Zinke, calixarene

ZINKE ZIEGLER Synthesiso1 Cahxarenes Synthesis of calixarenes (a basket-llke macrocyclic compound)... 

The bromination and acetylation reactions show that the calixarenes are capable of undergoing conventional electrophilic substitution reactions without rupture of the macrocyclic ring. Zinke et al.18) reported the nitration of p-tert-butylcalixarene (ring size uncertain) and obtained a material that failed to melt up to 400 °C, exploded when heated more strongly, and had a nitrogen analysis in agreement with a tetranitro-calixarene. Attempts to obtain a nitration product from calix[4]arene 59,... 

The original Zinke synthesis employed NaOH as the base to induce the condensation of / -alkylphenols and formaldehyde, and base induction remains the method of choice noi only for the three major calixarenes 2, 4, and 6 (R = tert Bu) but also for the two minor calixarenes 3 and 5 (R = tert B x). With NaOH (in small amounts) as the base and refluxing diphenyl ether as the solvent, a 50% yield of pure p-rcrr-butyicalix[4]arene 2 is produced."" With KOH (in larger amounts) as the base and refluxing xylene as the solvent, ca. 85% yields of p-tert-butylcalix[6]arene 4 are produced.With NaOH (in small amounts) as the base and refluxing xylene as the solvent, ca. 65% yields o/p- err-butylcalix[8]arene d are produced.The p- crr-butylcalix[5]arene and p-... 

The formation of calixarenes was first reported by Zinke [59]. In general, the condensation of 4- alkylphenols with methanal leads to the formation of such materials in the presenee of bivalent metal salts and alkaline ions, respectively (equation 11). 

This apparent controversy was resolved by the seminal work of David Gutsche who developed reproducible synthetic procedures for the family of vase-like compounds, which in 1975 he called Calixarenes. David became interested in the chemistry of the Zinke compounds because he was a consultant to the Petrolite Corporation that produced surfactants for the oil industry. One of their products was a linear ohgomer obtained from reaction of p-tert-butylphenol and formaldehyde. Problems in the production process led to a detailed study of the reaction and during the more detailed investigations the Petrolite team rediscovered the crystalline Zinke compound. David s personal interest in these macrocyclic molecules was their possible use as platforms for enzyme mimics, in particular the Aldolase catalysis. Although he never realized such an artificial enzyme, David devoted... 

This issue is to celebrate the 50th anniversary of the proposal of a macrocyclic structure for the calixarenes. In February 1944, Zinke and Ziegler published an article entitled Zur Kenntnis des Hartungsprozesses von Phenol-Formaldehyde-Harzen in Chemische Berichte, volume 77, page 264. Here, they proposed a cyclic tetrameric structure (CnHi40)4 for an oligomer extracted from the condensation product mixture obtained by reacting p-tert-butylphenol with formaldehyde in the presence of sodium hydroxide. 

Key words History of chemistry, calixarenes, Zinke, Ziegler, Honel. 

Before the "Early History of Calixarene Chemistry finally ended, the Zinke paradigm worked once more. This event is known as the Petrolite Chapter [5, 38]. The PETROLITE Corporation was founded in 1916 and is located in Webster Groves, Missouri, not far from St. Louis, and thus not far from Washington University, St. Louis, C. D. Gutsche s working place. Its original products were demulsifiers for resolving cmde oil emulsions. In the fifties, a Petrolite demulsifier... 

Note added in proof The term ZINKE ZIEGLER Synthesis of Calixarenes has recently been added to the vocabulary of Organic Name reactions [55]. 

---