Indole derivatives. 138. Synthesis of α-(5-indolyl)ethylamine and 5-(2-aminoethoxy)- and 5-(aminoethylthio)tryptamines

The reaction of 5-acetylindole with hydroxylamine with subsequent reduction of the resulting oxime gave -(5-indolyl)ethylamine. Coupling of 4-(2-phthalimidoethoxy)- and 4-(2-phthalimidoethylthio)phenyldiazonium chlorides with ethyl -acetyl--phthalimidovalerate, subsequent cyclization of the resulting hydrazones, hydrolysis, decarboxylation, and removal of the phthalyl protecting group led to the formation of 5-(2-aminoethoxy)- and 5-(2-aminoethylthio)tryptamines, respectively.For Communication 137, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 46–48, January, 1992.     

3-ethyl-3-phenylazetidinone-2—I. Synthesis of (R)-, (S)- and (RS)-monomer,polymerization and properties of polymers

Synthesis and optical resolution of 3-ethyl-3-phenylazetidinone-2 were improved to obtain (RS)-, (R)- and (S)-monomers having optical purities up to 98%, which could successfully be determined by ¹H-NMR 250 MHz using tris[3-(2,2,2-trifluoro-l-hydroxymethylidene)d-camphorato]europium III as a shift reagent. These monomers were polymerized anionically in HMPT using potassium salt as a catalyst and by the addition of 1-acetyl-4,4-dimethylazetidinone-2 as a chain initiator. Optical purity of the starting monomer seemed to be maintained in the resulting polymers, the thermal properties of which were found to depend on the mean length of the stereoblocks contained in the chain. While the reactivity, in particular the case of polymerization, of monomer increased with the optical purity, no evidence could be obtained for stereoregulation by a preferential incorporation of a monomer enantiomer according to the configuration of the growing chain end unit.     

Synthetic methods for (Exo,Exo)- and (Exo-,Endo)-2,6-Diarylbicycio [3:3:0] octane lignans: Syntheses of (±)-aptosimon, (±)- styraxin, (±)- asarinin,and (±)- pluviatilol

Short practical syntheses are reported of the title lignans (9a) , (9c) , (13a), and (13b).     

2-Polyfluoroalkylchromones. 11. Synthesis and structures of 5-hydroxy-3-(2-hydroxyaryl)-5-polyfluoroalkyl-Δ2-pyrazolines and 3(5)-(2-hydroxyaryl)-5(3)-polyfluoroalkylpyrazoles

The reaction of 2-hydroxy-2-polyfluoroalkylchroman-4-ones with hydrazine affords 5-hydroxy-3-(2-hydroxyaryl)-5-polyfluoroalkyl-²-pyrazolines, whereas 2-polyfluoroalkylchromones under similar conditions produce 3(5)-(2-hydroxyaryl)-5(3)-polyfluoroalkylpyrazoles. 5-(2-Hydroxyaryl)-1-methyl-3-polyfluoroalkylpyrazoles were synthesized in the reaction with methylhydrazine, and the reaction with phenylhydrazine afforded regioisomeric 3(5)-(2-hydroxyphenyl)-1-phenyl-5(3)-polyfluoroalkylpyrazoles.     

Asymmetric synthesis of (?)-(R)-massoia lactone, (R)-δ-decalactone, and (+)-(3R,5R)-3-hydroxydecano-5-lactone. Formal synthesis of verbalactone

A simple and efficient procedure for the asymmetric synthesis of (?)-(R)-massoia lactone, (R)-??-decalactone, and (+)-(3R,5R)-3-hydroxy-1,5-decanolide is described. Verbalactone was synthesized using Heck allylation at the key stage of construction of the carbon skeleton.     

Cyclization of α- and β-amino ketones. (Review)

In this review data on the synthesis of three-, four-, five-, and six-membered heterocycles, as well as of condensed heterocyclic compounds from -amino ketones and Mannich bases are classified for the first time.Samara State Technical University, Samara 433100, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 723–735, June, 1999.     

Why are SiX5(-) and GeX5(-) (X = F, Cl) stable but not CF5(-) and CCl5(-)?

The possible existence of the CF(5)(-), CCl(5)(-), SiF(5)(-), SiCl(5)(-), GeF(5)(-), and GeCl(5)(-) anions has been investigated using ab initio methods. The species containing Si and Ge as central atoms were found to adopt the D(3h)-symmetry trigonal bipyramidal equilibrium structures whose thermodynamic stabilities were confirmed by examining the most probable fragmentation channels. The ab initio re-examination of the electronic stabilities of the SiF(5)(-), SiCl(5)(-), GeF(5)(-), and GeCl(5)(-) anions [using the OVGF(full) method with the 6-311+G(3df) basis set] led to the very large vertical electron detachment (VDE) energies of 9.316 eV (SiF(5)(-)) and 9.742 eV (GeF(5)(-)), whereas smaller VDEs of 6.196 and 6.452 eV were predicted for the SiCl(5)(-) and GeCl(5)(-) species, respectively. By contrast, the high-symmetry and structurally compact anionic CF(5)(-) and CCl(5)(-) systems cannot exist due to the strongly repulsive potential predicted for the X(-) (F(-) or Cl(-)) approaching the CX(4) (CF(4) or CCl(4)). The formation of weakly bound CX(4)···X(-) (CF(4)···F(-) and CCl(4)···Cl(-)) anionic complexes (consisting of pseudotetrahedral neutral CX(4) with the weakly tethered X(-)) might be expected at low temperatures (approaching 0 K), whereas neither CX(5)(-) (CF(5)(-), CCl(5)(-)) systems nor CX(4)···X(-) (CF(4)···F(-) and CCl(4)···Cl(-)) complexes can exist in the elevated temperatures (above 0K) due to their susceptibility to the fragmentation (leading to the X(-) loss).     

Studies on Flavans. III. The Total Synthesis of (±)-7,4′-Dihydroxy-3′-methoxyflavan, (±)-7,3′-Dihydroxy-4′-methoxyflavan,and (±)-7,4′-Dihydroxyflavan

Abstract

The first total synthesis of (±)-7,3′-dihydroxy-4′-methoxyflavan (1) and (±)-7,4′-dihydroxy-3′-methoxyflavan (2), along with the synthesis of (±)-7,4′-dihydroxyflavan (3), three naturally occurring flavans, were described. The key step is the cyclization of 1,3-diaryl-1-propanol by BF₃·Et₂O.     

Non-thiazolidinedione antihyperglycaemic agents. Part 4: Synthesis of (±)-, (R)-(+)- and (S)-(−)-enantiomers of 2-oxy-3-arylpropanoic acids

The synthesis of a new series of potent 2-oxy-3-arylpropanoic acid antihyperglycaemic agents in both racemic and non-racemic form is described. Resolution of racemic acids 1 is accomplished via amide formation with either (S)-2-phenylglycinol or (S)-4-benzyloxazolidin-2-one as complementary resolving agents.