Synthetic routes to the stereoisomers of 2,4-dimethylpentane-1,5-diol derivatives

Five different routes to every stereoisomer of non-symmetric derivatives of 2,4-dimethylpentanedioic acid and/or of O-monoprotected 2,4-dimethylpentane-1,5-diols, which are common building blocks for the total synthesis of many polypropionates, have been investigated. Alkylation of the lithium enolate of N-propanoylpseudoephedrine turned out to be the most appropriate method, in connection with the synthesis of fragment C1-C5 of amphidinolide K.     

Formation of spiro and ansa derivatives in the reaction of 2,2,3,3,4,4-hexafluoropentane-1,5-diol with cyclotriphosphazene: Comparison with 2,2,3,3-tetrafluorobutane-1,4-diol

Reaction of cyclophosphazene, N₃P₃Cl₆ (1), with the sodium derivative of the fluorinated diol, 2,2,3,3,4,4-hexafluoropentane-1,5-diol (2), in THF solution at room temperature afforded five isolated products, whose structures have been characterised by X-ray crystallography and ¹H, ¹⁹F and ³¹P NMR spectroscopy: the mono-spiro compound, N₃P₃Cl₄(OCH₂CF₂CF₂CF₂CH₂O) (3), its ansa isomer (4), a di-spiro derivative N₃P₃Cl₂(OCH₂CF₂CF₂CF₂CH₂O)₂ (5), its spiro-ansa (6) isomer and the tri-spiro compound N₃P₃(OCH₂CF₂CF₂CF₂CH₂O)₃ (7). Quantitative ³¹P NMR measurements of the soluble portion of the reaction mixture show that in the reaction of (1) with the sodium derivative of the fluorinated pentanediol (2) there is a small preference for spiro compounds compared to ansa compounds (ratio ca. 1.3:1), similar to the analogous reaction of (1) with the sodium derivative of the fluorinated butanediol where there is a slightly greater proportion of spiro compared to ansa compounds (ratio ca. 1.5:1). The relative proportions of spiro and ansa compounds is likely to depend on the fine balance in stabilities of the different medium-sized rings in the fluorinated pentanediol (spiro, 8- and ansa, 10-membered rings) compared to the fluorinated butanediol (spiro, 7- and ansa, nine-membered rings) derivatives of cyclophosphazene.     

Polynuclear heterocyclic systems based on naphthalene-1,5-diol: I. Reaction of naphthalene-1,5-diol and its derivatives with β-dicarbonyl and α,β-unsaturated carbonyl compounds

Reactions of naphthalene-1,5-diol and its derivatives (5-methoxynaphthalen-1-ol, 2-bromo-5-methoxynaphthalen-1-ol, and 2,6-di-tert-butylnaphthalene-1,5-diol) with ethyl acetoacetate, acetylacetone, and p-methoxycinnamic acid under acidic conditions (HCl, HClO₄, CF₃CO₂H) gave substituted benzo[h]-chromenes, naphtho[1,2-b]pyrylium salts, and 3,4-dihydrobenzo[h]chromenes, respectively. Possible mechanisms were proposed for the observed acid-catalyzed heterocyclizations.     

Controlled reversal of chemoselectivity in reactions of allyltitanium ate complexes with carbonyl compounds

Allyltitanium ate complexes react either aldehyde- or ketone-selectively, depending upon the nature of the ligands at titanium.     

Some new derivatives of 2-butene-2,3-diol cyclophosphoric acid

Conclusions The following 2-oxo-4,5-dimethyl-1,3,2-dioxaphospholenes have been prepared: the 2-chloro-, 2-diethylamino-, 2-di-n-butylamino-, and 2-ethylmercapto- derivatives.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2362–2364, October, 1968.     

