Insights into the bromination of 3-aryl-5-methyl-isoxazole-4-carboxylate: Synthesis of 3-aryl-5-bromomethyl-isoxazole-4-carboxylate as precursor to 3-aryl-5-formyl-isoxazole-4-carboxylate

Results of the detailed investigations on the bromination of the methyl group of 3-aryl-5-methyl-isoxazole-4-carboxylate a precursor to obtain 3-aryl-5-formyl-isoxazole-4-carboxylate are described. The products generated during the study have been utilized as substrates for the syntheses of isoxazole-fused heterocycles.

Studies toward the construction of substituted piperidine-2-ones and pyridine-2-ones from Baylis-Hillman adducts: Discovery of a facile synthesis of 5-methyl-4-oxo-6-aryl-3-aza-bicyclo[3.1.0]hexane-1-carboxylates

Studies toward the construction of functionalised piperidone derivatives from derivatives of Baylis-Hillman adducts are described. Interestingly the 6-oxo-4-aryl-piperidine-3-carboxylates generated during the study serve as precursor for the facile synthesis of 4-oxo-6-aryl-3-aza-bicyclo[3.1.0]hexane-1-carboxylates

Application of primary allyl amines afforded by the Baylis-Hillman adducts for heterocyclic synthesis: Generation of 5-benzyl-4(3H)-pyrimidinones and 2-benzylidene-2,3-dihydro-pyrrolizin-1-ones

The applications of the primary allyl amines afforded by the acetyl derivative of Baylis-Hillman adducts of acrylate for the synthesis of heterocycles using robust reactions are described. In the first strategy a one-pot synthesis of 5-benzyl-4(3H)-pyrimidinones have been achieved via N-formylation of the amines in the presence of neat formamide followed by ammonium formate-mediated cyclization. These pyrimidinones have been demonstrated to be excellent precursor to the 4-pyridinamine derivatives. In the second strategy the synthesis of 2-benzylidene-2,3-dihydro-pyrrolizin-1-ones have been accomplished via treatment of allyl amine with dimethoxyfuran followed by saponification and PPA-mediated intramolecular cyclization.

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.