Study on the Ring Eulargment Reaction: Synthesis of 7,8,13, 13a-tetrahydroisoindolo[1,2-b][3]benzazepine and 5,6,8,9,14,14a-hexahydroisoquino[1,2-b][3]benzazepine

In our research on the ring enlargement of certain N-heterocycles, a general procedure for the ring enlargement with the insertion of an extra -CH2- was improved and shown in Scheme I1.Scheme IThe procedure had been carried out with such N-heterocycles as 2-methyl-1,2,3,4-tetrahydroisoquinoline2, tetrahydroberberine and strychnine3 with expected results. Thus, the procedure shown in Scheme I provides a new approach to the synthesis of larger N-heterocycles.Isoindolo[1,2-b][3]benzazepines a…     

Synthesis, Conformations and Inclusion Properties of Homocalix[3]arenes

A new type of host is introduced: homocalix[3]arenes containing three aromatic units. Phane synthesis leading to molecules which may be termed, in the most general sense, homocalix[3]arenes, are outlined in a brief overview. The design, synthesis, conformations and host properties of homocalix[3]arenes are described in detail.     

New Approach to Synthesis of Tetrahydroisoquino[2,l-c] [1,3]-benzodiazepine

A concise and efficient synthesis of the new compounds tetrahydroisoquino [2,1-c] [1,3] benzodiazepine 5 and 7 is reported.     

Synthesis of cyclic hemiketals and spiroketals from dioxanorbornanes

[reaction: see text] A new method for the synthesis of substituted pyranone hemiketals from dioxanorbornanes via SmI(2) is described. Also reported is a synthesis of spiro[4.5]ketals from analogous intermediates via acid-promoted deprotection/ketalization.     

Rearrangement of 2-[1(3h)-oxodihydrobenzo[c]furan-3-yl] quinuclidin-3-ones to tetrahydrobenzo[b]quinolizines. A novel synthesis of benzo[b]quinolizine ring systems.

A new two step synthesis of benzo[b]quinolizine ring systems via the rearrangement of 2-[1(3H)-oxodihydrobenzo[c]furan-3-yl] quinuclidin-3-ones is described.     

Highly effective synthetic methods for substituted 2-arylbenzofurans using [3,3]-sigmatropic rearrangement: short syntheses of stemofuran a and eupomatenoid 6

A new and efficient synthesis of 2-arylbenzofurans has been achieved via a route involving acylation and subsequent [3,3]-sigmatropic rearrangement of oxime ethers. Its synthetic utility is demonstrated by a short synthesis of stemofuran A and eupomatenoid 6 in which no procedure for protection of the phenolic hydroxyl groups is needed. [reaction--see text]     

Synthesis of Benzo[d]Benzo[2,3][1,4]Diazepino[1,7-b]Isothiazole,a New Heterocyclic Ring System

A facile synthesis of benzo[d]benzo[2,3][1,4]diazepino[1,7-b] isothiazole, a new heterocyclic ring system is reported.     

A new approach to construct full-length glycosylphosphatidylinositols of parasitic protozoa and [4-deoxy-Man-III]-GPI analogues

A new [2 + 2 + 2] approach to construct GPI molecules through the efficient synthesis of glucosamine-inositol and tetramannose intermediates led to a total synthesis of a GPI-anchor of Trypanosoma cruzi, and also afforded a key intermediate for the synthesis of valuable [4-deoxy-Man-III]-GPI analogues.     

A New Efficient Synthesis of p-Nitrocalix[4]arene

A new efficient synthesis of p-nitrocalix[4]arene from calix[4]arene by using nitrogen dioxide is described.The compound is an useful intermediates for the introduction of other functional groups to obtain N containing substituted calix[4]arene.The reaction mechanism is briefly discussed.     

Synthesis and Diels-Alder reactions of the benzo[4,5]thieno [2,3-c]pyrrole ring system

The first synthesis of the parent compound of the benzo[4,5]thieno[2,3-c]pyrrole ring system and its derivatives, as well as their Diels-Alder reactions with DMAD and N-phenylmaleimide are reported. A new synthesis of the benzo[4,5]thieno[2,3-d]pyridazine ring system is also described.     

Synthesis of polycyclic mixed phenothiazine-phenoxazine organic dyes

A convenient synthesis of new polycyclic mixed phenothiazine-phenoxazine compounds is described. The cross-coupling of 2,4-diaminothiophenol with 2,3-dichloro-1,4-naphthoquin one at room temperature gave reddish brown 10-amino-6-chlorobenzo[a]phenoxazin-5-one which was converted into a benzoxazinophenothiazin-12-amine in 58% yield via reaction with 2-aminothiophenol under anhydrous basic conditions. A three-component one-pot synthesis improved the yield of benzoxazinophenothia-12-amine to 81% a in shorter time compared to two steps reactions. The synthesis of new azomethine derivatives of benzo[a]benzo[5,6] [1,4] oxazino [3,2-c] phenothiazin-12-amine with extended conjugations and excellent yields were also reported. The structural assignments of the prepared compounds were established by combine Ultraviolet-Visible, Fourier Transform Infrared, ¹H and ¹³C Nuclear Magnetic Resonance Spectroscopies, Mass Spectrometry and elemental analytical data. The ease of preparations in high yields and their intense colourations make these compounds applicable as dyestuffs.     

