Rearrangement of substituted tricyclo[2.1.0.02,5]pentan-3-ones

Treatment of 1,5-bis(hydroxymethyl)tricyclo[2.1.0.0^2,5]-pentan-3-one (III) with triphenyl phosphine and carbon tetrachloride results in deep-seated rearrangement to the keto furan, 3-oxybicyclo-[3.3.0]octa-1,4-dien-7-one, VI; the analogous reaction with carbon tetrabromide is normal and yields, the anticipated dibromide IV. Cyclopentadienone intermediates account for the latter reaction and for a dimer formed from 1,5-dimethyltricyclo[2.1.0.0^2,5] pentanone (Ia) upon treatment with iodine.     

Rearrangement of 1,4-benzodiazepin-2,4-diones to 3,l-benzoxazin-4-ones

Treatment of 7-chloro-3,4-dihydro-1H-1,4-benzodiazepin-2,5-dione (Ia) with refluxing acetic anhydride in the presence of pyridine afforded 6-chloro-2-methyl-4H-3,1-benzoxazin-4-one (IIa). A plausible reaction path for this novel rearrangement reaction is described: Ia → 4-acetyl-7-chloro-3,4-dihydro-lH-1,4-benzodiazepin-2,5-dione → 7-chloro-1,4-diacetyl-3,4-dihydro-lH-1,4-benzodiazepin-2,4-dione → IIa. When 7-chloro-3,4-dihydro-4-methyl-lH-1,4-benzodiazepin-2,5-dione (Ib), 3,4-dihydro-4-methyl-1H-1,4-benzodiazepin-2,5-dione (Id) and 3,4-dihydro-1-methyl-1H-1,4-benzodiazepin-2,5-dione (Ie) were allowed to react with acetic anhydride under conditions similar to those used for the rearrangement reaction, only acetylation occurred.     

Investigation of reactions of the organozinc reagents prepared from zinc and dialkyl dibromomalonates with the derivatives of 2-arylmethyleneindan-1,3-dione and 5-arylmethylene-2,2-dimethyl-1,3-dioxane-4,6-dione

Organozinc compounds prepared from dialkyl dibromomalonates and zinc react with 2-arylmethyl-eneindan-4,6-diones, 5-arylmethylene-2,2-dimethyl-1,3-dioxane-4,6-diones, as well as with 2-[4-(1,3-dioxoindan-2-ylidenemethyl)phenyl]methyleneindan-1,3-dione and 5-[4-(2,2-dimethyl-4,6-dioxo-1,3-dioxane-2-ylidenemethyl)phenyl]methylene-2,2-dimethyl-1,3-dioxane-4,6-diones to form dialkyl 3-aryl-1′3′-dioxaspiro(cyclopropane-2,2′-indan)-1,1-dicarboxylates, dimethyl 3-aryl-6,6-dimethyl-5,7-dioxa-4,8-dioxaspiro[2,5]octan-2,2-dicarboxylates, dialkyl 2-{4-[3,3-bis (alkoxycarbonyl)-1′,3′-dioxaspiro(cyclopropane-2,2′-indan)-1-yl]phenyl}-1′,3′-dioxaspiro[cyclopropane-2,2′-indan]-1,1-dicarboxylates, and dialkyl 2-{4-[2,2-bis(alkoxycarbonyl)-6,6′-dimethyl-4,8-dioxo-5,7-dioxaspiro[2,5]oct-1-yl]phenyl}-6,6-dimethyl-4,8-dioxo-5,7-dioxaspiro[2,5]octan-1,1-dicarboxylate respectively.     

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.     

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.     

Reactions of stabilizer compounds. III. Oxidative reactions of some 2′-hydroxy-2-phenylbenzotriazole light stabilizers in the AIBN-initiated autoxidation of cumene

Oxidative decay of number of commercially important 2′-hydroxy-2-phenylbenzotriazole light stabilizers during the AIBN-initiated autoxidation of cumene at 65°C is described. The reactivity of the hydroxyphenylbenzotriazoles studied increased in the order 2-(2′-hydroxy-5′-methyl)phenylbenzotriazole (Ia) < 2-(2′-hydroxy-3′,5′ -di-tert-pentyl)phenylbenzotriazole (Ie) < 5-chloro-2-(3′,5′-di-tert-butyl-2′-hydroxy)phenylbenzotriazole (Ic) < 5-chloro-2-(3′-tert-butyl-2′-hydroxy-5′-methyl)phenylbenzotriazole (Ib). The major product from the reaction of Ib was identified as the cumylperoxycyclohexa-2,5-dienone (III). The possible occurrence of these reactions during the degradation of stabilized polymers is discussed.     

