1,2-Oxopalladation versus pi-allyl palladium route. A regioconvergent approach to a key intermediate for cyclopentanoids synthesis. New insights into the Pd(II)-catalyzed lactonization reaction

Regioconvergent synthesis of the key lactone 1 from an equimolar mixture of the two olefins 4 and 5 was achieved by unique Pd(II) chemistry. The synthetic versatility of lactone 1 has been demonstrated in the synthesis of iridoids and of the endo-Corey lactone 2, which is a key intermediate for the F(2)-isoprostane synthesis. Upon exposure of the sodium salts of 4 and 5 to a catalytic amount of Pd(OAc)(2) under oxygen, in the presence of AcOH, an isomeric lactone 12 was obtained in addition to the title compound 1. The Pd(II) lactonization was optimized by fine-tuning all the factors participating in the catalytic cycle: solvent, oxidant, co-oxidant, and Pd(II) source. The Hosokawa's heterobimetallic couple emerged as the catalyst of choice. With a Cu(II)-Pd(II) couple, the redox process was transferred to copper, and the formal oxidation state of palladium remained constant during the reaction. By virtue of this new methodology, lactone 1 was obtained in a rewarding 60% yield, along with isomeric lactone 12 in 30% yield. A detailed mechanistic study was carried out in order to elucidate the formation of lactones 1 and 12. Lactone 1 was formed from either olefin 8 or olefin 10; on the other hand, lactone 12 was formed exclusively from olefin 10. An intramolecular 1,2-acyloxypalladiation was invoked for the transformation of 8 into 1, whereas the pi-allyl complexes 13 and 11 were involved in the transformation of olefin 10 into 12 and 1, respectively.     

High-density lipoproteins contribute to the alpha-1-globulin zone in capillary electrophoresis of human serum proteins

Alpha-1-antitrypsin (AAT) and alpha-1-acid glycoprotein (AAG) are reported to be the main proteins contributing to the alpha-1-globulin capillary zone electrophoresis (CZE) zone, but the sum (AAT + AAG) showed lower than the alpha-1-globulin. We investigated the role of high-density lipoprotein (HDL), an additional protein migrating in the alpha-1-globulin zone, as a possible cause for such a gap. In a set of 98 sera we measured the alpha-1-globulin with a dedicated clinical capillary electrophoresis system, and AAT, AAG and apolipoprotein A-1 (ApoA) by immunonephelometry. The alpha-1-globulin were consistently higher than the sum (AAT + AAG), by (mean value +/- standard deviation) 1.70 +/- 0.88 g/L in 49 sera with low ApoA, and by 3.59 +/- 0.75 g/L in 49 sera with high ApoA. Corresponding figures in the comparison alpha-1-globulin/(AAT + AAG + ApoA) were reduced to 1.08 +/- 0.77 g/L and 1.67 +/- 0.70 g/L. It is concluded that HDL significantly contribute to the CZE alpha-1-globulin zone, but do not completely explain the differences between the electrophoretic and the immunochemical measurements. However, CZE alpha-1-globulin measurements give information about increases of the two major acute phase proteins comparable to specific protein measurements.     

On tides in the strait of Messina

Summary A classical measurement of tides in the Messina strait made by Vercelli (1922–1923) is described. As Defant studied the same data with a linear barotropic model, a baroclinic, nonlinear theory is discussed. Some model equations are then discussed.

---

Riassunto Si discutono le classiche misure di Vercelli (1922–1923) di maree nello Stretto di Messina. Dato che queste misure furono studiate da Defant con un modello baroclinico, noi possiamo sottolineare aspetti teorici non lineari riguardanti proprietà barocliniche. Si discutono anche modelli teorici.

---

Резюме Описывается классическое измерение приливов в Мессинском проливе, проведенное Верчелли в 1922–23 г.г. Так как Дефан исследовал те же данные с помощяю линейной баротропной могели, то обсуждается бароклинная нелинейная теория. Затем обсуждаются некоторые моделые уравнения.

---

---

Work supported by a CNR grant, Progetto Finalizzato Oceanografia.     

Identification of Structure–Activity Relationships from Screening a Structurally Compact DNA‐Encoded Chemical Library

Methods for the rapid and inexpensive discovery of hit compounds are essential for pharmaceutical research and DNA‐encoded chemical libraries represent promising tools for this purpose. We here report on the design and synthesis of DAL‐100K, a DNA‐encoded chemical library containing 103 200 structurally compact compounds. Affinity screening experiments and DNA‐sequencing analysis provided ligands with nanomolar affinities to several proteins, including prostate‐specific membrane antigen and tankyrase 1. Correlations of sequence counts with binding affinities and potencies of enzyme inhibition were observed and enabled the identification of structural features critical for activity. These results indicate that libraries of this type represent a useful source of small‐molecule binders for target proteins of pharmaceutical interest and information on structural features important for binding.     

On the currents in the Messina Strait linear and nonlinear tidal components on the sill

Summary A harmonic analysis of the longitudinal component of the sea current velocity (collected by Vercelli at the narrowest section of the Strait of Messina during the years 1922–23) has been performed. By the synthesis of various tidal frequencies the least-square fitting gave a functionF(t) in fairly good agreement with the experimental curvef(t). The average error is 10%. The results have evidenced the importance of the nonlinear tidal components in the water circulation within the Strait of Messina.

---

Riassunto è stata effettuata una dettagliata analisi armonica sui dati relativi alla componente longitudinale della velocità della corrente marina (le misure sono state eseguite da Vercelli nella sezione più piccola dello stretto di Messina negli anni 1922–23). Attraverso la sintesi di varie frequenze mareali ed utilizzando il metodo dei minimi quadrati si è ottenuta una funzione ?teorica?F(t) in buon accordo con la curva sperimentalef(t) ricavata dai dati sperimentali raccoltiin situ. L'errore medio è del 10%. I risultati di questa analisi hanno messo in evidenza l'importanza delle componenti non lineari delle onde di marea per lo studio della circolazione marina nello stretto di Messina.

---

Резюме Проводится гармонический анализ продольной компоненты скорости морских течений (данные получены Верчелли вблизи Мессинского пролива в течение 1922–1923 гг.). Используя синтез различных приливных частот, подгонка с помощью метода наименьших квадратов дает функциюF(t), которая довольно хорошо согласуется с экспериментальной кривойf(t). Средняя ошибка составляет 10%. Полученные результаты подтверждают важность нелинейных приливных компонент при циркуляцииводы в Мессинском проливе.

---

---

Work supported by a grant of CNR, Progetto Finalizzato Oceanografia.     

A study of hadronic decays of the ϒ′

We present a detailed study of the decays ?′ → π⁺π^?? and ?′ → π⁰π⁰?, where the ? decays subsequently to e⁺e^? or μ⁺μ^?. The results are obtained from a sample of 146 000 ?′ decays observed with the CUSB detector at the Cornell Electron Storage Ring. We derive branching fractions of (18.9 ± 2.6)% for ?′ → π′π^?? and (10.3 ± 2.3)% for ?′ → π⁰π⁰?, and determined partial widths for these decays. Invariant mass and angular distributions of both the π⁺π^? and π⁰π⁰ systems are presented. We also set a limit on the branching fraction for ?′ → η? of less than 0.2% at the 90% confidence level.