A versatile approach to the synthesis of 9(Z)-unsaturated acyclic insect pheromones from undec-10-enoic acid

A general approach to the synthesis of 9(Z)-unsaturated acyclic insect pheromones from undec-10-enoic acid was developed. The method comprises the conversion of the acid into undec-10-enyl acetate, shortening of its carbon chain to afford dec-9-enyl acetate (via 11-acetoxyundecanoic acid), and a two-step transformation of the latter into the key intermediate, dec-9-yn-1-ol, by sequential bromination—dehydrobromination. The elimination of two HBr molecules from the dibromide is effectively performed using Bu¹OK in the presence of dibenzo-18-crown-6 as the catalyst. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1637–1639, August, 1998.     

Cyclization of 2,6-dialkoxy acetophenone hydrazones in the presence of polyphosphoric acid (PPA)

Cyclization of a series of 2,6-dialkoxy acetophenone hydrazones gave 3-methyl-4-alkoxyindazoles with elimination of the 2- or 6-alkoxy group in the presence of PPA. The reaction mechanism was discussed.     

Cyclization of 2-(1′-alkyl-2′-alkenyl)anilines in polyphosphoric acid

The cyclization of 2-alkenylarylamines in polyphosphoric acid (PPA) with 1,2 and 1,3 shifts of the -alkyl substituent of the alkenyl fragment leads to the formation of indoline and indane compounds. Cis- and trans-stereoisomers of 2-methyl-4-ethyl-1-aminoindane formed without displacement of the -substituents as well as 2-methyl-2-propylindoline are obtained from 2-(1 -methyl-2 -pentenyl)-aniline.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2811–2814, December, 1990.     

Synthesis of 7-oxo-8-aza-10a-homoprost-13-enoic acid

The synthesis of a prostaglandin E₁ analog, 7-oxo-8-aza-10a-homoprost-13-enoic acid, is reported.     

Synthesis of trans-10-hydroxydec-2-enoic acid and related compounds

Syntheses of the two stereoisomeric 10-hydroxydec-2-enoic acids are described. The trans-isomer is identical with the main fatty acid isolated from royal jelly of honeybees.

Some compounds closely related to this trans-acid have also been prepared.

A convenient process for the preparation of 10-acetoxy-decanoic acid from castor oil has been developed.     

Electrophilic intramolecular cyclization of functional derivatives of unsaturated compounds: V. Cyclization of anilides of styrylacetic acids in polyphosphoric acid

Anilides of styrylacetic acids at heating in polyphosphoric acid undergo an intramolecular cyclization giving 1,5-diarylpyrrolidin-2-ones, 5-aryl-1,3,4,5-tetrahydro-2H-benzazepin-2-ones, and 5-(3-fluorophenyl) dihydrofuran-2(3H)-one, where the ratio of the products depends on the character of the aromatic substituents in the amide and styrene fragments of the substrate.     

Cyclization of 2-methoxy-6-(substituted benzyloxy)acetophenone hydrazones in the presence of polyphosphoric acid(PPA)

Cyclization of 2-methoxy-6-benzyloxy acetophenone hydrazone gave 3-methyl-4-meth-oxy indazole and 3-methyl-4-methoxy-7-benzyl indazole in the presence of polyphosphoric acid(PPA).The hydrazone was probably converted to 2-hydroxy-6-methoxy acetophenone hydra-zone and 2-hydroxy-3-benzyl-6-methoxy acetophenone hydrazone followed by cyclization to thecorresponding indazoles in acidic conditions.Cyelization of 2-methoxy-6-(halo or alkyl or arylbenzyloxy)acetophenone hydrazones gave similar products.Cyclization of 2-methoxy-6-(p-nitrobenzyloxy)acetophenone hydrazone gave 2-(p-nitrophenyl)-3-methyl-4-methoxy benzo-furan and 3-methyl-4-methoxy indazole while 2-methoxy-6-(m-nitrobenzyloxy)acetophenonehydrazone gave 3-methyl-4-methoxy indazole,3-methyl-4-methoxy-7-(m-nitrophenyl)indazole and3-methyl-4-(m-nitrobenzyloxy)indazole.     

