从邻苯二酚合成3,4-亚甲二氧基苯甲醇

胡椒醇;从邻苯二酚合成3;4-亚甲二氧基苯甲醇     

Mass spectrometric synthesis. II. The reaction of catechol with acetone in a protic medium

The reaction of catechol with acetone, carried out in the chemical ionization chamber of a VG ZAB 2F mass spectrometer and in the presence of a protic medium (CH₅+), leads to 2,2-dimethyl-1,3-benzodioxole. This has been proved by exact measurements and collisionally activated dissociation mass analyzed ion kinetic energy spectra.     

Ruthenium/TFA-catalyzed coupling of activated secondary propargylic alcohols with cyclic 1,3-diones: furan versus pyran ring formation

A catalytic system consisting of the 16-electron allyl-ruthenium(II) complex [Ru(eta(3)-2-C3H4Me)(CO)(dppf)][SbF6] (dppf = 1,1'-bis(diphenylphosphino)ferrocene) and trifluoroacetic acid (TFA) has been used to promote the coupling between secondary propargylic alcohols and cyclic 1,3-diketones. The nature of the resulting products was found to be dependent on the ring size of the dicarbonyl compound employed. Thus, whereas 6,7-dihydro-5H-benzofuran-4-ones have been selectively obtained starting from 1,3-cyclohexanediones, via furan-ring formation, the use of 1,3-cyclopentanedione leads instead to 6,7-dihydro-4H-cyclopenta[b]pyran-5-ones via a pyran-ring formation process.     

Nuclear magnetic resonance study of the molecular structure of 1,3-benzodioxole and 1,3-indandione partially oriented in nematic solvents

The molecular structures of 1,3-benzodioxole and 1,3-indandione partially oriented in nematic solvents have been studied by NMR. Results for 1,3-indandione agree well with a planar model. The structural parameters are similar to those obtained by X-ray studies. No keto-enol tautomerism is observed. An anomalous structural result is obtained for 1,3-benzodioxole if the molecule is assumed to be planar. Dipolar couplings agree well with puckered model. The puckering angle is found to be about 15.5° ± 2°, similar to the values observed for TTF, TSeF and 2,5-dihydrofuran.     

One-step synthesis of some polyfluoroalkylated 1,3-benzodioxoles, 4H-1,3-benzodioxins and dibenzo[d,f] [1,3]dioxepins

Several polyfluoroalkylated heterocyclic compounds containing methylenedioxy group such as 2-(F-alkyl) substituted 1,3-benzodioxole, piperonal, 4H-1,3-benzodioxin, 1,3-dioxolane and 6-(F-alkyl) substituted dibenzo[d, f][1,3]dioxepin have been prepared through double Michael-addition reactions of 2,2-dihydropolyfluoroalkanoates with the corresponding diphenols or diols in high yields.     

One-step synthesis of some polyfluoroalkylated 1,3-benzodioxoles, 4H-l,3-benzodioxins anddibenzo[d,f] [l,3]dioxepins

Several polyfluoroalkylated heterocyclic compounds containing methylenedioxy group such as 2-(F-alkyl) substituted 1,3-benzodioxole, piperonal, 4H-1,3-benzodioxin, 1,3-dioxolane and 6-(F-alkyl) substituted dibenzo[d,f][1,3]dioxepin have been prepared through double Michael-addition reactions of 2,2-dihydropolyfluoroalkanoates with the corresponding diphenols or diols in high yields.     

Synthesis and structure of 2,2′-spirobi(1,3-benzodioxole) derivative prepared from 3,5-di(<Emphasis Type="Italic">tert</Emphasis>-butyl)-1,2-benzoquinone

3,5-Di(tert-butyl)-1,2-benzoquinone reacted with 1,2,3-trimethylbenzimidazolium iodide led to the formation of 2,2′-spirobi[4,6-di(tert-butyl)-1,3-benzodioxole]. The reaction mechanism was suggested. The structure of 2,2′-spirobi[4,6-di(tert-butyl)-1,3-benzodioxole] was established by means of X-ray diffraction analysis.     

A novel synthesis of diaminomethanes

Diaminomethanes have been synthesized by reaction of 1,3-benzodioxole and 1,3-benzoxathiole with a double amount of sodium dialkyl and alkyl aryl amides.     

