Dimethylated P-cyclodextrin

Monflier et al. (1995) have intensified the rate of the oxo reaction of sparingly soluble olefins like 1-decene using dimethyl p-cyclodextrine, which seems to form inclusion complexes with the olefin and deliver it in the aqueous phase. 

Monflier et al. (1997) have suggested Pd catalysed hydrocarboxylation of higher alpha olefins in which chemically modified P-cyclodextrin (especially dimethyl P-cyclodextrin) is u.sed in water in preference to a co-solvent like methanol, acetone, acetic acid, acetonitrile, etc. Here, quantitative recycling of the aqueous phase is possible due to easy phase separation without emulsions. A similar strategy has been adopted by Monflier et al. (1998) for biphasic hydrogenations for water-in.soluble aldehydes like undecenal using a water-soluble Ru/triphenylphosphine trisulphonate complex with a. suitably modified p-cyclodextrin. 

Separation of the enantiomers of a series of local anaesthetics through their interaction with dimethyl p-cyclodextrin included In the running buffer. Redrawn from Reference 6. 

Table 14.3 Association constants of some enantiomers of some local anaesthetics with dimethyl P-cyclodextrin and their mobilities in free solution...

A chiral selector can also be dissolved in the IL solvent and be subsequently coated on the capillary wall [38]. In this approach, the achiral [C4CiIm]Cl was used to dissolve permethylated p-cyclodextrin (p-PM) and dimethylated P-cyclodextrin (p-DM). The chromatographic separations obtained from these two columns were compared to two commercially available CSPs based on p-PM and p-DM dissolved in polydimethylsiloxane. From a set of 64 chiral molecules separafed by fhe commercial p-PM column, only 21 of the molecules were enantioresolved by the IL-based p-PM column. Likewise, from a collecfion of 80 analytes separated by the p-DM column, only 16 analytes could be separated on the IL-based p-DM column. The authors also noted a considerable enhancement in the separation efficiency of fhe IL-based CSPs. This resulf, coupled to fhe loss of enantioselecfivify for mosf separations, suggests that the imidazolium cation may occupy the cavity of the cyclodextrin preventing the analyte-cyclodextrin inclusion complex-ation that is crucial for chiral recognition. The ability for ILs to form inclusion complexes wifh cyclodextrin molecules has been recently studied by Tran and coworkers using near-infrared spectromefry [39]. 

Celebi, N. and Nagai, T. 1988. Improvement of dissolution characteristics of piromidic acid by dimethyl-p-cyclodextrin complexatiotfDrug Dev. Ind. Pharm14 63-75. 

Hydroxy propyl-p-cyclodextrin and especially dimethyl-p-cyclodextrin have been shown to enhance the pulmonary bioavailability of insulin in rats, and indications were found of a relatively low acute mucotoxicity. " ... 

Szatmari, I. Vargay, Z. Pharmacokinetics of dimethyl-P-cyclodextrin in rats. Proceedings of the 4th International Symposium on Cyelodextrins. Huber, O., Szejtli, J., Eds. Kluwer Academic Publishers Dordrecht, Netherlands, 1988 407 13. 

Dimethyl-P-cyclodextrin 2-hydroxyethyl-P-cyclodextrin 2-hydroxypropyl-P-cyclodextrin 3-hydroxypropyl-P-cyclo-dextrin trimethyl-P-cyclodextrin. 

Surface tension 62 mN/m (62 dynes/cm) at 25°C Method of manufacture dimethyl-P-cyclodextrin is prepared from P-cyclodextrin by the selective methylation of all C2 secondary hydroxyl groups and all C6 primary hydroxyl groups (C3 secondary hydroxyl groups remain unsubstituted). 

Dilute ammonia solution Dilute hydrochloric acid Dilute phosphoric acid Dilute sulfuric acid Dimethyl-P-cyclodextrin Dioctyl phthalate Dipotassium edetate Docusate calcium Docusate potassium Dodecyl gallate... 

Hermans WAJJ, Deurloo MJM, Romeyn SG, et al. Nasal absorption enhancement of 17 P-estradiol by dimethyl-P-cyclodextrin in rabbits and rats. Pharm Res 1990 7 500-503. 

Horiuchi, Y, Kikuchi, M., Hirayama, F. etal. Improvement of bioavailability of menaquinone-4 by dimethyl-p-cyclodextrin complexation following oral administration. Yakugaku. Zasshi 1988,108, 1093-1100. 

Kikuchi, M., Uekama, K. Enhancement of antimmor activity of carmofur (HCFU) by dimethyl-p-cyclodextrin complexation in P-388 leukemia-bearing mice. Xenobiotic Metab. Dispos. 1988, 3, 267-273. 

