Mechanism and Reactivity of Rh-Catalyzed Intermolecular [5+1] Cycloaddition of 3-Acyloxy-1,4-Enyne (ACE) and CO: A Computational Study.

The first theoretical study on the mechanism of [RhCl(CO)2]2-catalyzed [5 + 1] cycloadditions of 3-acyloxy-1,4-enyne (ACE) and CO has been performed using density functional theory (DFT) calculations. The effect of ester on reactivity of this reaction has been investigated. The computational results have revealed that the preferred catalytic cycle involves the sequential steps of 1,2-acyloxy migration, CO insertion, reductive elimination to form ketene intermediate, 6π-electroncyclization, and aromatization to afford the resorcinol product. The 1,2-acyloxy migration is found to be the rate-determining step of the catalytic cycle. The electron-rich p-dimethylaminobenzoate substrate promotes 1,2-acyloxy migration and significantly increases the reactivity by stabilizing the positive charge building up in the oxocyclic transition state.

3-Acyloxy-1,4-enyne: a New Five-carbon Synthon for Rhodium-Catalyzed (5+2) Cycloadditions.

Seven-membered rings are ubiquitous in natural products and pharmaceutical agents and their syntheses continue to stimulate the development of novel synthetic methods. The (5+2) cycloaddition is one of the most efficient ways to access seven-membered rings since the 2-carbon components (alkenes, alkynes, or allenes) are readily available. Prior to our study, however, there was only one type of transition metal-catalyzed (5+2) cycloaddition: the reaction between vinylcyclopropanes and alkenes, alkynes, or allenes. We recently developed a new type of transition metal-catalyzed (5+2) cycloaddition, where the 5-carbon building block is 3-acyloxy-1,4-enyne (ACE). Our recent progress on Rh-catalyzed intra- and intermolecular (5+2) cycloadditions of ACEs and alkynes is summarized in this article. Using chiral propargylic esters, bicyclic products were prepared in high optical purity by the intramolecular (5+2) cycloadditions. Monocyclic seven-membered rings were synthesized by intermolecular (5+2) cycloaddition of ACEs and alkynes. Kinetic studies indicated that the rate of this intermolecular cycloaddition was significantly accelerated when the acetate was replaced by dimethylaminobenzoate. DFT calculations suggested that novel metallacycles were generated by a Rh-promoted oxidative cycloaddition of 1,4-enynes accompanied by a 1,2-acyloxy migration of propargylic esters.

Synthesis of Naturally Occurring Tropones and Tropolones.

Tropones and tropolones are an important class of seven-membered non-benzenoid aromatic compounds. They can be prepared directly by oxidation of seven-membered rings. They can also be derived from cyclization or cycloaddition of appropriate precursors followed by elimination or rearrangement. This review discusses the types of naturally occurring tropones and tropolones and outlines important methods developed for the synthesis of tropone and tropolone natural products.

Arthroplasty infection by Priopionibacterium granulosum treated with reimplantation despite ongoing purulent-appearing fluid collection.

We present the first case of infection in a native or prosthetic joint by Propionibacterium granulosum in which a patient developed symptoms of prosthetic hip infection 5 years after primary surgery. The patient required multiple operative debridements to eradicate the infection and was successfully reimplanted despite an ongoing purulent-appearing, although sterile, fluid collection at the time of reimplantation. There is no clinical or laboratory evidence of infection at 3 years post-reimplantation, and the patient has a well-functioning total hip arthroplasty. P granulosum is a low-virulence but highly-inflammatory organism. It seems to produce a large fluid collection that may require multiple debridements. To our knowledge, there are no reported cases of native or prosthetic joint infection from P granulosum. We present the first case here.

Rhodium-catalyzed acyloxy migration of propargylic esters in cycloadditions, inspiration from the recent "gold rush".

