Addition of aniline

The conversion of the diazoaminobenzene into aminoazobenzene is promoted by the addition of aniline hydrochloride even more readily than by that of free hydrochloric acid. The aniline hydrochloride dissociates in solution giving hydrochloric acid and aniline the former promotes the formation of the above equilibrium, and the latter by increasing the active mass of the free aniline further accelerates the condensation to aminoazobenzene,... 

The second major route to diarylamiaes is the condensation of an aromatic amine with a phenol. Aniline [62-53-3] phenol [108-95-2] and 3.5% phosphoric acid at 325°C gives a 50% yield of DPA (23). Apparently, this reaction iavolves the addition of aniline to the keto form of the phenol. Thus, naphthols and hydroquiaone are more reactive and give higher yields of product. This is the preferred route to A/-phenyi-2-naphthyiamiQe, 4-hydroxydiphenyiamiQe, and diphenyl- -phenylenediamine (24). 

Figure 5-23. RIP diagram for the general acid-catalyzed addition of anilines to dicyanamide.

Kemp utilized a very similar oxo-diester 49. Not only was this ketone reactive enough to form an enamine using p-nitroaniline 48, but 49 underwent bis-addition of aniline 48, providing 50 in 64% yield. Intermediate 50 smoothly cyclized to provide quinolone 51 which was utilized to prepare a diacylaminoepindolidione, a template to study the folding of 3-pleated sheets. 

This information coupled with the proposed mechanism of the Conrad-Limpach reaction, reasonably lead to the below proposed mechanisms. Conjugate addition of aniline and elimination of alcohol provides the P-anilinoacrylate 14, which upon heating to 180-320 °C gives species, like 34a,b, which undergo 6n-electrocyclization to 35 or 36, respectively. Loss of ethanol from 36 gives 35 and tautomerization provides 4-... 

Intermediate arylamidine, 6S, is prepared by the aluminum chloride-catalyzed addition of aniline to the nitrile function of 4-cyanothiazole (67), Amidine, 65, is then converted to its N-chloro analog (69) by means of sodium hypochlorite. On base treatment, this apparently undergoes a nitrene insertion reaction to produce thiabendazole (70), ... 

Secondary amines can be added to certain nonactivated alkenes if palladium(II) complexes are used as catalysts The complexation lowers the electron density of the double bond, facilitating nucleophilic attack. Markovnikov orientation is observed and the addition is anti An intramolecular addition to an alkyne unit in the presence of a palladium compound, generated a tetrahydropyridine, and a related addition to an allene is known.Amines add to allenes in the presence of a catalytic amount of CuBr " or palladium compounds.Molybdenum complexes have also been used in the addition of aniline to alkenes. Reduction of nitro compounds in the presence of rhodium catalysts, in the presence of alkenes, CO and H2, leads to an amine unit adding to the alkene moiety. An intramolecular addition of an amine unit to an alkene to form a pyrrolidine was reported using a lanthanide reagent. 

The reaction mechanism clearly involves the oxidative addition of aniline to an unsaturated Ir(I) complex (Scheme 4-4). Interestingly, the azametallacyclobutane intermediate could be characterized by single-crystal X-ray diffraction [141]. This result confirms that insertion of an olefin into the M-H bond is less favorable than insertion into the M-N bond [142]. 

Whereas the reactions of allenephosphonates 171 (R2 = OEt) with primary aliphatic and aromatic amines 172 and the reactions of the phosphane oxides 171 (R2 = Ph) with aliphatic amines 172 afford the conjugated addition products 173 always in good yields, the addition of anilines to 171 (R2 = Ph) leads to an equilibrium of the products 173 and 174 [231]. However, treatment of both phosphane oxides and phos-phonates of type 171 with hydroxylamines 172 (R3 = OR4) yields only the oximes 174 [232, 233]. The analogous reaction of the allenes 171 with diphenylphosphinoylhy-drazine furnishes hydrazones of type 174 [R3 = NHP(0)Ph2] [234],... 

The addition of aniline to phenyl isothiocyanate which leads to the re-formation of diphenylthiourea is described in the succeeding paragraph. 

Reactions of amines with alkenes have been reviewed298,299. Alkali metal amides are active homogeneous catalysts for the amination of olefins. Thus diethylamine and ethylene yield triethylamine when heated at 70-90 °C at 6-10 atm in the presence of lithium diethylamide and /V./V./V. /V -tetrarncthylcthylcncdiaminc. Solutions of caesium amide promote the addition of ammonia to ethylene at 100 °C and 110 atm to give mixtures of mono-, di- and triethylamines300. The iridium(I)-catalysed addition of aniline to norbomene affords the anilinonorbomane 274301. Treatment of norbomene with aniline... 

