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.     

Two-fragment α-adrenolytics. 4. Synthesis of phosphorylated derivatives of 2-aryloxyethylamines and N-phenylpiperazine

The reactions of 3-chloropropylphosphonates, 3-chloropropylthiophosphonates, or 3-chloropropylphosphinates with 2-aryloxyethylamines or N-phenylpiperazine afford the corresponding 3-(2-aryloxyethylamino)propylphosphonates and -phosphinates or 3-(4-phenylpiperazin-1-yl)propylphosphonates and -phosphinates. The compounds obtained exhibit -adrenolytic and hypotensive activities, the latter being found to depend on the substituents at the P atom.     

Chemical Modification of Kanamycin A. II. Nucleophilic Displacement Reactions of Kanamycin-A-4″-sulfonates

Abstract

Reactions of 2′,3′,4′,2″,6″-penta-O-acetyl-tetra-N-tert-butyloxycarbonyl-kanamycin-A-4″-brosylate (4b) or-4″-triflate (4c) with acetate, thiolacetate, azide, and fluoride, respectively, result in the formation of the corresponding derivatives of 4″-epi-kanamycin A (5a-d). While 4b invariably forms an elimination byproduct (9), the only side—reaction of 4c consists in a neighboring group attack with formation of a 3″-epi-4″-cyclic urethane (7). Removal of the protecting groups yields 4″-epi-(6a), 4″-thio-4″-epi-(6b), 4″-deoxy-4″-fluoro-4″-epi-(6d), 4″-azido-4″-deoxy-4″-epi-(6c), and after hydrogenation of the latter, 4″-amino-4″-deoxy-4″-epi-kanamycin A (6f).

Methyl 2,6-di-O-acetyl-3-amino-3-N-tert-butyloxycarbonyl-3-deoxy-4-O-triflyl-β-D-glucopyranoside (1b) served as a model to anticipate preparation, handling, and reactivity of 4c.     

Studies on Agarofurans VIII. Synthesis of the Metabolites of 4-Butyl-a-agarofuran

Agarofurans have been found to be active on the nervous system in our institute. 4-Butyl-a-agarofuran 1 is a promising drug candidate. In order to explore the pharmacokinetics of 1, the metabolism of 1 in vitro was studied with liver microsomes from rats. Five metabolites were isolated and structures were identified as compounds 2-6. But the absolute configuration of 2,4,5 and the position of carbonyl in 3 could not be unambiguously determined. Further determination was limited by the smal…     

Photocrosslinking of Silicones. Part XV. Cationic Photocrosslinking of α, ω, 4-Terminated Disiloxanes

Abstract

The photoinduced cationic crosslinking of α, ω-terminated disiloxanes (epoxy, vinyl ether, propenyl ether) has been investigated by means of Real-Time IR spectroscopy. A lipophilic iodonium salt and three lipophilic sulfonium salts were used as photoinitiator. The crosslinking rate is influenced by the type of α, ω-terminated disiloxane used and differed by a factor of more than 100 from the aliphatic epoxy to the vinyl ether derivatives. Moreover, the sulfonium salts were found to have a lower initiation efficiency than the lipophilic iodonium salt in the various systems studied. These results are in good agreement with the quantum yield of proton formation in a hexamethyldisiloxane/dimethoxyethane mixture. The final degree of conversion is larger with the ene derivatives than with the epoxy derivatives. The application of a kinetic method allows us to estimate the rate constant of the termination step (k_t and for the propenyl derivative the rate constant of the propagation step kp. The termination step can be described by means of a first order reaction. k_t was found to depend on the light intensity and the type of initiators used, whereas k_p is independent of the initiator used.     

Kinetics of oxidation of β-picoline to nicotinic acid over vanadia-titania catalyst. 4. Kinetic model

A kinetic model for the β-picoline oxidation over vanadia-titania catalyst is presented. The model covers the reaction mechanism, temperature dependences and a system of kinetic equations. The activation energies and constants in these equations are calculated.     