Transition metal-catalyzed acyloxy migration of propargylic esters offers versatile entries to allene and vinyl carbene intermediates for various fascinating subsequent transformations. Most π-acidic metals (e.g. gold and platinum) are capable of facilitating these acyloxy migration events. However, very few of these processes involve redox chemistry, which are well-known for most other transition metals such as rhodium. The coupling of acyloxy migration of propargylic esters with oxidative addition, migratory insertion, and reductive elimination may lead to ample new opportunities for the design of new reactions. This tutorial review summarizes recent developments in Rh-catalyzed 1,3- and 1,2-acyloxy migration of propargylic esters in a number of cycloaddition reactions. Related Au- and Pt-catalyzed cycloadditions involving acyloxy migration are also discussed.

Transfer of chirality in the rhodium-catalyzed intramolecular [5+2] cycloaddition of 3-acyloxy-1,4-enynes (ACEs) and alkynes: synthesis of enantioenriched bicyclo[5.3.0]decatrienes.

Chiral bicycles: Enantioenriched bicyclo[5.3.0]decatrienes were prepared from readily available chiral 3-acyloxy-1,4-enynes (ACEs) for the first time. In most cases, the chirality of the ACEs could be transferred to the bicyclic products with high efficiency. Inversion of the configuration was observed, thus confirming the predictions of previous computational studies.

Rhodium-catalyzed intra- and intermolecular [5 + 2] cycloaddition of 3-acyloxy-1,4-enyne and alkyne with concomitant 1,2-acyloxy migration.

A new type of rhodium-catalyzed [5 + 2] cycloaddition was developed for the synthesis of seven-membered rings with diverse functionalities. The ring formation was accompanied by a 1,2-acyloxy migration event. The five- and two-carbon components of the cycloaddition are 3-acyloxy-1,4-enynes (ACEs) and alkynes, respectively. Cationic rhodium(I) catalysts worked most efficiently for the intramolecular cycloaddition, while only neutral rhodium(I) complexes could facilitate the intermolecular reaction. In both cases, electron-poor phosphite or phosphine ligands often improved the efficiency of the cycloadditions. The scope of ACEs and alkynes was investigated in both the intra- and intermolecular reactions. The resulting seven-membered-ring products have three double bonds that could be selectively functionalized.

Catalytic enantioselective halolactonization of enynes and alkenes.

New organocatalysts have been developed for the enantioselective halolactonization of (Z)-1,3-enynes and 1,1-disubstituted alkenes. In the case of 1,3-enynes, the carboxylate nucleophile and halogen electrophile were added to the conjugated π-system from the same face. Up to 99% ee was achieved for the 1,4-syn-bromolactonization of conjugated (Z)-1,3-enynes. Based on the results from the enyne halolactonization, a second generation of catalysts was designed for simple olefins. Up to 91% ee was observed for chlorolactonization of 1,1-disubstituted alkenes. The catalysts developed for the enantioselective halolactonization of both enynes and alkenes are composed of a cinchona alkaloid skeleton tethered to a urea group.

Local treatment of malignant gliomas by direct infusion of specific monoclonal antibodies labeled with 131I: comparison of the results obtained in recurrent and newly diagnosed tumors.

Two murine monoclonal antibodies, BC-2 and BC-4, raised against tenascin and labeled with 131I were infused locally in the site of neoplastic disease by means of a removable (16 patients) or indwelling (34 patients) catheter. Fifty patients bearing a malignant glioma were treated. Twenty-six of these were suffering from recurrent disease; their tumors relapsed within 9 months (median) after treatment. The remaining 24 cases had a newly diagnosed tumor, and local radioimmunotherapy (RIT) was given immediately after surgery and radiochemotherapy. All efforts were made to reduce the tumor before the infusion of the radiopharmaceutical. Therefore, 22 cases with relapsing glioma underwent additional debulking surgery, which led to total or subtotal removal of tumor in 9 of the patients. Altogether, 28 patients had intralesional RIT when the disease was minimal or microscopic. Conversely, 22 cases underwent local RIT with a tumor the diameter of which was > 2 cm. In many cases, the infusions were repeated up to six times to achieve complete destruction of the neoplastic tissue. The local treatment did not give rise to systemic or to cerebral adverse effects. The labeled monoclonal antibodies, given directly in the site of the lesion, concentrated in very high amount in the neoplastic tissue and remained fixed in the target for a long period of time. For these reasons, the radiation dose to the tumor was remarkable (on average > 30,000 cGy/cycle) and consequently led to promising results. The median survival was, in total, 20 months (18 in recurrent tumors and 23 in newly diagnosed lesions). Moreover, median survival was 17 months in patients with bulky tumors (both recurrent and newly diagnosed tumors) and 26 months in patients with minimal or microscopic disease. The median time to progression was 3 months in recurrent and 7 months in newly diagnosed gliomas. Finally, RIT produced 3 CRs (all in recurrent tumors), 6 PRs (4 in recurrent and 2 in newly diagnosed), and 11 stabilizations of disease (4 in recurrent and 7 in newly diagnosed). In 19 cases (13 recurrent and 6 newly diagnosed) the progression of tumor was recorded. Eleven patients (2 recurrent and 9 newly diagnosed) who were treated by RIT when their disease was minimal and nondetectable by radiological methods remained disease-free and were classified as NED. The overall response rate (NED plus CR plus PR) was 40% (34.6% recurrent and 45.8% newly diagnosed).(ABSTRACT TRUNCATED AT 400 WORDS)