A New Route to the Synthesis of 7-Functionalised Bicyclo[2.2.1]Heptane Derivatives

A new route to the synthesis of 7-functionalised bicyclo[2.2.1]heptane derivatives having a bridgehead alkoxy group is described involving Wolff rearrangement of α-diazo ketone in a bicyclo[2.2.2]octane derivative.     

Contractive Annulation: A Strategy for the Synthesis of Small,Strained Cyclophanes and Its Application in the Synthesis of [2](6,1)Naphthaleno[1]paracyclophane

A new synthetic strategy (contractive annulation) for the synthesis of highly strained cyclophanes has been conceived and its viability has been demonstrated through a nine‐step synthesis of [2](6,1)naphthaleno[1]paracyclophane from [2.2]paracyclophane.     

Contractive Annulation: A Strategy for the Synthesis of Small,Strained Cyclophanes and Its Application in the Synthesis of [2](6,1)Naphthaleno[1]paracyclophane

A new synthetic strategy (contractive annulation) for the synthesis of highly strained cyclophanes has been conceived and its viability has been demonstrated through a nine‐step synthesis of [2](6,1)naphthaleno[1]paracyclophane from [2.2]paracyclophane.     

Expeditious synthesis of N-bridged heterocycles via dipolar cycloaddition of pentafulvenes with 3-oxidopyridinium betaines

A new and highly versatile approach towards the synthesis of bicyclo[6.3.0]undecanes and bicyclo[5.3.0]decanes was accomplished. The methodology adopted involved [6+3] and [3+2] cycloaddition reactions of pentafulvenes with 3-oxidopyridinium betaines generated either by the action of a base on the pyridinium salt or thermally from pyridinium betaine dimer. These well-functionalized bicyclo[6.3.0]undecanes and bicyclo[5.3.0]decanes offer a wide range of synthetic options, which can be expected to translate into a variety of rapid and efficient synthesis of natural products.     

A new method for the formation of the imidazo[4′, 5′; 3,4] pyrido[2,3-b]indole ring: Formal synthesis of the alkaloids from marine origin grossularines-1 and 2

A new synthesis of the 2-dimethylamino-4-hydroxy-6-methoxymethyl-3H-imidazo[4′, 5′:3,4] pyrido[2,3-b]indole, used as key intermediate in the total synthesis of the alkaloids grossularines-1 and -2, based on the step-wise formation of the pyridine and imidazole rings, is described.     

Synthèse du mèthyl-1 diformyl-2,3 pyrrole,de la méthyl-1 pyrrolo[2,3-d] pyridazine et de la méthyl-1 oxo-6 (6h)cycloheptatrieno[b] pyrrole

This communication describes the synthesis of l-methyl-2,3-diformylpyrrole. This new compound is used to prepare a new heterocycle, l-methylcyclohepta[b]pyrrol-6-one and thus allows a new synthesis of l-methylpyrrolo[2,3-d]pyridazine.     

Synthesis of Indolo[2,3‐a]pyrrolo[3,4‐c]carbazoles via the Oxidative Cyclization of Bisindolylmaleimides with Pd(TFA)2/Cu(OAc)2

A new synthetic approach for the synthesis of indolo[2,3‐a]pyrrolo[3,4‐c]carbazoles based on the Cu²⁺/Pd²⁺ catalytic system is described. The optimum condition is established via a systematic screening and utilized for the synthesis of four indolocarbazole aglycones with a satisfied yield.     

Unexpected chemical and electrochemical properties of M3N@C80 (M = Sc, Y, Er)

The unexpected isomerization of N-ethyl [6,6]-pyrrolidino-Y3N@C80 to the [5,6] regioisomer is reported, as well as the synthesis, characterization, and electrochemical analysis of Er3N@C80 derivatives. A complete electrochemical study of the M3N@C80 species (M = Sc, Y, Er) and their derivatives is presented. We introduce electrochemistry as a new tool in the characterization of the [5,6] and [6,6] regioisomers of trimetallic nitride endohedral metallofullerenes.     

Application of the Rh(II) cyclization/cycloaddition cascade for the total synthesis of (+/-)-aspidophytine

[Structure: see text] A new strategy for the synthesis of (+/-)-aspidophytine has been developed and is based on a Rh(II)-catalyzed cyclization/dipolar cycloaddition sequence. The resulting [3+2]-cycloadduct undergoes an efficient Lewis acid mediated cascade that rapidly provides the complete skeleton of aspidophytine. The synthesis also features a mild decarbomethoxylation reaction.