Studies on the synthesis of heterocyclic compounds. XI. Cleavage of 1,3-benzodioxoles by magnesium bromide-acetic anhydride

The cleavage reaction of some 1,3-benzodioxole derivatives with magnesium bromide and acetic anhydride has been studied. The reactions have been carried out in acetonitrile solution at room temperature. In all of the 1,3-benzodioxoles studied, the opening of the heterocyclic ring with formation of bromides, alkenes and their corresponding products of hydrolysis have been observed. The competitive electrophilic substitution on the benzene ring was very limited and was insignificant when a large excess of the cleavage reagent was used. The structures of newly prepared compounds have been determined by elemental analysis, spectroscopic data and comparison with authentic samples.     

Unexpected Direction of Iodocyclization of 3-Allylthio-5-phenyl-4H-1,2,4-triazole

The reaction of 3-allylthio-5-phenyl-4H-1,2,4-triazole with iodine to give a mixture of 5,6-dihydro-5-iodomethyl-3-phenyl[1,3]thiazolo[2,3-c][1,2,4]triazole, 6,7-dihydro-6-iodo-3-phenyl-5H-[1,2,4]triazolo[3,4-b][1,3]thiazine, 5,6-dihydro-6-iodomethyl-2-phenyl[1,3]thiazolo[3,2-b][1,2,4]triazole, and 6,7-dihydro-6-iodo-2-phenyl-5H-[1,2,4]triazolo[5,1-b][1,3]thiazine has been studied. The structure of the products obtained was established using ¹H NMR spectroscopy of their dehydriodination products.     

Synthesis and antimicrobial study of linked heterocyclics containing Pyrazole-pyrimidine-thiazolidin-4-one

A new series of linked heterocyclics, 3-[4-(4-chlorophenyl)-6-(3,5-dimethyl-1-phenyl-1H-4-pyrazolyl)-2-pyrimidinyl]-2-(aryl/heteryl)-1,3-thiazolan-4-ones (6a-j), has been synthesized by the one-pot cyclo-condensation of 4-(4-chlorophenyl)-6-(3,5-dimethyl-1-phenyl-1H-4-pyrazolyl)-2-pyrimidinamine (5), aryl/heteroaryl aldehyde and thioglycolic acid. The structures of the synthesized compounds have been confirmed via IR, (1)H-NMR, (13)C-NMR, MS and elemental analyses. Further, all the newly synthesized compounds 6a-j have been assayed for their antimicrobial activity against Gram-positive and Gram-negative bacteria and fungi. The compounds containing moieties like 4-nitrophenyl (6c), 3-nitrophenyl (6d), 4-dimethylaminophenyl (6g), 2-furyl (6i) and 1,3-benzodioxole (6j), at 2-position of thiazolidin-4-one ring exhibited good inhibitory activity against all the tested organisms.     

Regioselective Synthesis of Polyfluoroalkyl Substituted 6,7‐Dihydrobenzisoxazolones

Regioselective methods for synthesis of hitherto unreported both 6,7‐dihydro‐1,2‐benzisoxazol‐4(5H)‐ones and 6,7‐dihydro‐2,1‐benzisoxazol‐4(5H)‐ones with perfluoroalkyl or halogenodifluoromethyl substituents have been developed. 3‐Polyfluoroalkyl‐6,7‐dihydro‐1,2‐benzisoxazol‐4(5H)‐ones were prepared by the cyclocondensation of 2‐polyfluoroalkanoylcyclohexane‐1,3‐diones with hydroxylamine. The regioisomeric 3‐polyfluoroalkyl‐6,7‐dihydro‐2,1‐benzisoxazol‐4(5H)‐ones were synthesized by the transformation of 2‐polyfluoroalkanoylcyclohexane‐1,3‐diones into their vinylogous chlorides, followed by the interaction of obtained crude 3‐chloro‐2‐polyfluoroalkanoyl‐2‐cyclohexen‐1‐ones with sodium azide in dimethylformamide.     

Cleavage of the ethereal bond : XI. The reaction of allylic organomagnesium halides with 1,3-benzoxathiole and 1,3-benzodioxole

Some reactions of 1,3-benzoxathiole and 1,3-benzodioxole with allylic Grignard reagents have been examined and found to give cleavage of the ether bond to form substitution products with almost complete allylic rearrangement.     

