Carbaldehyde aniline

Knoevenagel condensation of the corresponding 3-methylfuran-2-carbaldehyde 379 and 3-methybenzo[4]furan-2-carbaldehyde 382 with diethyl malonate followed by bromination with iV-bromosuccinimide (NBS) in the presence of dibenzoyl peroxide afforded bromides 380 and 383, respectively. Treatment of 380 and 383 with benzylamine, isopropylamine, /-butylamine 3-hydroxypropylamine, aniline and -toluidine in ethanol yielded furo[2,3-c]pyrroles 381 and benzo[4,5]furo[2,3-c]pyrroles 384, respectively (Scheme 41). The yields of furopyrroles 381 are only moderate (16-46%), because these compounds are highly sensitive to acid, and partially polymerized upon silica... 

The result of treating 5-bromofuran-2-carbaldehyde with aniline is more complex and a salt resulting from anil formation and bromide displacement is formed (70CB2992). 

For example, 5,7-dimethyl-2-(4-tolyl)benzoxazole and the Schiff s base from diphenyl-4-carbaldehyde and aniline react at 60-65 °C to yield 5,7-dimethyl-2-(4 -phenylstilben-4-yl)benzoxazole (35) [40704-04-9] [63],... 

One equivalent each of unsubstituted aniline, substituted aniline, and pyridine-2-carbaldehyde were mixed in DMSO. Following equilibration, no free aldehyde could be detected An equilibrium mixture of imines and free anilines was observed in each case. Once the equilibrium had stabilized, half of an equivalent of copper( I) was added, and the equilibrium population of the two free anilines was again measured. 

A 13C-NMR spectroscopic study in solution of the tautomers of several anils derived from salicylaldehyde and from 2-hydroxynaphthalene-l-carbaldehyde having the same amino part (141-145, Scheme 17) has been reported.82 Variable-temperature NMR spectroscopy and comparison with appropriate models show that while salicylideneanilines exist as phenolic tautomers, naphthylidene-anilines exist as equilibrium mixtures containing appreciable amounts ofboth enol and keto tautomers, the latter being slightly predominant (Table 9). In fact, there is a negligible shift in the equilibrium on changing the electronic effect of the R substituent. 

The phosphomolybdic acid (PMA, H3PMO12O40) promoted Kabachnik-Fields reaction of 2-cyclopropylpyrimidine-4-carbaldehyde (364), various anilines or benzothiazole amines (365), and diallg l phosphites, allowed efficient synthesis of pyrimidine substituted a-aminophosphonates (366) (Scheme 109)/ ... 

This reaction is restricted to derivatives of N-benzylideneaniline since cyclohexane carbaldehyde or pivaldehyde with aniline give the product in less than 10% yield. More surprisingly, the reaction of acylzirconocene chloride 38 with imine proceeds with a Bronsted acid, even in aqueous media. Although, the hydrolysis of acylzirconocene into aldehyde is a well-known process (see Scheme 12.22), the reaction with N-phenyl imine is much faster. Under 20mol% HCl/THF, the... 

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