Glucopyranosyl isothiocyanate using

Direct and indirect chromatographic methods were developed and compared in systematic examinations for the enantioseparation of P-amino acids direct separation of underivatized analytes involved the use of commercially available Crownpak CR(-I-), teicoplanin, and ristocetin A CSPs [148], while indirect separation was based on precolumn derivatization with 2,3,4,6-tetra-G-acetyl-f)-D-glucopyranosyl isothiocyanate (GITC) or A - a-(2,4-dinitro-5-fluorophenyl)-L-alaninamide (EDAA, Marfey s reagent), with subsequent separation on a nonenantioselective column. 

To evaluate the enantiomeric purity of (S,S)/(R,R)-statine, racemic mixtures and en-antiomerically enriched samples are analyzed by HPLC after derivatization with 2,3,4,6-tetra-0-acetyl- 3-D-glucopyranosyl isothiocyanate (GITC, 51 Scheme 21 and Table 7).[49 The GITC method also allows the determination of the enantiomeric composition of ethyl esters of statine analogues.[44 491 Another assay to determine the optical purity of statine has been developed, and uses l-G1u-NCA to produce dipeptides with different retention times in HPLC.[18]... 

Novel methods for reversed-phase, pressurized liquid-chromatographic resolution of nonesterified amino acid enantiomers by the formation of diastereoisomers using two chiral reagents, namely, 2,3,4,6-tetra-0-acetyl-/3-D-glucopyranosyl isothiocyanate (2) and 2,3,4-tri-O-acetyl-a-D-arabinopyranosyl isothiocyanate (30), have been reported.96,97... 

Alternative Reagents. 1-(1-Phenyl)ethyl isocyanate (PEI) is a cheaper alternative to NEI however, diastereomers formed from NEI are usually easier to separate by liquid chromatography. Other alternatives are also used, e.g. in determining the enantiomeric purity of 3-aminoquinuclidine, PEI, NEI, 2,3,4,6-tetraacetyl-p-D-glucopyranosyl isothiocyanate, and (R,R)- and (S,S)-0,0-dibenzoyltartaric acid anhydride are all employed successfully. Mandelic Acid and Mosher s reagent, a-methoxytrifluoromethylphenylacetyl chloride, may not be quite as effective as NEI when resolutions are carried out by liquid chromatography. ... 

To investigate the influence of the stereochemistry of the anomeric position on the inhibitory activities, the -anomer of trehazolin (252) was synthesized from the azide 239 and the /3-D-glucopyranosyl isothiocyanate derivative 254 [187]. To avoid anomerization and contamination of the a-anomer, 2-chloro-l-methylpyridinium iodide 255 was used in place of 2-chloro-3-ethylbenzoxazolium tetrafluoroborate 245 for the ring formation (O Fig. 9). 

To overcome the problems derived from formation of anomeric mixtures when O-benzylated glycosyl halides are used as precursors, Ledford and Carreira52 have disclosed an elegant synthesis of 2,3,4-tri-O-benzyl-a-D-glucopyranosyl isothiocyanate (10) based on the use of l,6-anhydro-2,3,4-tri-0-benzyl-/t-i)-glucopyranose (9) as the glycosyl donor. Treatment of 9 with tetra-n-butylammonium thiocyanate and boron trifluoride-etherate complex provided 10 in 50% yield with total control of the anomeric configuration (Scheme 5). 

Jochims [134] and Hassan s [135] groups reported the efficient use of l-aza-2-azoniaallene salts 119 and 0-acetylated j6-D-glucopyranosyl isothiocyanate 89 for the preparation of glucopyranosylimino-l,3,4-thiadiazoles 121 and 122. These salts, prepared from chloroalkylazo derivatives 118 and antimony (V) chloride, can undergo 1,3-dipolar cycloadditions with multiple bonds-containing compounds, such as alkynes, alkenes, isocyanates, isothio-... 

It should be emphasized that these factors are not pre-requisites but merely indicate structural features which can be used to identify the more useful reagents e.g. thioureas from catecholamines and 2,3,4,6-tetra-O-acetyl- -D-glucopyranosyl isothiocyanate (GITQ and 2,3,4-tri-O-acetyl-a-D-arabinopyranosyl isothiocyanate (AITC) were separated [12] because of their structural rigidity and hydrophobicity, even though the distance between the chiral centres is greater than three bonds. ... 

Tetra-O-acetyl- and benzoyl-P-D-glucopyranosyl isothiocyanate continue to find use as derivatizadon reagents in h.p.Lc. methods for resolving enandomeric amines as their diastereomeric glycosylthiourea derivadves. Terminal epoxides could be similarly resolved when reacted with butylamine prior to derivadzadon. ... 

Indirect chiral separation was performed derivatizing metoprolol, oxprenolol, and propranolol with 5-(- -)-benoxaprofen chloride, pindolol with 2,3,4,6-tetra-0-acetyl-/S-D-glucopyranosyl-isothiocyanate and propranolol, alprenolol, pindolol, oxprenolol, and bunitrolol with f -(—)-l-(l-naphthyl)ethyl isocyanate. The formed derivatives were further resolved to antipodes using achiral stationary phases. 

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