Hydrogenation of 2- tert -butylphenol over Ni catalyst

The hydrogenation of 2-tert-butylphenol was studied in regard to possibilities of influencing selectivity, namely the ratio ofcis- andtrans-isomers of 2-tert-butylcyclohexanol in the final reaction mixture. The hydrogenation reactions were carried out using the catalyst Ni/Al₂O₃. During the hydrogenations, a higher content of thecis-isomer was attained, when simultaneously the final reaction mixture contained 2-tert-butylcyclohexanone. The content of this intermediate, which primarily hydrogenated to thecis-isomer, increased with a decreased pressure and after the addition of acetic acid into the reaction mixture.     

N-(2-Thenyl)derivatives of aminoalkyltriethoxysilanes,-silatranes and 2,2-dimethyl-1,3-dioxa-6-aza-silacyclooctane

The reactions of aminoalkylethoxysilanes and 2,2-dimethyl-1,3-dioxa-6-aza-2-silacyclooctane with 2-(chlormethyl)thiophene and its 5-chloroderivative lead to the correspondingN-(2-thenyl) derivatives. TheN-methyl-N-(2-thenyl)aminomethyltriethoxysilane and 5-chlorothyenyl derivative formed are converted by triethanolamine into silatranes.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 384–386, February, 1995.     

Formation of sodium 6-hydroxy-2-naphthoate in the <Emphasis Type="Italic">Kolbe-Schmitt</Emphasis> reaction

This work is an extension of our investigation of the mechanism of the Kolbe-Schmitt reaction of sodium 2-naphthoxide. The carboxylation reaction of sodium 2-naphthoxide in the position 6 is examined by means of the B3LYP/LANL2DZ method. After the initial formation of sodium 2-naphthoxide-CO₂ complex, the carbon of the CO₂ moiety performs an electrophilic attack on the naphthalene ring in position 8. Further transformations lead to the formation of sodium 6-hydroxy-2-naphthoate. Our findings are in good agreement with the experimental results on the carboxylation reaction of sodium 2-naphthoxide. Correspondence: Svetlana Marković, Faculty of Science, University of Kragujevac, 34000 Kragujevac, Serbia.     

Five unusual natural carbohydrates from <Emphasis Type="Italic">Actinosynnema pretiosum</Emphasis>

Five unusual hexose derivatives were isolated from the carbohydrate portion of the solid-state fermentation extract of Actinosynnema pretiosum ssp. auranticum ATCC 31565, which is a producing strain of maytansinoids that are a family of 19-membered macrocyclic lactams having extraordinary cytotoxic and antineoplastic activities. Their structures were determined to be 2-deoxy-α-D-arabino-hexopyranose (1), 2-deoxy-β-D-arabino-hexopyranose (2), 3,6-anhydro-2-deoxy-α-D-arabino-hexcofuranose (3), 3,6-anhydro-2-deoxy-β-D-arabino-hexofuranose (4), and 2-(D-glycerol-1,2-dihydroxyethyl)furan (5) by NMR spectroscopic experiments. Published in Khimiya Prirodnykh Soedinenii, No. 5, pp. 481–483, September-October, 2008.     

On the condensation of 2,2-difluoro-4-methyl-benzo[d]-1,3,2-dioxaborines with cyano acetic acid derivatives. Formation and transformation of 3-cyano-4-methyl-benzo[b]pyran-2-ones and their 2-imine precursors

Summary By condensation of 2,2-difluoro-4-methyl-benzo[d]-1,3,2-2H-dioxaborines (12) with cyano acetic acid derivatives in presence of weak bases, 3-cyano-4-methyl-benzo[b]pyran-2-ones (13) or their 3-cyano-4-methyl-benzo[b]pyran-2-imine precursors (14) are available in satisfactory yields.

