3634-86-4

Upstream product

• 50-00-0 formaldehyd 
• 98-27-1 2-Methyl-4-t-butylphenol 

Downstream Products

• 13747-35-8 bis[2-hydroxy-3-methylphenyl]methane 

Relevant academic research and scientific papers

Macrocyclic nonviral vectors: High cell transfection efficiency and low toxicity in a lower rim guanidinium calix[4]arene

(Figure Presented) New multivalent cationic lipids, one of them showing high efficiency and low toxicity in cell transfection, have been obtained by attaching guanidinium groups at the lower rim of calix[4]arenes.

Partial OH → Me Replacement in the Calixarene Scaffold: Preparation, Conformation, and Stereodynamics of Tetra-terf-butyl-25,27-dihydroxy-26,28-dimethylcalix[4]arene and Its Dimethyl Ether Derivative

The first example of the replacement of hydroxyl groups of a calixarene by methyls is described. Reaction of the bis(spirodienone) calixarene derivative 3B with MeLi afforded the bis addition product 4 which is derived, as shown by X-ray crystallography, from attack on the face of the carbonyls which is anti to the ether oxygen. The reaction of the alternant bis(spirodienone) calixarene derivative 3A with excess MeLi resulted in addition to the C=O groups, but with a concomitant cleavage of the spiro bonds. Ionic hydrogenation (CF3COOH/Et3SiH) of this product (5) yielded 5,11,17,23-tetra-tert-butyl-25,27-dihydroxy-26,28-dimethylcalix[4]arene (6) while ionic hydrogenation of 4 resulted in fragmentation of the macrocyclic ring. Calixarene 6 adopts a 1,3-alternate conformation both in solution and in the solid state. 6 is conformationally flexible, and an inversion barrier of 15.1 kcal mol-1 was measured for it by DNMR. The dimethyl ether derivative of 6 (i.e., 7) exists in a partial cone (paco) conformation and undergoes two distinct dynamic processes possessing barriers of 13.3 and 18.1 kcal mol-1. Molecular mechanics calculations predict correctly the preferred conformation of 6 and 7 and indicate that the topomerization pathways resulting in the mutual exchange of the protons within a methylene group are the following: 1,3-alt → paco(CH3) → 1,2 alt → paco(CH3)* → 1,3-alt* for 6, and paco(CH3) → 1,3-alt → paco(OCH3) → 1,2 alt → paco(OCH3)* → 1,3-alt* → paco(CH3)* for 7 with calculated barriers of 15.0 and 16.1 kcal mol-1, respectively.

Molecular Design and Characterizations of New Calixarene-based Gelators of Organic Fluids

We have found that certain calixarenes having long acyl groups at the p-positions (e.g., 5,11,17,23,29,35,41,47-octadodecanoylcalixarene-49,50,51,52,53,54,55,56-octol: 28C12) act as excellent and unique gelators of various organic solvents (e.g., toluene, carbon tetrachloride, carbon disulfide, hexane, isopropanol, etc.).The sol-gel phase transition temperatures (Tgel) could be determined by the inverted test-tube method or by the DSC method.The change in the aggregation mode at the phase transition temperature was directly observable by an optical microscope: below Tgel the fibrillar network (diameter ca. 1 μm) appeared whereas above Tgel it 'melted' down.It was shown on the basis of these mesurements that the sol-gel phase transition occurs reversibly.The spectroscopic studies using 1H NMR and IR spectroscopy and the comparative experiments using the analogues of 28C12 (nine cyclic and six non-cyclic) established that the prerequisites for the formation of the stable organic gels are (i) the intermolecular C=O...HO hydrogen-bonding interaction to form the three-dimensional network and (ii) the moderate affinity of gelators with solvent molecules.The results offer important strategies useful for the molecular design of new gelators of organic fluids.