A route to benzodithiophene systems by exploiting a ligand-free Suzuki-Miyaura coupling reaction in deep eutectic solvents

Benzo[1,2-b:4,3-b\u2019]dithiophene (BDT) and its derivatives belong to an interesting class of thiophene-based aromatic \uf070-conjugated compounds that are widely studied as functional organic materials inserted, for instance, as units in mono and polydisperse oligomers [1], or as \uf070-spacers in push-pull organic chromophores for photovoltaic applications [2]. Moreover, BDTs are key intermediates for the synthesis of inherent chiral tetrathia[7]helicenes, which are an attractive class of heterohelicenes with unique physicochemical and chiroptical properties due to their helix-like structure [3]. Thus, BDT is a key starting molecule which can allow access to more complex and interesting systems through a selective and judicious functionalization of the \uf061 and \uf062-positions of the terminal thiophene rings. Building on our recent studies on the synthesis and functionalization of BDTs [4], we questioned whether a novel class of 2,7-diarylsubstituted BDTs 1 (Figure 1) could be synthesized via a palladium-catalysed Suzuki-Miyaura reaction between heteroaryl halides 2 and organoboron derivatives 3 in Deep Eutectic Solvents (DESs), which have proven to be effective as sustainable and environmentally responsible reaction media in several transition-metal-catalyzed reactions [5].In this communication, we report our preliminary results on the preparation of diarylsubstituted BDTs 1, and discuss the substrate scope of the proposed protocol. Some of the compounds so far obtained display interesting photophysical properties, which are currently under investigation

Document Recognition for a Million Books

National Science Foundation and the Institute for Museum and Library Service

Angiotensin-(1–7) infusion is associated with increased blood pressure and adverse cardiac remodelling in rats with subtotal nephrectomy

ACE (angiotensin-converting enzyme) 2 is expressed in the heart and kidney and metabolizes Ang (angiotensin) II to Ang-(1–7) a peptide that acts via the Ang-(1–7) or mas receptor. The aim of the present study was to assess the effect of Ang-(1–7) on blood pressure and cardiac remodelling in a rat model of renal mass ablation. Male SD (Sprague–Dawley) rats underwent STNx (subtotal nephrectomy) and were treated for 10 days with vehicle, the ACE inhibitor ramipril (oral 1 mg·kg−1 of body weight·day−1) or Ang-(1–7) (subcutaneous 24 μg·kg−1 of body weight·h−1) (all n = 15 per group). A control group (n = 10) of sham-operated rats were also studied. STNx rats were hypertensive (P<0.01) with renal impairment (P<0.001), cardiac hypertrophy (P<0.001) and fibrosis (P<0.05), and increased cardiac ACE (P<0.001) and ACE2 activity (P<0.05). Ramipril reduced blood pressure (P<0.01), improved cardiac hypertrophy (P<0.001) and inhibited cardiac ACE (P<0.001). By contrast, Ang-(1–7) infusion in STNx was associated with further increases in blood pressure (P<0.05), cardiac hypertrophy (P<0.05) and fibrosis (P<0.01). Ang-(1–7) infusion also increased cardiac ACE activity (P<0.001) and reduced cardiac ACE2 activity (P<0.05) compared with STNx-vehicle rats. Our results add to the increasing evidence that Ang-(1–7) may have deleterious cardiovascular effects in kidney failure and highlight the need for further in vivo studies of the ACE2/Ang-(1–7)/mas receptor axis in kidney disease

Increased Urinary Angiotensin-Converting Enzyme 2 in Renal Transplant Patients with Diabetes

