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We describe the case of a 33-week preterm infant who developed nonimmune hydrops fetalis secondary to a kaposiform hemangioendothelioma (KHE). The tumor was successfully treated with vincristine, prednisone, ticlopidine, and aspirin. KHE can be an unusual cause of hydrops fetalis; in such cases, diagnosis can be challenging since generalized edema can obscure KHE.

Informe depositado en la Dirección General de Patrimonio de la Comunidad de Madrid., Informe técnico de la intervención arqueológica llevada a cabo en los restos de la Guerra Civil existentes en la Casa de Campo de Madrid. Se describen los resultados de las excavaciones y prospecciones en una trinchera republicana de la Casa de Vacas de noviembre de 1936., Financiación: Institute of Field Research, NEARCH: New Scenarios for Community‐ Oriented Archaeology (UE), GPAC‐Universidad del País Vasco, Nottingham University.

[Resumen] Las palabras del arquitecto Robert Mallet-Stevens “el decorado debe presentar al personaje antes de que éste aparezca, debe indicar su posición social, sus gustos, sus hábitos, su estilo de vida, su personalidad” muestran la importancia de la escenografía. Dar voz a aquello que no puede expresarse mediante el diálogo se convierte en su función principal. En las películas fantásticas, la escenografía, como extensión de la arquitectura, se adentra en mundos de culturas imaginarias e imposibles construcciones que debe resultar verosímiles. Este es el caso de El Señor de los Anillos, obra cumbre de J.R.R Tolkien. La adaptación cinematográfica de Peter Jackson enfrentó las dificultades propias del género y los riesgos de llevar una obra tan conocida a la gran pantalla. Para solventarlos, la dirección artística se valió de todas las modalidades de escenografía a su alcance y de un planificado diseño que llevaba más de cuarenta años esperando a ser usado: los bocetos del propio autor y las ilustraciones de Alan Lee y John Howe. [Abstract] The words of the architect Robert Mallet-Stevens “the set must present the character before he has even appeared. It must indicate his social position, his tastes, his habits, his lifestyle, his personality” show the importance of the scenography. To give voice to what the dialogue cannot express becomes its principal function. In fantastic films, the scenography, as an extension of architecture, ventures in worlds of imaginary cultures and impossible constructions, which have to pass as real. This is the case of The Lord of the Rings, J.R.R. Tolkien’s masterpiece. Peter Jackson’s cinematographic adaptation faced the difficulties of the genre and the risks of taking such a recognized piece to the big screen. To solve this, the artistic direction used all the scenography modalities they could, along with a planned design that had been awaiting for more than forty years to be used: the author’s sketches, and Alan Lee and John Howe’s illustrations. [Resumo] As palabras do arquitecto Robert Mallet-Stevens “o decorado debe presentar ó personaxe antes de que este apareza, debe indicar a súa posición social, os seus gustos, os seus hábitos, o seu estilo de vida, a súa personalidade” mostran a importancia da escenografía. Dar voz a aquelo que o diálogo non pode expresar convértese na súa función principal. Nas películas fantásticas, a escenografía, como extensión da arquitectura, intérnase en mundos de culturas imaxinarias e imposibles construcións que debe facer pasar por reais. Este é o caso de O Señor dos Aneis, obra cume de J.R.R. Tolkien. A adaptación cinematográfica de Peter Jackson enfrontou as dificultades propias do xénero e os riscos de levar unha obra tan coñecida á gran pantalla. Para resolvelos, a dirección artística valeuse de tódalas modalidades de escenografía ao seu alcance e dun planificado deseño que levaba máis de corenta anos esperando para ser usado: os bosquexos do propio autor e as ilustracións de Alan Lee e John Howe. Traballo fin de grao (UDC.ETSA). Estudos en arquitectura. Curso 2016/2017

La utilizacion de enzimas fibroliticas exogenas comerciales (celulasas y xilanasas) ha sido ampliamente empleada en produccion animal, con la finalidad de complementar la actividad de las enzimas endogenas, para lograr un incremento en la respuesta de produccion de leche. En esta investigacion se pretende utilizar como alternativa el uso de enzimas exogenas obtenidas del sustrato gastado de Pleurotus ostreatus con el fin de evaluar los parametros productivos de cabras. Los resultados mostraron que la inclusion en la dieta de este extracto enzimatico, tuvo efecto sobre la ganancia diaria de peso, produccion de leche y consumo de alimento. Lo que sugiere que el extracto enzimatico obtenido del sustrato gastado de Pleurotus ostreatus, puede ser una alternativa para mejorar los parametros productivos de las cabras. Palabras clave: leche, extracto enzimatico, cabras.

