A one-step synthesis of 2,3-dihydro-4H-pyran-4-ones from 3-ethoxy alpha,beta-unsaturated lactones

[reaction: see text] Addition of diverse nucleophiles to the unsaturated lactone 2 that results from hetero Diels-Alder reaction of Brassard's diene 1 with aldehydes leads to an efficient and general approach to the synthesis of 2,3-dihydro-4H-pyran-4-ones 3.     

Synthesis of the thioamide derivatives of methyl vinyl ketone and their cyclization to 2,3-dihydro-4H-thiopyran-4-ones

A novel synthesis of thioamide derivatives of methyl vinyl ketone and their cyclization to 2,3-dihydro-4H-thiopyran-4-ones were developed. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 201–204, February, 2006.     

Synthesis of 2,3-disubstituted indole using palladium(II)-catalyzed cyclization with alkenylation reaction

The reaction of ethyl 2-ethynylphenylcarbamate derivative with alkenes in the presence of a palladium(II) catalyst, copper dichloride and tetrabutylammonium fluoride (TBAF) produced 2-substituted 3-ethenylindoles during refluxing. The intramolecular cyclization reaction of ethyl 2-ethynylphenylcarbamates, which have an ethenyl part in the ethynyl group, was also used to produce carbazole derivatives.     

Solution-phase parallel synthesis of 2,3-dihydro-1,5-benzothiazepin-4(5H)-ones

Practical and efficient parallel methods have been developed for the synthesis of 7,8-disubstituted 2,3-dihydro-1,5-benzothiazepin-4(5H)-ones and 3,7,8-trisubstituted 2,3-dihydro-1,5-benzothiazepin-4(5H)-ones. This benzothiazepin-4(5H)-one skeleton possesses three or four diversity points. Furthermore, three novel tricycles integrating a benzothiazepin-4(5H)-one scaffold with other privileged structures, such as benzimidazole, benzimidazolone, and thio-benzimidazole, were also developed. The synthetic strategy provides an efficient way to access the benzothiazepinone core, starting from commercially available 1,5-difluoro-2,4-dinitrobenzene (DFDNB), and also allows further derivation of the strategically anchored functionalities.     

Electron impact-induced fragmentation of 2,3-dihydro-1,5-benzothiazepin-4(5H)-ones

The electron impact-induced fragmentations of 2,3-dihydro-1,5-benzothiazepin-4(5H)-ones and some related compounds were investigated. On the basis of low- and high-resolution measurements, metastable ion studies by means of mass-analysed ion kinetic energy spectroscopy and collision-induced dissociation experiments, the main fragmentation pathways were established. The effect of methyl and phenyl substituents at the C(2) and C(3) positions of the heterocyclic ring on the fragmentations was also studied. The (1,3) ring splitting was investigated in some detail, using semi-empirical molecular orbital calculations.     

Novel syntheses of 2,3-dihydro-1,5-benzothiazepin-4(5h)-ones and 2h-1,4-benzothiazin-3(4h)-ones

Nucleophilic additions of alpha-mercaptoalkanoate esters and beta-mercaptoalkanoate acids to benzoquinone diimines, followed by cyclization with trifluoroacetic acid or 1,3-dicyclohexylcarbodiimide (DCC), provide novel, high-yielding syntheses of 2H-1,4-benzothiazin-3(4H)-ones (3a-f) and 2,3-dihydro-1,5-benzothiazepin-4(5H)-ones (5a-c), respectively.     

Recyclization of 4-methyl(phenyl)-2,3-dihydro-1h-1,5-benzodiazepin-2-ones

Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, p. 997, July, 1989.     

Novel buron heterocycles. I. 2,3-dihydro-1,3,2-benzodiazaborin-4(III)-ones and 1,2-dihydro- 1,3,2-benzodiazaborines

A series of 2,3-dihydro-1,3,2-benzodiazaborin-4(IH)-ones have been prepared and their ir spectra compared with those of their carbon isosteres. Solvolysis of these boron compounds in ethanol has been followed by uv and reveals a relationship between structure and rates of ethanol-ysis. Unexpectedly, these boron heterocycles, in contrast to their carbon isosteres, dissolve in aqueous alkali to form stable anions and the significance of this is discussed. The 1 :1 adducts of 1 and phosphorus oxychloride has been utilized to prepare two derivatives of the very stable 1,2-dihydro-2-phenyl-1,3,2-benzodiazaborin heterocycle.     

Stannous chloride in alcohol: a one-pot conversion of 2-nitro-N-arylbenzamides to 2,3-dihydro-1H-quinazoline-4-ones

A novel one-step synthesis of 2,3-dihydro-1H-quinazolin-4-ones from 2-nitrobenzamides is reported. These reactions are mediated by stannous chloride in 0.02 M methanolic or ethanolic HCl solution and proceed in good yields.     

