摘要:

It has been found that the thiocarbonate, or (alkylthio)carbonyl derivative, serves as a versatile blocking group for the synthesis of partial ester derivatives of carbohydrates. The (alkylthio)carbonyl group is readily substituted in pyridine solution, is stable to mild acid conditions, but is decomposed by mild oxidation. Crystalline methyl 4,6-di-O-benzoyl-α-D-glucopyranoside has been synthesized and its structure proved by an independent synthesis of its 2,3-di-O-phenylcarbamate derivative. Methyl 4,6-di-O-benzoyl-β-D-glucopyranoside was also synthesized and its structure proved by acetylation to the known 2,3-di-O-acetyl derivative.

ISSN:0008-4042    

DOI:10.1139/v62-313

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

Methylation of the anhydro base derived from 1-methyl-3,4-dihydro-β-carboline methiodide is accompanied by ring opening and yields 3-[2-acetylindolyl]-β-ethyltrimethylammonium iodide, and not a 2,2-dialkyl-1-methylene-1,2,3,4-tetrahydro-β-carbolinium salt, as reported.

ISSN:0008-4042    

DOI:10.1139/v62-314

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

The methiodide of 3,4-dihydro-β-carboline yields a dimeric anhydro base which, on heating, disproportionates to a β-carboline and a tetrahydro-β-carboline derivative, and on methylation is converted to 3-[2-formylindolyl]-β-ethyltrimethylamnionium iodide.

ISSN:0008-4042    

DOI:10.1139/v62-315

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

The diffuse absorption bands of HON14O, HON16O, DON16O, and DON15O in the near ultraviolet have been examined. Transitions from both rotational isomers of nitrous acid contribute to the vibrational structure, with the excited state σ(N=O) stretching vibrations active in the most intense progressions. The cis–trans energy separation increases from 500 cal/mole in the ground state to 1200 cal/mole in the upper state. This is attributed to weakening of the internal hydrogen bond in the cis state upon an electronic promotion of primarilynO → π* type. The accompanying change in geometry is responsible for the appearance of the cis ground-state δ(ONO) bending mode in the spectrum.

ISSN:0008-4042    

DOI:10.1139/v62-316

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

Polysaccharide B-1459 is the first bacterial polysaccharide reported to contain pyruvic acid as a constituent. The polysaccharide, isolated as the potassium salt, was shown to be composed ofD-glucose,D-mannose, andD-glucuronic acid, acetic acid, and pyruvic acid in the ratio 2.8:3.0:2.0:1.7:0.51–0.63. One-third of the total mannose was released readily as free mannose by graded acid hydrolysis with only a slow loss of the high solution viscosity. The remainder of the mannose was isolated as the acid-stable aldobiouronic acid 2-O-(β-D-glucopyranosyluronic acid)-D-mannose. Partial acid hydrolysis and preparative paper chromatography afforded two higher oligosaccharides: an aldotriouronic acid composed of glucuronic acid β-linked 1,2 to mannose with glucose as the reducing end group, and what appears to be an aldotetraouronic acid composed of glucuronic acid, mannose, and glucose.

ISSN:0008-4042    

DOI:10.1139/v62-317

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

Whole starch, amylose, amylopectin, and glycogen (polymeric carbohydrates of the α-D-glycosidic linkage type) were nitrated by nitric acid in the presence of phosphoric anhydride and stability properties of the nitrated products were studied. Crude amylose nitrate is more stable than amylopectin nitrate and the latter is less stable than the whole-starch nitrate as judged by the Bergmann–Junk test. The stability of glycogen nitrate is closely similar to that of amylopectin nitrate.Appreciable stabilization of the crude nitrates was brought about by boiling with slightly alkaline water for long periods (60–70 hours). All stabilized samples were found to possess closely similar stability properties. The Bergmann–Junk values of all examined nitrates ranged from 2.2 to 1.7 mg of nitrogen per gram sample; the latter value seems to represent the maximum stabilization which could be attained for the polymeric carbohydrate nitrates of the α-D-glycosidic linkage type. In the case of cellulose nitrate (β-D-glycosidic linkage type) Bergmann–Junk values of 1 to 1.25 mg of nitrogen were obtained.

ISSN:0008-4042    

DOI:10.1139/v62-318

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

Seed oils were hydrolyzed under mild conditions and the major conjugated fatty acid of each oil was isolated and identified. In two families, species which were closely related botanically contained different but isomeric acids. Thus, in the Bignoniaceae,Jacarandacheloniahadcistrans,cis-8,10,12-octadecatrienoic acid as a major acid whileCatalpaspeciosahadtrans,trans,cis-9,11,13-octadecatrienoic acid. In the Cucurbitaceae,Momordicacharantiahad the ordinarycis,trans,trans-9,11,13-octadecatrienoic (α-eleostearic) acid whileM.balsaminahadcis,trans,cis-9,11,13-octadecatrienoic (punicic) acid.M.balsaminais a new and convenient source of punicic acid. α-Eleostearic acid was identified as a major acid in examples of Valerianaceae and Rosaceae. Further proof was obtained that the fatty acid ofCalendulaofficinalis(Compositae) istrans,trans,cis-8,10,12-octadecatrienoic acid.

ISSN:0008-4042    

DOI:10.1139/v62-319

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

Sesquiterpene compounds were effectively separated by gas chromatography and identified by infrared spectrophotometry. Examples given include the recovery and characterization of β-caryophyllene and β-humulene from oil of balsam copaiba, of α- and β-vetivone from oil of vetiver, and of α- and β-santalol from oil of sandalwood.

ISSN:0008-4042    

DOI:10.1139/v62-320

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

The alkaloids ofLycopodiumclavatumvar.megastachyonhave been examined and two hitherto unreported alkaloids, lycoclavine and acetyllycoclavine, were isolated and their structures determined. The nuclear magnetic resonance spectra of these and related compounds are discussed in terms of the conformation of ring B in these alkaloids.

ISSN:0008-4042    

DOI:10.1139/v62-321

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

The controlled periodate degradation of the synthetic xylan resulted in the formation of ethylene glycol, glycerol, xylose, and at least eight non-reducing oligosaccharides. The composition, approximate D.P., periodate oxidation, and possible structure of these oligosaccharides are reported and discussed.

ISSN:0008-4042    

DOI:10.1139/v62-322

出版商:NRC Research Press    

年代:1962

数据来源: NRC