Loco-regional radioimmunotherapy of high-grade malignant gliomas using specific monoclonal antibodies labeled with 90Y: a phase I study.

A Phase I radioimmunotherapy trial was conducted in which radioconjugated monoclonal antibody (MAb) was directly infused into the tumor or postoperative tumoral bed in patients with high-grade malignant glioma. BC-4, a murine MAb that recognizes tenascin, was used in these studies. The MAb was labeled with 90Y, a pure beta emitter with maximum energy of 2.284 MeV, which can penetrate into tissue up to 0.5-0.7 cm. Stable 90Y-labeled MAb conjugates were prepared using the chelator p-isothiocyanatobenzyl derivative of diethylenetriaminepentaacetic acid (ITC-Bz-DTPA), obtaining >95% labeling efficiency and conserving the antibodies' immunoreactivity (>85%). Twenty patients, 2 with anaplastic astrocytoma and 18 with glioblastoma, were included in the study. All of the patients had been treated previously with conventional therapies (surgery, external radiotherapy, and chemotherapy) and presented with progressive disease not amenable to further treatment. A dose-escalation study was performed using doses ranging from 5-30 mCi (185-1110 MBq) of 90Y-labeled MAb BC-4. The protein dose of MAb was always 1 mg. Three patients were treated at the 5, 10, 15, and 20 mCi levels, and the 25- and 30-mCi doses were each administered to 4 patients. Systemic toxicity was completely absent in all of the patients. The maximum tolerated dose to the brain was 25 mCi (925 MBq). The average dose to the tumor was 3200 cGy/mCi. Doses to the liver, bone marrow, and kidneys were below 10 cGy/mCi in all of the cases. Biodistribution studies demonstrated that the 90Y-labeled MAb accreted exclusively in the neoplastic area without any diffusion into the normal brain or other normal organs. No clinical responses were recorded because of the very advanced stage of disease at the time of radioimmunotherapy.

Rhodium-Catalyzed Intermolecular [5+1] and [5+2] Cycloadditions Using 1,4-Enynes with an Electron-Donating Ester on the 3-Position.

Various 3-acyloxy-1,4-enynes could be employed in rhodium-catalyzed intermolecular [5+1] and [5+2] cycloadditions with CO or alkynes, respectively. The rate of these cycloadditions could be accelerated significantly by using 1,4-enynes with an electron-donating ester on the 3-position. The scope of rhodium-catalyzed [5+1] and [5+2] cycloadditions were examined by using 1,4-enynes bearing an electron-donating ester.

Rhodium-Catalyzed Stereoselective Intramolecular [5 + 2] Cycloaddition of 3-Acyloxy 1,4-Enyne and Alkene.

