N-Acetylation and several N-alkylation reactions have been carried out for the previously synthesized 4,11-dimethoxynaphtho[2,3-f]indole-5,10-dione.

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In reactions with some α-halo ketones (3-bromo-1,1,1-trifluoropropan-2-one, 1-acetyl-2-bromoindolin-3-one, and α-bromoacetophenone), thioacetamide and a series of thioamides of aromatic and heteroaromatic acids are transformed into 4-hydroxy-Δ2-thiazolines rather than into thiazoles (the expected Hantzsch reaction products). To the contrary, thiazoles are produced in the reactions of the same α-halo ketones with thioamides of phenylacetic, diphenylacetic, 3-indolylacetic, or cyanoacetic acids. The abnormal course of the Hantzsch reaction in the former case results from the fact that 4-hydroxy-Δ2-thiazolines, which are intermediates in the thiazole synthesis, undergo virtually no dehydration under the Hantzsch reaction conditions. The ease of dehydration of hydroxythiazolines under the conditions of the thiazole synthesis and the possibility of the spontaneous thiazole synthesis depend on the nature of the substituent at position 2 and, consequently, on the structure of the starting thioamide. The Me, Ar, and Het substituents impede dehydration, whereas substituents containing the α-methylene (methine) unit at the C(2) atom of the thiazoline moiety substantially facilitate this reaction. The conditions for the dehydration of 4-acetyl-2-methyl-8b-hydroxy-3a,8b-dihydro-4H-thiazolo[5,4-b]indole under basic catalysis were found, and a new procedure was developed for the preparation of thiazoles and 2-R-thiazolo[5,4-b]indoles, whose synthesis presents difficulties or is impossible under standard conditions.

Based on the results of studies of the deuterium exchange and dehydration of 4-hydroxy-Δ2-thiazolines and 2-R-4-acetyl-8b-hydroxy-3a,8b-dihydro-4H-thiazolo[5,4-b]indoles containing the α-methylene (methine) unit at the C(2) atom, the mechanism of dehydration of these compounds generated as intermediates in the Hantzsch synthesis of thiazoles and 2-R-4-acetyl-4H-thiazolo[5,4-b]indoles was proposed. This mechanism includes an additional step of the formation of the corresponding Δ3-thiazolines. According to the results of quantum chemical calculations, this is energetically more favorable than the dehydration in terms of the commonly accepted mechanism. In some cases, an acidic medium impedes the dehydration of 4-hydroxy-Δ2-thiazolines or their cyclic analogs. The proposed mechanism provides an explanation for the empirical data on the differences in the reactivities of both thioamides and α-haloketones, which have remained unexplained in terms of the commonly accepted mechanism. The spontaneous thiazole synthesis is virtually impossible starting from thioamides of aromatic or heteroaromatic acids and α-haloketones bearing electron-withdrawing α′ substituents or cyclic bromoindoxyl-type haloketones. In the thiazole synthesis from these starting components, it is expedient to perform dehydration under basic catalysis.

The new modification of accq-tag-HPLC method for the rapid analysis of L-proline and GABA in culture medium is presented. We have shown the influence of the concentration of L-isoleucine added to cultere medium on GABA accumulation. Accumulation of γ-aminobutiric acid (GABA) in the culture broth of E. coli strains is proved using mass-spectroscopy and NMR methods.

We obtained perhydro-1,2,3-oxathiazine 2,2-dioxides by cyclization of 4-N-benzylamino-4-tetramethylene(phenyl-, methylphenyl-, dimethyl)but-1-enes in conc. H2SO4 at 25°C. When treated with an alcoholic solution of base, the oxathiazines are converted to 2-substituted and spiro-annelated 1-benzyl-4-methylazetidines.

Acylation of substituted 4-(furyl-2)-4-arylaminobut-1-enes with maleic anhydride provided 2-allyl-6-carboxy-4-oxo-3-aza-10-oxatricyclo[5.2.1.01,5]dec-8-enes in high yield under mild reaction conditions. The Diels–Alder adducts are formed via an initial amide formation followed by a stereoselective intramolecular [4+2] exo-cycloaddition reaction. Treatment of the tricyclic compounds with phosphoric acid at high temperatures (70–120°C) promoted cyclic ether opening, intramolecular cyclization and aromatization to give the corresponding tetracyclic compounds, 5,6,6a,11-tetrahydro-10-carboxyisoindolo[2,1-a]quinolines, in moderate yields. The influence of the acid and the reaction temperature on the cyclization reactions are also discussed.

A new modification of the accq-tag-HPLC technique for the rapid determination of L-proline and γ-aminobutyric acid (GABA) in a culture medium is proposed. The concentration of L-isoleucine added to the culture medium is shown to influence the accumulation of GABA. The accumulation of GABA in the culture media of E. coli strains is confirmed by the data of mass spectroscopy and NMR.

The [3+2] cycloaddition of acrylonitrile to the N-oxide of 5-methyl-4,5-dihydro-3H-spiro[benz-2-azepine-3,1'-cyclohexane] under conditions of both kinetic and thermodynamic control proceeds without regioselectivity or stereoselectivity with the formation of eight isomeric 1-cyano- and 2-cyano-7-methyl-1,2,4,6,7,11b-hexahydro-5H-spiro[isoxazolidino[3,2-a]benz-2-azepine-5,1'-cyclohexanes], six of which were isolated in an individual state. Their structure and stereochemistry were established by 1H NMR.

