Triphenylphosphite/pyridine

A variety of condensing agents, such as triphenylphosphite/pyridine [4,5] and DBOP/triethylamine [6], which are used in amounts equivalent to functional groups on monomers, had been developed by the 1980s, whereas new catalysts that promote condensation polymerization exactly with a catalytic amount were developed in the last decade. 

Finally, a synthetic approach should be mentioned yielding polyamides containing cyclic OESs as part of the repeating unit [78]. The cyclic dicarboxylic acid (53c) was prepared from (53a) and (53b) by a conventional procedure and polycondensed with 4,4 -diamino-diphenylmethane using the triphenylphosphite-pyridine method. 

The Step 1 product (1.37 g Mn 26,000 daltons), 4-aminobenzoic acid (2.24 mmol), triphenylphosphite (5 mmol), and LiCl (0.09 g) were dissolved in 30 ml A-methyl-pyrroUdinone/pyridine solution, 80 20, and heated to 100°C for 4 hours. The reaction mixture was then precipitated in an excess of water/methanol, 1 1, fdtered, and washed with methanol. The material was dried overnight under vacuum at 40°C, and the product was quantitatively isolated. 

Liu and co-workers have elaborated [137] a highly efficient method for the synthesis of spiroimidazolinones 99 via a microwave-assisted three-component one-pot domino reaction of a protected amine, an amino acid ester and a carboxylic acid in the presence of triphenylphosphite in pyridine, providing the desired... 

The approach used depends on the selective dehydration of hydroxy-isopropyldihydrofuroquinolines to produce terminal olefins. Acid-catalyzed dehydration resulted in the exclusive formation of the more stable isopropylfuroquinolines, e.g. 95. Although other conventional procedures were also largely unsuccessful, reaction of the hydroxy-isopropyldihydrofuroquinoline 93 with thionyl chloride and pyridine gave the terminal olefin 94, which was converted into O-methylptelefolonium salt (84). Triphenylphosphite dihalides in the presence of base, however, proved to be effective reagents. Thus, the phosphite dibromide and potassium carbonate reacted with platydesmine to give olefin 97 predominantly, which was converted into dubinidine (87) by treatment with osmium tetroxide. Ptelefolone was the only product formed when the 6,8-dimethoxy-4-quinolone 92 was treated successively with triphenylphosphite dichloride and with pyridine. 

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