Synthesis, Structure, and Growth-Regulating Activity of 1-(6,9-Dimethyl-1,4-dioxa-8-azaspiro[4,5]dec-8-ylmethyl)-1H-pyridin-2-one

1-(6,9-Dimethyl-1,4-dioxa-8-azaspiro[4,5]dec-8-ylmethyl)-1H-pyridin-2-one was prepared by the Mannich reaction from 6,9-dimethyl-1,4-dioxa-8-azaspiro[4,5]decane, formaldehyde, and pyridin-2-one in alcohol. Its structure was proved by NMR spectroscopy. This compound exhibits a growth-regulating activity.     

Synthesis of novel imidazo[1,2-a][3,1]benzothiazines 4, imidazo[1,2-a]-[1,2,4]benzotriazines 5, and 4H-imidazo[2,3-c]pyrido[2,3-e][1,4]oxazines 6

Starting from the readily available 2-aminobenzhydrols ( 7 ), 3-amino-1,2,4-benzotriazine ( 11 ) and 2-amino-3-pyridinol ( 12 ), novel derivatives of 5-phenyl-5H-imidazo[1,2-a][3,1]benzothiazine-2-carboxylic acid, ethyl ester ( 4 ), imidazo[2,1-c][1,2,4]benzotriazine-2-carboxylic acid, ethyl ester ( 5 ) and 4H-imidazo[2,3-c]pyrido-[2,3-e][1,4]oxazine ( 6 ) were prepared.     

Reaction of polyfluorinated cyclohexa-2,4-dienones with aryl nitrile oxides

Reaction of 1,3-dipolar cycloaddition of 6-chloropentafluorocyclohexa-2,4-dienone, 6-chloro-3-(pentafluorophenoxy)tetrafluorocyclohexa-2,4-dienone, and perfluoro-6-phenoxycyclohexa-2,4-dienone with aryl nitrile oxides proceeds highly stereoselectively at the c C=O group of the dienone providing in a high yield mixtures of diastereomeric fluorine-containing 3-aryl-1,4-dioxa-2-azaspiro[4,5]deca-2,6,8-trienes. The reaction of the latter with sodium pentafluorophenolate proceeds along the type of allyl substitution affording polyfluorinated 3-aryl-8-phenoxy-1,4-dioxa-2-azaspiro[4,5]deca-2,6,9-trienes.     

Synthesis and antibacterial activity of 1-(substituted-benzyl)-6-fluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acids and their 6,8-difluoro analogs

Alkylation of 6,7-difluoro-4-hydroxyquinoline-3-carboxylic acid ethyl ester with substituted-benzyl chlorides gave 1-(substituted-benzyl)-6,7-difluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid ethyl esters. Their treatment with piperazine or N-methylpiperazine in pyridine yielded 1-(substituted-benzyl)-6-fluoro-1,4-dihydro-4-oxo-7-(l-piperazinyl)quinoline-3-carboxylic acid ethyl esters which were hydrolyzed with aqueous sodium hydroxide and then acidified with hydrochloric acid afforded the desired 1-(substituted-benzyl)-6-fluoro-1,4-dihydro-4-oxo-7-(1-iperazinyl)quinoline-3-carboxylic acids. The 6,8-difluoro analogs were prepared similarly using 6,7,8-trifluoro-4-hydroxyquinoline-3-carboxylic acid ethyl ester as a starting material. Some of these quinolones demonstrated fairly good antibacterial activities. Among them, 6-fluoro-1-(4-fluorophenylmethyl)-1,4-dihydro-7-(1-iperazinyl)-4-oxoquinoline-3-carboxylic acid ( 7d ) and 6,8-difluoro-1-(3-fluorophenylmethyl)-1,4-dihydro-7-(1-piperazinyl)-4-oxoquinoline-3-carboxylic acid ( 8c ) are two of the best.     

Reaction of 1,3-thiazolidine-4-carboxylic and 1,4-tetrahydro-thiazine-3-carboxylic acid esters with isocyanates and isothiocyanates and structures of the reaction products

7-Thia-1,3-diazabicyclo[3.3.0]octane-2,4-diones and 7-thia-1,3-diazabicyclo[4.3.0]-nonane-2, 4-diones, as well as their thio analogs, were obtained by the reaction of (S)-1,3-thiazolidine-4-carboxylic and 1,4-tetrahydrothiazine-3-carboxylic acid esters with isocyanates and isothiocyanates. Intermediate reaction products, viz., heterocyclic derivatives of urea, were isolated. The three-dimensional structures of the 3-methyl-4-oxo-7-thia-1,3-diazabicyclo[3.3.0]octane-2-thione and 3-methyl-4-oxo-7-thia-1, 3-diazabicyclo[4.3.0]nonane-2-thione molecules were determined by x-ray diffraction analysis.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1327–1332, October, 1985.     

