The use of 4,6-disubstituted pyrimidine-5-aldehydes in the synthesis of meso-tetraarylporphyrins
摘要:
A new type of double picket-fence porphyrin, bearing pyrimidine rings at the meso-positions was prepared from the corresponding pyrimidine-5-aldehydes using either Rothemund or McDonald condensation reactions. (C) 1999 Elsevier Science Ltd. All rights reserved.
Diastereoselective intramolecular hetero Diels–Alder approach towards polycyclic heterocycles
摘要:
Several different heterocyclic aldehydes, derived from pyrazole. pyrimidine, pyridine, indole and thiazole, were converted to polyheterocyclic compounds containing four to seven rings. The key steps in the sequence were a Knoevenagel condensation of the aldehyde and a heterocyclic carbonyl compound, such as pyrazolone and isoxazolone, followed by an intramolecular hetero Diets-Alder reaction. Most final products were isolated with high yield and diastereoselecivity. The isoxazolo fused cycloadducts formed interesting spiro-adducts upon heating. The cis nature of the bridging hydrogens of the heterocycles was evidenced by X-ray diffraction analysis.(dagger) (C) 2002 Elsevier Science Ltd. All rights reserved.
Diastereoselective intramolecular hetero Diels–Alder approach towards polycyclic heterocycles
作者:Erik Ceulemans、Marieke Voets、Sabine Emmers、Koen Uytterhoeven、Luc Van Meervelt、Wim Dehaen
DOI:10.1016/s0040-4020(01)01153-x
日期:2002.1
Several different heterocyclic aldehydes, derived from pyrazole. pyrimidine, pyridine, indole and thiazole, were converted to polyheterocyclic compounds containing four to seven rings. The key steps in the sequence were a Knoevenagel condensation of the aldehyde and a heterocyclic carbonyl compound, such as pyrazolone and isoxazolone, followed by an intramolecular hetero Diets-Alder reaction. Most final products were isolated with high yield and diastereoselecivity. The isoxazolo fused cycloadducts formed interesting spiro-adducts upon heating. The cis nature of the bridging hydrogens of the heterocycles was evidenced by X-ray diffraction analysis.(dagger) (C) 2002 Elsevier Science Ltd. All rights reserved.
The use of 4,6-disubstituted pyrimidine-5-aldehydes in the synthesis of meso-tetraarylporphyrins
A new type of double picket-fence porphyrin, bearing pyrimidine rings at the meso-positions was prepared from the corresponding pyrimidine-5-aldehydes using either Rothemund or McDonald condensation reactions. (C) 1999 Elsevier Science Ltd. All rights reserved.