Nowadays, probiotics have been utilized as starter cultures in the elaboration of fermented dairy products such as cheese. The survival of probiotic microorganisms in this type of products is very important in order to have a beneficial effect after their consumption. In addition to this, milk proteins are considered an important source of bioactive peptides. These peptides have been identified in hydrolyzed products of milk proteins and dairy products such as cheese. In this study, the protective effect on the survival of Lactobacillus rhamnosus GG was determined in a cheese which was inoculated only with this probiotic microorganism, and in another cheese additionally inoculated with Lactobacillus bulgaricus 2772 (exopolysaccharide producer bacteria). The ripening of these cheeses took place for 28 days at two different temperatures (4°C and 14°C). The proteolytic capacity was analyzed by measuring the concentration of free amino groups, through the trinitrobenzenesulfonic acid method (TNBS). The separation of peptides was carried out by polyacrylamide gel electrophoresis (SDS-PAGE) with 15% T. At the end of the study it was found that the population density was higher in the cheeses ripened at 14°C while at 4°C, it decreased. A higher proteolytic activity at 14°C was also observed and it was determined by a higher concentration of free amino groups. Likewise, during the analysis of electrophoresis gels, a higher concentration of peptides smaller than 10 kDa was found in the samples of cheeses ripened at 14°C. These results increase the expectations to find peptides with a biological function.

Novel analogs of L-prolyl-L-leucylglycinamide (PLG) were synthesized wherein the prolyl residue was replaced with other amino acids based on a 3,5-disubstituted proline scaffold. In some examples, the L-leucyl residue was also replaced by L-valine. These analogs were tested for their ability to enhance the binding of [(3)H]-N-propylnorapomorphine to short isoform of human dopamine D₂ receptors. Compounds 18b and 19b, increased [(3)H] NPA binding at concentrations between 10(-12) and 10(-9) M, which is similar to the effect of PLG in this assay and, provides evidences that these compounds are acting as allosteric modulators of dopamine D₂ receptors.

An expedient and concise Ugi-based approach for the rapid assembly of pyrazin-2(1H)-one-based frameworks has been developed. This convergent approach encompasses skeletal, functional and stereochemical diversity, exhibiting an unusually high bond-forming efficiency as well as high structure and step economies. The method involves the use of readily available commercial reagents and is an example of the reconciliation of structural complexity with operational simplicity in a time- and cost-effective manner.

Endocannabinoids activate two types of specific G-protein-coupled receptors (GPCRs), namely cannabinoid CB1 and CB2. Contrary to the psychotropic actions of agonists of CB1 receptors, and serious side effects of the selective antagonists of this receptor, drugs acting on CB2 receptors appear as promising drugs to combat CNS diseases (Parkinson's disease, Huntington's chorea, cerebellar ataxia, amyotrohic lateral sclerosis). Differential localization of CB2 receptors in neural cell types and upregulation in neuroinflammation are keys to understand the therapeutic potential in inter alia diseases that imply progressive neurodegeneration. Medicinal chemistry approaches are now engaged to develop imaging tools to map receptors in the living human brain, to develop more efficacious agonists, and to investigate the possibility to develop allosteric modulators.

SI

En el artículo se trata una temática que debiera abordarse con mayor frecuencia e intensidad en la Educación Primaria. La Seguridad en el contexto escolar es una cuestión de vital importancia y crear una conciencia y cultura preventiva desde la infancia construirá unos futuros trabajadores comprometidos por preservar su integridad. Igualmente, se aporta una propuesta didáctica innovadora mediante ABP (Aprendizaje Basado en Proyectos) para llevar a cabo en el Segundo Tramo de la etapa de Educación Primaria. This article is about a subject that should be treated with greater frequency and intensity in Primary Education. Security at school context is a matter of vital importance and creating awareness and preventive culture from childhood will build future workers committed to preserve their integrity and health. It also describes an innovative educational proposal by PBL(Project Based Learning) that can be carried out in the Second Section of the Primary Education.