Amphiphilic propane-l,2-diol derivatives incorporating calamitic structural units

Novel amphiphilic propane-1,2-diol derivatives incorporating a wide variety of calamitic structural units, like biphenyl, dicyclohexyl. phenylbemzoate, phenyl pyrimidine and phenylthiadiazole, were synthesized and their mesomorphic behaviour studied. Most of these compounds exhibit broad smectic A and C mesophases in the water-free state. These mesophases could be stabilized further by addition of water. The transition temperatures depend mainly on the hydrophilic properties of the rigid core and on the length of the spacer by which the core is connected to the diol unit.     

1,1,4,4-tetranitrobutane-2,3-diol and its derivatives. 2. Chlorination and bromination of 1,1,4,4-tetranitrobutane-2,3-diol. crystal structure of halogen derivatives of 1,1,4,4-tetranitrobutane-2,3-diol

The bromination of 1,1,4,4-tetranitrobutane-2,3-diol in 60% acetic acid gave 1,4-dibromo-1,1,4,4-tetranitrobutane-2,3-diol in satisfactory yield. The chlorination of 1,1,4,4-tetranitrobutane-2,3-diol under analogous conditions gave 1,4-dichloro-1,1,4,4-tetranitrobutane-2,3-diol as a crystal hydrate. Drying of this latter product in vacuum over phosphorus pentoxide gave 1,4-dichloro-1,1, 4,4-tetranitrobutane-2,3-diol in quantitative yield. The structures of these products were determined by x-ray diffraction structural analysis. The crystal chemical analysis and quantum chemical calculations established an increase in secondary oxygen-halogen interactions in the halodinitromethyl fragment with increasing atomic number of the halogen atom.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2372–2380, October, 1991.     

The chemistry of 1,5-diketone derivatives. 2. Preparation of 2-hydroxy-1,3,5-triphenyl-1,5-pentanedione and some heterocycle derivatives

The preparation of 2-hydroxy-1,3,5-triphenyl-1,5-pentanedione by the addition of -hydroxy- or -acetoxyacetophenone to chalcone is described. The 2-hydroxy-1,5-diketone obtained does not show a tendency to form an intramolecular hemi-acetal; instead, an acetate is formed. Reaction with hydroxylamine hydrochloride gives 3-aza-2,8-dioxa-1,4,6-triphenylbicyclo[3.2.1]oct-3-ene, and with ammonium acetate 2,4,6-triphenylpyridine and 3-amino-2,4,6-triphenylpyridine are formed. On reaction with p-toluenesulfonic acid the hydroxydiketone is converted into 3-oxo-2,4,6-tripheny1-2,3-dihydro-4H-pyran.Communication 1, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1321–1324, October, 1986.     

Stereoinversion in the diastereoselective acylation of benzoxazine derivatives with 2-aryloxypropionyl chlorides

Russian Chemical Bulletin - A comparative study of the kinetic resolution of racemic derivatives of 3,4-dihydro-3-methyl-2H-[1,4]benzoxazine using racemic 2-aryloxypropionyl chlorides was...     

Electrophilic selenocyclization in 2-ene-1,5-diol systems: unexpected oxetane vs. tetrahydrofuran formation

Electrophile-induced cyclization of (E)- and (Z)-2-ene-1,5-diols to tetrahydrofurans and oxetanes is described. Significant differences between the present report and previous work have been noted. A tentative model is proposed.     

Friedel-Crafts acylation of 5-hydroxybenzimidazole derivatives

The Friedel-Crafts acylation of 5-hydroxybenzimidazole and its 2-methyl and 1-ethyl-2-methyl derivatives proceeds exclusively at C⁴ and only with aliphatic acid derivatives.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1928–1931, August, 1991.     

1,4- and 1,5-bromine shifts in the acylation of alkynes

Conclusions Acylation of alkynes with - or-bromoacylium tetrafluoroborates forms substituted Z--bromovinyl ketones as a result of the conjugate addition of the acylium cation and 1,4- or 1,5-bromine migration from the acyl group.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1559–1562, July, 1978.     