Angiotensin-converting enzyme 2 (ACE2) is expressed in the kidney and may be a renoprotective enzyme, since it converts angiotensin (Ang) II to Ang-(1-7). ACE2 has been detected in urine from patients with chronic kidney disease. We measured urinary ACE2 activity and protein levels in renal transplant patients (age 54 yrs, 65% male, 38% diabetes, n = 100) and healthy controls (age 45 yrs, 26% male, n = 50), and determined factors associated with elevated urinary ACE2 in the patients. Urine from transplant subjects was also assayed for ACE mRNA and protein. No subjects were taking inhibitors of the renin-angiotensin system. Urinary ACE2 levels were significantly higher in transplant patients compared to controls (p = 0.003 for ACE2 activity, and p≤0.001 for ACE2 protein by ELISA or western analysis). Transplant patients with diabetes mellitus had significantly increased urinary ACE2 activity and protein levels compared to non-diabetics (p<0.001), while ACE2 mRNA levels did not differ. Urinary ACE activity and protein were significantly increased in diabetic transplant subjects, while ACE mRNA levels did not differ from non-diabetic subjects. After adjusting for confounding variables, diabetes was significantly associated with urinary ACE2 activity (p = 0.003) and protein levels (p<0.001), while female gender was associated with urinary mRNA levels for both ACE2 and ACE. These data indicate that urinary ACE2 is increased in renal transplant recipients with diabetes, possibly due to increased shedding from tubular cells. Urinary ACE2 could be a marker of renal renin-angiotensin system activation in these patients

Ligand-Free Cobalt-Catalyzed Cross-Coupling Reaction Between Organoaluminum Reagents and (Hetero)Aryl and Alkyl Bromides

Transition-metal catalyzed cross-coupling reactions are some of the most important C−C bond-forming protocols and have been widely applied both in academic research and in industry. Since the discovery of cross-coupling reactions in the early 1970’s, a great number of catalytic systems using organoboron, organotin, organosilicon, organozinc or organozirconium, and organomagnesium as coupling reagents have been developed. In contrast, coupling reactions employing organoaluminum reagents are very rare. These reagents exhibited high chemoselectivity and good compatibility of functional groups in C−C bond formation reactions. Moreover, aluminum exhibits low toxicity and is one of the most inexpensive and earth-abundant metals. As part of our current research interest in developing new catalytic synthetic methodologies, in this communication we report a very general, cobalt catalyzed cross coupling reaction between alkyland aryl-aluminum compounds with alkyl- and (hetero)aryl bromides, affording the C(sp2)−C(sp2) and C(sp3)−C(sp2) cross-coupled products in good to excellent yields. Catalyzed by the cheap and commercially available CoCl2, without external ligands or bases, the reactions proceed smoothly with a wide range of substituted bromides, decorated by electrodonating and electro-withdrawing group, providing a versatile methodology for cobalt-mediated cross-coupling processes

Recent advances in metal-, organo-, and biocatalyzed one-pot tandem reactions under environmentally responsible conditions

Because of their handedness and wide scope, transitionmetal-, organo-, and biocatalyzed tandem processes have become routine and highly sought-after methodologies because they dramatically increase synthetic efficiency, while decreasing the number of laboratory operations, the quantities of chemicals and solvents used, producing in a simpler way highly complex organic molecules with the desired selectivity. In this current opinion, recent examples of the use of metal-, organo-, and biocatalyzed tandem processes run under environmentally responsible conditions (e.g., use of water, biobased solvents, or without additional solvents) are showcased, highlighting practical and valuable aspects

Reazioni Mediate e Catalizzate Da Metalli In Solventi Non Convenzionali: Aspetti Sintetici e Meccanicistici

Green chemistry integrates environmentally safe and sustainable technologies for chemical research and production. Classical synthetic protocols, even with widespread applicability, have various drawbacks due to the use of harsh conditions, long reaction times, and the generation of large amounts of waste. Over the past few years, our research group has been focusing on the development of methodologies with a low ecological footprint using the so-called Deep Eutectic Solvents (DESs) and water as environmentally responsible reaction media and catalysts, thereby reshaping several organic transformations, which are traditionally carried out using toxic and often harmful petroleum-based volatile organic compounds. In this context, metal-mediated and metal-catalysed organic reactions have been successfully accomplished in the aforementioned reaction media under mild conditions and under airLa chimica verde comprende tecnologie sostenibili e sicure per l’ambiente, la ricerca e la produzione chimica industriale. I protocolli sintetici classici, presentano vari inconvenienti dovuti all’uso di condizioni di reazione drastiche, tempi lunghi e produzione di grandi quantità di rifiuti. Negli ultimi anni, il nostro gruppo di ricerca si è concentrato sullo sviluppo di metodologie a basso impatto ambientale, basate sull’utilizzo di acqua o miscele eutettiche a basso punto di fusione sia come mezzi di reazione che come catalizzatori. In questo contesto, reazioni organiche mediate e catalizzate da metalli sono state realizzate con successo nei suddetti mezzi in condizioni blande, all’aria e in tempi brev