Trimethyl-/3-cyclodextrins

LOD, limit of detection a-CD, a-cyclodextrin, fS-CD, (3-cyclodextrin CM-(3-CD, carboxymethyl- -cyclodextrin DM-p-CD, dimethyl- -cyclodextrin HP-(3-CD, hydroxpropyl- -cyclodextrin TM-(3-CD, trimethyl-(3-cyclodextrin, S- -CD, sulfated (3-cyclodextrin, SB- -CD, sulfobutyl-/i-cyclodextrin. 

Asymmetric Allylation. One of the recent new developments on this subject is the asymmetric allylation reaction. It was found that native and trimethylated cyclodextrins (CDs) promote enantiose-lective allylation of 2-cyclohexenone and aldehydes using Zn dust and alkyl halides in 5 1 H2O-THF. Moderately optically active products with ee up to 50% were obtained.188 The results can be rationalized in terms of the formation of inclusion complexes between the substrates and the CDs and of their interaction with the surface of the metal. 

PLATE I Determination of the enantiomeric purity of active pharmaceutical ingredient (main compound = MC, peak I is the enantiomeric impurity). Conditions lOOmM sodium phosphate buffer pH = 3.0, lOmM trimethyl -cyclodextrin, 60 cm fused silica capillary (effective length 50 cm) X 75 pm I.D., injection 10 s at 35 mbar, 25°C, 20 kV (positive polarity) resulting in a current of approximately lOOpA, detection UV 230 nm. The sample solution is dissolved in a mixture of 55% (v/v) ethanol in water. (A) Typical electropherogram of an API batch spiked with all chiral impurities, (B) overlay electropherograms showing the selectivity of method toward chiral and achiral impurities, a = blank, b = selectivity solution mixture containing all known chiral and achiral compounds, c = API batch, d = racemic mixture of the main compound and the enantiomeric impurity. 

Often dual chiral recognition systems ]462,463] involving mixtures of chiral SOs have been shown to enhance enantioselectivity. With dual systems of cyclodextrins (CDs), cationic mono(6-amino-6-deoxy)-p CD and a neutral CD (trimethyl-p-CD or dimethyl-p CD), it could be illustrated that arylpropionic acid enantiomers were baseline resolved, while with a single SO, no or insufficient separation of the enantiomers could be achieved [462J. 

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

Method of manufacture trimethyl-P-cyclodextrin is prepared from P-cyclodextrin by the complete methylation of all C2 and C3 secondary hydroxyl groups along with all C6 primary hydroxyl groups. 

Poly(benzimidazole) can be used as the reactive polymer for the preparation of side chain-type polyrotaxane via the alkylation on nitrogen. Osakada et al. showed that deprotonation of poly(benzimidazole) followed by N-alkylation with alkyl bromide-terminated pseudorotaxane consisting of 2,3,6-trimethyl-/1-cyclodextrin gave a novel side chain-type polyrotaxane (Scheme 38) [206]. Poly(benzimidazole) having a long -hydroxyalkyl group as the side chain can form an inclusion complex with 2,3,6-trimethyl-/l-cy-... 

Brij BSA Bu CBDTS CD CHIRAPHOS Cn COD Cp Cp CTAB DBA = seep.78 = bovine serum albumin = butyl = tetrasulfonated cyclobutane-DIOP, 37, see p. 17 = cyclodextrin = 2,3-bis(diphenylphosphino)butane = 1,4,7-trimethyl-1,4,7-triazacyclononane = 1,5-cyclooctadiene = r 5-cyclopentadienyl = ti5-CsMe5, r 5-pentamethylcyclopentadienyl = hexadecyltrimethylammonium bromide = 1,5-diphenyl-l, 4,-pentadiene-3-one (dibenzylideneacetone)... 

Fig. 3 GC-MS traces of PMANs derived from permethylation of (3-cyclodextrin, a Using NaOH-DMSO base b using dimsyl base. Peak 1 is due to 2,3,6-trimethyl-4-0-acetyl-glucose, and peak 2 to 2,6-dimethyl-3,4-di-0-acetyl-glucose. The latter peak is evidence of under-methylation of the 3-cyclodextrin at position 3 of each glucose residue...

Kawai M, Inoue Y, Critical difference in chiral recognition of N-benzyloxy-carbonyl-D/L-aspartic and -glutamic acids by mono- and bis(trimethyl-ammonio)-y -cyclodextrins A calorimetric and NMR study, J. Am. Chem. Soc. 2001 123 5360-5361. 

Hexyl neopentanoate Hydroxypropyl-a-cyclodextrin Hydroxypropyl-p-cyclodextrin Hydroxypropyl-y-cyclodextrin lodofenphos Isooctane Isosafrole Lindane Malaoxon Maleic anhydride Methanesulfonic acid Methyl isothiocyanate Nicotine N-Nitrosodiethanolamine N-Nitrosodimethylamine 2,2 -Oxybis (4,4,6-trimethyl)-1,3,2-dioxaborinane Parathion-methyl PEG-3 dimethyl ether Pennyroyal (Hedeoma pulegiodes) oil n-Pentane Perchloropentacyclodecane Potassium amyl xanthate Potassium n-butyl xanthate... 

He described how di- and trimethyl-i(- and fl-cyclodextrins could be used to improve the stability, solubility, dissolution rate and bioavailability of different drugs such as HCFU (6), Prednisolone and Vitamins Kl, K2 and K3. Looking to the future, the applications of hydroxypropylated, ethylated and maltosylated cyclodextrins were described. 

Columns (stationary phase) CHIRALDEX G-TA (Gamma trifluoroacetyl) CHIRALDEX B-DP (Beta dipropionyl) Rt-BDEXsm (Beta dimethyl, mono-t-butyl) Cyclosil-B (Beta dimethyl, mono-t-butyl) A-DEX 120 (Alpha methyl) B-DEX 120 (20% Beta methyl) G-DEX 120 (Gamma methyl) Chrompak Cyclodextrin- -2,3,6-M-19 (Beta trimethyl) Chrompak Chirasil-Dex C B (Beta unknown bonded phase)... 

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