1,3-Dipolar cycloaddition reactions of 7-alkenyl- or 7-alkynyl-8-azidomethyltheophyllines

1988 ◽  
Vol 53 (2) ◽  
pp. 319-328 ◽  
Author(s):  
Dušan Hesek ◽  
Alfonz Rybár ◽  
František Považanec ◽  
Augustin Martvoň ◽  
Jaroslav Kováč
Keyword(s):  
Thionyl Chloride ◽  
Sodium Azide ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Thermally Induced ◽  
Intramolecular Cycloaddition ◽  
Phosphorus Tribromide

8-Azidomethyltheophillines XI-XIV, containing dipolarophilic alkenyl or alkynyl (i.e. allyl, 2-butenyl, cinnamyl, and 2-propynyl) groups in position 7, undergo thermally induced 1,3-dipolar intramolecular cycloaddition under formation of 7-substituted 1,3-dimethyl-2,4-dioxo-1,2,3,4,6,6a,7,11-octahydro(1,2,3)triazolo[1’,5’:1,2]pyrazino[5,4-f]purines XV-XVII and 1,3-dimethyl-2,4-dioxo-1,2,3,4,6,11-hexahydro(1,2,3)triazolo[1’,5’:1,2]pyrazino[5,4-f]purine (XVIII), respectively. The compounds were synthesized starting from 8-hydroxymethyltheophilline (I) which was alkylated to give 7-alkenyl- and 7-alkynyl-8-hydroxymethyltheophillines III-VI and these were converted into the corresponding 8-halogenomethyl derivatives VII-X by treatment with thionyl chloride or phosphorus tribromide. Reaction of VII-X with sodium azide afforded the 8-azidomethyl derivatives XI-XIV.

1,3-Dipolar cycloaddition reactions of monocyclic aziridines with dimethyl 1-cyclobutene-1,2-dicarboxylate

1994 ◽  
Vol 72 (10) ◽  
pp. 2108-2117 ◽  
Author(s):  
Kiyoshi Matsumoto ◽  
Hirokazu Iida ◽  
Takane Uchida ◽  
Yoshimi Yabe ◽  
Akikazu Kakehi ◽  
...  
Keyword(s):  
Ring Opening ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Thermally Induced ◽  
X Ray ◽  
Orbital Interactions ◽  
Dipole Interactions

The thermally induced [2 + 3] cycloadditions of certain monocyclic aziridines to dimethyl 1-cyclobutene-1,2-dicarboxylate are described. The structures of the resulting bicyclic adducts were established unambiguously by X-ray analyses. The stereochemistries of the [2 + 3] adducts were interpreted in terms of dipole–dipole interactions and secondary orbital interactions. In certain cases an initial thermal conrotatory ring opening of the cyclobutene to 2,3-di(methoxycarbonyl)-1,3-butadiene precedes the [2 + 3] cycloaddition, affording the unexpected pyrrolidine adducts 12a and 12b. The structures and stereochemistries of the latter established by X-ray analysis strongly suggest that secondary orbital interactions between the phenyl and ester groups control and stereochemistry of the reactions.

Synthesis of 2,5-Disubstituted 1,3,4-Oxadiazoles and Their Precursors

1994 ◽  
Vol 59 (8) ◽  
pp. 1892-1896 ◽  
Author(s):  
Eva Jedlovská ◽  
Edita Gavláková
Keyword(s):  
Characteristic Feature ◽  
Spectral Data ◽  
Building Block ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Mass Spectral Data ◽  
Intramolecular Cycloaddition ◽  
Mass Spectral ◽  
H Nmr ◽  
New Compounds

The characteristic feature of many commercial agrochemicals and drugs is the 5-nitro-2-furyl or 2,5-dimethyl-3-furyl building block. Within the scope of our research aimed at utilization of dipolar cycloaddition reactions to prepare new compounds with potential biological and phytoeffectorial activity, we report on the synthesis of some substituted hydrazones I and their intramolecular cycloaddition to 2,5-disubstituted 1,3,4-oxadiazoles II. The basic IR, 1H NMR as well as mass spectral data of final products are presented.

Multicomponent 1,3-Dipolar Cycloaddition Reactions in the Construction of Hybrid Spiroheterocycles

2013 ◽  
Vol 17 (18) ◽  
pp. 1929-1956 ◽  
Author(s):  
Natarajan Arumugam ◽  
Raju Kumar ◽  
Abdulrahman Almansour ◽  
Subbu Perumal
Keyword(s):  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions

π-Facial Selectivity in 1,3-Dipolar Cycloaddition Reactions of α-Methylidene-γ-lactone Substituted by 4-Methyl-2,6,7-trioxabicyclo[2.2.2]octan-1-yl Group in γ-Position

2002 ◽  
Vol 67 (3) ◽  
pp. 353-364 ◽  
Author(s):  
Petr Melša ◽  
Ctibor Mazal
Keyword(s):  
Double Bond ◽  
Carboxylic Acid ◽  
Nitrile Oxide ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Enantiomerically Pure ◽  
Nitrile Imine ◽  
Facial Selectivity ◽  
Excellent Selectivity

Diastereoselectivity of 1,3-dipolar cycloaddition reactions of benzyl azide, diazomethane, a nitrile oxide and a nitrile imine to α-methylidene-γ-lactone dipolarophile was effectively controlled by a bulky γ-substituent, 4-methyl-2,6,7-trioxabicyclo[2.2.2]octan-1-yl in γ-position of the dipolarophile. The dipoles added from the less hindered face of the double bond with an excellent selectivity. Enantiomerically pure dipolarophile was prepared from the easily available (S)-5-oxotetrahydrohydrofuran-2-carboxylic acid.

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