El objetivo fue determinar la relación entre la percepción del Sistema Nacional de Pensiones y financiamiento de obligaciones previsionales del Sistema Nacional de Pensiones, Línea flujo ONP, 2015. El análisis del proceso del flujo del sistema nacional de pensiones en el Perú, es de importancia por ello, de método Hipotético Deductivo, con una población fue de 270 funcionarios del Sistema Nacional de Pensiones, la muestra es probabilística de 159 personas. El tipo fue básico, diseño no experimental_correlacional y transaccional, sobre la Percepción del Sistema Nacional de Pensiones y financiamiento de obligaciones previsionales del Sistema Nacional de Pensiones, Línea flujo ONP, 2015, a través de la evaluación de sus distintas dimensiones, cuyos resultados se presentan a nivel descriptivo e inferencial. La investigación concluye que existe evidencia significativa para afirmar que: La percepción de Sistema Nacional de Pensiones tiene relación positiva (r = 0.308) y significativa (p = 0.000) con el financiamiento de las obligaciones previsionales según los funcionarios de la Línea flujo ONP, 2015, lo que indica que a mejor efectividad del sistema nacional de pensiones, habrá mayor eficiencia en el financiamiento de las obligaciones previsionales, por lo tanto se rechazó la hipótesis nula y se aceptó la hipótesis alterna. Lima Norte Escuela de Posgrado Dirección

High yield syntheses of one chiral sulfonyloxyiminomalononitrile and four alkyl sulfonyloxyiminocyanoacetate derivatives (3a-e), to be used in asymmetric hetero-Diels-Alder additions, are described.

Starting from readily available N-benzyl protected methyl 3,5-bis(hydroxymethyl)pirrolidinecarboxylate a number of racemic methyl t-3,t-5-disubstitutedprolinates have been synthesised, thus opening a practical way towards the preparation of a variety of putative proline-mimetics. In this context, N-Boc protected derivatives proved to be better intermediates than their N-benzyl counterparts in terms of cleanness and overall yield of the synthetic procedure.

A new series of 9-deazaxanthine derivatives with various substituents at the heterocyclic system were synthesized and evaluated for their binding affinities for the four human recombinant adenosine receptors, A(1)-A(3) subtypes. A number of the 9-deazaxanthines derivatives 3a-m showed moderate-to-high affinity for hA(2B) receptors, with compound 3f showing a 32-fold selectivity for A(2B) over A(1) and a 2750-fold selectivity for A(2B) over A(2A).

The synthesis of an important set of 3-furfurylxanthine derivatives is described. Binding affinities were determined for rat A(1) and human A(2A), A(2B) and A(3) receptors. Several of the 3-furfuryl-7-methylxanthine derivatives showed moderate-to-high affinity at human A(2B) receptors, the most active compound (10d) having a K(i) of 7.4 nM for hA(2B) receptors, with selectivities over rA(1) and hA(2A) receptors up to 14-fold and 11-fold, respectively. Affinities for hA(3) receptors were very low for all members of the set.

The first members of a new family of heterocarbobicyclic nucleoside analogues have been synthesized from the cis/trans mixture of (4-amino-5,6-dihydro-4H-cyclopenta[b]thiophen-6-yl)methanols (cis/trans-7). The separation of the cis and trans intermediates during the preparation of the 6-chloropurine derivatives allowed a separate preparation of the purine heterocarbanucleosides cis-10 and trans-11, from which cis-12-14 and trans-16-18 were obtained by replacement of the 6-chloro substituent with amino, hydroxy, and cyclopropylamino groups. Additionally, the 6-phenylpurinyl analogues cis-15 and trans-19 were prepared from cis-10 and trans-11 using Suzuki-Miyaura methodology. In tests of antiviral and cytostatic activities, compound 11 showed cytostatic activity against Molt4/C8 human T lymphoblastic leukemia cells. Antiviral activity was shown by compounds 15 and 19 against Punta Toro virus and Coxackie virus B4 (compound 11). © Georg Thieme Verlag Stuttgart.

In order to identify a high-affinity, selective antagonist for the A2B subtype adenosine receptor, more than 40 1,8-disubstituted-3-(3-methoxypropyl) xanthines were prepared and evaluated for their binding affinity at recombinant human adenosine receptors, mainly of the A2A and A2B subtypes. Some of the 1-ethyl-3-(3-methoxypropyl)-8-aryl substituted derivatives 15(a-m) showed moderate-to-high affinity at human A2B receptors, with compound 15d showing A2B selectivity over the other A receptors assayed (A1, A2A, A3) of 34-fold or over. © 2009 Elsevier Ltd. All rights reserved.

