Aminomethylene compounds

The somewhat unusual aminomethylene compound 22 has been described by Senning and Kelly (40). Its H NMR spectrum shows a hindered rotation of the NEt2 group with a barrier of ca. 14 kcal/mol, and an enantiomerization process... 

Yields are in the range 50-70%. The reaction of (3) with nucleophiles at 80 results in elimination of ethanol and formation of an aminomethylene compound. Thus the amide acetal (4) reacts with nilromelhane to give (5) in 60% yield. 

The reagent reacts with enolizable active methylene compounds to give tri-methylsilyl ethers (equation I). Nonenolizable active methylene compounds react to form aminomethylene compounds (equation II). ... 

P-Aminomethylation 23, 643 Aminomethylenation s. Dimethyl aminomethylenatioii Aminomethylene compounds... 

When the enamine is in conjugation with a carbonyl function, as in a-aminomethylene aldehydes (528,529), ketones (530), or esters (531), a Michael addition is found in vinylogous analogy to the reactions of amides. An application to syntheses in the vitamin A series employed a vinyl lithium compound (532). 

At low temperature a 1 1 adduct of thioacetic acid and an enamine could be prepared (709). The previously described reaction of aminomethylene ketones with hydrogen peroxide was extended to bisaminomethylene compounds. However, acylated cyclohexenamines led to cyclopentane-carboxamides (770), Trichloromethyl adducts of enamines and the rearranged amine derivatives were described in a further study (777). 

Phenylmercury derivatives of 3-aminomethylene-l-methyloxindols have also been investigated (79KGS65). For studies of the effect of substituents on the electronic structure of silver and potassium salts of 3-(aryl)imi-nooxindole see 76MI2. The keto-enol and imino-enamine tautomerism of compounds of type 127 (with 128 and 129) has been investigated (85KGS921). 

Coronaridine subtype alkaloids are widely spread in Tabernaemontana. The iboga skeleton is particularly susceptible to oxidation at aminomethylenes C-3 and C-5 and at benzylic C-6. Very often, the fundamental compounds are accompanied by the oxidation products at these positions. 

Cyclization of diethyl N-[cyclohepta(6)pyrrrol-2-yl]aminomethylene-malonates (1676), by heating in xylene, t-butylbenzene, or tetralin at reflux temperature, gave cyclohepta[4,5]pyrrolo[l, 2-a]pyrimidine-3-carboxyl-ates (1677) in 46-90% yields (87BCJ1053). Cyclization were also carried out in a mixture of phosphoryl chloride and polyphosphoric acid. While compound 1676 (R = COOEt) gave 1677 (R = COOEt) in 95% yield, the unsubstituted 1676 (R = H) afforded a mixture of 1677 (R = H) and 4-hydroxycyclohepta[4,5]pyrrolo[2,3-b]pyridine-3-carboxylate (1678) in 7% and 48% yields, respectively. The nitrogen bridgehead compound (1677, R = H) could not be transformed into pyridine derivative (1678). 

Nucleophilic attack at the fully conjugated 1,3,5-triazine usually results in ring cleavage. Thus, active methylene compounds react with 1,3,5-triazine in aminomethylenation reactions. A three-component reaction of cyclopentadiene with 1,3,5-triazine and a secondary amine leads to /V,7V-di substituted pentafulven-6-amines (304) and N2-(6-pentafulvenyl)formamidines (305)... 

With tetracyanoethylene the 1-methyl derivative of 63 (R = H) led to compounds of type 226 with diethyl azodicarboxylate, to compounds of type 226 and with diethyl azodicarboxylate, to compounds of type 227.114 The 3-formyl and the 3-aminomethylene group of the pyrido[l,2-a] pyrimidines (222 R = H and 224) underwent condensation with compounds containing an active methylene group.297-299,303 The 3-formyl group has also been reacted with primary amines,285 hydrazines.98,260,285 semicarbazide and thosemicarbazide.98... 

Depending on the work-up conditions, Vilsmeier-Haack formylation of 4-oxo-6,7,8,9-tetrahydro-4//-pyrido[l,2-a]pyrimidines gave various 9-sub-stituted pyrido[l,2-a]pyrimidines (240 -242).284,319 The 9-aminomethylene derivatives (240) were transformed by hydrolysis in 0.5 N hydrochloric acid to the 9-formyl compounds (241 R3 = H), by ethanolic hydrogen chloride to... 

The pyrolysis of aminomethylene derivatives of Meldrum s acid has also been studied extensively. The parent compound 395 loses acetone and CO2 at 400 °C to give 396, which at higher temperatures isomerizes to 397 which loses CO to give ethynylamine (398)159. A range of cycloalkylamino compounds such as 399 reacts similarly on FVP at 500-600 °C to give the methyleneketene 400, but under the conditions this undergoes... 

Method E, which assumes the N(7)-C(7a) bond formation in the cyclization step, is also rarely used in the synthesis of thienopyridines. For example, the method (1997H255, 1998JMC(E)33, 1998PS21) for the preparation of 4-oxo-4,7-di-hydrothieno[2,3-Z>]pyridine-5-carboxylic acid esters 54 is based on intramolecular /V-nucleophilic substitution of (E/Z)-aminomethylene derivatives of (2,5-dichloro-3-thenoyl)acetic acid esters 52 in the presence of a strong base. Esters 52 and products of their alkaline hydrolysis 56 have an antibacterial action the influence of the substituents on the biological activity of the resulting compounds was studied. 

Many examples of ICC of the examined type are known amongst complexes of ligands of heterocyclic series [269]. Thus, nickel [886] and copper [887] complexes 496 of aminomethylene derivatives of 5-selenopyrazolone 471 (X — Se) have been obtained and structurally characterized. A series of coordination compounds has been synthesized on the basis of 2-selenohydrido derivatives of azines 497 [8,13,888-894] ... 

The ICC, synthesized on the basis of 4-aminomethylene derivatives of 5-imine-, oxo-, thio-, and selenoderivatives of pyrazole, are represented most widely. The coordination units MN4, MN202, MN2S2, and MN2Se2, respectively, are found in them [100,134,176-186], Thus, the methods A and B (4.49) were used for obtaining ICC of type 868 (X = NR, R-Het, compound 222) [187] ... 

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