Cycloaddition Reactions: Reaction of 3-Methyl-2-phenylpyrrocoline with Dimethyl Acteylenedicarboxylate

Reaction of 3-methyl-2-phenylpyrrocoline(I) and dimethyl acetylenedicarboxylate(II) in refluxing toluene furnishes cis-7',8-dihydro.4,5,8,9-tetramethoxycarbonyl-7'-phenyl-7' -methylazocino(2,1,8-cd]pyrrolizine (III) and trans-7',8-dihydro-4,5,8,9-tetramethoxycarbonyl-7-phenyl-7'-methylazocino[2,1,8-cd]pyrrolizine (IV), while the same reaction at ambient temperature yields 1-[(1,2-trans-dimethoxycarbonyl)vinyl]-3-methyl-2-phenylpyrrocoline (V) and 1-[(1,2-cis-di(methoxycarbonyl)vinyl)--methyl-2- phenylpyirocoUne (V) and 1-[(I,2-cis-di(methoxycarbonyl)Yinyl]-3-metbyl-2-phenylpyrrocoline(VI) as the major products. The structure of IV has been determined by X-ray crystallography.A possible mechanism of formation of these products is also discussed.

Expeditious synthesis of 5,6,7 ,8-tetrahydro-imidazo[1,2-a ] pyrimidin-2-ones and 3,4,6,7 ,8,9-hexahydro-pyrimido[,2-a ] pyrimidin-2-ones

A convenient synthesis of new 5,6,7 ,8-tetrahydro-imidazo[ 1,2-a]pyrimidin-2-ones and 3,4,6,7 ,8,9-hexahydro-pyrimido[1 ,2a]pyrimidin-2- ones from the Baylis-Hillman adducts of acrylonitrile and their derivatives is described. A common strategy employed to achieve the syntheses of title compounds involved generation of diamines from different Baylis-Hillman derivatives followed by treatment with cyanogen bromide at reflux temperature to trigger a double intramolecular cyclization.

Synthesis of substituted 1H- and 3H-1-benzazepines: Rearrangement of 2-alkoxycarbonyl-1H-1-benzazepines to isoquinolines

The SnCl2-mediated reduction of nitro groups in 2-nitro-4-(2-nitro-benzylidene)-alkanoates and 4-nitro-2-(2-nitro-alkylidene)-alkanoates afforded via SN2′ reaction of ethyl nitroacetate and nitroethane with the acetyl derivatives of Baylis-Hillman adducts afforded by 2-nitro-substituted benzaldehydes leads to facile synthesis of substituted 1H-1-benzazepine and 3H-1-benzazepine. During the study an unprecedented rearrangement of 2-alkoxycarbonyl-1H-benzazepine to substituted isoquinoline has been observed.