A number of 1,3-dialkyl-9-deazaxanthines (9-dAXs), bearing a variety of N-substituted benzyloxycarbonylamino substituents at position 8, were prepared and evaluated for their binding affinity to the recombinant human adenosine receptors (hARs), chiefly to the hA(2B) and hA(2A) AR subtypes. Several ligands endowed with excellent binding affinity to the hA(2B) receptors, but low selectivity versus hA(2A) and hA(1) were identified. Among these, 1,3-dimethyl-N-3'-thienyl carbamate 15 resulted as the most potent ligand at hA(2B) (K(i)=0.8 nM), with a low selectivity versus hA(2A) (hA(2A)/hA(2B)=12.6) and hA(1) (hA(1)/hA(2B)=12.5) and a higher selectivity versus hA(3) (hA(3)/hA(2B)=454). When tested in functional assays in vitro, compound 15 exhibited high antagonist activities and efficacies versus both the A(2A) and A(2B) receptor subtypes, with pA(2) values close to the corresponding pK(i)s. A comparative analysis of structure-affinity and structure-selectivity relationships of the similar analogues 8-N-substituted benzyloxycarbonylamino- and 8-N-substituted phenoxyacetamido-9-dAXs suggested that their binding modes at the hA(2B) and hA(2A) ARs may strongly differ. Computational studies help to clarify this striking difference arising from a simple, albeit crucial, structural change, from CH(2)OCON to OCH(2)CON, in the para-position of the 8-phenyl ring.

Resumen: Objetivo: conocer el tipo de unidades de cuidados intensivos neonatales (UCIN) que proporcionan asistencia respiratoria neonatal en España y sus características. Material y método: encuesta multicéntrica estructurada para conocer la actividad asistencial respiratoria prestada por las UCIN en 2005. Resultados: contestaron 96 unidades neonatales con una representatividad estimada en un 63%, con un intervalo entre el 3 y el 92%, según las áreas geográficas; las unidades IIIc se encuentran en el rango superior. Contestaron la encuesta 26 unidades tipo IIb (27%), 16 IIIa (17%), 40 IIIb (42%) y 14 IIIc (14%). Las camas totales de intensivos de nivel III fue de 541 (1,2 camas cada 1.000 recién nacidos vivos; intervalo, 0,7-1,7). La media de camas por unidad fue de 4,1 para las IIIa, 2,8 para las IIIb y 14,6 para las IIIc. En las unidades de nivel III, la relación camas/médicos fue de 2,4 camas/medico y la de camas/enfermeras 2,8 camas/enfermera (2,2 en nivel IIIc). Hubo un total de 13.219 ingresos, de los que el 54% precisó ventilación (el 36% en las IIIa y el 65% en las IIIc). La posibilidad de reanimación en el paritorio con mezcla de gases (aire y oxígeno) sólo la tiene el 42% de las IIIb y IIIc. La relación respirador/cama fue de 1/1; el 63% puede proporcionar ventilación de alta frecuencia (VAF). Todas disponen de sistemas de presión positiva continua nasal (CPAP-n). Sistemas para aplicar ventilación nasal intermitente están disponibles en el 25% de las IIIa, el 58% de las IIIb y el 64% de las IIIc. Todas las IIIc y el 93% de las IIIb pueden proporcionar oxido nítrico inhalado. Cuatro unidades disponían de ECMO. Conclusiones: la media de camas de UCIN de nivel III cada mil nacidos está en el límite bajo de lo recomendable, con notables diferencias regionales. La necesidad de ventilación mecánica fue del 54%. La relación de camas por enfermera fue de 2,8. Existe una buena dotación de respiradores (1 por cama) con alta disponibilidad de VAF (63%). Todas las unidades disponen de CPAP-n. Abstract: Aim: To learn the characteristic of the neonatal intensive care units (NICUs) that offer neonatal respiratory assistance in Spain. Material and method: A structured survey was developed and sent to all Spanish neonatal units to learn about the respiratory care offered in 2005. Results: A total of 96 Units answered the survey, with an estimated representatively of 63%, with a range from 3 to 92%, depending on the geographical area. Level IIIc Units were in the upper range. Answer the survey 26 units type IIb (27%), 16 IIIa (17%), 40 IIIb (42%) and 14 IIIc (14%). The total number of level III NICU beds was 541 (1.2 beds per 1000 livebirths; range, 0.7–1.7). The mean number of beds per NICU was 4.1 in level IIIa Units, 2.8 in those IIIb and 14.6 in type IIIc NICUs. In level III NICUs, the bed per physician ratio was 2.4 and that of beds per registered nurse was 2.8 (2.2 in level IIIc NICUs). There were a total 13,219 admissions, 54% of those needed mechanical ventilation (36% in IIIa and 65% in level IIIc NICUs). Oxygen blenders for resuscitation at birth were available in 42% of level IIIb and IIIc NICUs. NICUs had one neonatal ventilator per bed, and 63% of units had high frequency ventilation available. All units had nasal-CPAP systems, 25% of level IIIa Units, 58% IIIb and 64% of those type IIIc had systems for nasal ventilation. All level IIIc and 93% of level IIIb NICUs were able to provide inhaled nitric oxygen therapy. Four NICUS offered ECMO. Conclusions: The mean number of NICU beds per 1000 livebirths is within the lower limits of those been recommended, and there were wide variations among different geographical areas. A 54% of those babies admitted to NICUs required mechanical ventilation. The mean number of NICU beds per registered nurse was 2.8. There was an adequate number of neonatal ventilators (one per bed) and 63% were able to provide HFV. All NICUs hand n-CPAP systems.

