One-pot syntheses of 2-pyrazoline derivatives

Hydrazinediium dithiocyanate and α,β-unsaturated ketones give in one-pot reactions 1-thiocarbamoyl-2-pyrazolines and 1-formyl-2-pyrazolines. The syntheses of pyridine-2-thiones, pyrimidine-2-thiones and bicyclo[2.2.2]octan-2-ones from ammonium thiocyanates and ketones by analogous procedures are reviewed. The mechanisms of the ring formations are discussed. Crystal structure analyses of a 1-thiocarbamoyl- and a 1-formyl-2-pyrazoline are given.     

One-pot enantioselective syntheses of iminosugar derivatives using organocatalytic anti-michael-anti-aza-Henry reactions

Organocatalyst-controlled asymmetric anti-Michael reactions of (tert-butyldimethylsilyloxy)acetaldehyde with a range of nitroolefins, followed by an intermolecular aza-Henry reaction with imine, provided iminosugar derivatives with five contiguous stereocenters in very high enantiomeric excess in one pot. The stereochemistry of the aza-Henry reaction was substrate controlled and is explained by a six-membered cyclic transition-state model.     

One-pot syntheses of 6-mercaptopurines (6MP) from 4,5-diamino-6-chloro-pyrimidines

A one-pot synthesis of 6-mercaptopurines from 4,5-diamino-6-chloro-pyrimidine, an aldehyde and elemental sulfur is presented. The key advantage of this procedure is that it utilizes the in situ generated H₂S to convert the chloro to a mercapto group.     

One-pot syntheses of novel pyrazole-containing bisphosphonate esters at room temperature

An efficient general synthetic approach has been developed to synthesize pyrazole-containing bisphosphonate (N-BPs) esters from chromenone derivatives via a sequential two-step reaction in one pot at ambient temperature in good to excellent yields. This protocol provides a new convenient method to prepare lipophilic bisphosphonate precursors with potential activities.     

The syntheses of pteridin-2-one derivatives from diaminomaleonitrile (DAMN)

1,3-Dimethyl-4-iminopteridin-2-one, 1,3-dimethylpteridine-2,4-dione, 1-methylpteridine-2,4-dione, 4-alkoxy-1-methylpteridin-2-one, and 4-alkylamino-1-methylpteridin-2-one were synthesized from diaminomaleonitrile (DAMN) through pyrazine-2,3-dicarbonitrile. The synthetic procedures consist of the condensation of DAMN with glyoxal, the nucleophilic substitution of pyrazine-2,3-dicarbonitrile with methylamine, the reaction of 3-methylaminopyrazine-2-carbonitrile with electrophiles such as methyl isocyanate and methyl chloroformate in the presence of sodium hydride, and the transformation of 3-(methoxycarbonylmethyl)aminopyrazine-2-carbonitrile into the pteridine derivatives.     

Alkyl(aryl)oxy derivatives of thulium(III)

The reactions of Tml₂(DME)₃ with phenol andtert-butyl alcohol afforded thulium(III)-alkoxyiodides ROTmI₂(DME)₂ (R=Ph and Bu^t, respectively). Their structures were determined by X-ray analysis. Monoiodides (RO)₂ TmI(THF)₂ were synthesized from TmI₃ (THF)₂ and ROH (taken in a ratio of 1∶2). Triphenoxides (RO)₃Tm (R=Ph or 2,4,6-Bu^t ₃C₆H₂) were prepared by the reactions of the naphthalene thulium complex [C₁₀H₈Tm(DME)]₂C₁₀H₈, with an excess of the corresponding phenol. The iodide catechoxide complex 3,6-Bu^t ₂C₆H₂O₂TmI(DME)₂ was prepared by the reaction of TmI₂(DME)₃ with 3,6-di-tert-butylbenzoquinone-1,2 or 3,6-di-tert-butylpyrocatechol. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1804–1807, September, 1999.     

Polyfuryl(aryl)alkanes and their derivatives

The reduction of 2-nitrophenyldifurylmethane with SnCl₂ leads to an indolenyl ketone as a result of intramolecular heterocycloaddition of the intermediately formed nitroso derivative. During the reduction of 2-nitroaryldifurylmethanes in the Zn+HCl or NH₂NH₂·H₂O+Pd/C systems, 2-aminoaryldifurylmethanes are formed; when treated with trityl perchlorate, their acetyl derivatives are converted into indolo[2,3-h]-1-oxazulenium perchlorates.For Communication 14, see [1].Kubansk State Technological University, Krasnodar. Severo-Osetinsk State University, Vladikavkaz. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1614–1621, December,1997.     

室温条件下硝酸铋高效催化“一锅法”合成4(3H)-喹唑啉酮衍生物

<正>4(3H)-喹唑啉酮及其衍生物具有抗疟疾、抗癌、抗痉挛、消炎、抗菌等多种生理活性[1-5]。因此,该类化合物的合成引起了人们极大的兴趣。1895年,Niementowski[6]发明了一种简单且易操作的合成4(3H)-喹唑啉酮的方法,该方法在1946年     

One-pot synthesis of azanucleosides from proline derivatives

Common cyclic amino acids, derived from proline and hydroxyproline, can be readily transformed into azanucleosides. The mildness of the reaction conditions, and the good yields obtained, make this procedure an interesting alternative to the conventional processes.     