---

Zur Kondensation von 2,2-Difluor-4-methyl-benzo[d]-1,3,2-2H-dioxaborinen mit Cyanessigsäure- Derivaten. Bildung und Umwandlung von 3-Cyano-4-methyl-benzo[b]pyran-2-onen und ihrer 2-Imino-Vorstufen

Zusammenfassung Durch Kondensation von 2,2-Difluor-4-methyl-benzo[d]-1,3,2-2H-dioxaborinen (12) mit Cyanessigsäure-Derivaten in Gegenwart von Hilfsbasen entstehen in befriedigenden Ausbeuten 3-Cyan-4-methyl-benzo[b]pyran-2-one (13) oder ihre 3-Cyan-4-methyl-benzo[b]pyran-2-imino-Vorstufen (14).

     

Synthesis of anthrathiopyrantriones by heterocyclization of alkynoyl derivatives of chloroanthraquinones

A procedure was developed for the synthesis of 2-substituted, including 2-alkenyl-substituted, 4H-anthra[1,2-b]thiopyran-4,7,12-triones and 4H-anthra[2,3-b]thiopyran-4,6,11-triones by cyclocondensation of vic-alkynoylchloroanthraquinones with Na₂S.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2205–2209, October, 2004.     

2-cyanopenta-(2E,4)-dienoic acid and its amide

Knoevenagel condensation of acrolein with NCCH₂COOK or NCCH₂CONH₂ in 1M aqueous solutions of K and Na phosphates gave 2-cyanopenta-(2E,4)-dienoic acid and its amide, respectively. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 363–365, February, 1998.     

Reaction of 6-methoxybenzo[b]furan-3(2H)-one and benzo[b]thiophen-3(2H)-one with 2-aryl-1,1-dicyanoethylenes as a convenient synthetic route to substituted 2-amino-4-aryl-1,3-dicyano-7-methoxydibenzo[b,d]furans and 2-amino-4-aryl-3-cyano-4H-benzothieno[3,2-b]pyrans

The reactions of 6-methoxybenzo[b]furan-3(2H)-one with 2-aryl-1,1-dicyanoethylenes and malononitrile or with aromatic aldehyde and two moles of malononitrile afford 2-amino-4-aryl-1,3-dicyano-7-methoxydibenzo[b,d]furans. The reactions of benzo[b]thiophen-3(2H)-one with 2-aryl-1,1-dicyanoethylenes or with aromatic aldehyde and one mole of malononitrile produce 2-amino-4-aryl-3-cyano-4H-benzothieno[3,2-b]pyrans.     

Synthesis of 4-thia analogues of isoquinoline alkaloids

Summary (±)-4-Thiacarnegin (3) was synthesized by reaction of 6,7-dimethoxy-3-methyl-2H-1,3-benzothiazinium iodide (2) with methyl magnesium iodide, thereby opening a new synthetic route to 4-substituted dihydro-2H-1,3-benzothiazines. Compound3 was also obtained by reduction of 6,7-dimethoxy-3,4-dimethyl-2H-1,3-benzothiazinium iodide (5). In a similar way, reduction of the quaternary salts9 a–c afforded the (±)-4-thia analogues of cryptostilin-I, -II and -III (10 a–c). The isomers of the former compounds (12 a–c) were also synthesized by reduction of the 4H-1,3-benzothiazinium salts11 a–c.

---

Synthese von 4-Thiaanalogen von Alkaloiden mit Isochinolingerüst

Zusammenfassung Aus 6,7-Dimethoxy-3-methyl-2H-1,3-benzothiaziniumjodid (2) wurde mit Methylmagnesiumjodid (±)-Thiacarnegin (3) dargestellt. Diese Reaktion bietet ein neues Verfahren für die Synthese von 4-substituierten Dihydro-2H-1,3-benzothiazinen.3 wurde auch durch Reduktion von 6,7-Dimethoxy-3,4-dimethyl-2H-1,3-benzothiaziniumjodid (5) erhalten. Die Reduktion der quartären Ammoniumsalze9 a–c ergab ebenfalls die Cryptostillin I-, II-, III-(±)-4-thiaanalogen Verbindungen (10 a–c). Reduktion der 4H-1,3-Benzothiazinium-Salze11 a–c lieferte die entsprechenden Isomeren12 a–c der obengenannten Verbindungen.

