Synthesis of methyl 2,6-dideoxy-β-D-arabino-, 3,6-dideoxy-β-D-ribo-, and 4,6-dideoxy-β-D-xylo-hexopyranosides

A convenient method is proposed for the synthesis of methyl 1,6-dideoxy-β-D-arabino-, 3,6-dideoxy-β-D-ribo-, and 4,6,dideoxy-β-D-xylo-hexopyranosides by the partial deoxygenation of methyl β-D-quinovopyranoside followed by liquid chromatography of the dideoxysugars. Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 741–743, November–December, 1991.     

Synthesis of methyl 2,6- and 3,6-dideoxy-α-L-arabino-hexopyranosides and methyl 4,6-dideoxy-α-L-lyxo-hexopyranoside

A convenient method of synthesizing methyl 2,6- and 3,6-dideoxy-α-L-arabinohexopyranosides and of methyl 4,6-dideoxy-α-L-lyxo-hexopyranoside is proposed. Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Branch, USSR Academy of Sciences, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 320–322, May–June, 1990.     

Stereospecific Synthesis of D-Glycero-D-ido-oct-2-ulose

Summary.  D-Glycero-D-gulo-heptose reacted with 2,2-dimethoxypropane to give its 2,3:6,7-di-O-isopropylidene derivative. Its base-catalyzed addition to formaldehyde resulted in the formation of 2,3:6,7-di-O-isopropylidene-2-C-(hydroxymethyl)-D-glycero-D-gulo-heptofuranose. After acid hydrolysis of this aldolization product, a new branched-chain aldose, 2-C-(hydroxymethyl)-D-glycero-D-gulo-heptose, was obtained, which was stereospecifically rearranged under the catalytic action of molybdic acid to D-glycero-D-ido-oct-2-ulose. Received October 17, 2000. Accepted December 4, 2000     

Synthesis of 4-azafluorene derivatives based on 9-(3,6-diphenylpyridazin-4-yl)-4-azafluorene

The reaction of 9-(3,6-diphenylpyridazin-4-yl)-4-azafluorene with n-butyl acrylate under conditions of the Michael reaction affords the product of the condensation at the methine group. When sterically hindered esters of methacrylic, crotonic, and cinnamic acid are utilized, the condensation does not occur, and the main reaction product under these conditions is 9-hydroxy-(3,6-diphenylpyridazin-4-yl)-4-azafluorene. The supposition concerning the existence of its conformers (rotamers) with different orientation of the diphenylpyridazinyl ring in relation to the azafluorene fragment was expressed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1508–1511, November, 1993.     

Synthesis of 3,6-diazahomoadamantane

Condensation of 1-phenylsulfanylpropan-2-one with 1,3,6,8-tetraazatricyclo[4.4.1.1^3,8]dodecane gave 1-phenylsulfanyl-3,6-diazahomoadamantan-9-one which was reduced to 1-phenylsulfanyl-3,6-diazahomoadamantane, and the latter was subjected to desulfurization over Raney nickel to obtain previously unknown 3,6-diazahomoadamantane. Heating of 9-phenyl-3,6-diazahomoadamantan-9-ols with Raney nickel resulted in reduction of the hydroxy group with formation of 9-phenyl-3,6-diazahomoadamantanes.     

Chiral building blocks from biomass: 2,5-diamino-2,5-dideoxy-1,4-3,6-dianhydroiditol

An efficient route towards the synthesis of 2,5-diamino-2,5-dideoxy-1,4-3,6-dianhydroiditol 4 has been developed resulting in significant improvements in both isolated yields and purity when compared to literature procedures. As a consequence, resin-grade 2,5-diamino-2,5-dideoxy-1,4-3,6-dianhydroiditol 4 has become available for laboratory scale step-growth polymer synthesis. Additionally, an interesting renewable chiral 2-amino-2-deoxy-1,4-3,6-dianhydroiditol 10, has been isolated.     

Synthesis of 1-(pyridin-4-yl)-3,6-diazahomoadamantane and its derivatives

Condensation of 1-(pyridin-4-yl)propan-2-one with 1,3,6,8-tetraazatricyclo[4.4.1.1^3,8]dodecane gave 1-( pyridin-4-yl)-3,6-diazahomoadamantan-9-one as intermediate product in the synthesis of 1-(pyridin-4-yl)-3,6-diazahomoadamantane and its derivatives having functional substituents at the bridging carbon atom in the homoadamantane skeleton.     

