Fluorinated aromatic diamines, reaction with

Reaction of Fluorinated Aromatic Diamines with Nitrous Acid... 

A new aromatic diamine monomer with four pendant -CF3 groups was successfully synthesized by a three-step reaction using w(4-fluorophenyl)sulfone and A-bromosuccinimide as starting materials. Then, a series of fluorinated poly(ether sulfone imide)s was conveniently prepared from the diamine and three aromatic dianhydrides (BPDA, BTDA, and ODPA) via one-step solution polycondensation. 

Novel fluorine-containing aromatic poly(azomethine)s are prepared by the reaction of hexafluoroisopropylidene-unit-containing aromatic diamines, 2,2-bis[4-(4-aminophenoxy)phenyl]-l,l,l,3,3,3-hexafluoropropane (17) and 2,2-bis(4-aminophenyl)-l, 1,1,3,3,3-hexafluoropropane (18) with terephthalaldehyde (19) or isophthalaldehyde (20)20 (Scheme 11). 

NASA-Langley provided a further improvement in processibility by replacing the methylenedianiline with a commercial aromatic diamine mixture that afforded even better handling characteristics (17). This type of product is formed by the reaction of formaldehyde with aniline as a precursor in isocyanate manufacture. Fluorine-containing thermoplastic polyimides and polyimides end capped with acetylene groups for cross-linking are also available as potential commercial high-temperature resins. 

Certain ten-substituted aromatic diamines can act as NCCCN binucleophiles in reaction with fluorinated acid derivatives to give pyrimidines. In particular, fused pyrimidine derivatives 658,659 and 661 were obtained from amines 657 [397] and 660 [398] by reaction with fluorinated anhydrides (Scheme 136). 

Aliphatic diamines (mostly 1,2-ethylenediamine) are much less studied and often give poor results in the reaction with fluorinated 1,2-bis-electrophiles possibly the only exception is diaminomaleonitrile (394), which also gives aromatic systems in these transformations. 

Vulcanization may be brought about by amines such as tetraethy-lene pentamine and hexamethylene diamine carbamate. It is believed that the process involves reaction of the diamine with the para fluorine atom on the aromatic ring ... 

A common method for the preparation of chain-fluorinated pyrazines relies on reaction of NCCN binucleophiles (i.e. 1,2-diamines) and fluorinated CC bis-electrophiles. This approach is especially valuable for the synthesis of quinoxalines and their hetero-analogues, since aromatic system is formed directly under reaction conditions. Therefore, most of the literature data concern heterocyclization with o-phenylenediamines, as well as the corresponding heterocyclic 1,2-diamines. 

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