Synthesis of isomeric 2-oxazolidinones from (1<Emphasis Type="Italic">R</Emphasis>,2<Emphasis Type="Italic">R</Emphasis>)-and (1<Emphasis Type="Italic">S</Emphasis>,2<Emphasis Type="Italic">S</Emphasis>)-2-amino-1-(4-nitrophenyl)-1,3-propanediols

A synthesis is reported for (4R,5R)-and (4S,5S)-4-hydroxymethyl-5-(4-nitrophenyl)oxazolidin-2-ones and (1′R,4R)-and (1′S,4S)-4-[hydroxy(4-nitrophenyl)methyl]oxazolidin-2-ones from (1R,2R)-and (1S,2S)-2-amino-1-(4-nitrophenyl)-1,3-propanediols. The effect of the experimental conditions on the formation of these compounds was studied. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1562–1570, October, 2007.     

The reactivity of N,N-dialkyl-N-(3-phenylsulfinyltetrahydrofuran-2-ylidene)ammonium bromide

trans-Stereoselective electrophilic cyclization of (2R*,SS*)-N, N-diisopropyl-2-phenylsulfinylpent-4-enamide under the action of bromine afforded (3R*,5S*, SS*)-N-(5-bromomethyl-3-phenylsulfinyltetrahydrofuran-2-ylidene)-N,N-diisopropylammonium bromide. Its transformations under the conditions of hydrolysis, dehydrobromination, and hydride reduction were studied. Dedicated to Academician V. A. Tartakovsky on the occasion of his 75th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1485–1490, August, 2007.     

Synthetic study of hepoxilins

Total synthesis of trioxilin (10S,11S,12S)-B₃ was performed starting from a hepoxilin synthon, (2S,3S)-2,3-epoxyundec-5-yn-1-ol, available from the corresponding allylic alcohol by Sharpless enantiodirected epoxidation. The synthesis features stereoselective (7 ∶ 1)syn-addition of the acetylenide anion to the intermediate (2S,3S)-2,3-(isopropylidenedioxy)undec-5-yn-1-al and regioselective partial hydrogenation of a triacetylene trioxilin precursor, which allowed the preparation of 14,15-dehydro-(10S,11S,12S)-TrXB₃. For part 8, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 545–551, March, 2000.     

Synthesis and Stereochemistry of (1S,3S,4S,7R11R)-3-(4-Nitrophenyl)-11-aza-2,6-dioxatricyclo[5,3,1,04,11]undecane

The reaction of (1S,2S)-2-amino-1-(4-nitrophenyl)-1,3-propanediol with glutaraldehyde has been studied. It has been established on the basis of AM1 and PM3 calculations and ¹H NMR spectra recorded in the presence of the shift reagent Eu(fod)₃ that (1S,3S,4S,7R,11R)-3-(4-nitrophenyl)-11-aza-2,6-dioxatricyclo[5,3,1,0^4,11]undecane is formed as the result of the reaction.     

Hydrazinolysis of Compounds Containing Oxazolidine Ring

We have studied hydrazinolysis of (4S,5S)-3-benzyl-4-hydroxymethyl-5-(4-nitrophenyl)oxazolidine, (1R,4S,5S)-1-(4-nitrophenyl)-1-aza-3,7-dioxabicyclo[3,3,0]octane, and (1R,4S,5S)-1-benzyl-4-(4-nitrophenyl)-1-azonia-3,7-dioxabicyclo[3,3,0]octane. We have shown that neutral compounds are decomposed with opening of the oxazolidine ring, while quaternary ammonium salts react with hydrazine in several directions.     

Synthesis of 20S-protopanaxadiol 20-O-β-D-glucopyranoside, a metabolite of Panax ginseng glycosides, and compounds related to it

A preparative semi-synthetic method was developed to prepare 20S-protopanaxadiol 20-O-β-Dglucopyranoside (1), a metabolite of Panax ginseng glycosides. The 20-O-•-D-glucopyranosides of 20S-hydroxydammar-24-en-3,12-dione, 3β,20S-dihydroxydammar-24-en-12-one, and 3β,12α, 20S-trihydroxydammar-24-ene were synthesized for the first time. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 364–369, July–August, 2006.     

The effect of anions in the coordination spherè of Mg complexes ofN-acetyldehydrophenylalanyl-(S)-valine on the diastereoselectivity of hydrogenation

Diastereoselective hydrogenation in ethanol over Pd/C ofN-acetyldehydrophenylalanyl-(S)-valine (1) as complexes with Mg salts of strong acids gives predominantlyN-acetyl-(S)-phenylalanyl-(S)-valine (de up to 60%). In the case of complexes of1 with Mg salts of weak acids, the sign of asymmetric induction changes. Data of¹⁹F NMR spectroscopy ofN-acetyldehydro(p-fluorophenylalanyl)-(S)-valine indicate that in the former case, the anion of a strong acid does not enter the coordination sphere of the complex, whereas in the larter case, the anion of the weak acid does. The nature of the solvent also influences the reaction stereoselectivity. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1704–1706, September, 1999.     

