Esterified quaternaries

Predicted concentration in a raw sewage for non-esterified quaternary intermediates calculated from per capita use, population served and prevailing plant flows. bMeasured. 

Description. Esterified quaternaries (or esterquats) are produced by the esterification of the hydroxyl group(s) of secondary or tertiary amino alcohols (e.g., diethanol amine, imidazoline derivative, etc.) with selected fatty acids. The above starting amino alcohols can result from the ethoxylation of straight amines. The resulting esteramine is further quatemized by adequate quatemizing agents (e.g., dimethylsulfate, methylchloride, etc.). 

HA and three different HA esters, supplied by Fidia Advanced Biomaterials SpA (Padua, Italy), were examined. HA esters were prepared by treating a quaternary ammonium salt of HA with an esterifying agent in a suitable aprotic solvent at a controlled temperature as described in detail elsewhere [2]. In this study we analyzed the following esters ethyl ester (HYAFF7), benzyl ester (HYAFFl 1), and dodecyl ester (HYAFF73 Figure 1). The materials used were both films and powders. Films were obtained by a phase inversion process from DMSO solutions as previously described [2,4]. 

Carbon-13 n.m.r. spectroscopy has been used to study benzylisoquinoline and tetrahydroisoquinoline alkaloids and their JV-methyl quaternary salts.30 N-Benzylpapaverinium bromide has been shown to undergo aerial oxidation in alkaline solution to 2-benzyl-6,7-dimethoxyisoquinolone and to give bases of general structure (10) with methylamine, benzylamine, and pyrrolidine.31 Chlorosulphonation of papaverinol affords the sulphonic acid ester (11), mild hydrolysis of which yields the acid (12), which with diazomethane is esterified and dehydrated to (13).32 N-Methyl-l,2-dihydropapaverine has been shown by kinetic studies and orbital-symmetry requirements to rearrange to the salt (14) by the route previously postulated.33... 

The codeimethines can be esterified [5, 32-34, 14, 16-17, 20, 35-37] and methylated. Methylation can be accomplished by methyl sulphate or methyl iodide and cold 1 N. alkali, when quaternary salts of the methyl ethers are obtained [38-39]. The methyl ethers, however, are best prepared by degradation of the corresponding codeine methyl ethers. In this way a- [39-40], y- [41], and e- [41-42] codeimethine methyl ethers have been prepared, and the first two named can be converted to the /3- and 8-isomers respectively on heating with alcoholic alkali [39, 41]. Emde degradation of codeine methyl ether metho-chloride affords exclusively a-codeimethine methyl ether [43]. Hofmann degradation of the methiodides of /3- [38] and e- [42] codeimethine methyl ethers affords methylmorphenol [xvi, R = Me], ethylene, trimethylamine, and methanol. 

Variables in the production of tributyl phosphate have been discussed. In the presence of relatively large amounts (5—15 molar equivalents) ofcaesium fluoride or quaternary ammonium fluorides, 2,2,2-trichloroethyl phosphate esters readily trans-esterify with alcohols the sequential replacement of trichloroethyl groups becomes slower, so allowing the preparation of mixed (including cyclic) trialkyl phosphate esters, with the exception of those from t-butyl alcohol. ... 

HOCH2CH2N(CH3)3+, a quaternary amine. The OH-group can be esterified with many groups esters are substrates. 

A resolution involving an enantioselective process has been described by Pirkle. The racemic N -protected leucine 22 was esterified by p-bromophenacyl bromide under phase-transfer conditions. The acid was transported from the aqueous phase into the organic phase (CCI4) selectively by the association of a quaternary ammonium chloride and a chiral selector 23. The extracted ester 24 (40%) showed 87% ee. Both the phase-transfer quaternary ammonium catalyst and the chiral selector were necessary for stereoselection [45]. 

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