Dimethyl diazene

A novel application of a phenyl aryldiazosulfone was found by Kessler et al. (1990). l-[4-(7V-Chlorocarbonyl-7V-methylamino)phenyl]-2-(phenylsulfonyl)diazene (6.18) is an acid chloride with a potential diazonio group. The above authors showed that in organic solvents (THF, etc.) this compound reacts easily, as expected, with nucleophiles (HNu), e.g., with aliphatic, aromatic, or heterocyclic amines, with cystine dimethyl ester, or with 4-methoxyphenol at the carbonyl function, yielding... 

More entries were used to test the valT3ity of equation 6 for reaction 1 than for the other families of initiators (Table I). Six of the thirteen entries for reaction 1 have AE(x) values bunched between -21 and -24 kcal/mole. It was felt that, by using all of these six entries, any bias in structure activity relationships would be decreased for this region of radical pi-delocalization energies. This group also includes those diazenes which are most used commercially, such as 2,2 -azobisisobutyronitrile (AIBN - entry 16 ) and dimethyl 2,2 -azobisisobutyrate (entry 14). 

SchlieBlich sei die Umsetzung von l,2-Dimethyl-5-nitro- bzw. l,2-Dimethyl-4-nitro-imidazol mit Kaliumcyanid in Ethanol bei 78° genannt, die zu Bis-[4-cyan-l,2-dimethyl-5-imidazolyl]-(54%) bzw. Bis-[5-cyan-l,2-dimethyl-4-imidazolyI -diazen-l-oxid (60%) fuhrt703. 

Auch durch Retro-Diels-Alder-Reaktion konnen Azoalkane erhalten werden. Die ther-mische Zersetzung von 1,2,3,6-Tetrahydro-pyridazin liefert vorzugsweise cis-Dimethyl-di-azen, wahrend das 2,3-Dimethyl- uberwiegend in trans-Dimethyl-diazen zerfallt. Zur stereochemischen Begriindung hierfiir s.Lit.3. 

Bis-[2,3-dimethyl-phenyl -diazen- 1-oxid wird nach Methode in 70% Ausbeute gewonnen. 2,6-disubstituierte Nitrobenzole liefem anstelle der gewtinschten Azoxybenzole jedoch Aniline. 

Die Bestrahlung von Azobenzolen in Anwesenheit von Sauerstoff fiihrt zu unterschied-lichen Resultaten. 4-Arylazo-l-hydroxy-naphthaline liefern nur 1,4-Naphthochinon. Kei-nerlei Oxidationsprodukte werden bei 4-Amino-4 -nitro-azobenzol erhalten. 4-Dimethyl-amino-2/,4 -dinitro-azobenzol liefert in 35-40% Ausbeute l-(4-Dimethylamino-phenyl)-2- (2,4-dinitro-phenyl)-diazen-l-oxid2. 

Lf[AlH4]/Ether RuckfluB 6 h 2,6-Dimethyl-anilin (+ Bis-[2,6-dime thy l-phenyt]-diazen) 53 [ + 21] 5... 

A,TV-Dimethyl-A -phenylthiourea has been shown to coordinate to Rh111 as an N—S bidentate involving four-membered chelate ring formation.154 N-Substituted thioamides also may bond in this manner.155 156 l-Amidino-2-thioureas (44) may behave either as N—S or as N—N bidentates, with this donor choice being dependent mainly on pH and the nature of the metal ion.157 As N—S donors they are known to stabilize lower oxidation states.158 As part of a study on Mo—S-containing complexes as models for redox-active molybdoenzymes, Dilworth et al. have shown that some p-(substituted)phenylhydrazines may coordinate as N—S bidentates in three different ways to one metal atom.159 The three diazenido, diazene and hydrazonido forms vary in their degree of deprotonation and therefore their anionic nature. 

Bnten 2,3-Dimethyl-4-hydrazino-3-hydroxy- E16a, 439 (N-Alkyl.) Diazen Diisopropyl- -N-oxid X/2, 787... 

Reaction of aryl vinyl ethers, however, invariably gives mixtures of diazetidines and oxadiazines. The ratio is mainly dependent on the nature of the substituent on the phenyl group and, in part, on the nature of the alkyl group of the dialkyl diazenedicarboxylate and the solvent substituents which enhance the nucleophilicity of the alkene and the electrophilicity of the diazene, and polar solvents that favor a polar mechanism, result in concurrent formation of the diazetidine as the predominant product and vice versa15, l< Similarly, diazetidines 7 and oxadiazines 8 are formed in comparable yields in the reactions of vinyl sulfides with dimethyl diazenedicarboxylate, the ratio is principally dependent on the nature of the sulfur substituent (aryl, alkyl)17. 

The cycloaddition of 1,3,5-cyclooctatriene and dimethyl diazenedicarboxylate gives the homologous tricyclic adduct 7 with endo configuration of the cyclobutane ring12, which has been converted to known tricyclic and tetracyclic diazenes. 

Dimethyl-5,5 -ozotetrozole ot Di(methyl-tetrozolyl) -diazene. See Bis(l-methyl-l,2,3,4-tetrazolyl-5)-dia2ene in Vol 2 of Encycl, p B151 L and M.M. Williams et al, JPhysChem 61, 263(1957). They give heats of combstn 770. Skcal/mole for ttans compd and 769.8 for cis compd. Heats of formation minus 189.3 for trans- and 188.6 for... 

Di[1-methyl-tetrazolyl-5]-diazene 1,1 -Dimethyl-5,5 -azotetrazole or Azo-di(l-methyltetrazole-5),... 

To a cold (0 "C), magnetically stirred solution of 4,4-dimethyl-3,5-diphenyl-3i/-pyrazole (2.4 g, 10 mmol) and cyclobutadieneirontricarbonyl (1.92 g, 10 mmol) in acetone (125 mL) under Nj was added ceric ammonium nitrate (27.4 g, 50 mmol) in portions over 30 min. The resultant slurry was poured into anhyd EtjO and the precipitated cerium salts were removed by filtration. The filtrates from two identical runs were evaporated and the combined crude product chromatographed (silica gel, EtjO/hexane 1 9). Recrystallization (hexane) gave 7,8-diaza-eui7o-9,9-dimethyl-l,6-diphenyltricyclo[4.2.1.0 ]nona-3,7-diene(9) as white crystals yield 4.09 g (68%) mp 153-154 "C (dec.). A solution of the diazene 9 (100 mg, 0.33 mmol) in EtjO (2 mL) was irradiated for 3 h with a 200-W Hanovia lamp (Pyrex filter). The progress of the reaction was monitored by TLC. Removal of the solvent gave 10 yield 90 mg (100%) mp 65-67 C. 

The intermolecular diyl trapping reaction provides a direct and simple route to the linearly fused tricyclopentanoid ring system. As illustrated in the first example of this pathway, heating the dimethyl diazene 9 to 70-75 °C in the presence of an excess of cyclopentenone afforded a 90-98% yield of cycloadducts 10-12 [4].Unfortunately, the process displayed... 

Commercially available dihydro-5-(hydroxymethyl)-4,4-dimethyl-2(3H)-furanone (42) was chosen as the starting material since it incorporated the essential structural features that are present in the acyclic chain of diazene 41. To synthesize both coriolin (3) and hypnophilin (4), enone 39 was selected as a common intermediate. While 39 had previously been converted to coriolin (3), its conversion to hypnophilin (4) had not been accomplished. 

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