Synthesis of derivatives of (S)-2-alkanols, components of pheromones ofDrosophila mulleri andRhyzopertha dominica, from (S)-(+)-3,7-dimethylocta-1,6-diene

Effective routes for the synthesis of (S)-2-acetoxytridecane, the sex pheromone of the fruit flyDrosophila mulleri, and (S)-1-methylbutyl 2-methyl- and 2,4-dimethylpent-2E-enoates, components of the aggregation pheromone of the lesser grain borerRhyzopertha dominica, were developed on the basis of (S)-4-methylhex-5-en-1-yl tosylate accessible from (S)-(+)-dihydromyreene. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1929–1931, November, 2000.     

Asymmetric Synthesis of （R）- and （S）-Moprolol

A simple and effective procedure for the enantioselective synthesis of （R）- and （S）-moprolol was described. The key step was the asymmetric synthesis of enantiopure （R）- and （S）-guaifenesin, which were synthesized from enantioenriched （R）-3-chloro-l,2-propanediol and （S）-epichlorohydrin via kinetics of hydrolysis resolution of racemic epichlorohydrin by chiral Salen-Co^Ⅲ complex. The e.e. values of both the optical compounds were above 98%, and the chemical structures of the target compounds were confirmed by ^1H NMR, ^13C NMR, IR, and MS.     

Synthesis ofS-(+)-methoprene

An optically active juvenile hormone analogue,S-(+)-methoprene (1), is synthesized in six steps from technical gradeS-(+)-3,7-dimethyl-1,6-octadiene ((+)-dihydromyrcene, e.e. –50%) by a novel procedure which begins with selective hydroalumination-oxidation to giveS-(-)-citronellol. This alcohol is oxidized to giveS-(-)-citronellal which on reaction with allylmagnesium chloride affords 6S, 10-dimethyl-1,9-undecadien-4 R/S-ol (5). Smidt-Moiseev oxygenation of 5 followed by dehydration leads to 6S, 10-dimethyl-3E,9-undecadien-2-one. The latter on treatment with isopropoxyethynylmagnesium bromide is transformed into isopropyl 3,7S,11-trimethyl-2E/Z,4,E,10-dodecatrienoate which upon Brown solvomercurationreduction in MeOH gives1 in 14% overall yield.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 108–109, January, 1993.     

Asymmetric hydrogenation of acetophenone catalyzed by cinchonidine stabilized Ir/SiO2

A series of silica (SiO₂) supported iridium catalysts stabilized by cinchona alkaloids was prepared and applied in the heterogeneous asymmetric hydrogenation of acetophenone. Cinchona alkaloids exhibited a marked ability to stabilize and disperse the Ir particles. In the presence of (1S,2S)-diphenylethylenediamine ((1S,2S)-DPEN)) as chiral modifier, the cinchonidine (CD) stabilized catalyst 5%Ir/2CD-SiO₂ exhibited excellent catalytic performance in the asymmetric hydrogenation of acetophenone in MeOH. Under the optimum conditions, the ee value of (R)-phenylethanol achieved 79.8% and no other product was produced, a higher enantioselectivity than that reported up to now for acetophenone hydrogenation catalyzed by the supported metal catalysts modified by chiral reagents. In particular, a synergistic effect between (1S,2S)-DPEN and CD was observed, which significantly accelerated the reaction rate and enhanced the enantioselectivity. The catalyst can be reused several times without a significant loss of activity and enantioselectivity.     

Synthesis of 1,11,11-trimethyl-3,6-diazotricyclo [6.2.1.0<Superscript>2,7</Superscript>]undeca-2,6-diene and 1,15,15-trimethyl-3,10-diazotetracyclo[10.2.1.0<Superscript>2,11</Superscript>.0<Superscript>4,9</Superscript>]pentadeca-2,4(9),5,7,10-pentaene from camphoroquinone enantiomers

Optically active camphordihydro-2,3-pyrazine and camphorquinoxaline were prepared from camphoroquinone enantiomers. It was shown that (1S,4R)-(+)-camphoroquinone was formed by oxidation of (1S,3R, 4R)-(−)-3-bromocamphor and (1R,4S)-(−)-camphoroquinone from (1R,3S, 4S)-(+)-3-bromocamphor, respectively. Camphor anhydride was a side product (6–10%) of the reaction. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 50–52, January–February, 2007.     