The first rhodium-catalyzed intramolecular [5 + 2] cycloaddition of 3-acyloxy 1,4-enyne and alkene was developed. The cycloaddition is highly diastereoselective in most cases. Various cis-fused bicyclo[5.3.0]decadienes were prepared stereoselectively. The chirality in the propargylic ester starting materials could be transferred to the bicyclic products with high efficiency. Electron-deficient phosphine ligand greatly facilitated the cycloaddition. Up to three new stereogenic centers could be generated. The resulting diene in the products could be hydrolyzed to enones, which allowed the introduction of more functional groups to the seven-membered ring.

Radioimmunotherapy of gastrointestinal cancer and glioblastomas.

Two groups of patients with gastro-intestinal (GI) tumours (41) and recurrent glioblastoma (GBM), (17) underwent radioimmunotherapy after the failure of traditional treatments. A number of different MAbs were employed (anti-CEA and anti-Tenascin) which were labelled with I-131. The radiopharmaceuticals were administered by the intraperitoneal and intratumoral routes. As a rule the cycles were repeated to enhance the effectiveness of RIT. No significant early or late adverse effects were recorded. HAMA development was observed in all GI cases but only in a few GBM patients. The cumulative dose delivered to the target tumors was considerable (mean 8,900 cGy) in the GI group, and was much higher in the GBM patients (mean 51,700 cGy) owing to the particular modality of injection. Survival improved in both series of patients. The objective responses to RIT were promising: in the GI group 10 complete remissions (CR) and 6 partial remissions (PR) were observed, while in the GBM group 3 long-lasting CRs and 3 prolonged PRs were documented.

Is carbohydrates-deficient transferrin the best test of the alcoholic etiology in acute pancreatitis?

AIM: To demonstrate if carbohydrates deficient transferrin (CDT) is the best marker to detect an excessive alcohol consumption as a cause of acute pancreatitis. MATERIAL AND METHODS: Prospective study of 60 patients consecutively admitted in our hospital. Acute pancreatitis were classified according to their different etiologies, alcoholic (11), probably alcoholic (4), biliary (25) and others (20). In all cases, we have compared CDT with classical quemical markers of alcohol abuse such as mean corpuscular volumen (MCV), gamma-glutamyltransferase (GGT) and aspartateaminotransferase (AST). Statistic correlations were done between the quantity of alcohol consumed and CDT, GGT, AST and MCV variables. RESULTS: Correlation between CDT and MCV with the excessive alcohol consumption was statistically significant. The acute pancreatitis caused by alcohol and the suspicious alcoholic group had a average CDT higher than the rest of the groups (p < 0.05). Taking a cut point with a CDT value of 20, the diagnosis capacity of the test to detect the alcoholic etiology was 82 and 92% of specificity. Taking a cut point with a MCV value higher than 95, sensibility was 67% and specificity was 82%. CONCLUSION: In our experience, the most efficient marker of the alcoholic etiology in acute pancreatitis was CDT.

[Virology, diagnostic tests, epidemiology and transmission mechanisms of hepatitis C virus infection]. / Virología, pruebas diagnósticas, epidemiología y mecanismos de transmisión del VHC.

The hepatitis C virus is a human virus, classified within a third type (Hepacivirus) of the Flaviviridae family. It is a spherical virus, of approximately 50 nm in diameter, with a glycoprotein covering that contains lipids, and its genome is a simple chain RNA molecule. It is characterised by a high degree of genomic heterogeneity, whose evolutionary consequence in the long term is the appearance of genetically different viral groups, genotypes and quasispecies. There are different diagnostic techniques for detecting hepatitis C virus infection. Serological assays: the detection of specific IgG against HCV by means of enzyme immunoassays is the most practical method for diagnosing infection by this virus. Supplementary immunblot tests are employed to confirm the specificity of the results of the EIA test. Molecular assays: qualitative and quantitative techniques have been developed for detecting RNA-HCV, based on the direct detection of the virions. The pathogeny of hepatitis C is not well understood. Its world prevalence is estimated at some 3%, which is why routine screening for its detection is not recommended. HCV transmission basically occurs through percutaneous exposure to infected blood, with higher rates observed in imprisoned persons, vagabonds, intravenous drug addicts, haemophiliacs and patients on haemodialysis. Although it can be transmitted sexually, it seems that this path is not very efficient, with a greater prevalence observed in persons with multiple sexual partners. Vertical transmission is estimated at some 2%, reaching 20% in cases of maternal coinfection with HIV.