Friedel-Crafts Polymers. 10. Polycondensation of 4-4′-Dichloromethlydiphenyl Ether with Phenol and Isomeric Cresols

Friedel-Crafts polycondensations of 4, 4′-dichloromethyldiphenyl ether (DDE) with phenol and isomeric cresols were carried out under different experimental conditions. The molecular weight of the polymer products was estimated by end group analysis, that of soluble products by VPO, and they were characterized by TGA and solution viscosity. DMF solutions of samples prepared from phenol and p- and m-cresols, but not those from o-cresol, showed abnormal viscosity behavior. However, the viscosity behavior of DMF-water solutions was normal. Abnormal vis-cisoty data of DMF solutions were correlated by an empirical relation. Curing of one fusible and soluble DDE-phenol polymer sample with hexamine was studied by measuring the percentage of cured material as a function of time at selected temperatures.     

4-hydroxy-2-quinolenes. 24. Improved synthesis and biological properties of hydrochlorides ofβ-dialkylaminoalkylamides of 1-alkyl-2-oxo-4-hydroxyquinoline-3-carboxylic acids

High-purity hydrochlorides of-dialkylaminoalkylamides of 1-R-2-oxo-4-hydroxyquinoline-3-carboxylic acids have been obtained from N-alkyl-2-carbalkoxyanilides of malonic acid. The synthesized compounds have been tested for certain forms of pharmacological activity.For Communication 23, see [1].Ukrainian Pharmaceutical Academy, Khar'kov 310002. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1400–1405, October, 1994. Original article submitted November 8, 1994.     

Highly Deoxygenated Sugars. II. Synthesis of Chiral Cyclopentenes via Novel Carbocyclization of C‐4 Branched Deoxysugars

Tri‐O‐acetyl‐d‐glucal (1) was converted via Ferrier type II rearrangement with high α‐selectivity to 2,3‐unsaturated methyl glycosides 2a and 2b using ferric chloride as the catalyst. Palladium induced allylic substitution with sodium tert‐butylacetoacetate as a nucleophile leads to C‐4 branched sugars. Subsequent hydrogenation followed by treatment with trifluoroacetic acid affords the highly functionalized chiral cyclopentene derivative 5a as a versatile chiral building block for cyclopentanoids.     

Synthesis and properties of thiazole halohydrazones. 2. Interaction of 2-α-chlorobenzylidenehydrazino-4-ethoxy-carbonylthiazole with nucleophiles

In the interaction of 2--clzlorobenzylidenehydrazino-4-ethoxycarbonylthiazole with nucleophiles, two competing reactions take place. 1) nucleophilic replacement of the chlorine atom to form the corresponding substitution product; 2) elimination of a hydrogen chloride molecule, concluding in cyclization of the intermediate nitrilimine to form 3 phenyl-5-ethoxycarbonylthiazolo(2, 3-c]-1, 2, 4-triazole. The direction taken by the interaction depends on the nature of the nucleophile and is determined primarily by the ratio of basicity and nucleophilicity of the agent.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, 256–259, February, 1994. Original article submitted December 30, 1993.     

Selectively Deoxygenated Derivatives of β-Maltosyl-(1→4)-Trehalose as Biological Probes. II. the Synthesis of the 4- and 4′″-Monodeoxygenated Analogues

ABSTRACT

Two derivatives of β-maltosyl-(1→4)-trehalose monodeoxygenated at positions 4 or 4′″ have been synthesized in [2+2] block syntheses. After the preparation of precursors with only one free hydroxyl group the deoxy function was introduced by a Barton-McCombie reaction. Thus, glycosylation of 2,3,6-tri-O-benzyl-α-D-glucopyranosyl 2,3,6-tri-O-benzyl-α-D-glucopyranoside (4) with octa-O-acetyl-β-maltose (3) gave tetrasaccharide 5 with only one free hydroxyl group at the 4-position. The 4′-position of an allyl maltoside was available selectively after removal of a 4′,6′-cyclic acetal and selective benzoylation of the 6′-position. Reduction of this derivative 11 afforded allyl O-(2,3-di-O-acetyl-6-O-benzoyl-4-deoxy-α-D-glucopyranosyl)-(1→4)-2,3,6-tri-O-acetyl-β-D-glucopyranoside (14), which was deallylated, activated as an trichloroacetimidate, and coupled to 2,3-di-O-benzyl-4,6-O-benzylidene-α-D-glucopyranosyl 2′,3′,6′-tri-O-benzyl-α-D-glucopyranoside (20). Several compounds were fully characterized by ¹H NMR spectroscopy. Deprotection furnished the monodeoxygenated tetrasaccharides 9 and 23.     