Classification of structurally related compounds fromAstragalus extract by correlation of the logk w andS

Summary The linear relationship between logk _w andS derived from molecular interactions and statistical thermodynamics was investigated by four series of different polar probe solutes. For each series of similar polar solutes, structurally related compounds with similar dipolarity/polarizability and hydrogen bonding energy, a linear relationship between logk _w andS was obtained. The more similar the solutes, the greater were the regression coefficients obtained. For two series of solutes with different strong polar groups resulting in different dipolarity/polarizability and hydrogen bonding energy, two parallel lines were observed in the logk _w-S plots. Each line represented one series of compounds and the distance between them indicated the difference in the dipolarity/polarizability and hydrogen bonding energy. Based on the parallel lines implying information on structurally related compounds in the logk _w-S plot, a method of classification of structurally related compounds was put forward and the linear logk _w-S correlation for unknown components in nonaqueous RP-HPLC analysis ofAstragalus extract with isopropanol-methanol mobile phase was studied. Two nearly parallel lines were obtained in the logk _w-S plot and two series of structurally related compounds were classified in this way.     

Synthesis of linear and angular anthraquinonoisothiazol-3-ones,their S-oxides,and S,S-dioxides

2-Methyltetrahydroanthra[2,3-d]isothiazole-3,5,10-trione and 2-R-tetrahydroanthra[2,1-d]isothiazole-3,6,11-triones were synthesized by the reactions of 3-chloro-9,10-dioxo-9,10-dihydroanthracene-2-carboxamide and 1-nitro-9,10-dioxo-9,10-dihydroanthracene-2-carboxamide with alkanethiols followed by cyclization of the resulting alkylthioamides into isothiazolones under the action of SO₂Cl₂. The products were oxidized to give the corresponding S-oxides and S,S-dioxides.     

Kinetic resolution of heterocyclic amines by reaction with optically active acid chlorides. The effect of reaction conditions on the diastereoselectivity of acylation of (±)-3-methyl-2,3-dihydro-4H-1,4-benzoxazine

The influence of the reaction conditions (solvent, base) on the diastereoselectivity of acylation of (±)-3-methyl-2,3-dihydro-4H-1,4-benzoxazine with (S)-naproxen and N-tosyl-(S)-proline chlorides was studied. The highest diastereoselectivity was observed for the reaction carried out in benzene in the presence of aliphatic tertiary amines.     

Asymmetric transfer hydrogenation of ketones catalyzed by rhodium and iridium complexes with chiral bidentate Schiff's bases

Rhodium and iridium complexes of Schiff's bases derived from (1R,2R)- and (1S,2S)-diaminocyclohexane catalyze asymmetric transfer hydrogenation of alkyl aryl ketones in PrⁱOH at room temperature to give chiral secondary alcohols (up to 65% ee).     

Synthesis of 3S-methylundec-1-ylbromide, a key synthon in the synthesis of (S,S,S)-diprionylacetate, from L-(-)-menthol

Three new approaches to the synthesis of 1-bromo-3S-methylundecane, a key synthon in the synthesis of (S,S,S)-diprionylacetate, a sex pheromone of pine sawflies of the genera Diprion and Neodiprion, were proposed based on chemo-and stereoselective transformations of L-(-)-menthol derivatives. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 73–76, January–February, 2006.     

The total synthesis of the archaebacterial C40-diol and its enantiomer based on (R)-5-acetoxy-4-methylpentanoic acid

Effective convergent syntheses of archaebacterial C₄₀-diol [(3R,7R,11S,15S,18S,22S, 26R,30R)-octamethyldotriacontane-1,32-diol] and its (3S,7S,11R,15R,18R,22R,26S,30S)-enantiomer have been accomplished using (R)-5-acetoxy-4-methylpentanoic acid as the only chiral building block. Both synthetic schemes include consecutive construction of mono- and diterpene fragments of the target molecules followed by dimerization using the Kolbe reaction or the oxidative self-condensation of the corresponding Grignard reagent.Deceased November 1, 1992.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1303–1309, July, 1993.     

New approach to nonracemic 1-alkylamino-3-aryloxypropan-2-ols belonging to β-blockers via cyclic sulfites

Nonracemic -blockers, viz., (S)-propranolol and (S)-timolol, were prepared from (S)-glycidol in three steps consisting in the reaction with SOCl₂ followed by the reaction of the resulting (4S)-4-chloromethyl-2-oxo-1,3,2-dioxathiolanes with the corresponding phenol and the final cleavage of (4R)-aryloxymethyl sulfites under the action of amines in DMF.     

Synthesis ofS-(+)-hydroprene

A novel path toS-(+)-hydroprene (1) starting from the technical gradeS-(+)-dihydromyrcene (2, e.e. 50%) is proposed. The latter was selectively transformed intoS-3,7-dimethyloctanal (5) in three steps including hydroalumination. The reactions of5 with allyl- or methallylmagnesium chloride followed, respectively, either by oxygenation in the presence of PdCl₂/CuCl or by ozonolysis, affordS,E-6,10-dimethyl-3-undecen-2-one (7) which was treated with ethoxyethynylmagnesium bromide to give the title juvenile hormone analogue in 23% overall yield.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No 1, pp. 110–112, January, 1993.