Ether cleavage of 4-heptyl-3-methylveratrole 121 using boron tribromide affords 4-heptyl-3-methylcatechol 122 (Scheme 38). Oxidation of the catechol 122 with o-chloranil to 4-heptyl-3-methyl-l,2-benzoquinone 123 and subsequent immediate addition of aniline leads to 5-anilino-4-heptyl-3-methyl-l,2-benzo-quinone 124. Unlike the very labile disubstituted ort/zo-quinone 123, compound 124 is stable and can be isolated. Palladium(II)-mediated oxidative cyclization of the anilino-l,2-benzoquinone 124 provides carbazoquinocin C 51. 

Table 6.1 Effect of fluoride on activity and stereoselectivity in the Ir-catalyzed addition of aniline to norbornene (Equation 6.5). ...

Chart 6.1 Catalyst precursors for the enantioselective addition of anilines to norbornenes [9,16,17],... 

One of the carbazole-l,4-quinones, 3-methoxy-2-methylcarbazole-l,4-quinone (941), required for the total synthesis of carbazomycin G (269), was already used as a key intermediate for the total synthesis of carbazoquinocin C, and was obtained by the addition of aniline (839) to 2-methoxy-3-methyl-l,4-benzoquinone (939), followed by oxidative cyclization with catalytic amounts of palladium(II) acetate (545,645) (see Schemes 5.124 and 5.125). Similarly, in a two-pot operation, 4-meth-oxyaniline (984) was transformed to 3,6-dimethoxy-2-methylcarbazole-l,4-quinone... 

Initiation involves a loss of two electrons and one proton from aniline to form a nitrenium ion (Eq. 2-223), which subsequently attacks aniline by electrophilic substitution (Eq. 2-224). Propagation proceeds in a similar manner by oxidation of the primary amine end of a growing polymer chain (Eq. 2-225) followed by electrophilic substitution (Eq. 2-226). The process has been referred to as reactivation chain polymerization to highlight the fact that the chain end formed after each addition of aniline must be reactivated to the nitrenium... 

The addition of anilines to styrene oxide was reported to also proceed in the presence of 10mol% 37 affording the corresponding P-amino alcohols 1-5 in yields ranging from 75% to 92% (Scheme 6.37). Additionally, urea derivative 37 (20mol% loading) was found to catalyze the addition of aniline (2.0 equiv.) to ( )-stilbene oxide (92% yield 5.9 d 30°C), the addition of thiophenol (2.0 equiv.) to 2-methoxy styrene oxide (85% 20h rt), and the alcoholysis of 4-methoxy styrene oxide with benzyl alcohol (2.0 equiv.) affording the respective P-alkoxy alcohol (82% 20h rt). 

Problem 20.37 Ouinoline is prepared by the Skraup reaction of aniline, glycerol and nitrobenzene. Suggest a mechanism involving Michael addition of aniline to an a,)3-unsaturated aldehyde, ring closure, and then dehydration and oxidation. 

Ballistites initially consisted of equal amounts by weight of nitroglycerine and soluble nitrocellulose CP2 with the addition of aniline or diphenylamine as stabilizers. It was found, however, that the presence of aniline and diphenylamine is detrimental to the stability of the powder, and they were therefore omitted. The valuable properties of centralite as a solvent of low basicity were then recognized and it was used both for its ability to dissolve the nitrocellulose and for its stabilizing action. 

We are going to look at a new kind of substitution reaction. Draw out the addition of aniline, PhNII2, to acetone to give a neutral adduct. ... 

A few examples are known using homogeneous transition-metal-catalyzed additions. Rhodium(III) and iridium(III) salts catalyze the addition of dialkylamines to ethylene.302 These complexes are believed to activate the alkene, thus promoting hydroamination. A cationic iridium(I) complex, in turn, catalyzes the addition of aniline to norbornene through the activation of the H—N bond.303 For the sake of comparison it is of interest to note that dimethylamino derivatives of Nb, Ta, and Zr can be used to promote the reaction of dialkylamines with terminal alkenes.304 In this case, however, C-alkylation instead of /V-alkylation occurs. 

