Paper is important to most historical and cultural relics, however, these paper heritages are facing a crisis of disappearance, damage aging. For increasing the strength, delaying aging, improving weak stability permeability former resins used for paper, another material necessary be produced on preservation protection items. The synthesis epoxy cyclohexane polyetherpolyol was as follows: Epoxy...

A. Introduction B. Acid-Catalysed Esterification and Transesterification 1. General mechanism 2. Methanolic hydrogen chloride 3. Methanolic sulfuric acid 4. Boron trifluoride-methanol 5. Other acidic catalysts C. Base-Catalysed Transesterification 1. General mechanism 2. Sodium and potassium methoxide catalysts 3. Organic base catalysis D. Diazomethane and Related Reagents 1. Diazomethane and m...

Condensation of 3beta-hydroxy-16-[(4-chlorophenyl)methylene]androst-5-en-17-one (1) with hydrazine hydrate in acetic acid afforded N-acetyl pyrazoline derivative 2, while condensation of 1 with semicarbazide afforded compound 3. Also, compound 1 was treated with hydrazine hydrate in absolute methanol or ethanol to afford the corresponding alpha-methoxy (4) and alpha-ethoxy (5) derivatives, whic...

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...

This paper describes the selective reductions with thioborane derivatives, zinc—modified cyanoborohydride, and the ate complex from diisobutylaluminum hydride and n-butyllithium. Reaction of carboxylic acids with 1,3,2-dithiaborinane in the presence of stannous chloride or boron trifluoride etherate in tetrahydrofuran gives 1,3-dithianes in high yields. The reaction of acids with thexylphenylth...