     

Acid-catalyzed decomposition of cyclohexanespiro-2-oxazolidine

Heating cyclohexanespiro-2-oxazolidine at 160–200°C in the presence of protic acids results in its decomposition to giveN-(2-hydroxyethyl)cyclohexylamine,N-(2-hydroxyethyl)-4,5,6,7-tetrahydroindole, and 2-cyclohexylidenecyclohexanone. The possible pathways leading to these compounds are discussed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1547–1548, August, 1997.     

Derivatives of <Emphasis Type="Italic">sym</Emphasis>-Triazine. 1. Synthesis and Conversions of Quaternary Methylammonium Salts of 2-Chloro-4,6-disubstituted 1,3,5-Triazines in Nucleophilic Substitution Reactions

New quaternary ammonium salts of monochloro-4,6-disubstituted 1,3,5-triazines have been obtained. These compounds are convenient synthons for the synthesis of new cyano, alkoxy, and other derivatives of sym-triazine. Some conversions of the synthesized salts have been studied. An elimination-isomerization reaction of the sym-triazine ring into a 2-oxo-1,2-dihydro-sym-triazine ring was discovered.     

Synthesis of some schiff bases of 3-aroyl-6-aryl-4-hydroxy-2H-pyran-2-ones

Summary The reaction of 3-aroyl-6-aryl-4-hydroxy-2H-pyran-2-ones (Ar=p-tolyl, 1,1-biphenyl-4-yl or thienyl) with aniline and substitutedo-phenylenediamine (R=H, CH₃ or Cl) yields a series of new Schiff bases2a–f in 51–72% yield. Bromination of1a gave the 5-bromo derivative1c, while the compounds1a,1b,2b,2e, and2f were converted into 2,6-diaryl-4H-pyran-4-ones3a–c. All products have been fully characterized.

---

Synthese von Schiff'schen Basen von 3-Aroyl-6-aryl-4-hydroxy-2H-pyran-2-onen

Zusammenfassung Die Reaktion von 3-Aroyl-6-aryl-4-hydroxy-2H-pyran-2-onen (Ar=p-Tolyl, 1,1-Biphenyl-4-yl oder Thienyl) mit Anilin und substituierteno-Phenylendiaminen liefert neue Schiff'sche Basen2a–f/bd in 51–72% Ausbeute. Bromierung von1a gab das 5-Bromderivate1c, während die Verbindungen1a,1b,2b,2e und2f in 2,6-Diaryl-4H-pyran-4-onen3a–c übergeführt wurden. Alle Produkte wurden voll charakterisiert.

     

A convergent synthesis of octadeca-2E, 13Z-dienyl acetate, a pheromone component ofSynanthedon tipuliformis C.

A convergent synthesis of octadeca-2E, 13Z-dienyl acetate, a pheromone component ofSynanthedon tipuliformis C., has been developed. The synthesis is based on cross-coupling of 8-iodooct-2E-en-I-ol THP ether with dec-5Z-enyl bromide catalyzed by CuBr. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1529–1531, August, 1997.     

Untersuchungen über Chinone, 10. Mitt. Zur Reaktion vonp-Benzochinon mit sekundären aliphatischen Aminen

Summary p-Benzoquinone (1) reacts with dialkylamines2a-d to 2-dialkylamino-p-benzoquinones3, 2,5-bis-dialkylamino-p-benzoquinones4, 2-dialkylamino-8-hydroxydibenzofuran-1,4-quinones5, and in pyridine also to 2-dialkylamino-5-p-hydroxy-phenoxy-p-benzoquinones6. A method affording almost exclusively3 has been developed which is also applicable to compounds2e-h.

     

4-(3-Cyanopyridin-2-ylthio)acetoacetates in synthesis of heterocycles

Substituted 2-amino-4-aryl-3-cyano-5-oxo-5,6-dihydro-4H-pyrano[2,3-d]pyrido[3",2":4,5]thieno[3,2-b]pyridines were synthesized by the reactions of 4-hydroxy-1H-thieno[2,3-b;4,5-b]dipyridin-2-ones with arylidenemalononitriles or by the three-component reactions of hydroxythienodipyridinones with aldehydes and malononitrile in DMF in the presence of triethylamine. Methods for syntheses of substituted 3-alkoxycarbonyl-6-amino-4-aryl-2-(3-cyanopyridin-2-ylthiomethyl)-4H-pyrans were developed on the basis of the reactions of 4-(3-cyanopyridin-2-ylthio)acetoacetates and arylidenemalononitriles or aldehydes and malononitrile. Ethyl 4-(3-cyanopyridin-2-ylthio)acetoacetate and 4-methoxybenzylidenecyanothioacetamide were used for the synthesis of 6-(pyridin-2-ylthiomethyl)-3-cyanopyridine-2(1H)-thione.     

