Synthesis and properties of analogs of pyridoxal

A method for the synthesis of analogs of pyridoxal-2-norpyridoxal, 6-methyl-2, 4-pyridoxal, and 6-methylpyridoxal—has been worked out. The reaction of 5-ethoxyoxazoles with maleic diesters gave diesters of substituted 3-hydroxycinchomeric acids, which were converted by reduction with lithium aluminum hydride into analogs of pyridoxine. The latter were oxidized with magnesium dioxide to the corresponding analogs of pyridoxal. The oximes of the aldehydes and their Schiff's bases with p-phenetidine have been obtained. Analogs of pyridoxamine have been obtained by the hydrogenation of the oximes. The UV absorption spectra of the compounds and the ratios of the ionic forms in aqueous solutions have been studied.     

Synthesis of analogs of pyridoxal 5′-phosphate and pyridoxamine 5′-phosphate

The following analogs of pyridoxamine 5′-phosphate (PAMP) have been synthesized by the direct phosphorylation of the corresponding amines: 2-nor-PAMP, 6-methyl-2-nor-PAMP, and 6-methyl-PAMP. A method for the synthesis of analogs of pyridoxal 5′-phosphate (PLP) by the phosphorylation of the Schiff's bases of the corresponding aldehydes with p-phenetidine and subsequent hydrolysis on a sulfonated resin has been worked out. 2-Nor-PLP, 6-methyl-2-nor-PLP, and 6-methyl-PLP have been obtained with yields of 53–73%. The spectral properties of the compounds obtained have been investigated.     

Convenient Method for Reduction of C-N Double Bonds in Oximes,Imines, and Hydrazones Using Sodium Borohydride–Raney Ni System

A practical method has been developed for reduction of C-N double bond in oximes, imines, and hydrazones with sodium borohydride catalyzed by Raney Ni. The reactions were carried out in basic aqueous solution, and the desired products were obtained in moderate yields after a simple procedure. This method can be applied to synthesize simpler aliphatic or aromatic amines and its analogs.     

Synthesis and structure of pyrazolo[5,1-a]isoindol-8-ones from Aromatic Ortho Diesters

The title compounds 2 , have now been shown to arise in certain cases from condensation of aromatic ortho-diesters with ketone, where formerly only indeno[1,2-c]pyrazol-4(1H)-ones 3 have been reported from such reaction. Heretofore 2 was obtained in a less direct fashion from phthalaldehydic acid esters. When hetero-aromatic diesters were employed, new heterocyclic ring systems as represented by 2a,b ,c were prepared for the first time. Structures of 2 have been verified from detailed ¹H and ¹³C nmr studies, while representative intermediates 4–9 in the condensation of diesters to 2 have been isolated and identified.     

Vitamin b6 analogs

The synthesis of 2- and 5-modified analogs of pyridoxine from which analogs of pyridoxal and pyridoxal 5-phosphate were obtained is described. The transition to analogs of pyridoxamine and pyridoxamine 5-phosphate is realized by hydrogenation of the oximes of these aldehydes.See [1] for communication XV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 655–660, May, 1974.     

Synthesis of analogs of pyridoxal 5′-phosphate and pyridoxamine 5′-phosphate

The following analogs of pyridoxamine 5-phosphate (PAMP) have been synthesized by the direct phosphorylation of the corresponding amines: 2-nor-PAMP, 6-methyl-2-nor-PAMP, and 6-methyl-PAMP. A method for the synthesis of analogs of pyridoxal 5-phosphate (PLP) by the phosphorylation of the Schiff's bases of the corresponding aldehydes with p-phenetidine and subsequent hydrolysis on a sulfonated resin has been worked out. 2-Nor-PLP, 6-methyl-2-nor-PLP, and 6-methyl-PLP have been obtained with yields of 53–73%. The spectral properties of the compounds obtained have been investigated.The authors heartily thank Academician A. E. Braunshtein for his constant interest in this work and for valuable advice.     

Synthesis of 3,4‐Dialkyl‐5‐(1‐oxo‐ethyl)‐3H‐thiazole‐2‐thiones Derivatives and Their Pesticidal Activity

By interaction of N‐methyl(ethyl)‐dithiocarbamate sodium salt with 3‐chloro‐pentane‐2,4‐dion the 1‐(3‐alkyl‐4‐methyl‐2‐thioxo‐2,3‐dihydro‐thiazol‐5‐yl)‐ethanones 1 , 2 and corresponding oximes 7 , 8 were synthesized. On the basis of the mentioned compounds hydrazono ( 3 , 4 ), ureayl and thioureayl ( 5 , 6 ) derivatives, substituted oximes ( 9 , 10 ) and azinyl oximes ( 11 , 12 ) were obtained. The structures of synthesized compounds were confirmed by proton nuclear magnetic resonance spectroscopy and elemental analysis. The pesticidal activities of synthesized compounds were studied. Some of the synthesized compounds simultaneously have shown growth stimulant and fungicidal activity.     

