Macrocycles 11. Polycondensations of aliphatic dicarboxylic acid dichlorides with catechol or bis-trimethylsilyl catechol

Abstract

When O,O′‐Bistrimethylsilyl catechol (BTSC) was polycondensed with adipoyl chloride in o‐dichlorobenzene the 10‐membered cyclic monomer was the main reaction product regardless of the concentration. Even the polycondensation in bulk yielded the macrocyclic monomer as the main product. Polycondensations of free catechol yielded similar results. Polycondensations of catechol or BTSC with suberoyl chloride, sebacoyl chloride, and decane‐1,10‐dicarbonyl chloride in concentrated solutions or in bulk yielded cyclic oligoesters as the main reaction products whereas linear oligoesters or polyesters were a minority. Polycondensations of BTSC with the longer diacid dichlorides in refluxing o‐dichlorobenzene under high dilution yielded the 12–14‐membered cyclic monomers as the main products. The molecular weights and the cyclic structure of all reaction products were characterized by mass spectrometery, fast‐atom bombardment (FAB) or MALDI‐TOF mass spectrometry. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3861–3870, 1999

Cyclic Polymers by Kinetically Controlled Step‐Growth Polymerization

“…Better results were obtained with the sebacic acid bisimidazolide (23). [34] Polycondensation with the diamine (20) in DMSO at 60 8C proved again to be close to the optimum but both molecular weight and extent of cyclization were slightly lower than the best results obtained with the bis(4-chlorophenyl)ester (21). Two characteristic differences are worth to be mentioned.…”

“…Firstly, the bisimidazolide is more sensitive to moisture and, thus, azeotropic drying of the reaction medium is advantageous. Secondly, polycondensations at 100 8C were successful (although inferior to those at 60 8C) in contrast to polycondensations of the bis(4-chlorophenyl)ester (21). Obviously, the neutral or weakly basic character of the liberated imidazole is an advantage at high temperature.…”

“…In the case of catechol, the ''pyridine method'' was compared with polycondensations of the bis(trimethylsilyl) derivative which were conducted in bulk (Equation (10)). [21] Nearly identical molar masses and MALDI-TOF mass spectra were obtained. The MALDI-TOF mass spectra proved the cyclic polyesters to be the most abundant reaction products up to the limit of these measurements at 6 000 Da.…”

“…However, it is clear that side reactions of acid chlorides are unavoidable in interfacial polycondensations, so that polyamides containing > 50 mol-% of cycles cannot be prepared in this way. The third approach studied in detail was based on polycondensations of free diamines (19) and (20) with the bis(4-chlorophenyl)ester of sebacic acid (21). [33] Solvent, temperature, time and the concentration of water were varied and optimized.…”

Cyclic polymers: Synthetic strategies and physical properties

“…Quite recently, a ROP of D,L-lactide catalyzed by a nucleophilic carbene at [20][21][22][23][24][25] C in solution was reported. 188 Up to 15 kDa, the MT mass spectra exclusively displayed peaks of cycles and proved total equilibration.…”