Opening of the three-membered ring in 4,6-di-tert-butylspiro[2,5]octa-3,6-dien-5-one under the action of magnesium halides

Conclusions The three-membered ring in 4,6-di-tert-butylspiro[2,5]octa-3,6-dien-5-one opens under the action of magnesium halides with the formation of 4-(-haloethyl)-2,6-di-tert-butylphenols.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 930–932, April, 1967.     

Polymerization of Acrylonitrile Initiated by 1,4-Dimethyl-1,4-bis(p-nitrophenyl)-2-tetrazene

The polymerization of acrylonitrile (AN) initiated by 1,4-dimethyl-1,4-bis(p-nitrophenyl)-2-tetrazene (Ie) was studied in dimethylformamide (DMF) at high temperature. The polymerization proceeds by a radical mechanism. The rate of polymerization is proportional to [Ie]^0.64 and [AN]^1.36. The overall activation energy for the polymerization is 21.5 kcal/mole within the temperature range of 115-130°C. The chain transfer of Ie was also undertaken over the temperature range of 120-135°C. The activation parameters for the decomposition of Ie at 120°C are k_d = 2.78 × 10^?6 sec^?1, ΔH^? = 40.8 kcal/mole, and ΔS^? = 19.5 cal/mole-deg, respectively.     

2,2′-Bifurylidene-5,5′-diones,Coumarins, 3a, 7a-dihydro-1H-inden-1-ones,and 5H-furo[3,2-b]pyran-5-ones from propyne and carbon monoxide

The [Co₂ (CO)₈]-catalyzed reaction between propyne and CO in acetone at 110° and 170 bar was re-investigated. There are five major products: (E)-3,4′-dimethyl-2,2′-bifurylidene-5,5′-dione ( 4 ), 3,5,8-trimethylcoumarin ( 8 ), 3a, 7a-dihydro-2,4,7,7a-tetramethyl-1H-inden-1-one ( 9 ), 2,6-dimethyl-5H-furo [3,2, -b]- pyran-5-one ( 11 ), and 2,7-dimethyl-5H-furo 3,2-b-pyran-5-one ( 12 ); of these, only one, 4 . had previously been recognized. In parallel experiments were obtained 2,6-dipentyl-5 H-furo[3,2-b]pyran-5-one ( 13 ), 2,7-dipentyl–5H-furo[3,2-b]pyran-5-one ( 14 ), 3a, 7a-dihydro-2,4,7,7a-tetrapentyl-1H-inden-1-one ( 15 ). And 3a, 7a-dihydro-2,4,6,7a-tetrapentyl-1H-inden-1-one ( 16 ) from hept-1-yne, and two further types of products from two atypical 1-alkynes: 3,6,9-tri(tert-butyl)-1-oxaspiro[4.4]nona-3,6,8-trien-2-one ( 20 ) from (tert-butyl)acetylene and the exo-dimer 21 of 2,5-bis(trimethylsilyl)cyclopenta-2,4-dien-1-one ( 22 ) from (trimethylsilyl)acetylene. Compounds 11,12 , and 20 were identified by X-ray analysis.     

Reactions of [(3,5-Di-<Emphasis Type="Italic">tert</Emphasis>-butyl-4-oxocyclohexa-2,5-dien- 1-ylidene)methyl]phosphonates with Phenols

Dialkyl [(3,5-di-tert-butyl-4-oxocyclohexa-2,5-dien-1-ylidene)methyl]phosphonates reacted with phenol and benzenediols in the presence of trifluoromethanesulfonic acid to give products of electrophilic substitution in the benzene ring, the corresponding diarylmethylphosphonates or [phenylenebis(arylmethylene)]- diphosphonates. The reaction of diphenyl [(3,5-di-tert-butyl-4-oxocyclohexa-2,5-dien-1-ylidene)methyl]phosphonate with 2-methylbenzene-1,3-diol at a ratio of 1: 1 afforded 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-6-hydroxy-7-methyl-2-phenoxy-2,3-dihydro-1,2λ⁵-benzoxaphosphol-6-one.     

Synthesis of 4H-pyrazolo- and 4H-pyrrolophenothiazin-4-one derivatives

5-Methyl- and 6-methyl-2-phenyl-2H-indazole-4,7-diones were condensed with 2-aminobenzenethiol or 6-substituted-3-aminopyridine-2(1H)thiones 4 to produce a new type of 5-methyl-2-phenyl-4H-pyrazolophenothiazin-4-ones or 8-substituted-7-aza-5-methyl-2-phenyl-4H-pyrazolophenothiazin-4-one derivatives. From 6-bromo-2,5-dimethyl-1,3-diphenyl-2H-isoindole-4,7-dione and 4 8-substituted-7-aza-2,5-dimethyl-1,3-diphenyl-4H-pyrrolophenothiazin-4-one derivatives were also prepared.     

