Esters of Substituted 2,3,7-Triazabicyclo[3.3.0]oct-3-ene-4-carboxylic acids and 1,2,7-Triazaspiro[4.4]non-2-ene-3-carboxylic acids in Alkylation and Acylation

Esters of substituted 2,3,7-triazabicyclo[3.3.0]oct-3-ene-4-carboxylic acids react with acetone in the presence of hydrogen chloride (bromide) affording esters of substituted 2-(1,1-dimethyl-3-oxobutyl)-2,3,7-triazabicyclo[3.3.0]oct-3-ene-4-carboxylic acids. Reactions of esters of substituted 2,3,7-triazabicyclo[3.3.0]octa-1(5),3-diene-4-carboxylic acids with 1-adamantanol in trifluoroacetic acid resulted in esters of substituted 2-(1-adamantyl)- 2,3,7-triazabicyclo[3.3.0]octa-1(5),3-diene-4-carboxylic acids.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 2, 2005, pp. 252–263.Original Russian Text Copyright © 2005 by Stepakov, Molchanov, Kostikov.     

Reduction of 7-aryl-6,8-dioxo-2-oxa-3,7-diazabicyclo[3.3.0]oct-3-ene-4-carboxylic and 7-aryl-6,8-dioxo-1-oxa-2,7-diazaspiro[4.4]non-2-ene-3-carboxylic acid esters

Ethyl 7-aryl-6,8-dioxo-2-oxa-3,7-diazabicyclo[3.3.0]oct-3-ene-4-carboxylates and ethyl 7-aryl-6,8-dioxo-1-oxa-2,7-diazaspiro[4.4]non-2-ene-3-carboxylates were selectively reduced with sodium tetrahydridoborate at the carbonyl group in the β-position with respect to the oxygen atom in the isoxazole ring.     

Reactions of Substituted 2,3,7-Triazabicyclo[3.3.0]oct-3-ene-4-carboxylic Acid Esters with Halogens

Substituted 2,3,7-triazabicyclo[3.3.0]oct-3-ene-4-carboxylic acid esters react with chlorine and bromine to give the corresponding 4-halo-2,3,7-triazabicyclo[3.3.0]oct-2-ene-4-carboxylates. Heating of the latter to 120°C under reduced pressure leads to elimination of nitrogen molecule and formation of 6-halo-3-azabicyclo[3.1.0]hexane-6-carboxylates.     

Thermolysis of 7-phenyl-2,3,7-triazabicyclo[3.3.0]oct-2-ene-6,8-dione

Thermolysis of the title compound in boiling xylene (138°) produces a 7.7/10.1/1.0 mixture of the N-phenylimides of cis-1,2-cyclopropanedicarboxylic acid, citraconic acid, and itaconic acid. The imides of citraconic and itaconic acids are produced by hydrogen shifts. A completely concerted mechanism involving simultaneous hydrogen shift and cleavage of both C-N bonds is unlikely in the present case because both hydrideshift products are formed and because the optimal arrangement for the hydrogen shift requires deformation of the imide ring and loss of imide resonance. The C? N bond strengths in the title compound should be quite different. The products can arise either from two parallel pathways involving nitrogen-containing dipoles or from a single nitrogen-free trimethylene fragment.     

Reaction of Substituted Methyl 2,3,7-Triazabicyclo[3.3.0]oct-3-ene-4-carboxylates and 1,2,7-Triazaspiro[4.4]non-2-ene-3-carboxylates with Iodinating Agents

Substituted methyl 2,3,7-triazabicyclo[3.3.0]oct-3-ene-4-carboxylates and 1,2,7-triazaspiro[4.4]non-2-ene-3-carboxylates react with N-iodosuccinimide (or the system iodine-silver trifluoroacetate) to give, respectively, methyl 6-iodo-3-azabicyclo[3.1.0]hexane-6-carboxylates or methyl 1-iodo-4,6-dioxo-5-azaspiro[2.4]heptane-1-carboxylates as mixtures of exo and endo isomers.     

Reaction of Substituted 6,8-Dioxo-2,3,7-triazabicyclo[3.3.0]oct-3-ene-4-carboxylates and 6,8-Dioxo-1,2,7-triazaspiro[4.4]non-2-ene-3-carboxylates with N-Fluoropyridinium Tetrafluoroborate

Substituted 6,8-dioxo-2,3,7-triazabicyclo[3.3.0]oct-3-ene-4-carboxylates react with N-fluoropyridinium tetrafluoroborate to give mixtures of exo and endo isomers of 6-fluoro-2,4-dioxo-3-azabicyclo[3.1.0]hexane-6-carboxylates. Analogous reaction of 6,8-dioxo-1,2,7-triazaspiro[4.4]non-2-ene-3-carboxylates results in formation of syn,anti-isomeric 1-fluoro-4,6-dioxo-5-azaspiro[2.4]heptane-1-carboxylates.     