Study of acylation reactions in 3-aminocarbostyril derivatives

Acylation of 3-amino-1(2H)-isoquinolinone may proceed at three points – at the oxygen atom of the carbonyl group, at the nitrogen atom of the 3-amino group, and at the carbon atom in position 4 of the isoquinolinone fragment. Factors influencing the results of the reactions have been determined, and conditions have been found for the synthesis of three types of products – 4-(acyl)-3-(R-amino)-1(2H)-isoquinolinones, N-(1-oxo-1,2-dihydro-3-isoquinolinyl)-R-amides, and esters of 3-(R-amino)-1-iso-quinolinol.     

Synthesis of 2-aryl-1,5-dihydro-1-azapyrene derivatives

Belorussian State Technological University, 220630 Minsk. translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7. pp. 1002–1003, July, 1995. Original article submitted Junne 26 1995.     

Synthesis and characterization of spiro-, ansa-, and spiro-ansa-cyclic derivatives of cyclotetraphosphazene with the reactions of pentane-1,5-diol

The reactions of octachlorocyclotetraphosphazatetraene, N₄P₄Cl₈ (1) with difunctional aliphatic reagent, HO-(CH₂)₅-OH (3) have aroused a good deal of attention, and four types of products have been realized: one 2-open chain-(1′-oxy-5′-hidroxy-pentane)-2,4,4,6,6,8,8-heptachlorocylotetraphosphazatetraene, N₄P₄Cl₇[O(CH₂)₅OH] (4); one 2,2-mono-spiro-(1′,5′-pentanedioxy)-4,4,6,6,8,8-hexachlorocyclotetraphosphazatetraene, N₄P₄Cl₆[O(CH₂)₅O] (5); its isomers 2,4-mono-ansa-((1′,5′-pentanedioxy)-2,4,6,6,8,8- hexachlorocyclotetraphosphazatetraene (6) and 2,6-mono-ansa-(1′,5′-pentanedioxy)-2,4,6,6,8,8-hexachlorocyclotetraphosphazatetraene (7); one 2,2,6,6-dispiro-(1′,5′-pentanedioxy)-4,4,8,8-tetrachlorocyclo- tetraphosphazatetraene, N₄P₄Cl₄[O(CH₂)₅O]₂ (8); two isomeric 2,4,6,8-bisansa-(1′,5′-pentanedioxy)-2,4,6,8-tetrachlorocyclotetraphosphazatetraene (9) and 2,6,4,8-bisansa-(1′,5′-pentanedioxy)-2,4,6,8-tetrachloro-cyclotetraphosphazatetraene (10); one 4,4,8,8-dispiro-2,6-ansa- (1′,5′-pentanedioxy)-2,6-dichlorocyclotetra-phosphazatetraene, N₄P₄Cl₂[O(CH₂)₅O]₃ (11), one 2,2,4,4,6,6-trispiro-(1′,5′-pentanedioxy)-8,8-dichlorocyclo-tetraphosphazatetraene, N₄P₄Cl₂[O(CH₂)₅O]₃ (12); and a 2,2,4,4,6,6,8,8-tetraspiro-(1′,5′-pentanedioxy)-cyclotetraphosphazatetraene derivative, N₄P₄[O(CH₂)₅O]₄, (13). The respective structures were deduced by means of elemental analysis, mass spectrum, and ³¹P, ¹H, and ¹³C nuclear magnetic resonance spectroscopic investigations.     

The acylation of 2-butyne by derivatives of 1- and 2-adamantanecarboxylic acids

Conclusions The acylation of 2-butyne by derivatives of 1- and 2-adamantanecarboxylic acid leads to the formation of 1,2-disubstituted and condensed adamantane derivatives.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2515–2521, November, 1979.     

Synthesis and acylation of 1,2,3,4-tetrahydroisoquinoline derivatives

1,2,3,4-Tetrahydroisoquinolines were synthesized, and their acylation was studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 780–783, June, 1993.