A. Yu. Tyurin

Synthesis of first nonannulated 1,2,3,4-tetrazine 1,3-dioxides

Thermolysis of o-diazidobenzotetrazine 1,3-dioxides was accompanied by cleavage of the C-C bond of the benzene ring to give nonannulated 1,2,3,4-tetrazine 1,3-dioxides. The structures of these first representatives of nonfused 1,2,3,4-tetrazines were confirmed by 13C and 14N NMR spectroscopy.

Nucleophilic substitution in benzo-1,2,3,4-tetrazine 1,3-dioxides

Nucleophilic substitution in nitro- and bromobenzo-1,2,3,4-tetrazine 1,3-dioxides (BTDOs) was studied. In most cases, the bromo and nitro groups are replaced by methylamino, dimethylamino, azido, and methoxy groups without opening of the tetrazine ring. It was illustrated with the reactions of dibromo-BTDOs with sodium methoxide that the reactivity of positions 5 to 8 in their benzene ring as regards nucleophilic substitution changes in the following order: 6 > 8 > 7 > 5. The structures of the BTDOs obtained were confirmed by 1H, 13C, and 14N NMR data.

Benzo-1,2,3,4-tetrazine 1,3-dioxides annulated with tetraazapentalene systems 3. Annulation at the C(7)—C(8) bond

Thermolysis of 7-azido-8-(2H-1,2,3-triazol-2-y1)-1,2,3,4-benzotetrazine 1,3-dioxide and 7-azido-8-(l H-1,2,3-triazol-l-yl)-1,2,3,4-benzotetrazine 1,3-dioxide afford new heterocyclic systems, viz., 7,11-dehydro-7H, 11H [1,2,3]triazolo[l′,2′:2,3][1,2,3]triazolo[4,5-f]-[1,2,3,4]benzotetrazine 1,3-dioxide and 7,9-dehydro-7 H, 9H [1,2,3]triazolo[2′,1′:2,3]-[1,2,3]triazolo[4,5-f][1,2,3,4]benzotetrazine 1,3-dioxide, respectively, and their thermal stability has been studied.

Annulated benzotetrazine 1,3-dioxides 2.* [1,2,5]Oxadiazolo[3,4-f ][1,2,3,4]benzotetrazine 1,3,7-trioxide

Thermolysis of 8-azido-7-nitrobenzotetrazine 1,3-dioxide led to benzotetrazine 1,3-dioxide annulated with the furoxan ring at the C(7)—C(8) bond. Complete assignment of the signals in the 13C NMR spectrum of the compound obtained was performed. Attempted syntheses of benzotetrazine 1,3-dioxides annulated with a furoxan ring at the C(6)—C(7) bond or two furoxan rings at the C(5)—C(6) and C(7)—C(8) bonds were unsuccessful.

Annulated benzotetrazine 1,3-dioxides 1. [1,2,5]Oxadiazolo[3,4-f][1,2,3,4]benzotetrazine 2,4,7-and 2,4,9-trioxides

Thermolysis of 6-azido-5-nitro-7-R-benzotetrazine 1,3-dioxides (R = H and Br) gave benzotetrazine 1,3-dioxides annulated with the furoxan ring at the C(5)-C(6) bond. According to the NMR data, these compounds at 297 K are equilibrium mixtures of two isomers with different positions of the N-oxide oxygen atom in the furoxan ring. Full assignment of signals in the 13C NMR spectra of the compounds obtained was accomplished.

Reactions of 1-aryl-2-bromodiazene 1-oxides with acids and bases

The reactions of 1-aryl-2-bromodiazene 1-oxides with HCl in nonaqueous media give aryldiazonium chlorides, while 1,3,3-substituted triazenes-1 are formed in the reactions with secondary amines. Using 2-{15N} label, it was shown that the aryl group does not migrate in these reactions.

Reaction of 1-aryl-2-alkenyldiazene 1-oxides with hydrogen chloride. Novel approach to the synthesis of functionally substituted arylhydrazones

The reaction of 1-aryl-2-alkenyldiazene 1-oxides with HCl yields arylhydrazones of α-chloroacyl chlorides, which eliminate HCl to give 1-aryl-2-(1-chloroalken-1-yl)diazenes. The latter add amines, alcohols, and carboxylic acids to give arylhydrazone chlorides with α-functional groups.

NOVEL REACTION OF 1-ARYL-2-BROMODIAZENE 1-OXIDES WITH OLEFINS. SYNTHESIS OF 1-ARYL-2-(2-BROMOALKYL)DIAZENE 1-OXIDES

The addition of 1-aryl-2-bromodiazene 1-oxides to olefins yields 1-aryl-2-(2-bromoalkyl)diazene 1-oxides (4). A radical mechanism of the reaction has been suggested. Compounds4 decompose to give bromohydrazones of formaldehyde and aldehydes. The structural factors that affect the rate of this process are discussed.

SYNTHESIS OF 1-ARYL-2-ALKENYLDIAZENE 1-OXIDES

Abstract1-Aryl-2-alkenyldiazene 1-oxides were prepared by the reactions of 1-aryl-2-bromodiazene 1-oxides with olefins followed by dehydrobromination of the intermediate 1-aryl-2-(β-bromoalkyl)diazene 1-oxides by triethylamine.

Synthesis of condensed pregnano[17,16-d]triazolines under high pressure

Condensed pregnano[17,16-d]triazolines were produced in 1,3-dipolar cycloaddition of 16-dehydropregnenolone acetate with organic azides at 10 kbar. The structure of the synthesized compounds was determined by using two-dimensional NMR spectroscopy (1H—1H COSY, NOESY, HSQC, and HMBC).