Five-membered 2,3-dioxo heterocycles: XCII. Reaction of 3-aroyl-1H-pyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones with ethyl (2Z)-(3,3-dimethyl-8-oxo-2-azaspiro[4.5]deca-6,9-dien-1-ylidene)ethanoate. Synthesis of bridged analogs of pyrrolizidine alkaloids

3-Aroyl-1H-pyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones reacted with ethyl (2Z)-(3,3-dimethyl-8-oxo-2-azaspiro[4.5]deca-6,9-dien-1-ylidene)acetate to give ethyl 6′-aryl-2′-(2-hydroxyphenyl)-11′,11′-dimethyl-3′,4,4′,13′-tetraoxospiro[2,5-cyclohexadiene-1,9′-(7′-oxa-2′,12′-diazatetracyclo[6.5.1.0^1,5.0^8,12]tetradec-5′-ene)]-14′-carboxylates whose structure was confirmed by X-ray analysis. The products may be regarded as bridged analogs of pyrrolizidine alkaloids, 7′-oxa-2′,12′-diazatetracyclo[6.5.1.01,5.08,12]tetradecanes.     

The synthesis of a pyrido[2,3-c]pyridazine: A cinnoline related to 6-fluoronalidixic acid

An analog of the pyrido[2,3-c]pyridazine ring system, 1-ethyl-6-fluoro-1,4-dihydro-7-methyl-4-oxopyrido-[2,3-c]pyridazine-3-carboxylic acid ( 13 ), related to both Cinoxacin ( 1 ) and nalidixic acid ( 2 ), has been synthesized. The reductive ring closure of 2-chloro-α-diazo-6-methyl-5-nitro-β-oxo-3-pyridinepropanoic acid, ethyl ester ( 7 ), proved to be the key reaction providing entry into the ring system.     

Hydroxymethylation of rhodanine

Rhodanine in alcohol solution reacts with formaldehyde aqueous solution to form 3-hydroxymethylrhodanine. In the presence of triethylamine occurred also bis-hydroxymethylation at 5 position of the thiazolidine ring, but we failed to isolate the 3,5,5-trishydroxymethyl derivative in an individual form. The treatment of crude rhodanine 3,5,5-trishydroxymethyl derivative with benzaldehyde in boron trifluoride etherate leads to thioxo-8-phenyl-7,9-dioxa-1-thia-3-azaspiro[4.5]decan-4-one. The dissolution of the latter in aqueous alkali followed by neutralization with acid gives 5-sulfanyl-2-phenyl-1,3-dioxane-5-carboxylic acid.     

Synthesis of polyheterocyclic compounds derived from 6-amino- 4-aryl-2-r-4h-furo[2,3-<Emphasis Type="Italic">b</Emphasis>]pyran-5-carbonitriles

Syntheses were developed for 4-aryl-6-ethoxy-2-R-furo[2,3-b]pyridine-5-carbonitriles and ethyl esters of 5-amino-4-aryl-7-methyl-2-R-1,9-dioxa-8-azacyclopenta[b]naphthalene-6-carboxylic acids based on the reaction of 6-amino-4-aryl-2-R-4H-furo[2,3-b]pyran-5-carbonitriles with ethyl acetoacetate and nucleophilic recyclization. The mechanisms of these reactions are considered.     

Synthesis of phenylacetylene containing 1,2,3-triazole group

Bromination of (E)-1-[4-(2-carboxy-vinyl)phenyl]-[1,2,3]triazole-4-carboxylic acid ethyl ester, which was synthesized in 90% yield by a Huisgen-type [3 + 2]-cycloaddition reaction between 3-(4-azidophenyl) acrylic acid and ethyl propiolate, in CHCl₃ followed by a debrominative decarboxylation reaction with Et₃N in DMF under microwave irradiation condition afforded stereoselective (Z)-1-(4-(2-bromovinyl)phenyl)-1,2,3-triazole-4-carboxylic acid ethyl ester in 94% yield. Treatment of (Z)-1-(4-(2-bromovinyl)phenyl)-1,2,3-triazole-4-carboxylic acid ethyl ester with EtONa in DMF afforded 1-(4-ethynylphenyl)-1,2,3-triazole-4-carboxylic acid ethyl ester in a yield of 90%.     

