13-顺-4-羰基维甲酸葡萄糖酯的合成与表征

13-顺维甲酸与溴代-2,3,4,6-四-O-乙酰基-α-D-吡喃葡萄糖在4-二甲氨基吡啶催化下合成了13-顺维甲酸葡萄糖酯(5),以二氧化锰为氧化剂,5经氧化成功地合成了新化合物13-顺-4-羰基维甲酸葡萄糖酯(6)。5和6的结构经1H NMR,13C NMR,IR和MS表征,结果表明5和6均为β-构型糖酯。     

Synthesis and Reactions of 4-Chromanones

Many natural products, such as the plant insecticides rotenone and ageratochromene (precocene), some fungitoxic phytoalexins, hashish constituents, vitamin E, and plant pigments, contain the chroman ring system as common structural unit. Some years ago we discovered a particularly simple entry to this class of heterocyclic compounds: The condensation of o-hydroxyacetophenones with aliphatic aldehydes and ketones in the presence of pyrrolidine leads to 4-chromanones in good yields. The scope of application and limitations as well as modification of this versatile synthesis are outlined; the accompanying tables give a good indication of the wealth and variety of possible substituents. The reaction of o-hydroxyacetophenone, e. g. with glyoxylic acid or with α,β-unsaturated ketones, proceeds atypically. The majority of the new chromanones can be used, inter alia, for the preparation of chromones, chromones and chromons, and for the synthesis of tricyclic and larger ring systems.     

Synthesis of 2- and 3-alkyl(aryl)-cis-1-thiadecalins

Conclusions For the first time cis- and trans-2- and 3-alkyl-cis-1-thiadecalins were synthesized and some of their physical constants were examined.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 393–399, February, 1989.     

Synthesis and Aromatization of Ethyl Esters of cis-4-(Methanesulfonyl)-cis-5-arylprolines. Unusual Synthesis of 5-Aryl-2-acetylpyrrole

Russian Journal of Organic Chemistry - 1-Bromovinyl and vinyl methyl sulfones undergo 1,3-dipolar cycloaddition reactions with azomethinylides generated in situ from ethyl N-benzylideneglycinates...     

Triethylenetetramine(3-sulfinatopropanoato-O,S)cobalt(III) isomers: Synthesis and structure of α-cis-[Co(Trien)(O2CC2H4SO2)]ClO4 · 2H2O and β-cis-[Co(Trien)(O2CC2H4SO2)]ClO4

The α-cis-and β-cis-isomers of (triethylenetetramine)(3-sulfinatopropanoato-O,S)cobalt(III) cation were synthesized and crystal structures of their perchlorates were established. The 3-sulfinatopropanoate anion, which forms six-membered ring with the Co atom, is bonded to the latter through the S atom and the carboxyl O atom.     

Reactions of Polyhalopyridines. 16. Synthesis and Reactions of 2,3,5,6-Tetrafluoro-4-perfluoroalkylthiopyridines

Identical reaction products, viz. 2,3,5,6-tetrafluoro-4-perfluoroalkylthiopyridines 3a-c, were obtained on thermal decomposition of Xe(II) bisperfluoroalkylcarboxylates in the presence of mercaptotetrafluoropyridine and bis(2,3,5,6-tetrafluoro-4-pyridyl) disulfide. Compounds 3a-c readily interact with N-, O-, and S-containing nucleophiles, though with the first two types of reactant only with substitution of fluorine atoms in position 2 of the pyridine ring. In the latter case products are obtained both with retention of the perfluoroalkylthio group on interaction with sodium N,N-dimethyldithiocarbamate, and with total fission of that group in the case of alkali metal methanethiolate and toluenethiolate.     

The Synthesis of 4-Arylcarbonyl-3-methoxycarbonyl-2-phenylfurans by Friedel-Crafts Acylation Reactions

Keto esters 8, 4-arylcarbonyl-3-methoxycarbonyl-2-phenylfurans, potential precursors of the synthesis of furofuran lignans, were obtained from dimethyl 2-phenylfuran-3,4-dicarboxylate 2.Diester 2 was selectively hydrolyzed to monoacid 6 followed by converting to its acid chloride 7.Friedel-Crafts acylation reactions of 7 with aromatic compounds afforded keto esters 8.The geometric structures of 8 and its precursors were elucidated and verified by NMR spectra.     

Reactions of 4-methylidenedioxolan-2-ones with 2-methyltryptamines. Synthesis of core analogs of aurantioclavine

4-Hydroxy-4,5,5-trimethyl-3-[2-(2-methyl-7-R-1H-indol-3-yl)ethyl]-1,3-oxazolidin-2-ones (R = H or Alk), which were synthesized from 4-methylidene-1,3-dioxolan-2-one and substituted 2-methyltryptamines, undergo intramolecular amidoalkylation when treated with polyphosphoric acid. First representatives of a new heterocyclic system, viz., oxazolo[3",4":1,2]azepino[5,4,3-cd]indole, which are core analogs of aurantioclavine, were prepared.     

Synthesis and Reactions of Some 1-Thiapyran-4-One Derivatives

The preparation of some 3,5-diarylidene-1-thipyran-4-one derivatives (Ia-e) was described. Oxidation of Ia, b and Ie with hydrogen peroxide gave the corresponding dioxides (IIa-c). Reaction of the 1-thiapyran-4-one derivatives with bromine, Grignard reagents, and amines were studied. Structural assignments are supported by spectral (UV, IR, and ¹HNMR) data.     

Efficient Synthesis of 4-Amino-4-deoxy-L-arabinose and Spacer-equipped 4-Amino-4-deoxy-L-arabinopyranosides by Transglycosylation Reactions

Methyl 4-azido-4-deoxy-β-L-arabinopyranoside has been synthesized in five steps starting from methyl β-D-xylopyranoside in a multigram scale without chromatographic purification in 78% overall yield. The transformation relied on selective tosylation/nosylation at O-4 followed by acylation, S(N)2 displacement with sodium azide and subsequent deprotection. The methyl 4-azido-4-deoxy-arabinoside was then converted into allyl, propenyl, ω-bromohexyl and chlorethoxyethyl spacer glycosides by transglycosylation with the respective alcohols in good yields and fair anomeric selectivity. Reduction of the azido group and further transformations of the aglycon afforded ω-thiol-containing spacer derivatives. Coupling to maleimide-activated BSA provided a potent immunogen which was used to generate murine and rabbit polyclonal sera binding to LPS-core epitopes containing 4-amino-4-deoxy-arabinose residues.     

Synthesis and Selected Reactions of 4(5)-Functionalized 2(3)-Furoyl Phosphonates

Russian Journal of General Chemistry - Approaches to the synthesis of a wide range of phosphorylated derivatives of 3-(furyl)acrylic acid and 4-(furyl)buten-2-one with various functional groups in...