The intramolecular Diels-Alder reaction of readily accessible 4-substituted 4-(N-furfuryl)aminobut-1-enes was studied and a new one-step method was developed for the synthesis of 6,8a-epoxy-1,2,3,4,4a,5,6,8a-octahydroisoquinoline (3-aza-11-oxatricyclo[6.2.1.0(1,6)]undec-9-ene) derivatives. The [4+2]-cycloaddition proceeds stereoselectively to form exo-adducts. The influence of substituents at the nitrogen atom in 4-(N-furfuryl)aminobut-1-enes on the cycloaddition pathway was examined.

The intramolecular Diels—Alder reaction of readily accessible 4-substituted 4-(N-furfuryl)aminobut-1-enes was studied and a new one-step method was developed for the synthesis of 6,8a-epoxy-1,2,3,4,4a,5,6,8a-octahydroisoquinoline (3-aza-11-oxatricyclo[6.2.1.01,6]undec-9-ene) derivatives. The [4+2]-cycloaddition proceeds stereoselectively to form exo-adducts. The influence of substituents at the nitrogen atom in 4-(N-furfuryl)aminobut-1-enes on the cycloaddition pathway was examined.

Acylation of 4-α-furyl-4-N-benzylaminobut-1-enes with maleic anhydride gave 4-oxo-3-aza-10-oxatricyclo[5.2.1.01,5]dec-8-ene-6-carboxylic acid via amide formation followed by intramolecular Diels–Alder reaction of furan (IMDAF). The cycloaddition proceeded under mild reaction conditions (25°C) and provided only the exo-adduct in quantitative yield. Treatment of this compound with PPA gave isoindolo[2,1-b][2]benzazepine derivatives via ring opening, aromatization and intramolecular electrophilic alkylation. In order to extend the scope of the reaction sequence, 7-oxo-5,11b,12,13-tetrahydro-7H-isoindolo[2,1-b][2]benzazepine-8-carboxylic acids were further transformed into useful synthetic intermediates.

The reactions of 3-acetyl-3-aza-11-oxatricyclo[6.2.1.0(1,6)]undec-9-ene and its 9,10-epoxy derivative with bromine and Ac(2)O/BF(3).OEt(2) under different conditions were studied. Unusual products of Wagner-Meerwein rearrangement bearing the olefin fragment (5-aza-2-oxatricyclo[6.2.1.0(3,9)]undecen-3-enes) were isolated and characterized by X-ray analysis.

ChemInformVolume 34, Issue 37 Heterocyclic Compounds First Synthesis of 6-Spiro[5-aza-2-oxatricyclo [6.2.1.03,9]undec-3-ene-6,1′-cyclohexane]. E. V. Nikitina, E. V. Nikitina Russ. Peoples′ Friendship Univ., Moscow 117198, RussiaSearch for more papers by this authorA. A. Safronova, A. A. Safronova Russ. Peoples′ Friendship Univ., Moscow 117198, RussiaSearch for more papers by this authorA. V. Varlamov, A. V. Varlamov Russ. Peoples′ Friendship Univ., Moscow 117198, RussiaSearch for more papers by this authorF. I. Zubkov, F. I. Zubkov Russ. Peoples′ Friendship Univ., Moscow 117198, RussiaSearch for more papers by this authorG. G. Aleksandrov, G. G. Aleksandrov Russ. Peoples′ Friendship Univ., Moscow 117198, RussiaSearch for more papers by this authorK. F. Turchin, K. F. Turchin Russ. Peoples′ Friendship Univ., Moscow 117198, RussiaSearch for more papers by this author E. V. Nikitina, E. V. Nikitina Russ. Peoples′ Friendship Univ., Moscow 117198, RussiaSearch for more papers by this authorA. A. Safronova, A. A. Safronova Russ. Peoples′ Friendship Univ., Moscow 117198, RussiaSearch for more papers by this authorA. V. Varlamov, A. V. Varlamov Russ. Peoples′ Friendship Univ., Moscow 117198, RussiaSearch for more papers by this authorF. I. Zubkov, F. I. Zubkov Russ. Peoples′ Friendship Univ., Moscow 117198, RussiaSearch for more papers by this authorG. G. Aleksandrov, G. G. Aleksandrov Russ. Peoples′ Friendship Univ., Moscow 117198, RussiaSearch for more papers by this authorK. F. Turchin, K. F. Turchin Russ. Peoples′ Friendship Univ., Moscow 117198, RussiaSearch for more papers by this author First published: 15 August 2003 https://doi.org/10.1002/chin.200337135Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume34, Issue37September 16, 2003 RelatedInformation

7-Aryl-4a-hydroxy-4a,6,7,7a-tetrahydroisoxazolo[4,5-b]quinuclidines have been prepared from 2-arylmethylene-3-quinuclidones and hydroxylamine and they are able to release NO upon mild oxidation with K3[Fe(CN6)] in basic medium.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Methods have been developed for the synthesis of mono- and bisacetyl derivatives of 2-hydroxyarylmethylene-3-quinuclidone oximes.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.