Dynamic Kinetic Resolution of 2,3-Dihydrobenzo[b]furans: Chemoenzymatic Synthesis of Analgesic Agent BRL 37959

An efficient asymmetric synthesis of (S)-2,3-dihydrobenzo[b]furan-3-carboxylic acid (8?a) and (S)-5-chloro-2,3-dihydrobenzo[b]furan-3-carboxylic acid (8?b) was established. Key to the success was the highly stereoselective enzymatic kinetic resolution of the corresponding methyl or ethyl esters that was further developed into a dynamic process. As a reliable and fast tool for analysing the enantiomeric excess, HPLC coupled with a CD detector was utilized. The route was completed by a Friedel-Crafts acylation of ethyl (S)-5-chloro-2,3-dihydrobenzo[b]furan-3-carboxylate (7?c) followed by saponification leading to (S)-5-chloro-2,3-dihydrobenzo[b]furan-3-carboxylic acid (2), an analgesic agent.     

One-pot synthesis of 2-oxa-7-azaspiro[4.4]nonane-8,9-diones using Mn(III)-based oxidation of 4-acylpyrrolidine-2,3-diones

2-Oxa-7-azaspiro[4.4]nonane-8,9-diones were newly synthesized in good yields by the Mn(III)-based reaction of a mixture of 1,1-diarylethenes and 4-acylpyrrolidine-2,3-diones. Under the stated reaction conditions, the pyrrolidinedione ring remained intact and became one of the two rings of the 2-oxa-7-azaspiro[4.4]nonanedione scaffold. The procedure was simple and the product was easily separated. The structure determination and the mechanism for the formation of the 2-oxa-7-azaspiro[4.4]nonanediones were also discussed.     

Rearrangements of 4-(2-Aminophenyl)-1,4-dihydro-2,6-dimethyl-3,5-pyridinedicarboxylic acid diethyl ester

The treatment of 4-(2-aminophenyl)-1,4-dihydro-2,6-dimethyl-3,5-pyridinecarboxylic acid diethyl ester (III) with refluxing toluene or pyridine afforded 1,2,3,6-tetrahydro-2,4-dimethyl-2,6-methano-1,3-benzodiazocine-5,11-dicarboxylic acid diethyl ester (IV) as the major product. In addition, the following minor products were isolated: 2-methyl-3-quinolinecarboxylic acid ethyl ester (V), 3-(2-aminophenyl)-5-methyl-6-azabicyclo[3,3,1]-hept-1-ene-2,4-dicarboxylic acid diethyl ester (VI), and 5,6-dihydro-2,4-dimethyl-5-oxobenzo[c][2,7]naphthyridine-1-carboxylic acid ethyl ester (VII). In contrast, acidic conditions caused the conversion of III into V in a 95% yield. The formation of the latter appears to involve IV as an intermediate, since IV degraded rapidly in acid to give V in a quantitative yield.     

Heterocycles [h]fused onto 4-oxoquinoline-3-carboxylic acid, part IV. Convenient synthesis of substituted hexahydro [1,4]thiazepino[2,3-h]quinoline-9-carboxylic acid and its tetrahydroquino[7,8-b]benzothiazepine homolog

Substituted [1,4]thiazepino[2,3-h]quinolinecarboxylic acid 3 is prepared by PPA-catalyzed thermal lactamization of the respective 8-amino-7-[(2-carboxyethyl)thio]-1,4-dihydroquinoline-3-carboxylic acid 9. The latter synthon is obtained by reduction of the 8-nitro-1,4-dihydroquinoline precursor 8 which, in turn, is made accessible via interaction of 3-mercaptopropionic acid with 7-chloro-1-cyclopropyl-6-fluoro-8-nitro-1,4-dihydroquinoline-3-carboxylic acid 7 in the presence of triethylamine. A benzo-homolog of 3, namely tetrahydroquino[7,8-b]benzothiazepine-3-carboxylic acid 6, is analogously prepared via the reaction of 2-mercaptobenzoic acid with 7, followed by reduction of the resulting 7-[(2-carboxyphenyl)thio]-8-nitro product 10 into the corresponding 8-amino derivative 11, and subsequent lactamization. The structures assigned to 3, 6 and 8-11 are based on microanalytical and spectral (IR, MS, NMR) data.     

