Investigation of the role of the pyrimidine ring in the main chain of polyamido acids and polyimides. 1. Supermolecular structure of polypyromellitimides based on 2,5-bis(p-aminophenyl)pyrimidine and its carbocyclic analog 4,4′-diaminoterphenyl

A detailed comparative study of polypyromellitamido acids and polyimides based on 2,5-bis(paminophenyl)pyrimidine and 4,4-diaminoterphenyl was conducted to determine the role of the nitrogencontaining pyrimidine ring in the main chain of the polymers. A model of the layer packing of polyimide chains in crystalline regions was proposed based on the data from x-ray structural analysis and quantum chemical calculations. The existence of tilted packing caused by partial displacement of the solvent molecules bound to the pyrimidine ring of the neighboring macromolecule with higher basicity in pyrimidine-containing polymers was hypothesized.Institute of Macromolecular Compounds, Russian Academy of Sciences, 199004 Saint Petersburg. Novosibirsk Institute of Organic Chemistry, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 10, pp. 2288–2296, October, 1992.     

Study of the temperature effect on IR spectra of crystalline amino acids,dipeptids, and polyamino acids. III. α-Glycylglycine

The IR spectra of α-glycylglycine (H₃ ⁺N-CH₂-CO-NH-CH₂-COO^?) are studied in the temperature range of 93 to 413 K. Changes in the spectra due to temperature variation are correlated with the previously obtained X-ray diffraction data on anisotropic compression of the structure and changes in the parameters of hydrogen bonding. Changes in the vibrational frequencies of NH ₃ ⁺ and COO groups in the IR spectrum of α-glycylglycine are compared to changes in the vibrational frequencies of the same groups in the IR spectra of polymorphs of glycine, L- and DL-serine.     

Derivatives of heterocyclic α-iminocarboxylic acids 3. Synthesis of N-alkoxycarbonyl and N-alkoxycarbonylalkenyl derivatives of α-iminocarboxylic acids

By the interaction of L-proline, L-thioproline, pipecolic acid, tetrahydro-1,4-thiazine-3-carboxylic acid, and diastereomeric esters of tetrahydro-1,4-thiazine-3,5-dicarboxylic acid with methyl chloroformate, methyl propiolate, and acetylenecarboxylic acid, we have obtained N-alkoxycarbonyl and N-alkoxycarbonylalkenyl derivatives of -iminocarboxylic acids. By the reaction of N-methoxycarbonyltetrahydro-1,4-thiazine-3-carboxylic acid with hydrazine hydrate, we have obtained 8-amino-7,9-dioxo-4-thia-1,8-diazabicyclo[4.3.0]nonane.For communication 2, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1561–1566, November, 1993.     

Studies in the field of derivatives of unsaturated phosphonic acids 21. Esters and amides of β-ethylhexoxyvinylphosphonic acid

Summary -(-Ethylhexoxy)-vinylphosphonic dichloride, diethyl, dipropyl, dibutyl, di-isobutyl, di-isoamyl, dihexyl, di-2-ethylhexyl, di-(methoxyethyl) and di(ethoxyethyl) esters of -(-ethylhexoxy)-vinylphosphonic acid, tetramethyldiamide, tetraethyldiamide and dipiperidide -(-ethylhexoxy)-vinylphosphonic acid were prepared and characterized.     

Esters ofβ -ketophosphonic acids. VII. The products of the reaction ofα-chlorocyclohexanone with the diethyl ester of ethylphosphonous acid and the sodium salt of the monoethyl ester of ethylphosphonous acid

Summary The action of diethyl ethylphosphonite on-chlorocyclohexanone gives cyclohexen-1-yl-1 -ethyl ethylphosphonate, Cyclohenen-1-yl-1-ethyl ethylphosphonate is also obtained by the action of sodium monoethyl ethylphosphonite on a-chlorocyclohexanone.     

Derivatives of heterocyclic α-iminocarboxylic acids. 4. Reduction of N-alkoxycarbonyl derivatives of α-iminocarboxylic acids

When N-methoxycarbonyl and N-benzoxycarbonyl derivatives of methyl esters of aziridine-2-carboxylic acid, L-proline, L-thioproline, and pipecolic acid interact with NaBH₄ in tert-butanol/methanol, the products of reduction of the C-methoxycarbonyl group of the original compounds are accompanied by bicyclic urethanes and oxazolidines. Reduction of N-maleates and N-fumarates of heterocyclic -iminocarboxylic acids leads to the formation of -hydroxymethyl-N-[4-(2-oxo-2,5-dihydrofuryl)] derivatives of pyrrolidine, piperidine, 1,3-thiazolidine, and 1,4-thiazan. In the latter case, 1-aza-2-hydroxymethyl-4-oxo-5-oxa-9-thiabicyclo [5.4.0]undecene-2 is also obtained. The N-maleates and fumarates of aziridine-2-carboxylic acid are reduced anomalously by sodium borohydride, forming 2-hydroxymethyl-2-(-hydroxyethyl)-3-oxa-1-azabicyclo[3.1.0]hexanes.For Communication 3 see [2].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1567–1573, November, 1993.     

