2,4,6-trinitrochlorobenzene

It is of interest to note that 2,4,6-trinitrochlorobenzene reacts similarly with 49 to give the cation of 138 isolated as the perchlorate. In the reaction of the enamino ketone (50) with trichloroacetyl chloride (77) the chloro-... 

Similar reaction of dithiocarboxylic acids 75 with 2,4,6-trinitrochlorobenzene (76) in ethanol at 0°C yields thioesters 77, which are then cyclized at room temperature to the final product 78 (77JCS(P1)1273). 2-Oxo- and 2-iminocy-clopentane derivatives 79 provided compounds 80a and 80b, respectively (Scheme 13) (73JCS(P1)1009, 75JCS(P1)1277). 

Thioxo-4-oxopyrimidines 110 treated with 2,4,6-trinitrochlorobenzene (76) are first arylated on the exocyclic thio group and the intermediates are then... 

Trinitrochlorobenzene (76) forms quartemary salts with some pyridine derivatives, e.g. with 3-amino-4-hydroxypyridine (196), and this fact narrows the... 

Trinitrochlorobenzene (76) treated with 1,3-propanedithiole and one equivalent of a base provided compound 479 and its treatment with additional base was reported to provide only small yields of benzodithiepine 480 (74CC672). A more recent work described that good yield (80%) of 480 was obtained by a treatment of 479 with triethylamine in benzene (76ZOR844). Similar treatment of 81 provided first spiro complex 481, which refluxed in acetone in the presence of triethylamine gave good yield of the denitrocyclization product 482 (Scheme 77) (92ZOR1496). 

As we ve seen, aromatic substitution reactions usually occur by an electrophilic mechanism. Aryl halides that have electron-withdrawing substituents, however, can also undergo nucleophilic aromatic substitution. For example. 2,4,6-trinitrochlorobenzene reacts with aqueous NaOH at room temperature to give 2,4,6-trinitrophenol. The nucleophile OH- has substituted for Cl-. 

Trinitrochlorobenzene (piciyl chloride) in pyridine-A -mcthylpyrrolidi-none (NMP) solutions were later used for the preparation of polyesters from dicarboxylic acids and diphenols or aliphatic diols,309 but better results have been obtained with sulfonyl chlorides and phosphorus compounds. 

Halogen substituents withdraw electron density from the aromatic nucleus but direct olp-through resonance effects. The result is that halobenzenes undergo nitration with more difficulty relative to benzene. The nitration of chlorobenzene with strong mixed acid gives a mixture of 2,4- and 2,6-isomeric dinitrochlorobenzenes in which the former predominates." The nitration of 2,4-dinitrochlorobenzene to 2,4,6-trinitrochlorobenzene (picryl chloride) requires an excess of fuming nitric acid in oleum at elevated temperature. Both are useful for the synthesis of other polynitroarylene explosives but only 2,4-dinitrochlorobenzene finds industrial importance (Sections 4.8.1.2 and 4.8.1.3). 

Trinitrochlorobenzene (picryl chloride) (87) can be prepared from the nitration of 2,4-dinitrochlorobenzene with nitronium tetrafluoroborate or mixed acid composed of fuming nitric acid and oleum. Picryl chloride is also synthesized from the reaction of phosphorous oxychloride with the pyridinium salt of picric acid. ... 

Chlorine was replaced by hydrogen in 2,4,6-trinitrochlorobenzene by heating with sodium iodide and acetic acid at 100° without the reduction of any nitro group [223]. 

For commercial production the Griesheim Chem. Fabrik is reported to have used a process in which 1 part of TNT is heated at 150-200° with a mixture of 5 parts of fuming nitric acid and 10 parts of concentrated sulfuric acid. In a process devised by J. Meyer,7 picryl chloride (2,4,6-trinitrochlorobenzene) is reduced by means of copper powder in hot aqueous alcohol. The reported details are 25 kilos of picryl chloride, 8 kilos of copper 8 Ber., 9, 402 (1876) Ann., 215, 345 (1882). 

Trinitrophenylamino)l,3-propanediol or 2-(2, 4, 6 - Trinitrophenylamino)-1,3-dihydroxy-propone (02N)3C H2.NH. CH-(CH2OH)2, mw 302.20, N 18.54%. Yel solid, mp 150° insol in petr eth, chlf, CC14 benz sol in w, ale, acet NB. Can be prepd by boiling an ale soln of 2-amino-1,3-propanediol with 2,4,6-trinitrochlorobenzene in the presence of Na acetate. It exploded on heating or on impact but milder than its higher nitrated product described below... 

In general the method is not as useful for the preparation of arylamines as for aliphatie amines. But the method becomes of preparative interest when the nuelear halogenated eompound eontains in addition some electron withdrawing substituents e.g., -NO2, -CN ete. in ortho and para positions. Thus, 2, 4, 6 trinitroaniline (pieramide) is readily prepared by the aetion of aqueous ammonia on 2, 4, 6 trinitrochlorobenzene (pieryl eholoride). 

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