgical approach

Juvenile polyposis of infancy is the most severe and life-threatening form of juvenile polyposis. This disease typically presents in the first two years of life with gastrointestinal bleeding, diarrhea, inanition, and exudative enteropathy. In very few reports concerning this entity, a large deletion in the long arm of chromosome 10 (10q23), encompassing the PTEN and BMPR1A genes, was found. The authors report a case of delayed diagnosis of juvenile polyposis of infancy at 6years of age. A 3.34Mb long de novo deletion was identified at 10q23.1q23.31, encompassing the PTEN and BMPR1A genes. The disease course was severe with diarrhea, abdominal pain, inanition, refractory anemia, rectal bleeding, hypoalbuminemia, and exudative enteropathy. A sub-total colectomy, combined with intraoperative endoscopic removal of ileal and rectal stump polyps, was required for palliative disease control

2-naphthalenesulfonyl as a tosyl substitute for protection of amino functions. Cyclic voltammetry studies on model sulfonamides and their preparative cleavage by reduction

With the aim to develop a practically useful, reductively more labile alternative to tosyl for protection of amino functions, initially a number of N-arenesulfonyl-protected heterocycles (pyrroles, imidazoles, indole, and carbazole) have been prepared and studied by cyclic voltammetry (CV). The recorded activation potentials vary from -1.32 to -1.99 V (vs SCE). In N-sulfonylazolides such as tosylindole the cathodic potentials are shifted by over 0.5 V compared to simple sulfonamides. An additional effect of the sulfonic acid component is also indicated. Among the compounds studied, 1- and 2-naphthalenesulfollylindole give CV peaks at about 0.4 and 0.2 V, respectively, less negative potential than tosylindole. To further investigate naphthalenesulfonyl for this purpose, we have also prepared a variety of simple 1- and 2-naphthalenesulfonyl derivatives and studied them similarly. They have activation potentials above -2.14 V and are all smoothly cleaved by Mg/MeOH. The latter reagent is capable of cleaving N-arenesulfonyl derivatives that give CV peaks above -2.30 V, whereas Al(Hg) requires potentials above about -1.7 V. Selective cleavage of 2-naphthalenesulfonyl in the presence of tosyl by Mg/MeOH is demonstrated. Several examples of reductive cleavage of arenesulfonyl derivatives with Mg/MeOH, Al(Hg), and electrolysis on a preparative scale are given.This work was supported by the Swedish Natural Science Research Council (NFR), the Swedish Research Council for Engineering Sciences (TFR), Carl Tryggers Stiftelse, Astra Draco AB, and the Fundacão para a Ciência e a Tecnologia (Portugal). B.N. gratefully acknowledges the RSC for a journals grant for international authors and the ISP for a fellowship, as well as the University of Yaoundé I for a leave of absence

Selective cathodic cleavage of unsymmetrical imidodicarbonates, acylcarbamates and diacylamides

A study of the selective cathodic cleavage of one of the alkoxycarbonyl or acyl groups from various imidodicarbonates, acylamides, and diacylamides is reported. The compounds investigated include all 15 possible combinations of the following groups in unsymmetrical N,N-diprotected derivatives of benzylamine: p-nitrobenzyloxycarbonyl, trichloroethyloxycarbonyl, toluene-p-sulfonyl, benzoyl, benzyloxycarbonyl, and tert-butyloxycarbonyl which can all be electrochemically cleavaged, except the last one. Initially the compounds were examined by cyclic voltammetry in order to measure the potentials associated with the cleavage of each group and afterwards they were electrolysed at constant potential in the presence of a proton donor. The following ranges in negative potential were recorded: 1.03-1.13 V [Z(NO2)], 1.8-2.14 V (Troc), 1.75-2.41 V (Tos), 1.88-2.52 V (Bz), and 2.83-2.9 V (Z), thus occasionally revealing a drastic effect of the auxiliary group. In the electrolytic experiments competitive attack by base occasionally led to mixtures of monoacylamides. However, all compounds apart from some of the trichloroethyloxycarbonyl derivatives could be selectively cleaved in 89-100% yields when an appropriate proton donor was used. Tentative explanations are given for the behaviour of the compounds studied and some conclusions are drawn

Inbreeding levels in Northeast Brazil: Strategies for the prospecting of new genetic disorders

A new autosomal recessive genetic condition, the SPOAN syndrome (an acronym for spastic paraplegia, optic atrophy and neuropathy syndrome), was recently discovered in an isolated region of the State of Rio Grande do Norte in Northeast Brazil, in a population that was identified by the IBGE (Brazilian Institute of Geography and Statistics) as belonging to the Brazilian communities with the highest rates of “deficiencies” (Neri, 2003), a term used to describe diseases, malformations, and handicaps in general. This prompted us to conduct a study of consanguinity levels in five of its municipal districts by directly interviewing their inhabitants. Information on 7,639 couples (corresponding to about 40% of the whole population of the studied districts) was obtained. The research disclosed the existence of very high frequencies of consanguineous marriages, which varied from about 9% to 32%, suggesting the presence of a direct association between genetic diseases such as the SPOAN syndrome, genetic drift and inbreeding levels. This fact calls for the introduction of educational programs for the local populations, as well as for further studies aiming to identify and characterize other genetic conditions. Epidemiological strategies developed to collect inbreeding data, with the collaboration of health systems available in the region, might be very successful in the prospecting of genetic disorders