Studies on Agarofurans Ⅳ. The Synthesis of 4-Substitutioned Agarofurans

Agarowoodoilwasfoundtobebioactiveinpharmacologicalscreeningforthenervoussysteminourinstitute.AgarofuransareonesmicturaltypeoftheimportantconstituentSofagarowoodoil.Q-Agarofuran(lh),oneofthemanyconstitUentsoftheoil,issuspectedofbeinganimportantcontributortothebioactivity.AlthoughseveralsynthesisofQ-agarofuran(fo)havebeendescribed'-',theyarenotsuitableforthesynthesisofitsanalogs.Thebioactivitiespromptedustodevelopanewroutetoa-agarofuran(fo)anditsanalogs.EarliersynthesisofQ-agarofuran(lb),with…     

Thermodynamics of the Dissociation of Carbonic Acid in Mixed Solvent.4. The System of NaHCO_3-Na_2CO_3-NaCl-Ethanol-Water

Theeffectofethanol-watermixtureontheseconddissociationconstantofcarbonicacidwasofinterestnotonlyforbiologistsbutalsoforchefestsandchemicalengineers,becauseitmayprovideusefulinformationinregardtotheidentificationofthenatureofthesesolute-solventinteractionpatternsinbinarysolventsystem"'.ThispaperreportStheseconddissociationconstantsofcarbonicacid,K,,atfivetemperaturesfrom278.15to318.15Kin5,15,25mass%ethanol-water"dxedsolventsdeterminedfrompreciseelnfmeasurementsincell(A)withoutliquidjunction:Pt…     

2-Benzopyrylium salts. 41. Intramolecular transformations of 4-1′-dimers of α-unsubstituted 2-benzopyrylium salts

Recyclization reactions of 4-1-dimers of 2-benzopyrylium salts leading to naphthalene derivatives are described. A new variant of the intramolecular Cannizzaro rearrangement has been discovered.For communication 40, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 175–180, February, 1991.     

Stereochemistry of cyclic compounds. Communication 59. Action of hypobromous acid on δ4(4a)-dodecahydro-4b-methyl-7-oxo-cis-1,2-phenanthrenedicarboxylic acid and its diester

Summary The reaction of N-bromoacetamide with ^4(4a)-dodecahydro-4b-methyl-7-oxo-cis-1,2-phenanthrenedicarboxylic acid and its ester was studied. The products correspond to the addition of bromine at C₄. A possible scheme is discussed for the mechanism of the simultaneously occurring secondary transformations.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1241–1243, July, 1964     

Oxidation of β-Hydroxynitrosamines to β-Ketonitrosamines with KMnO4-Metal.SO4.XH2O in Non-Aqueous Media

The oxidation of β-hydroxynitrosamines to the corresponding β-ketonitrosamine is reported. The reactions carried out in benzene or dichloromethane using powdered KMnO₄-CuSO₄.5H₂O, or KMnO₄-MgSO₄.7H₂O. Work-up of the reaction and purification of the product requires only a filtration through magnesium sulfate and chromatography through a short Florisil column.     

Investigations of 2,3′-biquinolyl. 9. Reaction of 1′,4′-dihydro-2,3′-biquinolyl with organolithium compounds

The 1,4-dihydro-2,3-biquinolyl reacts with organolithium compounds to form the mixture of 4-R-1,4-dihydro-2,3-biquinolyls and 2-R-1,2-dihydro-2,3-biquinolyls in the ratio analogous to the conversion in the series of 2,3-biquinolyl. The utilization of the complex, the organolithium compound-TMEDA, in this process leads, after treatment of the reaction mixture with water, exclusively to 2-R-1,2-dihydro-2,3-biquinolyls. Treatment with methyl iodide leads to 1-methyl-2-R-1,2-dihydro-2,3-biquinolyls.     

“Remote” dianions-I. Utility of 4-phenylsulfonylbutanoic acid in the mild conversion of aldehydes and ketones to lactones.

Ketones and aldehydes are converted to lactones in high yield by stepwise treatment with the dianion of 4-phenylsulfonylbutanoic acid and trifluoroacetic anhydride.