Synthesis and biological activity of certain O-pyrimidinylketoximes

By the interaction of substituted chloropyrimidines with the sodium salts of oximes of aliphatic and alicyclic ketoximes, series of O-(4,6-dimethyl-2-pyrimidinyl)- and O-(2,4-dimethyl-6-pyrimidyl)ketoximes have been obtained. Through reactions of 2-methyl-4,6-dichloropyrimidine with salts of ketoximes, the corresponding monosubstituted and disubstituted products have been synthesized. The biological activities of the synthesized substances have been investigated.Erevan Institute of the National Economy, Erevan 375025. M. V. Lomonosov Moscow State University, Moscow 119899. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 950–956, July, 1997.     

3,3-Dialkyltriazencarbonsäure-Derivate durch oxydative Hydro-Acyl-Elimination von 3,3-Dialkyltriazan-1,2-dicarbonsäure-Derivaten

3,3-Dialkyltriazenecarboxylic Derivatives by Oxidative Hydro-Acyl-Elimination from 3,3-Dialkyltriazane-1,2-dicarboxylic Derivatives The preparation and some properties of esters and amides of 3,3-dialkyltriazenecarboxylic acids ( 6 ) are described. These novel triazenes 6 were obtained by treatment of diesters, diamides and ester-amides of 3,3-dialkyltriazane-1,2-dicarboxylic acids ( 3 ) with lead tetraacetate, when an elimination of the COOR- or the CONHR-group at N(2) together with the H-atom at N(1) took place. The precursor triazanes 3 were readily available from the addition of secondary amines 2 to diesters, diamides or ester-amides of diazenedicarboxylic acid ( 1 ). The spectral properties of the triazanes 6 , including the ¹⁵N-NMR signals of one example, are compared with those of the triazanes 3 . They express the structural features due to conjugation in 3,3-dialkyltriazenecarboxylic derivatives, including the resistance to rotation around the N(2), N(3)-bond.     

Heterocyclic N-glycosyl derivatives—XIII: Reaction of 6-chloropurine and benzotriazoles with acetylated glycals

Acid-catalysed reactions of tri-O-acetyl-D-glucal with benzotriazole, 5,6-dimethylbenzotriazole, 5,6-dichlorobenzotriazole and 6-chloropurine have been found to give anomeric mixtures of the corresponding 2′,3′-unsaturated N-glycosyl derivatives with the α-anomers preponderating. When tri-O-acetyl-D-galactal was used the 3′,4′,6′-tri-O-acetyl-α- and β-D-lyxo-hexopyranosyl nucleoside analogs were obtained. The conformation and anomeric configuration of all the N-glycosyl compounds obtained were assigned by NMR studies.     

Heterocyclic Esters of 1,1'-Ferrocenedicarboxylic Acid

Acylation of hydroxyl-containing heterocyclic compounds with 1,1'-ferrocenedicarbonyl chloride afforded diheteryl-1,1'-ferrocenedicarboxylates. Bisaldehyde-containing diesters were obtained by acylation of hydroxybenzaldehydes. The condensation of the latter with 2-naphthylamine or 4-phenylazoaniline resulted in the formation of the corresponding azomethines. The reduction of bisaldehyde-containing diesters furnished ferrocene-containing diols. Ferrocene tetrahydrobenzo[a]acridine-11-(7H)-one derivatives were synthesized as a result of the three-component cascade heterocyclization of ferrocene bisaldehyde-containing diesters with 2-naphthylamine and dimedone.     

Synthesis of bicyclic diesters of malonic and succinic acids

Monoesters of malonic and succinic acids have been prepared in high yields by the BF₃·OEt₂-catalyzed addition of the acids to bicyclo[2.2.1]hept-2-ene. The synthesized monoesters were introduced in the reaction of esterification with saturated monoatomic alcohols С₂–С₇ in the presence of the KU-2-8 catalyst in the H-form, and the corresponding mixed diesters of dicarboxylic acids were obtained in high yields.     

Enzyme-Mediated Regioselective Acylations of Flavonoid Disaccharide Monoglycosides

Flavonoid disaccharide monoglycosides have been acylated by the catalytic action of the protease subtilisin in anhydrous pyridine. The effects of the nature of the sugars and of the interglycosidic bonds on the regioselectivity of the reactions have been analyzed. The selectivity was excellent with rutin ( 1 ), hesperidin ( 2 ), naringin ( 6 ), and quercetin 3-O-[O-(β-D -glucopyranosyl)-(1→4)-α-L -rhamnoside] ( 9 ), giving single monoesters on their glucose moieties (see la , 2a , 6a , and 9b , resp.); quite interestingly, in the last compound, acylation did not occur at the free primary OH group but at the secondary OH? C(3?). On the other hand, a mixture of mono- and diesters was obtained with the flavonoid peltatoside ( 7 ).     

