Phthalazine ketones

The reactions of anhydro 2-aryl-3-hydroxythiazolo[2,3-a]phthalizinium hydroxides (171) with methyl propiolate (87EUP226196 88EUP294599), dimethyl acetylenedicarboxylate (85JOC1677), or fumaronitrile (85JOC1677) gave 4//-pyrido[2,l-a]phthalazin-4-ones (173) via cycloadducts 171. When methyl vinyl ketone was reacted with 171 (R = H), in addition to 9% of 4//-pyrido[2,l-a]phthalazin-4-one (173, R = H, R = COMe), a cycloadduct was also isolated (85JOC1677). 

A novel formal inverse-electron-demand hetero-Diels-Alder reaction between 2-aryl-a,/3-unsaturated aldehydes and ketones produces dihydropyran derivatives stereo-specifically.161 The inverse-electron-demand Diels-Alder reaction of 3,4-r-butylthio-phene 1-oxide with electron-rich dienophiles shows vyn-jr-face and endo selectivity.162 (g) The inverse-electron-demand Diels-Alder reaction of dimethyl l,2,4,5-tetrazine-3,6-dicarboxylate with a variety of dienophiles produces phthalazine-type dihydrodiol and diol epoxides which were synthesized as possible carcinogens.163... 

Derivatives of the 2,3- and 3,4-benzologues of (9) were prepared from 3-(2-pyridyl)-2,l-benz-isoxazoles, and from a thiazolo[2,3-a]phthalazine with methyl propiolate <87EUP226196,88EUP294599), DMAD, fumaronitrile and methyl vinyl ketone <85JOCl677>, respectively. 

But of prime importance with regard to the final separation process is the nature of the membrane-forming polymer its hydrophihdty, charge density, polymer structure and molecular weight Typical polymers used in this phase-separation process are cellulose esters (most commonly CA), polyamides, poly(amide-hydra-zides), polyimides, (sulfonated) polysulfones, poly(phenylene oxide) and (sulfona-ted) poly(phthalazine ether sulfone ketone). 

Jian X, Dai Y, He G, Chen G. Preparation of UP and NP poly (phthalazine ether sulfone ketone) membranes for high temperature apphcation. J MembrSci 1999 161(1-2) 185-91. 

Copoly(arylene ether nitrile ketone)s with a phtha-lazinone moiety can be synthesized by a nucleophilic substitution of 4-(4-hydroxylphenyl)-2,3-phthalazin-l(2H)-one and 2,6-dichlorobenzonitrile (DCBN) to 4,4 -difluoro benzophenone [54]. The materials are amorphous and soluble in dipolar aprotic solvents, such as A-methyl pyrrolidione, A,A-dimethylace-tamide, and chloroform at room temperature. It is possible to cast the materials into transparent, strong, and flexible films. 

X. Shao, W. Liu, Q. Xue (2004) The tribological behavior in micrometer and nanometer TiOj particle-filled poly(phthalazine ether sulfone ketone) composites, J. Appl. Polym. Sci. 92,906. 

Hay has reported the synthesis of poly(aryl ether ketones) containing o-dibenzoylbenzene moieties by the polymerization of 1,2-bis(4-fluorobenzoyl) benzene with various bisphenolates in DM AC (32). Transformation of the o-dibenzoyl(benzene) moiety in the polymer chain to a heterocycle by cyclization with small molecules was developed as a means of increasing the pol5mer chain stiffness and solvent resistance. It was demonstrated that reaction of the polymer with hydrazine monohydrate in the presence of a mild acid in chlorobenzene converted the poly(aryl ether ketone) to a poly(aryl ether phthalazine), a new class of heterocyclic-containing polyether (Scheme V) (33). Likewise, reaction of the polymer with benzylamine in a basic medium led to amorphous, thermally stable poly(aryl ether isoquinolines) (Scheme V) (34). Another example of the use of the o-benzoyl cyclization strategy is the intramolecular ring closure of poly(aryl ketones) containing 2,2 -dibenzoylbiphenyl units to form poly(aryl ether phenanthrenes) (35-37). 

The poly(ether ketone)s can be converted to poly(ether phthalazine)s 21 or poly(ether isoquinoline)s 22 by reaction with hydrazine and benzylamine, respectively. This conversion results in polymers in which there is considerable straightening of the polymer chains and this results in substantial increases in the glass transition temperatures (30 - 40 °C), in the solution viscosities, and in the apparent molecular weights as measured by GPC using polystyrene standards. 

The cyclic ether ketones 24 can also be converted to the corresponding phthalazines and isoquinolines which can also be polymerized at elevated tempertaures in the presence of a catalyst. 

Shao X, Tian J, Liu W, Xue Q and Ma C, Tribological properties of Si02 nanoparticle filled-phthalazine ether sulfone/phthalazine ether ketone (50/50 mol%) copolymer composites , J Appl Polym Sci 2002 85 2136-44. 

Shao X, Tian J, Liu W M, Ma C L and Xue Q J, Friction and wear properties of nanometer Ti02 particle-filled poly(phthalazine ether sulfone ketone) composites , Polym Mater Sci Eng 2003 19(3) 208-11 (in Chinese). 

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