Non‐mutagenic organic pigment intermediates. II. Isomorphous 2,2′‐di­chloro‐5,5′‐dipropoxy­benzidine and 2,2′‐di­methyl‐5,5′‐dipropoxy­benzidine

The title compounds, C₁₈H₂₂Cl₂N₂O₂ and C₂₀H₂₈N₂O₂, respectively, are isomorphous. The mol­ecules lie at general positions in the unit cell. In each structure, chemically equivalent but crystallographically inequivalent amine N atoms exhibit different degrees of pyramidalization. The structures exhibit weak N—H⋯N hydrogen bonding, which is influenced by the differences in hybridization around the amine N atoms. The torsion angles across the bi­phenyl linkage for the two compounds are 67.2 (2) and 68.3 (3)°.     

Synthesis and properties of fluorinated polyimides. 1. Derived from novel 4,4″‐bis(aminophenoxy)‐3,3″‐trifluoromethyl terphenyl

A new diamine monomer, 4,4″‐bis(aminophenoxy)‐3,3″‐trifluoromethyl terphenyl (ATFT) was synthesized that led to a number of novel fluorinated polyimides by solution as well as thermal imidization routes when reacted with different commercially available dianhydrides like pyromellatic dianhydride (PMDA), benzophenone tetracarboxylic acid dianhydride (BTDA), or 2,2‐bis(3,4‐dicarboxyphenyl) hexafluoropropane (6FDA). The polyimides ATFT/BTDA and ATFT/6FDA derived from both routes were soluble in several organic solvents such as N,N‐dimethylformamide, N,N‐dimethylacetamide, and dimethyl sulfoxide. The polyimide ATFT/PMDA was only soluble in N‐methylpyrollidone. The polyimide films had low water absorption of 0.3–0.7%, low dielectric constants of 2.72–3.3 at 1 Hz, refractive indices of 1.594–1.647 at 589.3 nm, and optical transparency >85%. These polyimides showed very high thermal stability with decomposition temperatures (5% weight loss) up to 532 °C in air and good isothermal stability; only 7% weight loss occurred at 400 °C after 7 h, and less than 0.6% weight loss was observed at 315 °C for 5 h. Transparent thin films of these polyimides exhibited tensile strengths up to 112 MPa, a modulus of elasticity up to 3.05 GPa, and elongation at break up to 21% depending on the repeating unit structure. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1016–1027, 2002     

1,6‐ and 1,7‐naphthyridines. IV. Synthesis of hydroxycarboxamide derivatives

A series of 8‐hydroxy‐1,6‐naphthyridin‐5(6H)‐one‐7‐carboxamides 1 and the isomeric 5‐hydroxy‐1,7‐naphthyridin‐8(7H)‐one‐6‐carboxamides 2 were synthesized. N‐Lactam unsubstituted compounds 1a‐c and 2a,b were obtained by alkoxide‐induced rearrangement of the corresponding quinolinimidoacetamides 3 . Compounds 1e,f and 2e,f were synthesized by heterocyclization of the corresponding quinolinamic esters 6 and 7 . Spectroscopic properties (uv, ir, ¹H and ¹³C nmr and ms) were analyzed and the proposed structures confirmed.