Synthesis and structure of the complex of 2-(2-pyridyl)-2-oxazoline with PdCl2

The reaction ofN-2-nitroxyethylpicolinamide with PdCl₂ afforded the new complexcis-[2-(2-pyridyl)-2-oxazoline-N,N′]dichloropalladium(u). The structure of this complex was established by X-ray diffraction analysis. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 561–563, March, 2000.     

Nucleophilic substitution of bromine in vicinal bromotrifluoroalkylamines

SecondaryN-(2-bromo-3,3,3-trifluoropropyl)-N-alkylamines cyclize under the action of bases to yield aziridines. TertiaryN-(2-bromo-3,3,3-trifluoropropyl)amines react with S-nucleophiles to give products of bromine substitution.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 955–957, May, 1994.     

Functional polymers. XII: Synthesis and polymerization of 2(2-vinyl-4-hydroxyphenyl)2H-benzotriazole and 2(3-vinyl-4-hydroxyphenyl)2H-benzotriazole

Condensation of diazotizedo-nitroaniline with 3-ethylphenol or with 2-ethylphenol followed by reduction of the resulting azo compound with zinc dust in sodium hydroxide solution gave 2-(2-ethyl-4-hydroxyphenyl)2H-benzotriazole and 2(3-ethyl-4-hydroxyphenyl)2H-benzotriazole, respectively. The individual compounds were acetylated, brominated withN-bromosuccinimide to the corresponding 1-bromoethyl compounds which were then dehydrobrominated with triethyl amine in acetonitrile and hydrolyzed to 2(2-vinyl-4-hydroxyphenyl)2H-benzotriazole or 2(3-vinyl-4-hydroxyphenyl)2H-benzotriazole. The two monomers could be polymerized and copolymerized with styrene and methyl methacrylate. The ethyl as well as the vinyl compounds and the corresponding polymers, when tested, are ineffective as ultraviolet absorbers as they have structures of 4-hydroxyphenyl rather than 2-hydroxyphenyl compounds with respect to the benzotriazole ring. A careful NMR analysis for the correct structural assignment is also described.Part XI:S. Yoshida andO. Vogl, Makromol. Chem., in press.     

Kolbe-Schmitt reaction of sodium 2-naphthoxide

The mechanism of the Kolbe-Schmitt reaction of sodium 2-naphthoxide is examined by means of the B3LYP/LANL2DZ method. After the initial formation of sodium 2-naphthoxide-CO₂ complex, the carbon of the CO₂ moiety performs an electrophilic attack on the naphthalene ring. Further transformations lead to the formation of sodium 2-hydroxy-1-naphthoate. Sodium 3-hydroxy-2-naphthoate is formed by a 1,3-rearrangement of the CO₂Na group. Our findings are in good agreement with the experimental results on the carboxylation reaction of sodium 2-naphthoxide. Correspondence: Svetlana Marković, Faculty of Science, University of Kragujevac, 34000 Kragujevac, Serbia     

The reactivity of N,N-dialkyl-N-(3-phenylsulfinyltetrahydrofuran-2-ylidene)ammonium bromide

trans-Stereoselective electrophilic cyclization of (2R*,SS*)-N, N-diisopropyl-2-phenylsulfinylpent-4-enamide under the action of bromine afforded (3R*,5S*, SS*)-N-(5-bromomethyl-3-phenylsulfinyltetrahydrofuran-2-ylidene)-N,N-diisopropylammonium bromide. Its transformations under the conditions of hydrolysis, dehydrobromination, and hydride reduction were studied. Dedicated to Academician V. A. Tartakovsky on the occasion of his 75th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1485–1490, August, 2007.