Synthesis of 2-Phenyl-3-oxa-5-azatricyclo[4.4.0.02 , 7]decan-4-one

Cleavage of the lactone ring in 7-phenylbicyclo[3.1.1]heptan-6,7-carbolactone by the action of ammonia and hydrazine and subsequent oxidative cyclization of the resulting hydroxy amide and hydroxy hydrazide gave a cyclic carbamate, 3-oxa-5-azatricyclo[4.4.0.0^{2 , 7}]decan-4-one.     

Some Diels–Alder adducts of 6-vinyl-1-oxa-4-thiaspiro[4.5]dec-6-ene

6-Vinyl-1-oxa-4-thia­spiro­[4.5]­dec-6-ene has been reacted with dienophiles, such as N-phenyl­male­imide (NPM), N-methyl­triazoline-2,5-dione (MTAD) and di­methyl­acetyl­ene di­carboxyl­ate (DMAD), to assess the 1,3-diastereofacial selection caused by the acetal function. In each case, a mixture of two diastereoisomers was produced. The crystal structures of the products of the addition of NPM and MTAD syn to the acetal oxy­gen, 2-phenyl-2,3,3a,4,5,5a,6,7,8,9,9a,9b-dodeca­hydro-1H-benz­[e]­iso­indole-6-spiro-2′-[1′,3′]­oxa­thiol­ane-1,3-dione, C₂₀H₂₁NO₃S, (IIa), and 2-methyl-5,7,8,9,10,10a-hexa­hydro-1H-1,2,4-triazolo­[1,2-a]­cinnoline-7-spiro-2′-[1′,3′]­oxa­thiol­ane-1,3-dione, C₁₃H₁₇N₃O₃S, (IIIa), respectively, and the product of the addition of DMAD syn to the acetal sulfur, di­methyl 1,2,3,4,4a,7-hexa­hydro­naphthalene-1-spiro-2′-[1′,3′]­oxa­thiol­ane-5,6-di­carboxyl­ate, C₁₆H₂₀O₅S, (IVb), have been determined. All three structures are composed of independent mol­ecules separated by normal van der Waals distances. The 1-oxa-4-thia heterocyclic ring has an envelope conformation in the three structures and the S—Csp³ bond distances differ significantly from each other, as observed in comparable structures; the remaining molecular dimensions are as expected.     

Synthesis of 1,7-dioxaspiro[5.5]undecanes and 1-oxa-7-thiaspiro[5.5]undecanes from exo-glycal

A new spirocyclization was developed for the synthesis of 1,7-dioxaspiro[5.5]undecanes and 1-oxa-7-thiaspiro[5.5]undecanes by reaction of exo-glycal with aryl alcohols or thiophenols in the presence of Lewis acid BF₃·OEt₂. The reaction proceeded through tandem Ferrier rearrangement, glycosylation, and Friedel–Crafts alkylation to provide the corresponding products in good to excellent yields.     

Synthesis and Characterization of S-Methylspiro[4.5]-dec-7-en-6-one and 6-methylspiro[4.5]dec-6-en-8-one

In connection with another problem, we required authentic samples of 8-methylsiro[4.5]dec-7-en-6-one (1) and 6-methyl-spire[4.5]dec-6-en-8-one (2). The former compound is not reported in the literature. Although there are two reports of the latter material,^1,2 the physical data ascribed to it do not agree. In this communication, we report the synthesis and characterization of the two isomers.     

Synthesis and fungicidal activity of substituted 6-azolylmethyl-7-benzylidenespiro[4.5]decan-6-ols

A series of halogen substituted 6-azolylmethyl-7-benzylidenespiro[4.5]decan-6-ols were obtained from spiro[4.5]decan-6-one in three steps: Claisen—Schmidt condensation with substituted benzaldehydes, conversion of 7-benzylidenespiro[4.5]decan-6-ones to oxiranes by reaction with dimethylsulphonium methylide followed by ring opening of oxiranes with 1,2,4-triazole or imidazole. In vitro testing of fungicidal activity of synthesized compounds against seven phytopathogenic fungi showed, that a number of compounds are more active than triadimenol.     

