Mesoionic Systems

N Bn O OCH3 O N Bn O NH O H2N Commercially available N Bn O NH O HN R3 N Bn O O N N R4 N Bn O NH O NC N Bn O NH O N N NH N N Bn O NH O O N N But Compound B NH2NH2 a or b or c condensation CHO R2 X OR1 O O a = b = (R1 = CH3, C2H5) (R2 = H, CH3, OH, NO2) NO2 c = Br(4) *R3 : CH2CO(COOR1) (2) : =CH(3-R2)Ph (3) *only from a, b oxidative cyclisation R4 : CH2CO(COOR1), : =CH(3-R2)Ph : (tBu)-Bn CuCN/ACN N O O NaN3 NH4Cl pyridine Cl O But Compound A (1) (6) (5) alkyl Commercially available Compound 1 Compound 2 and 3 Compound A Compound 5 N Bn O OCH3 O methyl 1-benzyl-5-oxopyrrolidine- 3-carboxylate N Bn O NH O H2N 1-benzyl-5-oxopyrrolidine-3-carbohydrazide N Bn O NH O HN R3 N Bn O O N N R4 N Bn O NH O NC 1-benzyl-N-cyano-5-oxopyrrolidine-3-carboxamide Compound 6 Compound B Isoamyl nitrite NaN3 sodium azide NH4Cl ammonium chloride N Bn O NH O N N NH N 1-benzyl-5-oxo-N-(2H-tetrazol-5-yl)pyrrolidine-3-carboxamide N Bn O NH O O N N But N-(5-(4-tert-butylphenyl)-1,3,4-oxadiazol-2-yl)-1-benzyl-5-oxopyrrolidine-3-carboxamide NH2NH2 hydrazine N O O Cl O But 4-tert-butylbenzoyl chloride Compound b (R2=H) Compound b (R2=CH3) Compound b (R2=OH) Compound b (R2=NO2) Compound c (alkyl=CH3) Compound c (alkyl=C2H5) Compound a (X=Br; R1=CH3) CHO H benzaldehyde CHO H3C 4-methylbenzaldehyde CHO HO 4-hydroxybenzaldehyde CHO O2N 4-nitrobenzaldehyde NO2 H3C Br 1-bromo-1-nitroethane NO2 C2H5 Br 1-bromo-1-nitropropane Br OCH3 O O methyl 3-bromo-2-oxopropanoate