Facile Synthesis of Novel Optically Active Poly(amide-imide)s Derived from N,N′-(Pyromellitoyl)-bis-l-alanine Diacid Chloride, Tetrahydropyrimidinone and Tetrahydro-2-thioxopyrimidine by Microwave-assisted Polycondensation

摘要

Seven new optically active poly(amide-imide)s (3a-g) were synthesized by microwave assisted polycondensation of N,N′-(pyromellitoyl)-bis-l-alanine diacid chloride (1) with seven different derivatives of tetrahydropyrimidinone and tetrahy-dro-2-thioxopyrimidine compounds (2a-g) by using a domestic microwave oven. The polycondensation reactions were carried out in the presence of a small amount of a polar organic medium that acts as a primary microwave absorber. Suitable organic media was o-cresol. The polycondensation proceeded rapidly, compared with the conventional melt polycondensation and solution polycondensation and it was almost completed within 10 min giving a series of poly(amide-imide)s (3a-g) with inherent viscosities about 0.22-0.42 dL/g. The resulting poly(amide-imide)s were obtained in high yield and were optically active and thermally stable. All of the above compounds were fully characterized by means of FTIR spectroscopy, elemental analysis, inherent viscosity (η_(inh)). solubilities test, and specific rotation. Thermal properties of the poly(amide-imide)s were investigated using thermal gravimetric analysis (TGA).