Stiihmer and Hess war b1M have reported addition of aniline, ) -naphthylamine, and others to ci - and bmu-atilbene oxide to afford tkreo and erythro adducts respectively, as shown in Eq. <627), Their observations are consistent with the premise that ring-opening is accompanied by Walden inversion at the site of nucJecphiJic attack. 

Pentosans. These compounds are polysaccharides which may he considered as anhydrides of pentose sugars, after the manner of the hexosans. sucrose, starch, from glucose, fructose. When pentosans or pentoses are heated with hydrochloric ot sulfuric acid, furfural C fljO CHO is formed, and addition of aniline produces a red color. Pentosans are present in gummy carbohydrates, in bran of wheat seed, and in woods. 

Schuckher also patented (1890) a method for the prepn of Nitrostarch which consisted of dissolving dried and pulverized starch in nitric acid, and pouring the soln into mixed nitric-sulfuric acid. After washing and drying, the Nitrostarch was stabilized by the addition of aniline... 

Upon heating the diarylthiourea with concentrated hydrochloric acid, it is partly converted into the aryl isothiocyanate (e.g. phenyl isothiocyanate or phenyl mustard oil, Expt 6.98, Method 1). A little hydrogen sulphide is evolved in a side reaction forming diphenylcarbodi-imide (4) which undergoes nucleophilic addition of aniline to yield triphenylguanidine (5), isolated from the reaction mixture as the hydrochloride. 

The kinetics of the addition of aniline (PI1NH2) to ethyl propiolate (HC CCChEt) in DMSO as solvent has been studied by spectrophotometry at 399 nm using the variable time method. The initial rate method was employed to determine the order of the reaction with respect to the reactants, and a pseudo-first-order method was used to calculate the rate constant. The Arrhenius equation log k = 6.07 - (12.96/2.303RT) was obtained the activation parameters, Ea, AH, AG, and Aat 300 K were found to be 12.96, 13.55, 23.31 kcalmol-1 and -32.76 cal mol-1 K-1, respectively. The results revealed a first-order reaction with respect to both aniline and ethyl propiolate. In addition, combination of the experimental results and calculations using density functional theory (DFT) at the B3LYP/6-31G level, a mechanism for this reaction was proposed.181... 

N-Methylaniline adds to cyclopropanone to give the expected carbinol amine in quantitative yield. 5-90> On the other hand, a mixture of addition products may be isolated from the reaction of cyclopropanone 5>90> or cyclopropanone ethyl hemiketal4) with aniline (Scheme 18). At — 78°C, the carbinol amine 104 (66%) and the dimeric species 105 (33%) were obtained when the reactants were present in stoichiometric amounts. With excess aniline, 104 was produced almost quantitatively. However, at 25 °C, both 104 and the dianilino product 106 were obtained. These products could be interconverted by the addition of aniline or cyclopropanone, respectively. At 125 °C, o-propionylaminopropiophenone (107) was formed, possibly by further reaction of the carbinol amine with cyclopropanone as shown. 4>... 

Aminoazobenzene (33) is obtained by coupling in a more strongly acid medium, but better still by heating 34 in aniline with addition of aniline hydrochloride. 

Condensation reactions remain popular for the synthesis of quinolines <2006JOC6592>. Some modern variations on these classic reactions include an example of a solventless system, and the use of indium(m) chloride on silica gel under microwave conditions (Equation 160) <2003T813>. These fast, clean, high-yielding reactions gave aromatized products under indium(m) catalysis after a typical Michael addition of aniline to vinyl ketone. 

Protonation of glycerol 6.4 catalyses dehydration via secondary carbonium ion 6.5 to give enol 6.6. Acid catalysed elimination of a second water molecule affords acrolein 6.7. Thus glycerol acts essentially as a protected form of acrolein, slowly releasing this unstable a,p unsaturated aldehyde into the reaction medium. Better yields are realised with this approach than if acrolein itself is present from the start. The reaction proceeds with a Michael addition of aniline 6.3 to acrolein, producing saturated aldehyde 6.8 which cyclises via an aromatic substitution reaction to alcohol 6.9. Acid-catalysed dehydration to 6.10 then oxidation yields quinoline 6.1. Nitrobenzene can be used as a mild oxidant, as can iodine and ferric salts. 

The addition of anilines to vinylarenes is catalysed by a combination of Pd (OCOCF3)2, a chelating Ws-phosphine such as DPPF and TfOH as a source of triflate anion.77... 

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