Addition anils

The aniline then reacts with the ap-unsaturated aldehyde by 1 4-addition the addition product, under the influence of strong acid, cyclises to form 1 2-dihydroquinaldine. The latter is dehydrogenated by the condensation products of aniline with acetaldehyde and with crotonaldehyde simultaneously produced ( .c., ethylideneaniline and crotonylideneaniline) these anils act as hydrogen acceptors and are thereby converted into ethylaniline and n-butyl-aniline respectively. 

The anil of the addition product may be the intermediate just prior to cyoliaation which then takes place with the elimination of aniline. 

Temperature control at -15° to -25°C was also required for maximum yield. The best results were obtained by maintaining a temperature of -20 to -25°C during the addition of citral anil to the acid and at -15°C for the duration of the reaction. At this temperature range, the formation of a-cyclocitral (III) is favored. Higher temperatures caused excessive polymer formation and favored formation of e-cyclocitral whereas lower temperatures caused a reduction 1n the yield of the citral mixture. At least part of the problem with the lower temperature reaction was the fact that the sulfuric acid tended to freeze around the inside of the reaction vessel causing the effective molar ratio of acid to anil to be reduced. These lower temperature reaction mixtures were also lighter in color which indicated less polymer formation but this was accompanied by a lower yield of cyclocitrals. 

Addition of aryl isocyanates to benzaldehyde and benzophenone anils... 

Transparent anil opaque colors or enamels are used with equal effect upon a white and almost opaque ground, suck as porcelain. Transparent colors are rendered opaque, by the addition of oxide of tin and oxide of aino is used for enlivening tbo different tints, a proporty peculiar to the oxide of that metal, and the effect of which is greatly enhanced by tho fact that it imparts no color to the glass it also Improves the sulphur-yellow colors of the oxide of antimony. 

Sulfonyl azides react with olefins at a temperature which is much lower than the decomposition temperature of the azides (120-150°). The isolated products are aziridines and anils. The addition can be conceived as a result of two consecutive reactions, namely a 1,3-dipolar cycloaddition of the azide to the olefin immediately followed by decomposition of the formed unstable triazoline. As no triazolines can be detected, these reactions can also be regarded as a concerted addition with concomitant loss of nitrogen. 

In a 100-ml. round-bottomed flask equipped with a reflux condenser are placed 1.00 g. (0.0035 mole) of 5a-androstan-17/ -ol-3-one (Note 1), 0.90 g. (0.0048 mole) of tosylhydrazide (Note 2), and 70 ml. of methanol (Note 3). The mixture is heated under gentle reflux for 3 hours then cooled to room temperature. To the solution is added 2.5 g. (0.075 mole) of sodium borohydride in small portions during one hour (Note 4) and the resulting mixture is heated under reflux for an additional 8 hours. The reaction mixture is cooled to room temperature and the solvent is removed under reduced pressure. The residue is dissolved in ether, transferred to a separatory funnel, anil... 

I mines.2 Bis(dichloroaluminum)phenylimide (1) is useful for conversion of ketones as well as aldehydes to imines because the by-product is a stable dialu-minoxane (equation I). In addition the reagent converts acid chlorides into amides. The reagent is particularly useful for preparation of the anil (3) of chalcone (2). 

Several factors must be considered when the experimental assay condi tions are developed The reaction rate depends on the concentrations ol substrate, enzyme, and necessary cofactors. In addition, the reaction rate is under the influence of environmental factors such as pH, temperature, anil ionic strength. Enzyme activity increases with increasing temperature until the enzyme becomes denatured The enzyme activity then decreases until all enzyme molecules are inactivated by denaturation. During kinetic mea surement, it is essential that the temperature of all reaction mixtures bi maintained constant. 

Certain aromatic imines undergo a similar cyclodehydrogenation to the phenanthridine. Benzylideneaniline (330) yields phenanthridine (331) only in sulfuric acid,355 whereas diphenylmethyleneaniline cyclizes in the presence of oxygen or iodine.356 Cyclizations have also been reported in Schiff s bases formed from a- and /J-naphthylamine357 and from 4-aminoquinoline,358 and in the mesomeric betaine 4,5-diphenyl-2-mercapto-l,3,4-thiadiazolium hydroxide.359 Irradiation of the anil of 2-aminonaphthalene (332) in ethanol, however, leads to incorporation of ethanol and the formation of 3-phenylbenzo[/]-quinoline (333).860 Additional photoproducts are obtained when the photolysis is carried out in w-hexanol.361... 

The stereochemical course of the Anil Synthesis is such that exclusive formation of trans products has been observed.11 This can be explained by consideration of the conformations of the intermediate addition product. The Newman projections (lOa-c) represent the three possible extreme conformations, and it can be seen that 10a, being the least sterically hindered, would be expected to be the most energetically... 

As previously mentioned, the methyl group of 2-(p-tolyl)-s-triazolo-[l,5-a]pyridine is inert under the conditions of the Anil Synthesis. However, introduction of a chlorine atom in ortho position to this methyl group enables reaction to be carried out at 20°-30°C (Section II,E,3). Thus, for example, from 2-(3-chloro-4-methylphenyl)-j-triazolo[l,5-a]pyridine (19) and Schiff s base 171, the stilbene 172 is formed. In the case of 2-phenyl-7-methyl-j-triazolo[l,5-a]pyridine (173), however, reaction with 171 gives the styryl derivative 174, without additional activation of the methyl group.19... 

The first attempt to add diazomethane to a Schiff base was made by Meerwein,326 and the first successful addition was observed by Mustafa.327 Anils bearing nitro groups on the phenyl rings gave a cyclic adduct to which a 1,2,4-triazoline structure was assigned.327 A later reexamination of the reaction established the correct orientation of addition, and the products of the reaction of diazomethane with Schiff bases were assigned a A2-l,2,3-... 

An investigation of the aziridinyl anil transformations in solutions without dipolarophiles addition was carried out in [89], where the behavior of the isomeric azirenoimidazoles 134 in benzene under UV-lamp irradiation was studied. Irradiation of the endo isomer at 50°C leads to the formation of cis-2,3-dihydro-2,3,5-triphenylpyrazine 140A (Scheme 1.42). 

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