One-pot synthesis of aryl biaryl sulfones

Synthesis of aryl biaryl sulfones 3 with good yields is described. The one-pot efficient synthetic route is carried by the NaH-mediated tandem [C3+C3] annulations of cinnamaldehydes 1 and propargylic sulfones 2 under the boiling THF conditions.     

Stereospecific syntheses of new manganese(I) isocyanide derivatives

Three series of cationic manganese(I) carbonyls are reported: [Mn(CO)_5-n(CNMe)_n(CNPh)]PF₆ (n = 1 → 4), [Mn(CO)_5-n(CNMe)(CNPh)_n]PF₆ (n = 1 → 4), and [Mn(dpe)(CO)_4-n(CNMe)_n]PF₆ (n = 1 → 4). Most of these compounds were prepared from a substituted metal carbonyl halide by replacement of halide ion by an added ligand (CNR or CO), such reactions requiring an added halide ion acceptor (Ag⁺ or AlCl₃). The added ligand enters the site of departing halide ion. It was possible to prepare isomers of many compounds reported, taking advantage of this stereospecificity. Structures of the products were defined, often unequivocally, by infrared and nmr spectroscopic data. Cyclic voltammetry showed that these compounds undergo one electron oxidations, the ease of oxidation determined by the nature of the ligand groups and the stereochemistry.     

One-pot synthesis of tripodal tris(2-aminoethyl)amine derivatives from seven molecular components

Complex tripodal tris(2-aminoethyl)amine (tren)-based ligands have been prepared in a single-pot reaction of tren with 3 equiv each of cyclohexenone and a benzaldehyde derivative (i.e., from seven components and three molecular types). The highest yield of product was obtained for p-nitrobenzaldehyde, the most electrophilic aldehyde used.     

Polyfuryl(aryl)alkanes and their derivatives. 14. Halochromism of polyfuryl(aryl)alkanes

It was concluded on the basis of the similarity between the electronic spectra of difurylarylmethanes and trifurylalkanes and the spectra of the corresponding arylfurylcarbinols and difurylcarbenium perchlorates in concentrated sulfuric acid that the appearance of color in the solutions of polyfuryl(aryl)alkanes in concentrated sulfuric acid results from their disproportionation at the carbon-carbon bond with the elimination of the furan ring. The disproportionation of difurylalkanes, containing a methine hydrogen atom at the central carbon atom, under these conditions is accompanied by hydride transfer.For Communication 13, see [1].Kubansk State Technological University, Krasnodar. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 738–741, June, 1996. Original article submitted February 21, 1996.     

Stereoselective syntheses of pharmaceutically relevant chiral tetrahydrofurans from (S)- and (R)-glyceraldehyde derivatives

A practically simple and flexible method of making chiral tetrahydrofurans of therapeutic relevance is reported from glyceraldehyde derivatives as chiral synthons. One of the stereocentres is derived from glyceraldehyde derivatives, while the other one is introduced by Sharpless asymmetric epoxidation using either (+)- or (−)-DIPT.     

Stereodivergent syntheses of anisomycin derivatives from D-tyrosine

[structures: see text] Enantiomerically pure 2-alkyl-3-acetoxy-4-iodopyrrolidines with all groups cis, and all adjacent groups trans (10 and 17), important precursors for the synthesis of pyrrolidinediols, have been prepared from D-tyrosine through regio- and diastereoselective reduction of a vinyl ketone and subsequent iodoamidation controlled by minimization of nonbonding steric interactions. Highly stereodivergent Woodward-Prevost methodology, applied to both iodopyrrolidines, yielded enantiomerically pure (2R,3R,4R)-, (2R,3R,4S)-, and (2R,3S,4R)-deacetylanisomycin (3, 4, and 5), each in excellent de. Incorporation of differential protection of the hydroxyl groups led to a one-pot synthesis of (2R,3R,4R)-anisomycin 2.     

One-pot formation of allylic chlorides from carbonyl derivatives

An efficient, one-pot method for the conversion of carbonyl electrophiles to allylic chlorides has been developed, by activating magnesium alkoxides in situ using TiCl4.     

Convenient syntheses of isomaltose derivatives from amygdalin

The isomaltose trichloroacetimidate 7 was synthesized in five steps from d-amygdalin. The key step in this series of reactions was the acid catalyzed rearrangement of the inter-glycosydic bond to give the thermodynamically more stable α-anomer. The reaction was also applied to different di-, tri-, and tetrasaccharide derivatives of amygdalin giving the corresponding rearrangement products.     

One-pot synthesis of bis (phenylimino dihydro thiazolyl-2H-chromene) derivatives

A novel series of bis (phenylimino dihydro thiazolyl-2H-chromene) derivatives have been synthesized through an efficient one-pot multicomponent approach involving different substituted of 3-(2-bromoacetyl)-2H-chromen-2-ones, phenyl isothiocyanates and para-phenylenediamine in presence of dimethylformamide solvent. The target compounds were obtained in a shorter reaction time through simple reaction work up with good yields. All the synthesized products were characterized by their spectral and analytical data like IR, ¹H NMR, ¹³C NMR, Roesy, and mass spectral data.