Synthesis of novel 3,5-disubstituted-dihydroisoxazoles from methyl undec-10-enoate and isoxazoles,triazole and tetrazolo-triazole from methyl undec-10-ynoate

The efficient cycloaddition reactions were carried out to afford the novel 3,5-disubstituted-dihydroisoxazoles from methyl undec-10-enoate and isoxazoles, triazole and tetrazolo-triazole from methyl undec-10-ynoate. The reactions occurred under relatively mild conditions and afforded the desired products in good yields.     

Cyclization of N-acetonylanthranilic acid

Conclusions 5-Methyloxazolo-(3,2a)-1,4-dihydro-4-quinolinone and traces of skatole are respectively formed when N-acetonylanthranilic acid is heated with acetic anhydride and with ethylene glycol.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2826–2828, December, 1971.In conclusion we express our gratitude to T. A. Petrova, T. M. Sedletska, N. A. Verevkina, and L. V. Shmelev for running the spectral studies.     

Homogenous one-pot synthesis of polyimides in polyphosphoric acid

A one-pot synthetic method to produce aromatic polyimides with high molecular weights from corresponding diamines and dianhydrides was developed, in which polyphosphoric acid (PPA) played a role of an excellent media for one-step synthesis of completely cyclized polyimides. The polymerization was carried out in the solid content of 10 wt/v% at 220 °C. The resulting products exhibited a homogeneous solution in the non-volatilizable PPA instead of precipitation form of the polyimides. The content of P₂O₅ in PPA had an influence on the molecular weight of the products, and the high percentage of P₂O₅ resulted in the relative high inherent viscosity. FTIR and Carbon-13 NMR were employed to analyze the structures and TGA was used to evaluate the thermal stability. The polyimides prepared by this one-step route exhibited good thermal properties and high values of activation energies for the degradation, on comparison with the polyimides prepared in DAMc by two-step polymerization method.     

Self-condensation reaction of aromatic tetraamines in polyphosphoric acid

Ladder and partial ladder polymers have been obtained by self-condensation reactions of 1,2,4,5-tetraaminobenzene, 3,3′,4,4′-tetraaminodiphenyl ether, 3,3′-diaminobenzidine and 3,3′,4,4′-tetraaminodiphenyl sulfone in polyphosphoric acid. The products thus obtained are highly colored compounds with good thermal stability. They seem to be made up of polyquinoxaline or dihydrophenazine or a mixture of these two recurring units. They are slightly soluble in methanesulfonic acid and concentrated sulfuric acid and have inherent viscosities in the 0.2 to 0.4 range.     

Cyclization of vinyl-o-carboranylacetic acid by sodium amide to 2,3-carboranocyclopentanocarboxylic acid

Conclusions Vinyl-o-carboranylacetic acid when treated with sodium amide in liquid ammonia undergoes intramolecular cyclization to 2,3-carboranocyclopentanocarboxylic acid.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2115–2117, September, 1976.     

Synthesis of 3,4-dihydroisoquinolines using nitroalkanes in polyphosphoric acid

Russian Chemical Bulletin - A new method for the synthesis of 6,7-dimethoxy-3,4-dihydroisoquinoline based on the reaction of 2-(3,4-dimethoxyphenyl)ethan-1-amine (homoveratrylamine) with aliphatic...     

Cyclization of benzoylcyanothioacetic acid arylamides

3-Arylamino-4-cyano-5-phenylpyrazoles and 3-aryl-4-phenyl-2-[(benzoyl)cyanomethyl-ene]-4, 5-thiazolines, respectively, were obtained by condensation of benzoylcyanothioacetic acid arylamides with hydrazine hydrate or withΩ-bromoacetophenone. 2-[(Benzoyl)-cyanomethyl] benzothiazole derivatives were synthesized by oxidative cyclization of benzoylcyanothioacetic acid arylamides.