Synthesis of 8-oxa-2-azaspiro[4.5]decane

A convenient synthesis of new 8-oxa-2-azaspiro[4.5]decane from commercially available reagents based on tetrahydropyran-4-carbonitrile and 1-bromo-2-fluoroethane has been developed. This compound is promising for the production of important biologically active compounds.

     

Synthesis and Crystal Structure of 4-(Dichloroacetyl)-1-oxa-4-azaspiro[4.5]decane

<正>The title compound 4-(dichloroacetyl)-1-oxa-4-azaspiro[4. 5] decane (CAS number 71526-07-3, C10H15Cl2NO2, Mr= 252.13) was obtained by the reaction of dichloroacetic acid with 1-oxa-4-azaspiro[4. 5] decane. The crystal is of monoclinic, space group P21ln with the unit cell constants: a = 5.9619(4),b= 10.0066(8), c = 20.0986(4) A,β = 90.194(3)°, V= 1199(4) A3,Z = 4, Dc= 1.397 g/cm3, F(000) = 528, μ(MoKα) = 0.522 mm-1, R = 0.0611 and wR = 0.1656 for 1276 observed reflections (I > 2σ(I)). X-ray analysis reveals that the cyclohexyl adopts a chair conformation and the compound is a chiral one.     

A novel and efficient route to the construction of the 4-oxa-tricyclo[4.3.1.0]decan-2-one scaffold

A short and efficient route to the synthesis of 4-oxa-tricyclo[4.3.1.0]decan-2-one scaffold 12 in good yield is reported. Essential to the synthesis was the implementation of selective protection of the catechol system in xanthone 2 with Ph₂CCl₂ and MOM groups. Subsequently, a biomimetic tandem Claisen/Diels-Alder reaction occurred to produce the desired tricyclic scaffold 11a as a single isomer. A rationalization of the excellent region and stereoselectivity of this transformation was also proposed.     

Synthesis,structure, and transformations of 1-aza-3-oxa-7-thiabicyclo[3.4.0]nonan-2-one

1-Aza-3-oxa-7-thiabicyclo[3.4.0]nonan-2-one was obtained by reduction of 3,4-dimethoxycarbonyltetrahydro-1,4-thiazine. The reduction of this product with lithium aluminum hydride led to 3-hydroxymethyl-4-methyltetrahydro-1,4-thiazine. The molecular and crystal structures of 1-aza-3-oxa-7-thiabicyclo[3.4.0]nonan-2-one were investigated by x-ray diffraction analysis.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1280–1285, September, 1986.     

Synthetic carbapenem antibiotics II. Stereoisomers of 7-hydroxyethyl-2,2,5-trimethyl-3-oxa-1-azabicyclo[4.2.O]octan-8-one

The titled compounds are key synthetic intermediates in the structure-activity relationship studies of novel 1-methyl carbapenem antibiotics. Preparation and structural determination of these stereoisomers by x-ray crystallography and proton NMR spectroscopy are reported.     

Synthesis of 1-p-Methoxyphenyl and 1-p-Methoxyphenyl-4-methylbicyclo-[2.2.1]heptan-7-one. The Oxidation of 7-Hydroxy-1-p-methoxyphenyl-4-methylbicyclo[2.2.1]heptan-7-carboxylic Acid with Lead Tetraacetate

A simple synthetic route to 1-p-methoxyphenyl and 1-p-methoxyphenyl-4-methylbicyclo [2.2.1]heptan-7-one 6b,a has been developed through benzilic acid rearrangement of the bicyclo[2.2.1]octandiones 2b,a. The oxidation of 7-hydroxy-1-p-methoxyphenyl-4-methylbicyclo[2.2.1]heptan-7-carboxylic acid 3a with lead tetraacetate gives the carbolactone 7a which is also formed by the reaction of the ketone 6a with m-chloroperbenzoic acid.