Synthesis and conformational analysis of 1-[2,4-dideoxy-4-C-hydroxymethyl-alpha-l-lyxopyranosyl]thymine

Previously different types of nucleosides with a six-membered carbohydrate moiety have been evaluated for their potential antiviral and antibiotic properties and as building blocks in nucleic acid synthesis. However, a pyranose nucleoside with a 1,4-substitution pattern like 1-[2,4-dideoxy-4-C-hydroxymethyl-alpha-l-lyxopyranosyl]thymine (4) has not been studied yet. Modeling suggested that this nucleoside would show the (4)C(1) conformation in contrast to anhydrohexitol nucleosides (1) whose most stable conformation is (1)C(4). The key to the synthesis of 4 involves the stereoselective introduction of the hydroxymethyl group onto the C-4 carbon of the pyranose sugar. Attempts to achieve this via hydroboration/oxidation of a C-4'-exocyclic vinylic intermediate selectively yielded the undesired alpha-directed hydroxymethyl group. Therefore, we envisaged another approach in which the C-4 substituent was introduced upon treatment of 2,3-O-isopropylidene-1-O-methyl-4-O-phenoxythiocarbonyl-alpha-l-lyxopyranose with beta-tributylstannyl styrene. This allowed stereoselective beta-directed introduction of a 2-phenylethenyl group at C-4, which was converted via oxidation/reduction (OsO(4), NaIO(4)/NaBH(4)) into the desired 4-hydroxymethyl group (20). The resulting 1-O-methyl-2,3,6-tri-O-acetyl-protected sugar was coupled with silylated thymine, using SnCl(2) as Lewis acid (22). After suitable protection, Barton deoxygenation of the 2'-hydroxyl function of the obtained ribo-nucleoside yielded the desired 2'-deoxynucleoside 4, indeed showing the expected equatorial orientation of the thymine ring ((4)C(1)).     

Synthesis of 2, 3-dideoxy-4-O-p-methoxybenzyl-L-erythro-hex-2-enono-1, 5-lactone

The synthesis of 2, 3-dideoxy-4-O-p-methoxy-benzyl-L-erythro-hex-2-enono-1, 5-lactone 9 from L-serine, using (1RS, 3S)-3, 4-isopropylidene-1-methoxy-1-phenylthio-butan-2-one 2 as key chiral intermediate, is described. Compound 9 is an interesting chiral precursor for the synthesis of L-sugars.     

Synthesis of titanium(iv) 3,6-di-tert-butylcatecholate complexes

Russian Chemical Bulletin - Two synthetic approaches were used for the synthesis of 3,6-di-tert-butylcatecholate derivatives of titanium(iv). These approaches are based on the exchange reaction...     

Synthesis of the Antibiotic 1,5-dideoxy-1,5-imino-d-mannitol

Abstract

Easily accessible benzyl 2,3-O-isopropylidene-α-D-mannofuranoside (1) was converted in six steps into benzyl 2,3-O-isopropylidene-5-N-benzyl-5-deoxy-6-O-benzyl-α-D-mannofuranoside or benzyl 2,3-O-isopropylidene-5-azido-5-deoxy-6-O-benzyl-α-D-mannofuranoside. Both compounds afforded, after hydrogenolysis and acidolysis, 1-deoxymannojirimycin in an overall yield of 38% based on 1.     

(3E)-胆甾-4-烯-3,6-二酮-3-肟及其类似物的合成

以胆甾醇为原料,经氯铬酸吡啶氧化生成胆甾-4-烯-3,6-二酮(2),2与盐酸羟胺反应合成了(3E)-胆甾-4-烯-3,6-二酮-3-肟(3),总收率66%。利用合成3的反应条件合成了两个3的类似物——(3E)豆甾-4-烯-3,6-二酮-3-肟(6)和(3E)-谷甾-4-烯-3,6-二酮-3-肟(7)。2,3,6和7的结构经NMR和IR表征。     

3,6-二氨基-N-异丁基邻苯二甲酰亚胺的合成

以3-硝基邻苯二甲酸为原料,经脱水成酐、氨解、还原酰化、硝化、水解、还原等六步反应合成了一种新型的环芳酰胺的构筑单元对苯二胺衍生物——3,6-二氨基-N-异丁基邻苯二甲酰亚胺,总收率16.4％,其结构经1H NMR,13C NMR和ESI-MS表征.