Synthesis and transformations of di-endo-3-aminobicyclo-[2.2.2]oct-5-ene-2-carboxylic acid derivatives

all-endo-3-amino-5-hydroxybicyclo[2.2.2]octane-2-carboxylic acid (13) and all-endo-5-amino-6-(hydroxymethyl)bicyclo[2.2.2]octan-2-ol (10) were prepared via dihydro-1,3-oxazine or g-lactone intermediates by the stereoselective functionalization of an N-protected derivative of endo-3-aminobicyclo[2.2.2]oct-5-ene-2-carboxylic acid (2). Ring closure of b-amino ester 4 resulted in tricyclic pyrimidinones 15 and 16. The structures, stereochemistry and relative configurations of the synthesized compounds were determined by IR and NMR.     

A simple organocobalt mediated synthesis of substituted 3-oxabicyclo[3.3.0]oct-6-en-7-ones

A range of substituted propargyl alcohols form ethers with allyl bromide in good yields; conversion of these ethers to the alkyne hexacarbonyl dicobalt complexes using Co₂(CO)₈, followed by intramolecular cyclisation gives substituted 3-oxabicyclo[3.3.0]oct-6-en-7-ones (4a–4e) in fair to moderate yields.     

Thermal rearrangement of 2-oxabicyclo[2.2.2]oct-5-eno-3-carboxylic acids

The decarboxylation of 2-oxabicyclo[2.2.2]oct-5-eno-3,3-dicarboxylic acid, obtained by hydrolysis of the Diels-Alder adduct of diethyl mesoxalate with cyclohexa-1,3-diene, gave two stereoisomeric γ-lactones of 2-hydroxy-1,2,5,6-tetrahydromandelic acid.     

4-Oxo-3-oxa-6,7-diazabicyclo[3.3.0]oct-6-ene and its isomerization

A product of addition of diazomethane to the double bond of crotonolactone — ¹-pyrazolinolactone — was obtained, and its isomerization to ²-pyrazolino-lactone in dry chloroform in the presence of triethylamine was studied. The structures of the compounds were confirmed by elementary analysis and the IR, UV, and PMR spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1610–1612, December, 1977.     

Novel dimerisation of bicyclo[3.3.0]oct-2-en-3-one

Application of the intramolecular Wadsworth-Emmons reaction to bicyclo[3..3.0]oct-2-en-3-ones results in the formation of a novel dimer (11) of the parent member (6) whose structure has been determined by X-ray crystallography.     

Reduction of 2-oxa-3,7-diazabicyclo[3.3.0]octanes

The reduction of 2-oxa-6-oxo-3-phenyl-4-(R-phenyl)-7-(4-nitrophenyl)3,7-diazabicyclo[3.3.0]octanes with hydrazine hydrate in the presence of Raney nickel gave the corresponding amino alcohols. X-ray diffraction analysis established the stereochemistry of the molecule in the crystal of 1-(4-anilino)-3-[anilino(phenyl)methyl]-4-hydroxypyrrolidone-2.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 890–894, July, 1992.     

Alkoxide-Accelerated [1,3] Sigmatropic Shift of Bicyclo[3.2.1]oct-6-en-2-ols to 8-endo-Hydroxybicyclo[3.3.0]oct-2-en-4-ones

Bicyclo[3.2.1]oct-6-en-2-ols 6 are shown to undergo [1,3] sigmatropic shift to afford 8-endo-hydroxy-bicyclo[3.3.0]oct-2-en-4-ones 8 under the influence of potassium hydride.     

Synthesis of 2,7-Diazabicyclo[3.3.0]octane and 2,7-Diazabicyclo[3.3.0]oct-4-ene Derivatives via Cyclization Reaction and Julia Reaction

2,7-Diazabicyclo[3.3.0]octan-4-ol (1) and 2,7-diazabicyclo[3.3.0]oct-4-ene (2) are synthesized by the desulfonylation using Mg-HgCl₂(cat.) of β-hydroxy sulfone derivatives which have been prepared via cyclization of sulfone ester derivative.     

Synthesis of esters of substituted 3-aminopyrrole-2-carboxylic acids from thioacrylamides and glycine esters

Morpholides of 3-[(alkoxycarbonylmethyl)amino]thioacrylic acids and esters of 3-morpholinopyrrole-2-carboxylic acids have been obtained from glycine esters and morpholides of 3-hydroxy- and 3-(dimethylamino)thioacrylic acids.Communication 10 of the series Products of the formulation of thioamides; for Communication 9, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 628–630, May, 1985.