Cyclopropanation of 2-arylmethylidenemalononitriles,alkyl 3-aryl-2-cyanoprop-2-enoates,and N-substituted 3-aryl-2-cyanoprop-2-enamides with bromine-containing zinc enolates

Zinc enolates derived from 2,2-dibromoindan-1-one and 2,2-dibromo-1,2,3,4-tetrahydronaphthalen-1-one reacted with 2-arylmethylidenemalononitriles, alkyl 3-aryl-2-cyanoprop-2-enoates, and N-substituted 3-aryl-2-cyanoprop-2-enamides to give, respectively, 3-aryl-1′-oxo-1′,3′-dihydrospiro[cyclopropane-1,2′-indene]-2-2-dicarbonitriles, 3-aryl-1′-oxo-3′,4′-dihydro-1′H-spiro[cyclopropane-1,2′-naphthalene]-2,2-dicarbonitriles, alkyl 3-aryl-2-cyano-1′-oxo-1′,3′-dihydrospiro[cyclopropane-1,2′-indene]-2-carboxylates, alkyl 3-aryl-2-cyano-1′-oxo-3′,4′-dihydro-1′H-spiro[cyclopropane-1,2′-naphthalene]-2-carboxylates, and N-substituted 3-aryl-2-cyanol-1′-oxo-3′,4′-dihydro-1′H-spiro[cyclopropane-1,2′-naphthalene]-2-carboxamides as a single diastereoisomer. The stereoconfiguration of the products was determined by ¹H and ¹³C NMR spectroscopy.     

A simple synthesis of 4-amino-6-methyl-1,1,1-trifluoro(trichloro)hepta-3,5-dien-2-ones and 2,2-dimethyl-6-trifluoromethyl-2,3-dihydro-4-pyridone

Treatment of 2,2-dimethyl-6-trifluoro(trichloro)methyl-2,3-dihydro-4-pyrones with ammonia gives 4-amino-1,1,1-trifluoro(trichloro)-6-methylhepta-3,5-dien-2-ones. Under similar conditions 1,1,1-trifluoro-2-hydroxy-6-methylhepta-2,5-dien-4-one and 6-chloro-1, 1,1-trifluoro-2-hydroxy-6-methylhept-2-en-4-one cyclize into 2,2-dimethyl-6-trifluoromethyl-2,3-dihydro-4-pyridone. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2263–2265, December, 1997.     

Reactions of bromine-containing organozinc compounds derived from α,α-dibromo ketones with 2-arylmethylideneindan-1,3-diones and 5-arylmethylidene-2,2-dimethyl-1,3-dioxane-4,6-diones

Bromine-containing organozinc compounds generated from 1,1-dibromo-3,3-dimethylbutan-2-one reacted with 2-arylmethylideneindan-1,3-diones and 5-arylmethylidene-2,2-dimethyl-1,3-dioxane-4,6-diones to give 3-aryl-2-(2,2-dimethylpropanoyl)spiro[cyclopropane-1,2′-indan]-1′,3′-diones and 1-aryl-6,6-dimethyl-2-(2,2-dimethylpropanoyl)-5,7-dioxaspiro[2.5]octan-4,8-diones, respectively. Reactions of 2-arylmethylideneindan-1,3-diones with bromine-containing zinc enolates derived from 1-aryl-2,2-dibromopropan-1-ones and 2,2-dibromo-1,2,3,4-tetrahydronaphthalen-1-one resulted in the formation of 2-aroyl-3-aryl-2-methylspiro-[cyclopropane-1,2′-indan]-1′,3′-diones and 2,3: 8,9-dibenzo-12-phenyldispiro[4.0.5.1]dodecane-1,4,7-trione, respectively.     

Five-Membered 2,3-dioxoheterocycles: XCV. Recyclization of 4-benzoyl-5-phenylfuran-2,3-dione at the action of substituted 1,3,3-trimethyl-2-azaspiro[4.5]dec-1-enes. Crystal and molecular structure of substituted 5-(2-azaspiro[4.5]dec-1-ylidene)cyclopent-3-ene-1,2-dione

4-Benzoyl-5-phenylfuran-2,3-dione reacts with 2′,5′,5′-trimethyl-4′,5′-dihydro-4H-spiro[naphthalene-1,3′-pyrrol]-4-one and 8-(2-methoxy-5-methylphenyl)-1,3,3,9-tetramethyl-2-azaspiro[4.5]deca-1,7-dien-6-one with the formation of (Z)-3-benzoyl-5-(5′,5′-dimethyl-4-oxo-4H-spiro[naphthalene-1,3′-pyrrolidin]-2′-ylidene)-4-phenylcyclopent-3-ene-1,2-dione, whose structure was proved by XRD analysis, and of (Z)-3-benzoyl-5-{8-(2-methoxy-5-methylphenyl)-3,3,9-trimethyl-6-oxo-2-azaspiro[4.5]dec-7-en-1-ylidene}-4-phenylcyclopent-3-ene-1,2-dione.     

