Ethoxy Substituents Research Articles

Synthesis and optical properties of water-soluble poly(p-phenylenevinylene)s

A novel conjugated polymer containing carboxylic acid and 2-[2-(2-methoxyethoxy)ethoxy]ethoxy substituents which is soluble in both organic solvents and aqueous bases is synthesized.

Dehydrogenative coupling of styrene with trisubstituted silanes catalyzed by nickel complexes

Trisubstituted silanes, e.g., Me n (EtO) 3− n SiH (where n=0–2) and Me 2PhSiH in the presence of nickel complexes, e.g., [Ni(acac) 2] and [Ni(cod) 2], undergo two reactions of dehydrogenative silylation of styrene to yield in both cases an unsaturated product— E-1-phenyl-2-silyl-ethene as well as products of styrene hydrogenation—ethylbenzene DS-1 and of hydrogenative dimerization of styrene—1,3-diphenylbutane—DS-2. The two reactions are accompanied by the hydrosilylation products H as well as redistribution of the silanes containing at least one ethoxy substituent. The catalytic examinations and identification of nickel square planar complexes suggest that the intermediates containing Ni–Si (I), Ni–H (II) and Ni–C (III) bonds are responsible for the catalysis.

Nitrogen inversion and N–O bond rotation in some hydroxylamine and isoxazolidine derivatives

A series of trisubstituted hydroxylamine derivatives, both cyclic and acyclic, has been prepared. The energy barriers in these hydroxylamines are found to be dominated either by nitrogen inversion or N–O bond rotation depending on the nature of the substituents attached to the nitrogen. In several series of compounds, having XC6H4CH2 substituents attached to nitrogen, Hammett free energy correlations are obtained with positive ρ values, indicating increased electron density at the transition state for the inversion process. Isoxazolidines with C(5) ethoxy substituents demonstrate a strong anomeric effect.

Participation of a medium chain acyl-CoA synthetase in glycine conjugation of the benzoic acid derivatives with the electron-donating groups

Glycine conjugation of a series of benzoic acid derivatives was investigated in bovine liver mitochondria. Benzoic acids with chlorine, methyl, methoxy, or ethoxy substituents in the para- or metapositions of the benzene ring showed a high degree of glycine conjugation. In contrast, the acids with cyano, nitro, amino, or acetylamino groups were conjugated to a small extent with glycine. A medium chain acyl-CoA synthetase that activates carboxylic acids was purified from bovine liver mitochondria. The purified medium chain acyl-CoA synthetase accepted not only medium chain fatty acids but also aromatic and arylacetic acids as substrates. There was a good correlation between the activity of the purified medium chain acyl-CoA synthetase and glycine conjugation of ten benzoic acids with electron-donating substituents. These findings indicate that the purified medium chain acyl-CoA synthetase is a major enzyme for glycine conjugation of benzoic acids with electron-donating groups in bovine liver mitochondria.

ChemInform Abstract: Reactions of Some 1,3‐Diaminonucleophiles with Azlactones.

AbstractThe azlactones (I), (VI) and (X) react with the isothiouronium halides (II) to give the products (III), (VII) and (XI), respectively.

Reactions of some 1,3-diaminonucleophiles with azlactones

Triethylamine-mediated reactions ofS-substituted isothiouronium halides (2) with unsaturated aziactones (1) gave the corresponding S-substituted 2-thiopyrimidines (3), S-substituted 3-thioacrylanilide (10), and 4-benzylidene-2-iminoimidazolidin-5-one (13), depending on the ethoxy, anilino, and phenyl substituents, respectively, at the 4-CC bond. Aminolyses of (3) afforded 2-aminopyrimidines (4). Tautomerism of compounds (3) and (13) was confirmed by their acetylation and/or hydrolysis. Basemediated condensation of compound (1c) with thiourea or urea in boiling ethanol was unsuccessful, but simple heating of these reactants at an elevated temperature gave 4-benzylidene-2-phenylimidazol-5(4H)-one (22).