Synthetic analogs of natural flavolignans. V. A new synthesis of 6-halogeno-1,3-benzodioxane analogs of silandrin and hydnocarpin

6-Halogeno-1,3-benzodioxane analogs of chalcones have been synthesized by various methods. Flavanone and flavone analogs of silandrin and hydnocarpin have been obtained from them. The structures of the new flavonoids have been shown by their PMR spectra.     

Synthesis, 1D and 2D NMR spectral assignments,and stereochemical studies of some 4,8,9,10-tetraaryl-1,3-diazaadamantan-6-one oximes

Structural Chemistry - A series of 4,8,9,10-tetraaryl-1,3-diazaadamantan-6-one oximes (4a-4e) have been synthesized. 1H and 13C NMR spectra of these oximes were recorded. Chemical shifts have been...     

Novel synthesis of 1,2,4‐triazolophanes and 1,3,4‐oxadiazolophanes: A dieckmann condensation approach

The Dieckmann condensation has been used for the first time for the syntheses of novel 1,2,4‐triazolophanes and 1,3,4‐oxadiazolophanes. The bis‐1,3,4‐oxadiazol‐2‐thiols 1a and 1b were reacted with ethyl bromoacetate to give the diesters 2a and 2b . Diesters 2a and 2b were treated under dry conditions with sodium methoxide in methanol to afford desired symmetrical 1,3,4‐oxadiazolophanes 3a and 3b . Similarly, diesters of macrocycle precursors containing 1,2,4‐triazole moiety, that is, 6a , 6b , 10 , 13a , 13b , and 13c were synthesized from 5a , 5b , 9 , 12a , 12b , and 12c , respectively. Dieckmann condensation of these diesters afforded symmetrical ketones 7a , 7b , 11 , 14a , 14b , and 14c . Extrusion of CO₂ was observed after in situ hydrolysis of the conventional Dieckmann product during neutralization by dilute mineral acids to afford highly symmetrical ketone in good yields. Further, the ketones 14a , 14b , and 14c were converted into their respective thiones by the reaction with Lawesson's reagent. All the products were synthesized with good yields, and structures were confirmed by various spectroscopic tools and elemental analyses. J. Heterocyclic Chem.,, (2012).     

Synthesis of some thiophene derivatives

The synthesis of thiopene derivatives from diacetylenic hydrocarbons has been described [1]. We have examined for the first time the reaction of diacetylenic diesters with hydrogen sulfide and with NaHS. The diacetylenic diesters react readily with hydrogen sulfide or NaHS in acetone at pH 9–10 to give 2,5-disubstituted thiopheries (see Table 1).Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 5, pp. 713–714, May, 1970.     

Synthesis and Evaluation of Chromogenic and Fluorogenic Analogs of Glycerol for Enzyme Assays

The branched glycerol analogs 1 and 2 were prepared. Mono‐ester derivatives of these triols undergo a chromogenic or fluorogenic reaction in the presence of NaIO₄. In contrast, both the diesters and the triols are themselves not chromogenic or fluorogenic. Diester derivatives of these triols can be used as probes for lipases. The tris‐phosphate derivative of 1 is a fluorogenic substrate for various phosphatases.     

Pyrimidines

Pyrimidine-2-aldoxime and 4,6-dimethylpyrimidine-2-aldoxime were obtained by oximation of the corresponding aldehydes. On the basis of spectral data, it was shown that the oximes have the syn configuration. syn-4, 6-Dimethylpyrimidine-2-aldoxtme is converted to the corresponding anti isomer by photochemical isomerization. 1-Methyl-2-oximidomethylpyrimidinium iodide was obtained by the action of methyl iodide on pyrimidine-2-aldoxime.See [1] for the preceding communication.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1422–1424, October, 1972.     

Synthesis,structure and cytotoxic activity of 2‐acetyl‐5‐trimethylsilylthiophene(furan) and their oximes

5‐Trimethylsilylderivatives of 2‐acetylthiophene and ‐furan have been regioselectively prepared by a one‐pot procedure from the corresponding 2‐acetylfuran or 2‐acetylthiophene using lithium N‐methylpiperazide (LNMP)–butyllithium–trimethylchlorosilane–water as the sequence of reagents. The ketones obtained were converted to the corresponding oximes. The structure of 2‐acetyl‐5‐trimethylsilylthiophene oxime (E‐isomer) has been studied by X‐ray diffraction. Formation of centrosymmetric dimers by means of H‐bonds has been observed. The intermolecular hydrogen bond O9? H…N8 length is 2.842(5) Å [H…N8 = 1.87 (6) Å, O9? H…N8 = 157(4)°]. Copyright © 2006 John Wiley & Sons, Ltd.