The synthesis of ω-thienylalkane acids from ω-chloroalkane acids

Summary We have worked out a preparative method for the synthesis of -thienylalkane acids by acylation of thiophene with -chloroalkane acid chlorides followed by conversion of the resulting -chloroalkyl(2-thienyl)ketones into the corresponding acids by reaction with sodium malonic ester or potassium cyanide, and reduction of the resulting products with their simultaneous hydrolysis.Here and later we mean -(2-thienyl)alkne acids.We take this opportunity to thank R. Kh. Freidlina, A. A. Beér, and M. A. Besprozvannii for giving us enough -chloroalkane acids.     

Synthesis of ω-(2-oxocyclododecyl)alkanoic acids by alkylation of cyclododecanone with ω-haloalkanoic esters under conditions of phase-transfer catalysis

(-(2-Oxocyclododecyl)alkanoic acids have been obtained by alkylation of cyclododecanone with alkyl 3-bromopropionate, 5-iodopentanoate, and 11 -bromoundecanoate under conditions of phase-transfer catalysis.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2521–2523, December, 1995.     

Hydrochloride method for the determination of monomer in the polycondensation of esters of α-amino acids

Summary A method is proposed for determining the monomer in the polycondensation of esters of-amino acids. The accuracy of the method was to within 1–1.5%.     

Catalyzed synthesis of β-amino acids esters

Russian Journal of Organic Chemistry -     

New method of synthesizing isopromedol and α-promedol

Summary Methods are proposed for the synthesis of the active analgesics, isopromedol and -promedol.     

Synthesis of esters ofpara-hydroxy substituted α-trifluoromethylmandelic acids

Methyl trifluoropiruvate in trifluoroacetic acid at 20 °C rapidly C-hydroxyalkylates various phenols at thepara-positions to afford the corresponding esters ofpara-hydroxy substituted -trifluoromethylmandelic acids.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 528–530, March, 1995.The present study was carried out with the financial support of the Russian Foundation for Basic Research (Project code 93-03-22696).     

A one step synthesis of ω-hydroxyacetylenic carboxylic acids

A convenient chemioseLective method to prepare ω-hydroxyacetylenic carboxylic acids from unprotected ω-alkyn-1 ols and ω-bromo acids is described.     

Ruthenium tetroxide oxidation of cyclic N-acylamines by a single layer method: formation of ω-amino acids

The ruthenium tetroxide oxidation of cyclic N-acyl amines by a 10% NaIO₄ aqueous solution containing tert-butanol as a single layer system resulted in the endo-cyclic C-N bond cleavage to afford the ω-amino acids as almost sole products in good yields, while a similar oxidation under the double layer using a NaIO₄ aqueous solution, and ethyl acetate gave the N-acyl lactams.     

Synthesis of aza-crown compounds by intramolecular cyclization of ω-amino acids

A method for the synthesis of aza-crown compounds by the intramolecular cyclization of -amino acids with subsequent reduction of the lactam to a macrocyclic amine was developed. 1,8-Diazacyclotetradecane and 1,8-dioxa-4,11-diazacyclotetradecane were synthesized in preparative yields. The structural assignments were made using the IR, ¹H and ¹³C NMR, and mass spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 247–255, February, 1992.     

A facile synthesis of chiral ω-allyl- and ω-n-propyllactones via asymmetric allylboration of formyl esters with B-allyldiisopinocampheylborane

Asymmetric allylboration of aldehydes containing an adjacent ester group with B-allyldiisopinocampheylborane, followed by hydrolysis and cyclization, provides the corresponding allyl substituted lactones in high yields and ≥92% enantiomeric excess. Hydrogenation of these lactones provides the corresponding propyl substituted lactones without any loss of optical purity.     

Concise syntheses of three ω-3 polyunsaturated fatty acids

The synthesis of the three ω-3 polyunsaturated fatty acids, eicosatetraenoic acid (3), docosapentaenoic acid (4), and stearidonic acid (5) has been achieved using eicosapentaenoic acid or docosahexaenoic acid as the starting materials.     

DSC-studies of phospholipids containing iso-branched and ω-cyclohexane fatty acids

Differential Scanning Calorimetry (DSC) and Differential Scanning Densitometry (DSD) was employed to study the phase behavior of phospholipids with iso-branched and ω-cyclohexyl fatty acids. Phosphatidylcholines (PC) and phosphatidylethanolamines (PE) with iso-branched fatty acids show complicated phase behavior with several gel-gel transitions with odd-even effects. These odd-even effects are even more pronounced for phosphatidylcholines with ω-cyclohexyl fatty acids (cyPCs). Odd-numbered cyPCs show a large main transition with strong hysteresis while the even-numbered cyPCs have several transitions but show no hysteresis. These differences in thermotropic behavior are also reflected in their molecular volumes. The odd-numbered cyPCs display much tighter packing in the gel phase than the even-numbered analogues. Binary mixtures of cyPCs with either straight chain PCs or iso-branched PCs show eutectic behavior. This is also observed when cyPCs of different chain length are mixed.     

Kinetic resolution of aromatic β-amino acids by ω-transaminase

Racemic aromatic β-amino acids have been kinetically resolved into (R)-β-amino acids with high enantiomeric excess (>99%) by a novel ω-TA with ca. 50% conversion.     

Stereoselective,nonracemic synthesis of ω-borono-α-amino acids

ω-Unsaturated α-amino acids are synthesized through condensation of allyl and propargyl bromides or of 9-bromoundecene with a Ni(II) complex of the Schiff base derived from glycine and BPB. Hydroboration with Ipc₂BH followed by oxidation with acetaldehyde affords enantiomerically pure ω-borono-α-aminocarboxylic acids.     

Asymmetric synthesis of α-amino acids by reduction of N-tert-butanesulfinyl ketimine esters

A highly regio- and diastereoselective reduction of various N-tert-butanesulfinyl ketimine esters with L-Selectride resulting in the formation of α-amino acids is reported. This method is quite general and also practical for the preparation of both enantiomers of aryl or aliphatic α-amino acids in high yields.     

Decomposition of benzenediazonium fluoborate in esters of α,β-unsaturated acids

Summary It was shown that In contrast to the Meerwein-Koelsch reaction, the decomposition of benzenediazonlum fluoborate In esters of ,-unsaturated acids proceeds by a heterolytlc mechanism with the phenyl attacking the -carbon and the carbalkoxyl group of these esters. The reaction with ethyl crotonate gave -methylatropic acid (after hydrolysis) and a small amount of a dibasic acid, C₁₄H₁₆O₄ (or C₁₄H₁₄O₄). With methyl acrylate it gave atropic acid, phenyl acrylate, and a smaller amount of -methyl--phenylglutaric acid. With methyl methacrylate It formed benzylacrylic acid and the product of further conversions of phenyl methacrylate, namely the keto phenol 2-methyl-5-hydroxyindan-1-one.     

Practical method for the synthesis of (R)-homopipecolinic acid and (R)-homoproline esters from ω-chloroalkanoic acids and available chiral amines

A practical synthesis of (R)-homopipecolinic acid methyl ester 1 and (R)-homoproline methyl ester 2 was performed utilizing (i) a direct intramolecular cyclization of ω-chloro-β-enamino esters 11 and 12, which were prepared from available (S)-1-phenylethylamine or (S)-1-(1-naphthyl)ethylamine and ω-chloro-β-keto esters 5 and 10, respectively and (ii) a highly diastereoselective NaBH₄ reduction followed by hydrogenolysis. The present method is a short-step process using inexpensive and readily available substrates and reagents with fewer wasted materials.