Microwave-assisted synthesis of novel 2,3-dihydro-4-pyridinones

Novel 2,3-dihydro-4-pyridinones were synthesized via the reaction of curcumin and primary amines or amine acetates under microwave irradiation. Montmorillonite K-10 was used as a catalyst. Reaction times did not exceed 120 s. The structures of the compounds were established by elemental analysis and from their mass, 1H- and 13C-NMR spectra.     

Novel tunable CuX(2)-mediated cyclization reaction of cyclopropylideneacetic acids and esters for the facile synthesis of 4-halomethyl-2(5H)-furanones and 4-halo-5,6-dihydro-2H-pyran-2-ones

[reaction: see text] A mixture of cyclopropylideneacetic acids (or esters) and CuBr(2) (or CuI/I(2)) in aqueous acetonitrile afforded 4-substituted 2(5H)-furanones or 3,4-substituted 5,6-dihydro-2H-pyran-2-ones in moderate to good yields. The selectivity of the reaction greatly depended on the reaction temperature.     

T3P-promoted synthesis of a series of novel 3-aryl-2-phenyl-2,3-dihydro-4H-1,3-benzothiazin-4-ones

A series of 11 novel 3-aryl-2-phenyl-2,3-dihydro-4H-1,3-benzothiazin-4-ones was prepared at room temperature by T3P-mediated cyclization of N-aryl-C-phenyl imines with thiosalicylic acid. This provides simple and ready access to N-aryl compounds in this family, which have been generally difficult to prepare.     

2,3-二氢-3,5-二羟基-6-甲基-4(H)吡喃-4-酮的合成及热裂解行为

以葡萄糖和哌啶为原料，合成、分离并鉴定了2，3－二氢－3，5－二羟基－6－甲基－4－（H）吡喃－4－酮（1），以空气氛下直接热裂解，SPME吸附热裂解挥发生产物的方式，分析鉴定了20个裂解的挥发性化合物，讨论了热裂解的可能过程。     

Indium-mediated regioselective mono-allylation of 1,5-dicarbonyl compounds and dehydrative cyclization to 2,3-dihydro-4H-pyran-4-ones and 3,4-dihydro-2H-[1,4]oxazines

An indium-mediated Barbier type mono-allylation of 1,5-dicarbonyl compounds and a subsequent acid-catalyzed dehydrative cyclization afforded 2,3-dihydro-4H-pyran-4-ones and 3,4-dihydro-2H-[1,4]oxazines.     

Formylation of 4-aryl-2,3-dihydro-1H-1,5-benzodiazepin-2-ones

The formylation of 8-chloro- and 8-methoxy-4-phenyl-2,3-dihydro-1H-1,5-benzodiazepin-2-ones with the Vilsmeier reagent leads to 3-dimethylaminomethylene derivatives which, in the case of the 8-chloro derivative, have been converted by hydrolysis in acetic acid into 8-chloro-3-formyl-4-phenyl-2,3-dihydro-1H-1,5-benzodiazepin-2-ones.Translated from Khimiya Geterotsiklicheskaya Soedinenii, No. 9, pp. 1262–1265, September, 1984.     

Palladium(II) and platinum(II) halide complexes with 2,6-dimethyl-4H-pyran-4-thione

Summary 2,6-Dimethyl-4H-pyran-4-thione (DMTP) acts as a sulphur donor towards Pt^II and Pd^II halides yielding adducts of general formula [M(DMTP)₂X₂] (M=Pd or Pt; X=Cl, Br or I). When complex syntheses are performed in benzene, the solvated species [M(DMTP)₂X₂]·C₆H₆ (M=Pd or Pt; X=Cl or Br) are obtained. The compounds have been characterized by i.r. and n.m.r. (¹H and¹³C) spectroscopy and by thermogravimetric data. The adduct geometry and the influence of benzene are discussed.     

Synthesis of 4-Pyridyl-2,3-dihydro-1H-1,5-benzodiazepin-2-ones

4-Pyridyl-2,3-dihydro-1H-1,5-benzodiazepin-2-ones were obtained by the condensation of ethyl nicotinoyl- or isonicotinoylacetates with o-phenylenediamine. Alkylation of the pyridylbenzodiazepinones with ethyl iodide under phase-transfer catalysis conditions occurred at the amide nitrogen of the heterocycle, whereas in nitromethane it occurred at the nitrogen of the pyridine substituent. Bromination with N-bromosuccinimide occurred at position 3 of the heterocycle. Pyridyldibenzodiazepinones underwent thermal rearrangement to derivatives of vinylbenzimidazole.