Syntheses of novel glycosylidene-spiro-heterocycles related to hydantocidin (original) (raw)
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Tetrahedron: Asymmetry, 2001
The reaction of per-O-acetylated 1-bromo-1-deoxy-a-D-arabinopyranosyl cyanide with thiocyanate ions gave the corresponding 1-deoxy-1-thiocyanato-a-and b-D-arabinopyranosyl cyanides. In the reaction of the per-O-acetylated 1-bromo-1deoxy-b-D-xylopyranosyl cyanide and its per-O-benzoylated b-D-glucopyranosyl analogue the corresponding 2-hydroxy-glycal esters formed in addition to the anomeric pair of thiocyanato-cyanides. The formation of 2,3,4,6-tetra-O-benzoyl-a-D-glucopyranosyl thiocyanate was demonstrated in the reaction of benzobromoglucose with thiocyanate ions. The equilibrium constant between 2,3,4,6-tetra-O-acetyl-1-deoxy-1-thiocyanato-a-and b-D-galactopyranosyl cyanides was determined. Based on this value, the equilibrium ratio for the 2,3,4,6-tetra-O-acetyl-a-and b-D-galactopyranosyl thiocyanates was calculated to be 94:6, and the anomeric effect of the SCN group was estimated to exceed 3 kcal/mol. X-Ray crystallographic data support endo-and exo-anomeric effects of the SCN moiety.
Croatica Chemica Acta, 2005
Dithioanalogues of cycloalkanespiro-5-hydantoins were prepared by reaction of the respective spirohydantoins with Lawesson's reagent or P 4 S 10 . Cycloalkanespiro-5-(2-thiohydantoins) and cycloalkanespiro-5-(4-hydantoins) were also synthesized from cycloalkanespiro-5-(2,4-dithiohydantoins) via different reaction pathways. The structures of the compounds obtained were verified by 1 H, 13 C NMR and IR spectroscopy. Quantum-chemical calculations at the ab initio level of molecular nonlinear characteristics were performed. Increase of polarizability a and the second hyperpolarizability g with enlarging the saturated ring was observed in all the structures studied.
Molecules (Basel, Switzerland), 2017
Reactions of O-peracylated C-(1-bromo-β-d-glucopyranosyl)formamides with thioamides furnished the corresponding glucopyranosylidene-spiro-thiazolin-4-one. While O-debenzoylations under a variety of conditions resulted in decomposition, during O-deacetylations the addition of MeOH to the thiazolinone moiety was observed, and with EtOH and water similar adducts were isolated or detected. The structure and stereochemistry of the new compounds were established by means of NMR and electronic circular dichroism (ECD) data supported by time-dependent density functional theory ECD (TDDFT-ECD) calculations. TDDFT-ECD calculations could efficiently distinguish the proposed epimeric products having different absolute configuration in the spiro heterocyclic ring.
Carbohydrate Research, 2014
A novel series of 2 0 -spiro pyrimidine pyranonucleosides has been designed and synthesized. Their precursors, 2 0 -C-cyano nucleosides 5a,b and 6a,b, were obtained by subjecting 1a,b to the sequence of selective protection of the primary hydroxyl group, acetalation, oxidation, and finally treatment with sodium cyanide. Deoxygenation at the 2 0 -position of cyanohydrins 5a,b or 6a,b led to the 2 0 -deoxy derivatives 9a,b. Fully deprotection of 5a,b, 6a,b, and 9a,b gave the desired 2 0 -C-cyano 7a,b, 8a,b, and 2 0 -C-cyano-2 0 -deoxy pyranonucleosides 10a,b, respectively. Mesylation of the corresponding cyanohydrins 5a,b and 6a,b afforded compounds 11a,b and 12a,b which after base treatment and subsequent deprotection furnished the spiro nucleosides 15a,b and 16a. The new analogues were evaluated for their potential cytostatic activities in cell culture.
Indian Journal of Chemistry -Section B
A new series of novel 3-(5-aryl/aryloxy methyl-1,3,4-thiadiazol-2-yl)-spiro-cyclohexane-1'2-thiazolidin-4-ones have been synthesized from a common intermediate, in good yields. These compounds have been screened for their antibacterial and antifungal activity against different pathogenic strains of bacteria and fungi. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) have been determined for the test compounds as well as for reference standards. Compounds 3c, 3d, 6c and 6d have shown good antibacterial activity where as compounds 3a, 3b, 6a and 6b have displayed better antifungal activity.
Zenodo (CERN European Organization for Nuclear Research), 2008
The title compounds were prepared by the condensation of tetra-0-acetyi-P-o-galactopyranosyl isothiocyanate with several amines, 2-aminobenzothiazole/substituted benzothiazoles and alcohols respectively. The structure of these new N-galactoside has been established on the basis of usual chemical transformations and IR, NMR and Mass spectral studies of some typical cases. Keywotds : N-Galactosides, galactosyl isothiocyanate, galactosyl thiocarbamides, galactosyl benzothiazolyl thiocarbamides, galactosyl thiocarbamates.
Tetrahedron: Asymmetry, 2001
A stereocontrolled synthesis of pyranoid and furanoid spironucleosides and spiro-C-glycosides (D-ribo and D-arabino configurations) of oxazolidines, oxazolines and perhydrooxazines via isothiocyanato sugar derivatives is reported. The intermediate isothiocyanates are prepared from sugar spiroketals by stereoselective opening of the acetal ring with trimethylsilyl N-and C-nucleophiles, and later formation of the isothiocyanato group.