Synthesis of 1,3-dihydrobenzo[c]furans from ortho-lithiated aryloxiranes

A general method for the synthesis of hydroxyalkyl 1,3-dihydrobenzo[c]furans from ortho-lithiated aryloxiranes and carbonyl compounds is described.     

Electron Donors for Organic Conductors. Alkylenedithio Derivatives of 1,3-Bis(1,3-dithiol-2-ylidene)-1,3-dihydrobenzo[c]selenophene

Methylene-, ethylene-, and propylenedithio derivatives of 1,3-bis(1,3-dithiol-2-ylidene)-1,3-dihydrobenzo[c]selenophene, MDT-, EDT-, and PDT-BDTBS have been synthesized. TCNQ complexes of MDT- and EDT-BDTBS showed fairly high conductivities and small activation energies even when measured on compressed pellets.     

Synthesis of benzo[c]selenophene and derivatives via new routes

[reaction: see text] Benzo[c]selenophene has been generated via facile bromination-dehydrobromination as well as oxidation of the 1,3-dihydrobenzo[c]selenophene. Benzo[c]selenophene thus generated has been lithiated in situ and treated with ClCOOEt to give the first functionalized derivative subject to X-ray crystallographic analysis.     

Quinazolines. VII. Synthesis of 1,3-Diamino-5,6-dihydrobenzo[f]quinazolines

Eighteen new 1,3-diamino-5,6-dihydrobenzo[f] quinazolines ( 6 , R. = alkyl, Cl, MeO) were synthesized via the condensation of appropriate 2-tetralones with cyanoguanidine under fusion conditions. Methods were developed for the preparation of a number of heretofore undescribed 2-tetralones as precursors. The final products can be viewed as conformationally rigid analogs of pyrimethamine ( 2 ), and are of interest as inhibitors of dihydrofolate reductase and as potential antimalarial and antitumor agents.     

Synthesis of benzo[b]selenophene and its methyl homologs

A method for the synthesis of benzo[b]selenophenes was perfected. 3-Oxo-2,3-dihydrobenzo[b]selenophene and 2-methyl-3-oxo-2,3-dihydrobenzo[b]selenophene exist only in the keto form. 3-Methylbenzo[b]selenophene was obtained by the reaction of 3-oxo-2,3-dihydrobenzo[b]selenophene with methylmagnesium iodide. Metallation of benzo[b]selenophene with butyllithium proceeds at the 2 position of the selenophene ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1475–1480, November, 1970.     

Facile separation of chiral 1,3-dihydrobenzo[c]furan derivatives using a d-xylose moiety as a protecting group

1,2-O-Isopropylidene-α-d-xylofuranose has been used to protect one aldehyde group of o-phthalaldehyde. This chiral protecting group acts as a resolving agent and this leads to separable diastereoisomers when a new stereogenic centre is created by the conversion of the second aldehyde group to a benzyloxyhydroxyethyl chain. These separated diastereoisomers were cyclised to 1,3-dihydrobenzo[c]furans with retention of chiral integrity at the C3 site thus allowing further elaboration to enantiomerically pure nucleoside analogues.     

Synthesis of 5,7-dihydrobenzo[a]phenazin-5-one derivatives

The synthesis, purification and spectroscopic characterization of several phenazines was undertaken with the goal of discovering useful or improved fluorescent probes.     

1,3-Benzothiazole-2-selenenyl chloride in the synthesis of 2,3-dihydrobenzo[d][1,3]selenazolo[2,3-b][1,3]thiazolium-4 derivatives

Cycloaddition of 1,3-benzothiazole-2-selenenyl chloride to alkenes leads to 2,3-dihydrobenzo[d][1,3]selenazolo[2,3-b][1,3]thiazolium-4 derivatives.     

Chemistry of benzo[b]selenophene

The bromination of benzo[b]selenophene with an equimolecular amount of bromine and its acetylation with acetic anhydride in the presence of boron trichloride etherate proceed to form a mixture of isomeric 2- and 3-substituted derivatives; 2,3-dibromobenzo[b]selenophene is formed on bromination with two equivalents of bromine. Benzo[b]selenophene-2-carboxylic acid, its acid chloride and methyl ester, as well as 2-acetylbenzo[b]selenophene, were synthesized from the lithium derivative of benzo[b]selenophene.See [1] for communication III.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 15–19, January, 1972.     

Tandem Henry/oxa-Michael route to the 1,3-disubstituted-1,3-dihydrobenzo[c]furan system

The reaction of ortho-formyl cinnamates and ortho-formyl-α-benzalketones with suitably substituted alkylnitro compounds in the presence of 1,1,3,3-tetramethylguanidine results in the formation of 1,3-disubstituted dihydroisobenzofurans. The reaction mechanism entails a base-mediated nitronate addition to the aryl formyl group followed by intramolecular alcoholate addition to the unsaturated component that then affords the isobenzofuran system.     

Synthesis of Perfluoroalkyl[1,2,4]triazolo[1,3]thiazinones

Russian Journal of General Chemistry -     

Chemistry of benzo[b]selenophene

2-Deutero-, 3-deutero-, 2,3-dideutero-, 2-methyl-3-deutero-, and 3-methyl-2-deuterobenzo[b]selenophenes were synthesized, and their PMR spectra were interpreted.See [1] for communication I.Translated from Khimlya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1382–1386, October, 1971.     

Synthesis of Benzobis[1,3]oxathiins

Two different synthetic concepts led to the formation of 17, 19 , and 29 , the first structural isomeric benzobis[1,3]oxathiins. Hetero‐Diels? Alder reactions of diethyl mesoxylate 14 and the open valence isomers of the benzobisthietes 12 and 18 yielded the linear benzobis[1,3]oxathiin 17 and its angular isomer 22 , respectively. The isomeric angular system 29 could be obtained by a twofold O,S‐acetalization reaction of the dihydroxydisulfanyl compound 27 and acetone ( 28 ).     

Synthesis of 4,6-dinitro-2-trihalogenomethyl-2,3-dihydrobenzo[b]furans

A method for the synthesis of previously unknown 4,6-dinitro-2-trihalogenomethyl-2,3-dihydrobenzo[b]furans has been elaborated. The method is based on condensation of 2,4,6-trinitrotoluene with fluoral or chloral in the presence of K₂CO₃ with subsequent intramolecular cyclization of the resulting 2-picryl-1-(trihalogenomethyl)ethanols. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 569–570, March, 2000.     

芳环缩合核苷衍生物的合成

A novel efficient synthetic route to 1,3-dihydrobenzo[c]furan glycone was developed and the corresponding 5-fluoro, 5-iodo uracil and guanosine derivatives, the aromatic analogues of the well known antiviral 2＇,3＇-dideoxy-2＇,3＇-dihydronucleosides （d4N）, were synthesized.     

Synthesis and cyclometalation of a pyrido[3,2-e]-2,10b-diaza-cyclopenta[c]fluorene-1,3-dione scaffold

The synthesis of a pyrido[3,2-e]-2,10b-diaza-cyclopenta[c]fluorene-1,3-dione scaffold is disclosed, which was synthesized using a Suzuki cross-coupling reaction and an intramolecular Heck cyclization as the key steps. This heterocyclic system can serve as a bidentate ligand as demonstrated by the formation and structural analysis of a derived ruthenium complex. The new scaffold constitutes an interesting candidate for the development of organometallic protein kinase inhibitors.