Tetranitro-9-fluorenylideneaminooxy propionic Acid

Procedures for the preparation of several compounds of considerable utility are described. These include 1,1 -carbonyl-diimidazole, which has been used in the preparation of esters, amides, and anhydrides, the hydrochloride and methiodide of l-ethyl-3-(3-dimethylamino)-propylcarbodiimide, which can be used for similar purposes and are especially useful in the preparation of peptides, and (+)- and (— )-< -(2,4,5,7-tetranitro-9-fluorenylideneaminooxy) propionic acid (TAPA), which is used for the resolution of polycyclic aromatic compounds. 

Tetranitro-9-fluorenylideneaminooxy)propionic Acid Universitd di Genova, Italy... 

Resolution p-Boronobenzoic acid. d-10-Camphorsulfonic acid. Di-p-toluoyl-L-tartrate, see Hydrazoic acid. Iodobenzenedichloride. d- and /-a-Methylbenzylamine. 1-Phenylethane-sulfonic acid, see l,3-Dibenzyl-2-methyl-l, 3,2-diazaphospholidine. (+) and (-)-a-)2,4,5,7-Tetranitro-9-fluorenylideneaminooxy)-propionic acid. 

In addition, these complexes, except 49a and 50a, form lyotropic columnar (oblique) and nematic phases when dissolved in linear, apolar organic solvents (alkanes) over wide temperature and concentration ranges. Interestingly, for some of them, 49b-c, an unexpected transition between two lyotropic nematic phases has been observed, for which a model has recently be proposed [93]. As for 48, formation of lyotropic nematic and columnar mesophases is also extended by n-n interactions with electron-acceptors, such as TNF, in apolar solvents (pentadecane). Induction of chiral nematic phases by charge transfer interactions, in a ternary mixture (49b/alkane/TAPA TAPA is 2-(2,4,5,7-tetranitro-9-fluorenylideneaminooxy)-propionic acid and is used (and is available commercially) enantiomerically pure), has recently been demonstrated for the first time [94], and opens new perspective for producing chiral nematic phase of disc-like compounds. 

Resolution of racemic 31 through formation of diastereotopic charge transfer complexes with optically active 2-(2,4,5,7-tetranitro-9-fluorenylideneaminooxy)propionic acid produced (-)-31 with [a]o-3640° (CHCI3). Newman, M. S. Lutz, W. B. Lednicer, D. J. Am. Chem. Soc. 1955, 77, 3420. 

Colho = columnar hexagcmal ordered phase, = monotropic transition, observed by polarising mio-oscopy on cooling 2,4,7-trinitrofluorenone (TNF, 5a), 6 chiral (->2-(2,4,5,7-tetranitro-9-fluorenylideneaminooxy)propionic acid ((-)-TAPA, 5b, commwcially available) or (2,4,7-trinitro-9-fluorenylidene)malonic bidiexadecylester (5c) [18]. The transition temperatures of this doncx Nd phase are given in TABLE 3. Here, due to the diind TAPA an induced chiral nonatic phase. 

Not only 2,4,7-trinitro-9-fluorenone (TNF) but also other electron acceptors, for example, TCNQ, 1,2,4,5-tetracyanoben-zene, the enantiomers of 2-(2,4,5,7-tetrani-tro-9-fluorenylideneaminooxy)-propionic acid (TAPA) or 2,4,5,7-tetranitro-9-fluore-none, and derivatives of the latter one, are effective in this type of mesophase induction [50]. In particular, a TNF derivative carrying two hexadecanoyl side chains (2,4,7-trinitrofluorenylidene-9-malonic acid bis(hexadecyl) ester) is remarkable because of the induction of a nematic columnar type (Ncoi) mesophase with hexakispen-... 

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