Electrochemical reduction mechanism of 2-thiouracil derivatives

The mechanism of the polarographic reduction of 2-thiouracil and its S-methyl and ethoxy derivatives with stabilized 2-thiol-4-keto or 2-thione-4-enol structure has been studied. 2-Thiouracil is not electroreducible in aqueous solutions. However, it exhibits a strong tendency to adsorption and association on the mercury electrode. 2-Thio-4-ethoxypyrimidine undergoes a 4 e −, 4 H + reduction which involves 2 e − reduction of the 3,4 NC bond, elimination of the ethoxy substituent to form 2-thiopyrimidine and 2 e −, 2 H + reduction of the latter to 3,4-dihydroderivative. For 2-thiomethyluracil, a model compound of the 2-thiol-4-keto form, the electroactive centre is shifted to C-2 and in a 2 e −, 2 H + reduction process the sulphur substituent undergoes elimination, to give pyrimidone-4; the latter can be further reduced at more negative potentials to tetrahydroderivatives (4 e − -process). Biological implications of these results have been discussed.

Electrochemical reduction mechanism of 2-thiouracil derivatives

Abstract The mechanism of the polarographic reduction of 2-thiouracil and its S-methyl and ethoxy derivatives with stabilized 2-thiol-4-keto or 2-thione-4-enol structure has been studied. 2-Thiouracil is not electroreducible in aqueous solutions. However, it exhibits a strong tendency to adsorption and association on the mercury electrode. 2-Thio-4-ethoxypyrimidine undergoes a 4 e−, 4 H+ reduction which involves 2 e− reduction of the 3,4 NC bond, elimination of the ethoxy substituent to form 2-thiopyrimidine and 2 e−, 2 H+ reduction of the latter to 3,4-dihydroderivative. For 2-thiomethyluracil, a model compound of the 2-thiol-4-keto form, the electroactive centre is shifted to C-2 and in a 2 e−, 2 H+ reduction process the sulphur substituent undergoes elimination, to give pyrimidone-4; the latter can be further reduced at more negative potentials to tetrahydroderivatives (4 e− -process). Biological implications of these results have been discussed.

New analogs of trimethoprim.

Possible goals and recent developments in the field of antimicrobial 2,4-diamino-5-benzylpyrimidines are discussed. Three analogs of trimethoprim--all bearing different substituents at position 4 of the benzyl moiety and one also having the methoxy groups replaced by ethoxy substituents--are characterized in some detail. These analogs exhibit physicochemical properties different from those of trimethoprim and are potent inhibitors of several dihydrofolate reductases. Because they differ from trimethoprim in lipophilicity, their in vitro activity, spectrum of activity, and pharmacokinetic properties also differ from those of trimethoprim. These differences are judged to be the reason for enhanced in vivo efficacy against several experimental infections. Distinct pharmacokinetic differences observed in dogs include a longer elimination half-life and a larger volume of distribution. These favorable properties indicate the potential value of further studies in humans.

Reaction of dihalocarbenes with chromenes under interphase-catalysis conditions

Reactions involving the interphase dichloro-and dibromocyclopropanation of 2H- and 4H-chromenes that contain ethoxy, aryl, alkyl, and hetaryl substituents in the pyran ring were studied. It is shown that products of addition of dihalocarbenes to the double bond of the chromenes are formed in high yields in all cases.

Electronic effect of and mutual polarizability in groups attached to oxygen via their C, Si, Ge, and B atoms

Relative acidity of triphenylhydroxy substituted germane and stannane is consistent with superior electrondonating effect of (C6H5)3Ge and (C6H5)3Sn groups in these compounds. Relative basicity data of alkyl(alkoxy) boranes, methanes, silanes, and germanes (RO)nZRm (Z = B, C, Si, and Ge) are compiled. The variation of the electronic effect parameter σ of fully alkylated RmZ-groups upon substitution of their alkyl with ethoxy substituent appears for Z=B and Si to be influenced by mutual polarizability effect of ethoxy substituents. Mutual polarizability of ethoxy substituents attached to carbon and germanium is negligible.

