Scintillator ageing of the T2K near detectors from 2010 to 2021

The T2K experiment widely uses plastic scintillator as a target for neutrino interactions and an active medium for the measurement of charged particles produced in neutrino interactions at its near detector complex. Over 10 years of operation the measured light yield recorded by the scintillator based subsystems has been observed to degrade by 0.9–2.2% per year. Extrapolation of the degradation rate through to 2040 indicates the recorded light yield should remain above the lower threshold used by the current reconstruction algorithms for all subsystems. This will allow the near detectors to continue contributing to important physics measurements during the T2K-II and Hyper-Kamiokande eras. Additionally, work to disentangle the degradation of the plastic scintillator and wavelength shifting fibres shows that the reduction in light yield can be attributed to the ageing of the plastic scintillator. The long component of the attenuation length of the wavelength shifting fibres was observed to degrade by 1.3–5.4% per year, while the short component of the attenuation length did not show any conclusive degradation

8a-Methyl-5,6,8,8a,9,10-hexa-hydro-10,12a-epoxy-isoindolo[1,2-a] isoquinolinium iodide

The title compound, C17H18NO+· I-, is an adduct resulting from an intra-molecular Diels-Alder reaction of methallyl chloride with 3,4-dihydro-1-furylisoquinoline. The cation comprises a fused penta-cyclic system containing three five-membered rings (dihydro-pyrrole, dihydro-furan and tetra-hydro-furan) and two six-membered rings (tetra-hydro-pyridine and benzene). The five-membered rings have the usual envelope conformations, and the central six-membered tetra-hydro-pyridine ring adopts the unsymmetrical half-boat conformation. In the crystal, cations and iodide anions are bound by weak inter-molecular hydrogen-bonding inter-actions into a three-dimensional framework

8a-Methyl-5,6,8,8a,9,10-hexa-hydro-10,12a-epoxy-isoindolo[1,2-a] isoquinolinium iodide

The title compound, C17H18NO+· I-, is an adduct resulting from an intra-molecular Diels-Alder reaction of methallyl chloride with 3,4-dihydro-1-furylisoquinoline. The cation comprises a fused penta-cyclic system containing three five-membered rings (dihydro-pyrrole, dihydro-furan and tetra-hydro-furan) and two six-membered rings (tetra-hydro-pyridine and benzene). The five-membered rings have the usual envelope conformations, and the central six-membered tetra-hydro-pyridine ring adopts the unsymmetrical half-boat conformation. In the crystal, cations and iodide anions are bound by weak inter-molecular hydrogen-bonding inter-actions into a three-dimensional framework

Aromatization of IMDAF adducts in aqueous alkaline media

In this paper, we propose a simple synthesis of isoindoline-4-carboxylic acids by means of the aromatization of 3a,6-epoxyisoindoles in alkaline media. The method is facile from an experimental point of view: a short-term (0.5-2h) reflux of epoxyisoindoles in 5% aqueous solutions of alkali leads to the target products in 40-90% yields. The absence of by-products, ease of isolation of the target products and applicability to acidophobic group bearing substrates favorably distinguishes the proposed procedure from previously utilized acid-catalyzed methods. The proposed strategy has been successfully utilized for isoindole containing compounds and nuevamine-type alkaloids. © The Royal Society of Chemistry 2012

Aromatization of IMDAF adducts in aqueous alkaline media

In this paper, we propose a simple synthesis of isoindoline-4-carboxylic acids by means of the aromatization of 3a,6-epoxyisoindoles in alkaline media. The method is facile from an experimental point of view: a short-term (0.5-2h) reflux of epoxyisoindoles in 5% aqueous solutions of alkali leads to the target products in 40-90% yields. The absence of by-products, ease of isolation of the target products and applicability to acidophobic group bearing substrates favorably distinguishes the proposed procedure from previously utilized acid-catalyzed methods. The proposed strategy has been successfully utilized for isoindole containing compounds and nuevamine-type alkaloids. © The Royal Society of Chemistry 2012

The first example of an intramolecular Diels-Alder furan (IMDAF) reaction of iminium salts and its application in a short and simple synthesis of the isoindolo[1, 2-a]isoquinoline core of the jamtine and hirsutine alkaloids

1-(2-Furyl)-3, 4-dihydroisoquinolines, easily prepared from readily available phenethylamines undergo tandem alkylation/[4+2]-cycloaddition with allyl halides. The reaction proceeds via 2-allyl-1-furyl-3, 4- dihydroisoquinolinium salt formation and subsequent intramolecular exo-Diels-Alder reaction of furan with the allyl fragment (IMDAF reaction). The adducts formed include the basic structural element of the isoindolo[1, 2-a]isoquinoline alkaloids jamtine and hirsutine. © 2010 Elsevier Ltd. All rights reserved

The first example of an intramolecular Diels-Alder furan (IMDAF) reaction of iminium salts and its application in a short and simple synthesis of the isoindolo[1, 2-a]isoquinoline core of the jamtine and hirsutine alkaloids

1-(2-Furyl)-3, 4-dihydroisoquinolines, easily prepared from readily available phenethylamines undergo tandem alkylation/[4+2]-cycloaddition with allyl halides. The reaction proceeds via 2-allyl-1-furyl-3, 4- dihydroisoquinolinium salt formation and subsequent intramolecular exo-Diels-Alder reaction of furan with the allyl fragment (IMDAF reaction). The adducts formed include the basic structural element of the isoindolo[1, 2-a]isoquinoline alkaloids jamtine and hirsutine. © 2010 Elsevier Ltd. All rights reserved

A new approach to construction of isoindolo[1,2-a]isoquinoline alkaloids Nuevamine, Jamtine, and Hirsutine via IMDAF reaction

The interaction between 1-furyl-1,2,3,4-tetrahydroisoquinolines and unsaturated acids derivatives (acryloyl, methacryloyl, and crotonoyl chloride, maleic and citraconic anhydride) was studied. It was shown that the reaction proceeds via amide formation and subsequent intramolecular Diels-Alder reaction of the furan (IMDAF). The [4+2] cycloaddition proceeded under mild reaction conditions (25-80 °C) and afforded only the exo-adduct in a high yield. With this method, a new approach to the isoindolo[1,2-a]isoquinoline system, the basic structural element of alkaloids Jamtine, Hirsutine, and Nuevamine, is proposed. © 2009 Elsevier Ltd. All rights reserved

A new approach to construction of isoindolo[1,2-a]isoquinoline alkaloids Nuevamine, Jamtine, and Hirsutine via IMDAF reaction

The interaction between 1-furyl-1,2,3,4-tetrahydroisoquinolines and unsaturated acids derivatives (acryloyl, methacryloyl, and crotonoyl chloride, maleic and citraconic anhydride) was studied. It was shown that the reaction proceeds via amide formation and subsequent intramolecular Diels-Alder reaction of the furan (IMDAF). The [4+2] cycloaddition proceeded under mild reaction conditions (25-80 °C) and afforded only the exo-adduct in a high yield. With this method, a new approach to the isoindolo[1,2-a]isoquinoline system, the basic structural element of alkaloids Jamtine, Hirsutine, and Nuevamine, is proposed. © 2009 Elsevier Ltd. All rights reserved