Gas-liquid partition chro~natography has been used to separate the fully acetylated derivatives of tetritols, pentitols, hexitols, heptitols, octitols, and anomeric glycoses. DISCUSSIONGas-liquid partition chromatography (G.L.P.C.) has already been shown to be a powerful technique for the preparative separation and for the qualitative and quantitative analysis of carbohydrate derivatives. Bishop and his co-workers (1, 2) were the first to report the separation of methyl 0-methyl glycosides by G.L.P.C. and have since demonstrated the use of such separations in the analysis of these derivatives obtained from the fission of methylated polysaccharides (3,4,5). Kircher (6) has also described the G.L.P.C. separation of methylated methyl glycosides employing other types of liquid phases. (7), 0-methyl-0-acetyl glycitols (S), 0-acetyl glycitols (9), and other carbohydrate derivatives (10) have also been successfully resolved using the G.L.P.C. technique. 0-Methyl aldonolactonesIn view of its potential use in the field of carbohydrate chemistry, a systematic program was undertaken in this laboratory t o explore the conditions under which favorable separations of a variety of carbohydrate derivatives inight be undertaken using G.L.P.C. This paper records the results obtained in investigations into the separation of glycitol and glycose acetates. Until recently the methods available for the separation of acetylated glycitols and glycoses involved coluinn chron~atography on a Magnesol-Celite or Silene E F -Celite ( l l a ) mixture using benzene -tert-butyl alcohol as the mobile phase, cellulose column chromatography, or paper chromatography ( l l b ) . I t is considered that the G.L.P.C. method of separation will provide a more rapid and refined procedure.The recorded separations were carried out using samples of the acetate derivatives (2-5 y ) developed on a Pye Gas Argon Chromatograph fitted with an ionization detector (12), and in cases where larger amounts of material (20-200 mg) were used for preparative work, the Burrell Kromo-Tog, Model K-2 apparatus was used. Experience with other types of chromatographic equipment showed that it was necessary for the sample to be injected directly onto the column packing material in order t o prevent the decomposition of the samples, which was observed when a dead space existed between the injection site and the beginning of the column packing material. In this connection it is important t o note that small gaps in the packing material itself should be avoided and that the detector should be placed as close as possible t o the end of column packing for satisfactory results.Acid-washed Chromosorb W or silver-coated Chromosorb W proved to be a suitable inert support which did not show excessive adsorption of the acetate derivatives. The non-polar liquid phases chosen were Apiezoil M vacuum grease or Dow Corning stopcock grease, and the polar phase selected was butailediol succinate polyester. Columns prepared containing 20% w/w of the non-polar liquid phases gave fair separa...

The reaction of the dimeric nitrosyl chloride adducts of tri-0-acetyl-D-glucal and tri-0-acetyl-Dgalactal with alcohols and phenols in dimethylformamide at room temperature provides the corresponding tri-0-acetyl-2-oximino-a-D-hexopyranoside in good t o excellent yields. The condensation can also be carried out in tetrahydrofuran in the presence of pyridine or simply in refluxing methylene chloride for the simple alkyl alcohols. The stereospecificity of the reaction is extreme; only products of one configuration for both glycosidic linkage and the oximino group were detected. This result is rationalized on the basis of a cis-configuration for a tri-0-acetyl-2-nitroso-D-glycal intermediate in the H1 half-chair conformation. The introduction of methyl groups on the carbon of the methoxy group of methyl a-D-glucopyranosides causes a progressive deshielding of the anomeric proton. The data indicate that isopropyl a-D-glycopyranosides avoid the orientation for the aglycon which has the anomeric hydrogen projecting between the two methyl groups of the aglycon. Methyl tri-0-acetyl-6-0-(tri-0-acetyl-2-oximino-~-~-ara6ir~o-hexopyranosyl)-~-~-gucopyranoside was prepared in 70% yield to illustrate the use of the method for the preparation of an a-linked disaccharide.

Cyclamate, cyclohexylamine, N-hydroxycyclohexylamine, and dicyclohexylamine can induce chromosomal damage in human leukocyte cultures.

Deoximation of 3,4,6-tri-O-acetyl-2-oximino-α-D-arabino-hexopyranosides to the corresponding 2-ulosides followed by borohydride reduction affords the α-D-glucopyranosides in excellent yields.

Hydrogenation of alkyl 2-oximino-or-D-arnbino-hexopyranosides in the presence of palladium on charcoal and hydrochloric acid gave mixtures of the alkyl 2-amino-2-deoxy-or-D-hexopyranoside hydrochlorides with the gluco and tnniii~o configurations in about 90% yields. The fraction of gl~tco compound varied substantially with the nature of the alkyl group; viz., methyl, 71 %; ethyl or 11-propyl, 62%; isopropyl, 80 %. More of the Inatvzo compound is formed, viz., isopropyl, 50 %, when the 3,4,6-triacetate of the oximinoglycoside is hydrogenated. Hydrogenation of methyl 6-0-(2-oximino-a-Dnrabit~o-hexopyranosy1)-8-D-glucopyranoside gave an about equimolar mixture of the two configurations.Canadian Journal of Chemistry, 46, 397 (1968) The occurrence of 2-amino-2-deoxy-a-glycopyranosyl groups in a wide variety of antibiotics (1) has rendered the synthesis of such glycosides (a-glycosaininides) a leading problem in carbohydrate chemistry. p-Glycosaminides in which the aglycon is either the residue of a simple alcohol or a more complex carbohydrate structure can normally be obtained via the KoenigsKnorr reaction or its modifications (2). The yield depends strongly on the complexity of the potential aglycon. To date there exists no controlled synthesis of complex a-glycosaminides in appreciable yield. Of the various methods employed, alcoholysis of the parent sugar or derivative in the presence of acid proceeds in best yield (3). However this method is inherently limited to simple acid-resistant alcohols. For more coinplex alcohols, for example appropriately blocked carbohydrate structures, only low yields of a-glycosaminides are available usually via Koenigs-Knorr type reactions (4). The reduction of the 2-oximino-a-hexopyranosides, which are formed in high yield on reaction of alcol~ols with the nitrosyl chloride adduct of acetylated glycals (5, 6), offered a new approach to these compounds and is the subject of this paper. The work is concerned mainly with the preparation of alkyl glycopyranosaminides from simple alkyl (methyl, ethyl, iz-propyl, and isopropyl) alcohols which are normally best prepared by alcoholysis of the aminosugars. Nevertheless, the data provide an insight to the factors which affect the stereochemical routes of the reductions. Also, the result obtained in the pre-'Presented at the Symposium on Synthesis, Organic Division, Chemical Institute of Canada, Banff, Alberta, August 31 -September 2, 1966.paration of a mixture of methyl 6-0-(2-amino-2-deoxy-a-D-glucopyran0syl)-p-D-glucopyranoside with the corresponding a-D-manno isomer is described as an illustration of an a-linked disaccharide synthesis.The alkyl 2-amino-2-deoxy-a-D-glucopyranosides formed in the reductions were identified by direct comparisons with authentic samples prepared from D-glucosamine and this comprises proof of the a-D-configuration for the parent oxinzino-glycosides.' The formation of alkyl 2 -amino -2-deoxy -a -D -mannopyranosides was based on this fact together with nuclear magnetic resonance (n.m.r.) data for these compoun...