Synthesis and structure of cyclopropano-annelated homosesquinorbornene derivatives containing pyramidalized double bonds: evidence for the sterical effect of a cyclopropyl group on the degree of C=C double-bond pyramidalization

[reaction: see text] endo- and exo-2,3,4,7-tetrahydro-1H-1,4-methanobenzocycloheptene-7-carboxylic acid ethyl esters have been synthesized, and their Diels-Alder cycloaddition reactions with maleic anhydride, dimethyl acetylenedicarboxylate and singlet oxygen have been investigated. The X-ray analysis of four adducts indicated the pyramidalization of the central double bond. Density functional theory calculations on the isolated products and model compounds showed excellent agreement between the experimental and theoretical determined butterfly angles. Furthermore, it has been shown that a cyclopropyl group fused to [2.2.2] system decreases significantly the degree of the pyramidalization which is attributed to the steric interactions between the cyclopropyl group and ethano bridge of the norbornene systems. Due to the instability of the bicyclic endoperoxides, their X-ray analysis could not be carried out. DFT calculations on model compounds showed increased bending in the case of the product obtained by the addition of singlet oxygen to endo-2,3,4,7-tetrahydro-1H-1,4-methanobenzocycloheptene-7-carboxylic acid ethyl ester.     

Reaction of methyl 1-bromocyclopentane-1-carboxylate with zinc and 3-aryl-2-cyanoprop-2-enamides

Reformatsky reaction of methyl 1-bromocyclopentane-1-carboxylic acid with 3-aryl-2-cyanoprop-2-enamides and their N-methyl derivatives afforded 10-aryl-6,8-dioxo-7-azaspiro[4.5]decane-9-carbonitriles and 10-aryl-7-methyl-6,8-dioxo-7-azaspiro[4.5]decane-9-carbonitriles, respectively.     

Interaction of enaminesof tetrahydropyridin-4-one and α,β-unsaturated acid chlorides

The interaction of N-tosyl-4-pyrrolidinyl-1,2,4,-tetrahydropyridine with acryloyl chloride and the methyl ester of 3-chloroformylacrylic acid was investigated. In addition to acylated derivatives of tetrahydropyridin-4-one, the methyl ester of 3-N-tosyl-3-acrylate-8,9-1[3.1.1]nonane-6-carboxylic acid was obtained.     

Syntheses based on 8-substituted 3-bromoacetyl-3,8-dimethyl-2,7-dioxaspiro[4,4]nonane-1,6-diones

By reaction of 8-substituted 3-bromoacetyl-3,8-dimethyl-2,7-dioxaspiro[4,4]nonane-1,6-diones with thiourea and substituted thioureas under Hansch reaction conditions, we have obtained the novel heterocycles 3-[2′-amino(arylamino)thiazol-4-yl]-3,8-dimethyl-2,7-dioxaspiro[4,4]nonane-1,6-diones. By reacting the above-indicated bromoacetyl spirodilactones with 5-aryl-3-mercapto-1,2,4-triazoles, we obtained 8-substituted 3-(aryl-3,8-dimethyl-1′,2′,4′-triazol-3′-yl)thioacetyl-2,7-dioxaspiro[4,4]nonane-1,6-diones. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 123–129, January, 2006.     

The Mannich reaction in the synthesis of N,S-containing heterocycles 3. Unexpected direction of the aminomethylation reaction of N-methylmorpholinium 1-amino-2,4-dicyano-4-ethoxycarbonyl-1,3-butadienethiolate. One stage cascade synthesis of new derivatives of pyrido[1,2-<Emphasis Type="Italic">a</Emphasis>][1,3,5]triazine

The interaction of N-methylmorpholinium 1-amino-2,4-dicyano-4-ethoxycarbonyl-1,3-butadienethiolate with primary amines and formaldehyde leads to the formation of ethyl esters of 7-cyano-6-thioxo-1,3,4,6-2H-pyrido[1,2-a][1,3,5]triazine-9-carboxylic acid in place of the expected derivatives of pyrido[2,1-b][1,3,5]thiadiazine. The structure of the ethyl ester of 7-cyano-3-phenyl-6-thioxo-1,3,4,6-2H-pyrido[1,2-a][1,3,5]triazine-9-carboxylic acid was demonstrated by X-ray structural analysis. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1075–1081, July, 2007.     

Synthesis of fluorine-containing 1,4-dioxa-2-azaspiro-[4.5]deca-2,6,9-trienes by reaction of polyfluorinated cyclohexa-2,5-dienones with nitrile oxides

4-Pentafluorophenoxy-, 4-nitro-, and 4-chloropentafluorocyclohexa-2,5-dien-1-ones and 3,4,5-tris-(pentafluorophenoxy)trifluorocyclohexa-2,5-dien-1-one react with some benzonitrile and acetonitrile oxides exclusively at the carbonyl group, leading to the formation of mixtures of diastereoisomeric fluorinated 1,4-dioxa-2-azaspiro[4.5]deca-2,6,9-trienes in good yield.