Starting from ( )-trans- and ( )-cis-3-hydroxymethyl-1-indanol, novel 6-substituted purinylcarbanucleoside derivatives of indan (5, 6, 9, 10, 15 and 17) were synthesized through a key coupling reaction with 6-chloropurine under Mitsunobu conditions. Suzuki-Miyaura reactions of the protected 6-chloropurine derivative with different arylboronic acids afforded the corresponding 6-arylpurinylcarbanucleoside derivatives. Finally, three new 5- halouracilcarbanucleosides (19, 20 and 21) were prepared by reaction of uracilcarbanucleoside 18 with different N-halosuccinimides. All of the new analogues were evaluated for antiviral activity against a wide variety of viruses.

cis-2,3-Diphenyl-6,7-dihydro-5H-cyclopenta[b]pyrazine-5,7-dimethanol, prepared by Diels-Alder reaction from cyclopentadiene and appropriately protected 2-imidazolone--followed by dihydroxylation, glycol protection, diamine deprotection, condensation with benzyl, glycol deprotection, oxidative cleavage and reduction--, was used to synthesize (+/-)-cis-([7-(6-chloro-9H-purin-9-yl)methyl]-2,3-diphenyl-6,7-dihydro-5H-cyclopenta[b]pyrazin-5-yl)methanol, a key intermediate for novel 1'-homocarbanucleosides based on a cyclopenta[b]pyrazine scaffold as shown by its conversion into several 6-substituted purinyl derivatives.

The hemiprotected diols 7 and 8, which are prospective precursors of carbanucleosides of this family, were prepared from the mesylates of the corresponding higher homologues by elimination of the mesyloxy group using 1,8-diazabicyclo[5.4.0]undec-7-ene followed by ozonolysis and reduction of the ozonide with sodium borohydride.

A number of protected 2-substituted 5,6,7,8-tetrahydro-5,8- methanoquinazoline-6,7-diols were prepared by condensation of amidines with (±)-exo,exo-5,6-(isopropylidenedioxy)-3-(pyrrolidinomethylene)bicyclo[2. 2.1]heptan-2-one. Deprotection of the 2-phenyl derivative was followed by its one-pot transformation into a 1:1 mixture of (±)-cis- and (±)-trans-2-phenyl-6,7-dihydro-5H-cyclopenta[d]pyrimidine-5,7-dimethanol by oxidative glycol cleavage and subsequent reduction with sodium borohydride. © Georg Thieme Verlag Stuttgart.

Resumen Se determinó la composición de la microbiota del queso de Aro que se comercializa en el municipio de Teotitlán de Flores Magón, Oaxaca, México. Se cuantificó el contenido de: mesófilos aerobios, psicrófilos, coliformes totales, Escherichia coli, Staphylococcus aureus, Salmonella, Enterococcus, Streptococcus, bacterias ácido lácticas, mohos y levaduras. Los resultados muestran que el queso de Aro contiene microorganismos alterantes, patógenos y de importancia industrial. Ninguna muestra analizada cumple con la NOM-243-SSA1-2010. Por lo tanto, este queso pueden ser un vehículo de transmisión de enfermedades alimentarias, por su elevado contenido de: E. coli, Staphylococcus aureus y Salmonella. La vida de anaquel del queso puede verse afectada provocando pérdidas económicas a los productores. Por otro lado, se pueden obtener microorganismos de importancia industrial (Lactobacillus y Streptococcus). Es necesario implementar sistemas se aseguramiento de la calidad que garanticen la producción de quesos inocuos.

