Cellulose hydroxymethyl ether

A plot of the temperatures required for clouding versus surfactant concentration typically exhibits a minimum in the case of nonionic surfactants (or a maximum in the case of zwitterionics) in its coexistence curve, with the temperature and surfactant concentration at which the minimum (or maximum) occurs being referred to as the critical temperature and concentration, respectively. This type of behavior is also exhibited by other nonionic surfactants, that is, nonionic polymers, // - a I k y I s u I Any lalcoh o I s, hydroxymethyl or ethyl celluloses, dimethylalkylphosphine oxides, or, most commonly, alkyl (or aryl) polyoxyethylene ethers. Likewise, certain zwitterionic surfactant solutions can also exhibit critical behavior in which an upper rather than a lower consolute boundary is present. Previously, metal ions (in the form of metal chelate complexes) were extracted and enriched from aqueous media using such a cloud point extraction approach with nonionic surfactants. Extraction efficiencies in excess of 98% for such metal ion extraction techniques were achieved with enrichment factors in the range of 45-200. In addition to metal ion enrichments, this type of micellar cloud point extraction approach has been reported to be useful for the separation of hydrophobic from hydrophilic proteins, both originally present in an aqueous solution, and also for the preconcentration of the former type of proteins. 

Butanediol t-Butyl methacrylate Cellulose acetate propionate Chromic acid Cocamine Copper nitrate (ic) Cl 1-15 pareth-7 Cl 1-15 pareth-9 Cl 1-15 pareth-12 Cyclodextrin 3-Cyclodextrin 1,3-Dichloro-2-propanol Dicocamine Diethylene glycol dimethyl ether DImethylaminopropylmethacrylamide Dimethyl terephthalate ElemI gum Feldspar Furfuryl alcohol Gilsonite Glycerin Hexamethylenediamine Hydroxymethyl dioxoazabicyclooctane N-(2-Hydroxypropyl) benzenesulfonamide Hydroxypropyl-a-cyclodextrin Hydroxypropyi-P-cyclodextrin Hydroxypropyl-y-cyclodextrin Hydroxystearic acid Isobornyl methacrylate Lead... 

This methodology was initially applied to a synthesis of (—)-alloyohimbane (82) (Scheme 3.13) (29). Readily available levoglucosenone (75), a product of cellulose pyrolysis, was the starting material. Diels-Alder reaction of 75 with 1,3-butadiene afforded adduct 76 which underwent Wolff-Kishner elimination and subsequent acylation to provide the bicyclic enol ether 77. Hydrolysis followed by oxidation and saponification afforded hydroxymethyl lactone 78 which was then condensed with tryptamine to yield the amide diol 79. Periodate cleavage of the diol was followed by conversion to chloride 80 which was cyclized to afford lactam 81. Subsequent Bischler-Napieralski cyclization followed by hydrogenation of the olefin moiety afforded the target ( )-alloyohimbane (82). 

---