FIGURE 4.2. Response surface plots of the (a) resolution between (D)Arg-Phe-PheOH and Tyr-(D)Arg-Phe-PheNH2 and (b) migration time of Phe-PheOH as the last migrating impurity as a fimction of the significant variables acetonitrile content and concentration of 2,6-dimethyl-P-cyclodextrin. (Reproduced with permission from Reference 25.)... 

Szejtli, J. (1983) Dimethyl-P-cyclodextrin as parente dmg carrier. J. Incl. Phenom. 1 135-150. 

Ueno, M., Ijitsu, T., Horiuchi, Y., et al. (1989) Improvement of dissolution and absorption characteristics of ubidecarenon by dimethyl-p-cyclodextrin complexation. Acta Pharm. Nord. 2 99-104. 

Uekama, K., Horiuchi, Y., Kikuchi, M., et al. (1988) Enhanced dissolution and oral bioavailability of a-tocopheryl esters by dimethyl-P-cyclodextrin complexations. J. Incl. Phenom. 6 167-174. 

Hoshino, T., Ishida, K., Me, T., et al. (1989) An attempt to reduce the photosensitizing potential of chlorpromazine with the simultaneous use of P- and dimethyl-P-cyclodextrins in guinea pigs. Arch. Dermatol Res. 281 60-65. 

Freeze-diying in the presence of heptakis-(2,6-0-dimethyl)-p-cyclodextrin... 

Isolation of intermediate, metastable polymorphs can generally be achieved by inhibiting their transformation to stable forms through the mediation of additives. A recent report on tiie isolation of a metastable form (Form IV) of tolbutamide (Figure 1, 3) is a case in point [17]. This species crystallized exclusively from an aqueous solution containing dimethylated p-cyclodextrin (DMB), whereas tiie stable form (I) crystallized in the absence of DMB. The proposed mechanism involves inhibition of the solution-mediated transformation of Form IV to Form I by complexation of tolbutamide with DMB. While not yet established as a general method, it is likely that this approach will be applied to the isolation of metastable polymorphs of other organic substrates. 

Selective substitution at the primary positions on two adjacent rings in cyclodextrins is now possible following the finding that l,3-di-(chlorosulfonyl)-4,6-dimethoxybenzene forms a cyclic disulfonate with these hydroxyl groups on heptakis-2,3-dimethyl P-cyclodextrin. Subsequent straightforward reactions led to 6a,6b-di-p-allyloxyphenyl-P-cyclodextrin permethyl ether. ... 

D.W. Armstrong, X. Wang, L.W. Chang, H. Ibrahim, G.R. Reid III and T.E. Beesley, Comparison of the Selectivity of P-cyclodextrin vs. Heptakis-2,3,-0-Dimethyl-P-cyclodextrin LC Stationary Phases for Structural and Geometric Isomers, J. Liq. Chromatogr. Relat. Technol, 20(20)(1997)3297. 

Yue J, Xu J, Chen Y, Chen SN (1994) Diterpenoid alkaloids from Aconitum talassicum. Phytochemistry 37(5) 1467-1470 Yue J, Xu J, Zhao Q, Sun H, Chen Y (1996) Diterpenoid tilkaloids from Aconitum leucostomum. J Nat Prod 59(3) 277-279 Yue ME, Jiang TF, Shi YP (2004) Fast determination of flavonoids in Hippophae rhamnoides and its medicinal preparation by capillary zone electrophoresis using dimethyl-P-cyclodextrin as modifier. Talanta 62(4) 695-699... 

Chiral stationary GC phases based on IL coating have been reported in which either a chiral IL was applied or a chiral molecule was dissolved within the IL film. Berthod et al. were the first to dissolve two chiral selector molecules, namely, permethylated-P-cyclodextrin (BPM) and dimethylated-p-cyclodextrin (BDM), in [BMIM]C1 and tested the as-prepared GC columns in the separation of 64 chiral compounds [41], Comparison with two commercial chiral columns, Chiraldex B-PM (20 m length, 250 pm inner diameter) and Chiraldex B-DM (20m length, 250 pm iruier diameter) was also made. The BDM-[BMIM]Cl-coated column produced efficiencies commonly 700% higher than the corresponding values obtained with the commercial BDM Chiraldex column. The difference was lower for the BPM-[BMIM]Cl-coated column, but stiU this column showed twice the efficiency compared to the BPM Chiraldex column. 

Inclusion Dimethyl p-cyclodextrin Aminoalcohols, carboxylic acids CE [9,10]... 

Tetradeca-O-Me Hepta-kis(2.6-dimethyl) cyclomaltoheptaose. Dimethyl-P-cyclodextrin. DIMEB [51166-71-3]... 

Dunethylamino)-2,3,6-trideoxy-ara >ino -hexose, D-726 3-(Dunethylamino)-2,3,6-trideoxy-/jxo -hexose, D-727 a-(5,6-Dimethylbenzimidazoyl)cobamide cyanide, V-26 Di-O-methylbergenin, B-29 Dimethyl-p-cyclodextrin, C-172... 

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