Über die herstellung molekulareinheitlicher cyclooligomerer und ihre spaltung. III. Mitt.: Modelle für matrizenreaktionen

Abstract

Zunachst werden Faktoren genannt, die eine synthetische Matrizenreaktion beeinflussen konnen. Dann wird die Herstellung von Estern a m Acrylsaurechlorid mit Phenolaten molekulareinheitlicher, phenolischer Mehrkernverbindungen (durch rationale Synthese') hergestellte Novolake) beschrieben. Es fanden sich Bedingungen, unter denen eine Polymerisation der Acrylsaurereste auf ein und dasselbe Molekiil beschrankt blieb. Diese neue Polymerisationsvariante wird intramolekulare Cyclooligomerisation genannt, da die erhaltenen Produkte molekulareinheitliche Cyclooligomere sind. Eine Hydrolyse dieser Cyclooligomeren ergab molekulareinheitliche Sauren, wie die Umsetzung mit p-Nitrobenzylbromid sowie Elementaranalysen und Molekulargewichtsbestimmungen der Ester zeigten. AuBerdem haben die molekulareinheitlichen oligomeren Acrylsauren sehr wahrscheinlich eine regelmaflige Sequenz van 1,3-verkniipften Grundbausteinen; diese schlieBt mit einer 1,2-verkniipften Einheit ab. Die 1,2-Verkniipfung stammt von der Abbruchreaktion mit einem Radikal aus dem Katalysator. Molekulareinheitlichkeit und die durch die molekulare Geometrie der phenolischen Tragermolekiile bedingte Sequenz der Acrylsaureeinheiten sind Kennzeichen einer synthetischen Matrizenreaktion. SUMMARY:The factors are enumerated which can influence a synthetic template reaction. The preparation of acrylyl esters of molecular homogeneous phenolic condensates (rationally synthesized') novolaks-) by treatment with acrylyl chloride is reported. These were polymerized under conditions which limited the propagation reaction of the acrylyl substituents to a single oligomeric molecule. This new variation of polymerization technique is named intramolecular cyclooligomerization since the products are molecular homogeneous cyclooligomers. Hydrolysis of these cyclooligomers yielded molecularly homogeneous acids, which were characterized by reaction with p-nitrobenzyl bromide as well as elemental analysis and molecular weight determinations of the p-nitrobenzyl oligo-acrylates. I n addition, the molecularly homogeneous oligo-acids very probably consist of a regular sequence of head to tail linkages which terminate with a head to head unit. The head to head structure results from termination by addition with a catalyst radical. The molecular homogeneity and the regular sequence of acrylic acid units are evidence for a synthetic template reaction. *) I. Mitt.:H.~mERER,Angew. Chem. 77(1965) 965; int. ed. 4 (1965) 952; 11. Mitt.: H. KiMIMERER und SH. OZAKI, Makromolekulare Chem. 91 (1966) 1. MHerstellung rnolekulareinheitlicher Cyclooligornerer.

Template Controlled Oligomerizations

“…Only methyl acrylate polymerization was arrested by template 64 to provide the macrocyclized product 96 in modest yield as a mixture of five diastereomers (Scheme [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. Vinyl acetate and acrylonitrile led only to uncontrolled polymerization, while vinylene carbonate did not react under the standard experimental conditions.…”

“…This curious observation refocuses concerns about yield loss to a critical choice that a template-bound pMMA radical 99 faces: macrocyclization to afford the controlled-8 Temdate Controlled Olipomerizations length oligomer 94 vs. addition of a fourth monomer to lead ultimately to 100 (Scheme [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. 10% of unreacted template was recovered.…”

Template Polymerization of Multi‐Vinyl Monomer with Poly(2‐hydroxyethyl methacrylate) Backbone

“…[16][17][18][19][20][21][22][23][24] Many types of multi-vinyl monomer in which vinyl groups are combined with the template chain through covalent bonds have been synthesized and polymerized. [16,[22][23][24] When the polymerization proceeds along template polymer, molecular weight, molecular weight distribution and architecture of product depend on those of the template molecule. For example, linear and cyclic poly(methacrylic acid) [PMAA] oligomers with degree of polymerization (DP ¼ 6, 7 and 14) were finely synthesized by using cyclodextrins as templates.…”

Atom Transfer Radical Polymerization of Poly(2-methacryloyloxyethyl methacrylate)

“…26 Many types of multivinyl monomers in which vinyl groups are combined with the template polymer chain through covalent bonds have been synthesized and polymerized by free radical polymerization to control the molecular weight and molecular weight distribution. 21,[27][28][29] One of the interesting features of the template polymerization is that a ladder polymer is formed by template polymerization of multivinyl monomer. However, the hindrance of gelation during the polymerization is difficult because the multivinyl monomer act as a cross-linker.…”

“…Template polymerization has been investigated to control molecular weight and molecular weight distribution of polymers. − When the polymerization is limited in template polymer chain and proceeds along the template polymer chain, molecular weight and molecular weight distribution of the daughter part obey those of the template polymer chain . Many types of multivinyl monomers in which vinyl groups are combined with the template polymer chain through covalent bonds have been synthesized and polymerized by free radical polymerization to control the molecular weight and molecular weight distribution. ,− …”