PMR-Spektren einiger Alkoxy-9-chlor-6-nitroacridine

The spectra of some 9-chloro-6-nitroacridines with methoxy substituents in position 1,4; 2,4; 3,4; 2,3; and ethoxy substituents in positions 1, 2, 3, were recorded. The influence of electron releasing alkoxy groups and electron withdrawing nitro groups on chemical shifts of protons in the 9-chloroacridinic cycle was discussed and PMR parameters were determined, comparatively with those of acridine and 9-chloroacridine. Good agreement between calculated and experimental values is observed. The spectrum of 9-chloro-1,2,3-triethoxyacridine shows for the four protons of the ringC. (H-5, H-6, H-7, H-8) anAMNX coupling pattern whose parameters were determined.

Reactions of bromoethoxyisoquinolines with potassium amide in liquid ammonia

AbstractOf the six possible isoquinolines with both a bromo and an ethoxy substituent in the pyridine nucleus, all, except 4‐bromo‐3‐ethoxyisoquinoline, react by simple nucleophilic substitution of the bromo atom and, if placed in position 1, of the ethoxy group. 4‐Bromo‐3‐ethoxyisoquinoline yields a complicated reaction mixture, containing in addition to substitution products dehalogenated compounds and at least five different substituted biisoquinolines.

Hydroboration. XXVII. The hydroboration of 1-butenyl and related vinyl derivatives containing representative substituents. An unusually powerful directive influence of the ethoxy substituent

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHydroboration. XXVII. The hydroboration of 1-butenyl and related vinyl derivatives containing representative substituents. An unusually powerful directive influence of the ethoxy substituentHerbert C. Brown and Richard L. SharpCite this: J. Am. Chem. Soc. 1968, 90, 11, 2915–2927Publication Date (Print):May 1, 1968Publication History Published online1 May 2002Published inissue 1 May 1968https://doi.org/10.1021/ja01013a032RIGHTS & PERMISSIONSArticle Views995Altmetric-Citations115LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

COENZYME SPECIFICITY OF NICOTINAMIDE-ADENINE DINUCLEOTIDE PHOSPHATE CYTOCHROME C REDUCTASE FOR FLAVIN PHOSPHATES.

Effects of changes in the structures of flavin phosphates were studied to assess the coenzyme specificity of nicotinamide-adenine dinucleotide phosphate cytochrome c reductase (NADPH: cytochrome c oxidoreductase, EC 1.6.2.3) from brewer's yeast. 1. 1. Among analogues of riboflavin 5′-phosphate which are symmetrically substituted in positions 6 and 7 of the isoalloxazine ring system, diethylriboflavin 5′-phosphate is as active as riboflavin 5′-phosphate, but decreasing activities are seen with the dibromo-, dichloro-, and diiodo-analogues. 2. 2. With analogues which are substituted in position 6 of the ring system, satisfactory activities of the 5′-phosphates of methyl- and, somewhat less, methyl-pyridinoriboflavin are observed; however carboxy and ethoxy substituents markedly diminish activity. 3. 3. Activities of 6,7-dimethylflavin phosphates bearing different side chains are progressively decreased with the shorter chains of the glycityl series of d-ribityl, d-erythrityl, and dl-glyceryl, respectively. Similarly with the alkyl chains, 2′, 3′, 4′-trideoxyribityl is better than 2′-deoxyglyceryl. 4. 4. Secondary hydroxyl groups on the chain confer greater activity, but are not obligatory as seen by the activities of 2′,3′,4′-trideoxyriboflavin 5′-phosphate and 2′-deoxyglyceroflavin 3′-phosphate. A reduction in activity is also seen when the 2′-hydroxy function is missing, as in 2′-deoxyriboflavin 5′-phosphate, or in l-configuration, as in d-araboflavin 5′-phosphate.