A new route to benzo[4,5]cyclohepta[1,2-b]naphthalenes: synthesis of radermachol

[formula: see text] Condensation of 3-phenylsulfonyl-1,3-isobenzofuranone (3) with benzocyclohept-6,7-en-5-ones such as 4 and 15 provides a straightforward, general method for synthesis of functionalized benzo[4,5]cyclohepta[1,2-b]naphthalenes (e.g., 5 and 16). This finding was used to achieve a brief and efficient preparation of 6,7-benzo-3,4-(1,4-dimethoxy-2,3-naphtho)-1,5-dioxosuberane (2), an established intermediate to the naturally occurring red pigment radermachol (1).     

Ortho-spirocarbonates and ortho-spirothiocarbonates: synthesis, functionalization and coupling

This paper describes a new efficient synthesis of 2,2′-spirobi-(1,3-benzoxathiole) (1), 2,2′-spirobi-(1,3-benzodithiole) (2) and 2,2′-spirobi-(1,3-benzodioxole) (3). Compound 3 has been functionalized by means of metallation reaction followed by electrophilic quenching to give carboxylic acids, aldehydes and alcohols. Furthermore compound 3 was subjected to homo-coupling and its dimeric structure was determined by XRD analysis.     

BF3·SiO2-catalyzed one-pot synthesis of α-aminophosphonates in ionic liquid and neat conditions

α-Aminophosphonates were synthesized in a simple and efficient method from the three-component condensation reaction of 5-amino 2,2-difluoro-1,3-benzodioxole, aromatic aldehydes, and diethyl phosphite by silica-supported boron trifluoride (BF₃·SiO₂) in ionic liquid ([bmim][HCl]) under solvent-free conditions at room temperature in good to excellent yields and short reaction times. The catalyst can be recovered and reused for several times without any significant loss of activity. It was observed that a homogeneous reaction medium proved beneficial for the yield of the reaction.     

Synthesis of oxazole and furan derivatives via Rh2(OAc)4-catalyzed C≡X bond insertion of cyclic 2-diazo-1,3-diketones with nitriles and arylacetylenes

Abstract

A convenient and efficient procedure for the synthesis of 2-substituted-6,7-dihydrobenzo[d]oxazol-4(5H)-ones and 2-aryl-6,7-dihydrobenzofuran-4(5H)-ones through a Rh₂(OAc)₄-catalyzed C≡X (X?=?N, C) insertion of cyclic 2-diazo-1,3-diketones with nitriles and aromatic alkynes has been developed. This reaction uses readily available starting materials and stable cyclic 2-diazo-1,3-diketone compounds, with desired products formed in good to high yields. A tentative mechanism involving a C≡X bond insertion and 1,5-dipolar electrocyclization/ring opening and cyclization sequence for this reaction is proposed.     

Chemistry of heteroanalogues of isoflavones. 15. Synthesis and study of the reaction of lanthanide

2-Ethyl substituted isoflavones have been synthesized. 7-Isopropyloxyisoflavones carrying 1,3-benzodioxole and 1,4-benzodioxan nuclei have been obtained from them. The spectral characteristics of the compounds obtained are discussed. The reaction of several of the products with various lanthanide shift reagents (LSR) has been studied. The preferred conformation of compounds in solution has been determined. It was shown that optically active LSR must not be used for obtaining quantitative data on the molecular conformation of a substrate due to the lack of effective axial symmetry in the adduct.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1631–1637, December, 1993.     

Mass spectrometric synthesis. 1—the reaction of catechol with 2,4-dimethyl-2,3-pentadiene

The reaction of catechol with 2,4-dimethyl-2,3-pentadiene, carried out in the chemical ionization chamber of a VG ZAB2F mass spectrometer, has been studied with respect to the partial pressure of the reacting species. The structure of the reaction product, 2,2-diisopropyl-1,3-benzodioxole, has been proved by exact mass measurements, B/E linked scans, labelling experiments and collisionally activated dissociation mass analysed ion kinetic energy spectra.     

Catalytic Asymmetric Synthesis of α-Quaternary Proline Derivatives by 1,3-Dipolar Cycloaddition of α-Silylimines

Going pro: The title reaction between α-silylimines and activated olefins proceeds in the presence of a Cu(I) /DTBM-Segphos catalyst system with excellent diastereoselectivity and enantioselectivity. This process provides straightforward access to highly enantioenriched 5-unsubstituted α-quaternary proline derivatives. TMS=trimethylsilyl, DTBM-Segphos=5,5'-bis[di(3,5-di-tert-butyl-4-methoxyphenyl)phosphino]-4,4'-bi-1,3-benzodioxole.