This working document provides a brief description of the sampling, laboratory analysis and estimation procedures conducted by IEO in the VIIIb ICES division to obtain the Spawning Stock Biomass (SSB) estimate for 2014 in this area by the application of the Daily Egg Production Method. The Working Document provides in addition preliminary estimates of all parameters of the DEPM and of SSB.

Informe técnico de las excavaciones y prospecciones arqueológicas en los restos de la Guerra Civil de Belchite y Mediana llevadas a cabo en septiembre de 2014.

Two new 6-aryl-substituted 1′(N)-homocarbanucleosides were prepared by Suzuki-Miyaura reactions of the protected 6-halopurine derivatives with phenylboronic acids. Additionally, 1′(N)-homocarbanucleosides of 6-chloropurine, 2-amino-6-chloropurine and 3-benzoyluracil were prepared by Mitsunobu reaction with a protected diol. From the uracil derivative, the corresponding 5-bromo- and 5-iodouracil compounds were also obtained. © Georg Thieme Verlag Stuttgart.

The asymmetric aza-Diels–Alder reaction of the (1R)-8-phenylmenthyl or (1R)-8-phenylisoneomenthyl glyoxylate-derived N-benzylimine with cyclopentadiene resulted in the enantioselective synthesis of the corresponding pure [(1S,3-exo)-2-benzyl-2-azabicyclo[2.2.1]hept-5-ene]-3-carboxylates (80 or 69% yield, respectively). Reduction of these cycloadducts with LiAlH4 afforded pure (−)-[(1S,3-exo)-2-benzyl-2-azabicyclo[2.2.1]hept-5-en-3-yl]methanol. Furthermore, a reaction sequence based on Barbier–Wieland degradation of both (1S,3-exo)-adducts afforded pure (+)-(1R)-2-benzoyl-2-azabicyclo[2.2.1]heptan-3-one. In the course of the two transformation sequences referred, the chiral auxiliaries were recovered in a virtually quantitative way.

The racemic heterobicyclic amino alcohols 6 and 7, which are of interest as intermediates in the synthesis of nucleoside analogues with heterobicyclic pseudosugars, were efficiently prepared from 2-thienylsuccinic acid via methyl 4-hydroxyimino-5,6-dihydro-4H-cyclopenta[b]thiophene-6-carboxylate [(±)-14]. The target compounds were obtainedtogether by direct reduction of (±)-14 with AlH3 in refluxing THF, and were separated by flash chromatography of their N-acetylated derivatives.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

A series of 1′-homocarbanucleosides was prepared by coupling a purine or pyrimidine to, or constructing it on, a protected 1-methylcyclopenta[c] pyrazole pseudosugar synthesized from (±)-(exo,exo)-1-methyl-4,5,6,7- tetrahydro-4,7-methanoindazole-5,6-diol by oxidative cleavage of the starting glycol, reduction of the resulting dialdehyde with NaBH4, and the protective monosilylation of the bis(hydroxymethyl) reduction product. © Georg Thieme Verlag Stuttgart.

The Diels–Alder reaction of protonated N -benzyl imine of methyl glyoxylate with cyclopentadiene in different solvents gave mixtures of exo / endo adducts. The exo / endo selectivity of the reaction was elucidated by NMR experiments. Theoretical calculations by means of density functional theory (DFT) at the B3LYP/6-31G(d) level have also been performed to elucidate the molecular mechanism of this reaction. The DFT results suggest a highly asynchronous concerted mechanism, which in turn can explain the preferred exo stereoselectivity of the reaction. Inclusion of solvent effects enhances the exo selectivity, and this effect increases with the polarity of the solvent, in good agreement with the experimental findings.

(−)-(1 R ,3 S )-3-Amino-2,2-dimethylcyclobutanecarboxylic acid and (+)-(1 R ,3 S )-3-amino-2,2-dimethylcyclobutylmethanol, which can be used to prepare enantiopure oligopeptides and cyclobutane-based carbocyclic nucleosides, were synthesized from (+)-(1 R )-α-pinene.