Marine natural products. XXVI. Biologically active tridecapeptide lactones from the Okinawan marine sponge Theonella swinhoei (Theonellidae). (2). Structures of theonellapeptolides Ia, Ib, Ic, and Ie

Five tridecapeptide lactones, named theonellapeptolides Ia (1), Ib (2), Ic (3), Id (4), and Ie (5), were isolated from the Okinawan marine sponge Theonella swinhoei. Following the structure elucidation of theonellapeptolide Id (4), the structures of theonellapeptolides Ia (1), Ib (2), Ic (3), and Ie (5) were determined on the basis of chemical and physicochemical evidence including high performance liquid chromatography and circular dichroism combined analysis of the amino acid compositions. Theonellapeptolides Ib (2), Ic (3), Id (4), and Ie (5) exhibit moderate cytotoxic activity towards for L1210 in vitro (IC50 1.6, 1.3, 2.4, and 1.4 micrograms/ml, respectively), and theonellapeptolide Ie (5) exhibits ion-transport activities for Na+ and K+ ions.     

Building libraries of skeletally diverse scaffolds from novel heterocyclic active methylene compound through multi-component reactions

Libraries of skeletally diverse potential bioactive polycyclic/spirocyclic heterocyclic compounds; 2-amino-7,9-dimethyl-5-oxo-4-aryl-4,5,6,7-tetrahydropyrano[2,3-d]pyrazolo[3,4-b]pyridine-3-carbonitrile, 2′-amino-7′,9′-dimethyl-2,5′-dioxo-6′,7′-dihydro-5′H-spiro[indoline-3,4′-pyrano[2,3-d]pyrazolo[3,4-b]pyridine]-3′-carbonitrile, and 5,5′-(arylmethylene)bis(4-hydroxy-1,3-dimethyl-1H-pyrazolo[3,4-b]pyridin-6(7H)-one) have been synthesized through a multi-component reaction using novel heterocyclic active methylene compound 4-hydroxy-1,3-dimethyl-1H-pyrazolo[3,4-b]pyridine-6(7H)-one as one of the building blocks. This protocol can be considered to be an efficient and eco-friendly strategy for diversity oriented synthesis.     

Hinnuliquinone,a bis-indolyl-2,5-dihydroxybenzoquinone pigment from nodulisphorium hinnuleum

A pigment, hinnuliquinone, isolated from the fungus $\text{Nodulisporium}$$\text{hinnuleum}$, has been shown to be 2,5-bis-[2-(1,1,-dimethyl-2-propenyl)1H-indol-3-yl-]-3,6-dihydroxy-2,5-cyclohexadiene-1,4-dione and to be biosynthesized from tryptophan and mevalonic acid.     

A New Protocol to Generate Catalytically Active Species of Group 4–6 Metals by Organosilicon-Based Salt-Free Reductants

Herein, we provide a new protocol to reduce various transition-metal complexes by using organosilicon compounds in a salt-free fashion with the great advantage of generating pure low-valent metal species and metallic(0) nanoparticles, in sharp contrast to reductant-derived salt contaminants obtained by reduction with metal reductants. The organosilicon derivatives 1,4-bis(trimethylsilyl)-2,5-cyclohexadiene ( 1 a ), 1-methyl-3,6-bis(trimethylsilyl)-1,4-cyclohexadiene ( 1 b ), 1,4-bis(trimethylsilyl)-1,4-diaza-2,5-cyclohexadiene ( 2 a ), 2,5-dimethyl-1,4-bis(trimethylsilyl)-1,4-diaza-2,5-cyclohexadiene ( 2 b ), 2,3,5,6-tetramethyl-1,4-bis(trimethylsilyl)-1,4-diaza-2,5-cyclohexadiene ( 2 c ), and 1,1′-bis(trimethylsilyl)-1H,1′H-4,4′-bipyridinylidene ( 3 ) all served as versatile reductants for early transition-metal complexes and produced only easy-to-remove organic compounds, such as trimethylsilylated compounds and the corresponding aromatics, for example, benzene, toluene, pyrazine, and 4,4′-bipyridyl, as the byproducts. The high solubility of the reductants in organic solvents enabled us to monitor the catalytic reactions directly and to detect any catalytically active species so that we could elucidate the reaction mechanism.     

Intramolecular [2+2]-cycloaddition of propargylic 2,3-allenoates for the efficient synthesis of 3-oxabicyclo[4.2.0]octa-1(8),5-dien-4-ones: a dramatic substituent effect

[2+2]-Cycloaddition reactions of propargylic 2,3-allenoates under conventional heating conditions afforded 3-oxabicyclo[4.2.0]octa-1(8),5-dien-4-ones, which contain both the biologically important 5,6-dihydropyran-2-one and cyclobutene units.