Synthesis of phosphinic acids on the basis of hypophosphites: IV. Synthesis of pseudo-γ-glutamylglycine and its enantiomers

A new method for construction of pseudopeptide molecules is proposed, exemplified by the synthesis of [3-amino-3-(hydroxycarbonyl)propyl][2-(hydroxycabonyl)ethyl]phosphinic acid (I) (pseudo--glutamylglycine), starting from ammonium hypophosphite. Enzymatic synthesis using immobilized penicillamidase allowed preparation of the enantiomers of acid I.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 8, 2004, pp. 1273–1278.Original Russian Text Copyright © 2004 by Ragulin.For communication III, see [1].This revised version was published online in April 2005 with a corrected cover date.     

Modifications based on coumarins. II. Synthesis ofα-monoglycerides of karatavic and galbanic acids and their phosphates

The synthesis has been performed of -monoglyceride derivatives of coumarins — karatavic and galbanic acids and their modified derivatives — phosphates. The structures of the compounds have been confirmed by IR, UV, PMR, and¹³C and³¹P NMR spectroscopies.A. B. Bekturov Institute of Chemical Sciences, Academy of Sciences of the Republic of Kazakhstan, Almaty Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 217–220, March–April, 1997.     

Protonation and complex formation of the cis and trans isomers of alicyclic β-amino acids

The protonation constants of β-alanine and the cis and trans isomers of aliphatic 2-amino-1-carboxylic acids containing a cyclohexane, cyclopentane or cyclohexene(4) ring were determined pH-metrically, as were the formation constants of their complexes with Ni²⁺, Cu²⁺, Hg²⁺ and Cd²⁺ ions. The analysis of about 70 formation constants revealed significant differences betweeen the behaviours of the different ligands, each of which has a fixed β-alanine conformation. It is concluded that complex formation is primarily determined by the nature of the fixed β-alanine conformation and in some cases by the type of aliphatic ring.     

Acetals of lactams and amides of acids. 72. Investigation of reaction of cyclic β-nitroenamines with p-benzoquinone

The process of condensation of p-benzoquinone with the secondary cyclic enamines 2-(2-nitromethylene)pyrrolidine, -piperidine, and -hexahydroazepine is very much dependent on the size of the saturated ring in these compounds. With increasing ring size, the content of derivatives of 5-hydroxybenzofuran decreases, and the quantity of derivatives of 5-hydroxyindole increases; with the seven-membered enamine, a substituted 6-hydroxyindole is also formed. For enamines of the pyrrolidine and piperidine series, 1,4-bis-2-(2-nitromethylene)pyrrolidono- or piperidinohydroquinones are also recovered.For Communication 71, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 357–362, March, 1992.     

Glycoconjugates of amino acids. Preparation throughN-alkylation of amino acids withN-chloroacetyl-β-glycopyranosylamines

Monoalkylation of amino acids of different structural types withN-chloroacetyl-glycosylamines was shown to be applicable for the preparation of glycoconjugates containing β-d-galactose,N-acetyl-β-d-glucosamine, β-d-mannose, and lactose residues. The glycoconjugates were synthesized from amino acids with secondary (sarcosine,l-proline) or primary (l-2- and 4-aminobutyric acids,l-tryptophan) amino groups as well as from various amino dicarboxylic acids (N-methyl-dl-aspartic,dl-aspartic,l-glutamic, anddl-2-aminoadipic acids). The derivatives obtained may be of interest for glycotargeting of physiologically active compounds of this series. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1377–1380, July, 1999.     

Recent topics in the syntheses of β-keto carboxylic acids and the derivatives

β-Keto carboxylic acids are key intermediates in organic syntheses, used for the development of fine chemicals, natural products, and various biologically relevant molecules. Their utilities stem from the structural features and facile bond formations, e.g., asymmetric reduction of carbonyl groups for the synthesis of β-hydroxy carboxylic acids and conjugated addition reactions through decarboxylative enolate nucleophiles, which utilize the amphiphilic reactivity of β-keto carboxylic acids. Despite their versatility and utilities, development of efficient and straightforward synthetic methods for β-keto carboxylic acids has not attracted considerable attention owing to their instability. As efficient synthetic strategies for β-keto carboxylic acids and their derivatives, reactions of α-diazoesters, acylation of malonate anions, cross-coupling reactions, and CO₂ insertion reactions are summarized in this review.     

Synthesis of the p-keto acids from benzimidazolium iodides and ethyl malonate

The reaction of benzhnidazole methiodide with ethyl malonate in the existence of base was studied,and a new convenient synthetic method of the β-keto acid was provided.     

Tetramic acids and indole derivatives from amino acid β-keto esters. Fine-tuning the conditions of the key Cu-catalyzed reaction

1,3,5-Trisubstituted tetramic acids and 2,3-disubstituted indole derivatives were prepared from β-keto esters derived from amino acids by their reaction with iodophenyl-2-trifluoroacetylamine under Cu-catalysis. Both heterocyclic systems were generated from the same starting materials by choice of the appropriate reaction conditions.