نتایج جستجو برای: boron trifluoride etherate
تعداد نتایج: 18231 فیلتر نتایج به سال:
An endocyclic pathway is proposed as a reaction mechanism for the anomerization from the β (1,2-trans) to the α (1,2-cis) configuration observed in glycosides carrying 2,3-trans cyclic protecting groups. This reaction occurs in the presence of a weak Lewis or Brønsted acid, while endocyclic cleavage (endocleavage) in typical glycosides was observed only when mediated by protic media or strong L...
tetrahydroisoquinolines, 1,2,3,4-tetrahydroquinolines, 2,3,4,5-tetrahydro-1H-3-benzazepines, 2-quinolones, erythrinan, homoerythrinan, isopavine and pavine alkaloids using an aromatic cyclization of the sulfonium ion in situ formed from a sulfinyl precursor (Pummerer reaction). The aromatic cyclization in the reaction using trifluoroacetic anhydride (TFAA) smoothly proceeded at room temperature...
Paper cultural heritages are valuable historical records and also abound in resources. Due to its organic property, paper is susceptible aging, destruction by environmental pollution human factors. At present, many countries the world facing problem of conservation. Coating reinforcement one methods for conservation, which choice reinforcing resin key. A transparent polyurethane, based on epoxy...
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