[Azathioprine-induced hepatotoxicity in a patient with Crohn's disease]. / Hepatotoxicidad inducida por azatioprina en paciente con enfermedad de Crohn.

Immunosuppressive drugs are among the pharmacological groups with the most theoretical potential to induce adverse reactions, including hepatic reactions. We report the case of a 35-year-old patient with Crohn's disease treated with azathioprine for steroid dependence which, after a hepatic biopsy, was diagnosed with nodular regenerative hyperplasia secondary to this treatment.

Effect of ester on rhodium-catalyzed intermolecular [5+2] cycloaddition of 3-acyloxy-1,4-enynes and alkynes.

We systematically examined the effect of different esters on the rhodium-catalyzed intermolecular [5+2] cycloaddition of 3-acyloxy-1,4-enynes and alkynes with a concomitant 1,2-acyloxy migration. Significant rate acceleration was observed for benzoate substrates bearing an electron-donating substituent. The cycloaddition can now be conducted under much more practical conditions for most terminal alkynes.

Quantitative evaluation on [9°Y] DOTATOC PET and SPECT imaging by phantom acquisitions and clinical applications in locoregional and systemic treatments.

AIM: The aim of this paper was to compare [9°Y]-PET and SPECT imaging quantification for dosimetric applications in targeted radionuclide therapy. METHODS: Imaging studies were carried out by SPECT-CT and PET equipment performing phantom tests first. [9°Y]-SPECT and PET scans were compared in terms of sensitivity, minimum detectable activity concentration, recovery coefficients (RCs) and system spatial resolution (FWHM). Quantitative evaluations by PET and SPECT acquisitions were then assessed in patients who received therapeutic activity of [9°Y]-DOTATOC directly injected into the surgical cavity by locoregional route in glioma treatment and by systemic route in neuroendocrine tumour patients who underwent intravenous infusion. Finally 3D-dose distributions by SPECT and PET images were obtained. RESULTS: Sensitivity was proven to be about fivefold higher for SPECT than for PET. To obtain a good-quality PET imaging, the minimum detectable activity concentration was determined to be equal to 1 MBq/mL compared with 0.05 MBq/mL that was sufficient to assess adequate SPECT imaging. RCs were 100% for volume ≥ 25.5 mL for PET and ≥ 110 mL for SPECT. FWHM was 7 mm for PET and 19 mm for SPECT scans. With regard to locoregional therapy, excellent imaging was obtained with both PET and SPECT. On the contrary, systemic administration did not permit us to obtain suitable PET imaging. PET and SPECT images were affected by considerable noise, whose influence is much more important in the quantitative evaluation of dose volume histograms rather than in the visual interpretation of images. CONCLUSION: [9°Y]-activity quantification is feasible by SPECT and PET imaging. For clinical applications, SPECT-CT is the best technique for visualizing the radiopharmaceuticals following systemic infusion, while both SPECT and PET scans are effective in analyzing locoregional distribution. Nevertheless PET study demonstrates the best spatial definition.

Rhodium-catalyzed carbonylation of 3-acyloxy-1,4-enynes for the synthesis of cyclopentenones.

Functionalized cyclopentenones were synthesized by a Rh-catalyzed carbonylation of 3-acyloxy-1,4-enynes, derived from alkynes and α,ß-unsaturated aldehydes. The reaction involved a Saucy-Marbet 1,3-acyloxy migration of propargyl esters and a [4 + 1] cycloaddition of the resulting acyloxy substituted vinylallene with CO.

Asymmetric aza-[3+3] annulation in the synthesis of indolizidines: an unexpected reversal of regiochemistry.

An enantioselective and diastereoselective aza-[3+3] annulation of pyrrolidine-based exo-cyclic vinylogous amides and urethanes with chiral vinyl iminium salts is described. This asymmetric annulation manifold is possible because of an unexpected regiochemical reversal whereby head-to-tail annulations dominated over the predicted head-to-head. It should find prevalent synthetic applications in the enantioselective synthesis of indolizidines.