Base catalyzed formation and ring cleavage of 2- acyl-4- alkoxycarbonyI- 4-cyano substituted cyclobexanoles

The reaction of 1, 3-diaryI-2-propen- 1 -ones [1 a, b] with ethyl cyanoacetate in absolute ethanol in the presence of a catalytic amount of KOH at 50-55°C afforded 3-aroyl-l-cyano-4-hydroxy-2,4, 6-triarylcyclohexanecarboxylates [2a,b]. Base-catalyzed ring cleavage of 2a,b in refluxing ethanolic KOH solution afforded the corresponding 3-aryl- 2-cyano-2-propenoic acid 4 along with 1 a, b. The structure of 2 was established through different spectroscopic techniques and confirmed via dehydration using thionyl chloride in refluxing pyridine afforded 3. However, reaction of la with ethyl cyanoacetate in refluxing ethanol in the presence of secondary amine [piperidine or morpholine] as a basic catalyst gave the open-chain Michael adduct 6. Treatment of the latter with ethanolic KOH solution yielded 1,5-pentanedione derivative 7. The relative configurations of 3b and 6 were determined through single crystal X-ray diffraction analysis

New benzopyrans and pyridine derivatives from [2-hydroxyaryl] - propenones

The [2-hydroxyaryl]-propenones [1] react with malononitrile in the presence of piperidine or catalytic amount of potassium hydroxide to give the corresponding benzopyrans. Warming [3] with excess ammonium acetate in absolute ethanol affords the hitherto unknown dihydropyridines [4], whereas, on boiling the propenones [1] with malononitrile in presence of ammonium acetate. Benzopyranopyridines [7] are produced along with the dihydropyridines [4]. [7] could be also obtained by reacting 3- cyano-8-methoxy coumarinimide with the corresponding ketone. Hydrolysis of both benzopyranopyridines [7] and dihydropyridines [4] affords oxo-analogues [8]. Reaction mechanisms have been discussed

Reaction of 1,3-diaryl-2-propene-1-ones with o-Phenylenediamine

The propenones [1a-f] react with o-phenylenediamine in solution to give mainly 2,4-diaryl-2,3-dihydro-1 H-1,5-diazepines [3a-f], respectively, whereas, the analogous propenones [1g-i] afford 2- arylbenzimidazoles. The effect of base catalysis was discussed. The diazepines were also obtained when the components reacted at 120C without a solvent, whereas, at higher temperature 2-arylbenzimidazoles were mainly obtained. Thermolysis of the dihydrodiazepenes afforded 2-arylbenzimidazoles retaining the 4-phenyl ring of the diazepine as the major product together, in some cases, with 2-arylbenzimidazole retaining the 2-substituent

Newer 1-acetyl-3,5-diaryl-2pyrazolines of inhibiting properties on aflatoxin formation by aspergillus flavus

Recently, it has been reported that 1,3,5-triaryl- Delta 2- pyrazolines show good inhibiting properties on aflatoxin formation by Aspergillus flavus

Reaction of tetrahalo-benzoquinones with 3- [2furyl] -1 [2-thienyl] -2-propen1-one and 1-aryl-5- [2-furyl] -3- [2-thienyl] -pyrazolines

It has been reported [1, 2] in our laboratory that the furan ring undergoes cycloaddition reaction with halo-o-benzoquinones. The quinones added readily, under very mild conditions, to the 4,5-double bond of the furyl residue of 2-vinylfurans to give adducts of the type [2] with retention of the vinyl side chain