Ullman condensation

Ullman condensation of m-trifluoromethylaniline (13) with o-iodobenzoic acid in the presence of copper-bronze affords flu-fenamic acid (14). An analogous reaction of o-chlorobenzolc acid with 2,3-dimethylaniline (15) gives mefenamic acid (16) meclofenamic acid (18) is obtained by Ullman condensation employing 2,6-dlchloro-3-methylaniline (17). 

Yet another approach to these compounds consists of substituting the piperazine ring onto the preformed heterocyclic moiety. Ullman condensation of the substituted thiosalyciclic acid (40-1) with ort/zo-chloronitrobenzene results in the displacement of chlorine by thiophenoxide and the formation of the thioether (40-2). The nitro group in this last intermediate is then reduced to an aniline (40-3) the resulting amino acid is then cyclized thermally to the lactam (40-4). Treatment of that with phosphorus oxychloride gives the imino chloride (40-5). Reaction with N-methylpiperazine leads to the replacement of chlorine by nitrogen and the formation of clothiapine (40-6) [39]. 

Deoxytazettine neomethide (31), a key degradation product of tazettine, has been prepared (Scheme 4).11 The biphenyl derivative (28), obtained in low yield by Ullman condensation, was converted into the cyano-oxepin (29) in two steps (34% overall yield). Reduction gave the amine (30), which upon resolution followed by reductive methylation provided a sample of (—)-deoxytazettine neomethide (31) that was identical (including optical rotation) with the degradation product of tazettine. 

Ullman reaction The synthesis of diaryls by the condensation of aromatic halides with themselves or other aromatic halides, with the concomitant removal of halogens by a metal, e.g. copper powder thus bromobenzene gives diphenyl. The reaction may be extended to the preparation of diaryl ethers and diaryl thio-ethers by coupling a metal phenolate with an aryl halide. 

In a synthesis of decinine a phenol was protected as a methanesulfonate that was stable during an Ullman coupling reaction and during condensation, catalyzed by calcium hydroxide, of an amine with an aldehyde. Aryl methanesulfonates are cleaved by warm sodium hydroxide solution. " ... 

Uniformly labeled 2,4-dichlorophenol- C (purchased from New England Nuclear Corp, Boston, Mass.) was used in the tracer preparation. This provided a label at all carbon positions in the dibenzo-dioxin structure. 2,7-Dichlorodibenzo-p-dioxin- C after initial cleanup by fractional sublimation, contained approximately 5% of an impurity, detected by thin layer chromatography (TLC) which gave mass peaks at 288, 290, 292, and 294 in the mass spectrometer, consistent with a trichloro-hydroxydiphenyl oxide. This is probably the initial condensation product of the Ullman reaction and is most likely 2-(2,4-dichlorophenoxy)-4-chlorophenol. It was removed easily by extractions with aqueous... 

Of these sources, Kirk-Othmer s Encyclopedia of Chemical Technology is particularly recommended for questions on chemistry and on end uses. For information on properties and on toxicity and handling hazards, Patty s Industrial Hygiene, Material Safety Data Sheets (MSDS), and the Aldrich catalog are very nseful. Questions on industrial chemistry should be directed to Ullman s Encyclopedia of Industrial Chemistry, and the texts by Chenier, Heaton, and White. Hawley s Condensed Chemical Dictionary is valuable as a source for dehnitions of the terms (language) of chemistry. 

Ullman and Letan [189] studied the effect of noncondensable gas on condensation of bubbles in a subcooled liquid. Bergles and Bar-Cohen [190] provide information on the use of direct contact condensation of bubbles in a so-called submerged condenser. Zangrando and Bharathan [191] established computer models to characterize direct contact condensation of low-density steam (with high noncondensable gas concentrations) on seawater. 

FIGURE 21.1 Two-stage process for production of pentasodium triphosphate, (a) Receiver, (b) heavy-duty pump, (c) combustion chamber, (d) spray tower, (e) west dust removal from flue gas, (f) sie, (g) mill, (h) pneumatic conveyor, (i) silo, (j) rotary kiln, (k) flue gas puriflcation, (1) condensation, (m) bucket chain, (n) sie, (o) bagging scale. (Reprinted from Shrodter, K., Bettermann, G., Staffel, T., Klein, T., Hofmann, T., Ullman s Encyclopedia of Industrial Chemistry, p. 127, Wiley-Vch, Weinheim, Germany, 2003. With permission.)... 

The condensation product with 4,4 -dichlorodiphenyl sulfone had a glass transition temperature of 25rC and a melting point of 389 C. One would expect it to have excellent toughness, comparable to that of polymer (8). Another polymer derived from (11), i.e. (12) which was made via the Ullman reaction, had a Tg of 235 C, a tensile strength of 11,500 psi, an elongation of 140% and a pendulum impact of greater than 590 ft. Ibs./in. ... 

Various attempts have been made to use cheaper chloromonomers. ICI patented an Ullman ether condensation route in which copper is used to catalyse the halide displacement. However copper residues had to be carefully removed since they were detrimental to the thermal stability of the polymer. It also seems possible that the balance of side reactions is such that PAEK produced from chloromonomers will be somewhat different to PAEK produced by more conventional routes. More recently Gharda Chemical has filed patents [8] on a route to PEK from a chloromonomer. The low cost monomer (hydroxychlorobenzophenone) is prepared by reaction of 4-chlorobenzoylchloride with phenol. 

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