Methylazulenes

Azulyl sulphoxides 127 have also been prepared by a reaction involving a direct electrophilic substitution on the azulene ring by alkane- or arenesulphinyl chlorides186 (equation 69). Preparation of the methyl and phenyl sulphoxides of 4,6,8-tri-methylazulene and 4,6,8-tri-isopropylazulene by this method resulted in fair yields (57— 72%). However, the substitution on azulene itself gave only low yields of the corresponding sulphoxides. 

The product is of satisfactory purity for use in the 4,6,8-tri-methylazulene preparation without further purification. Re-crystallization of a small sample of the 2,4,6-trimethylpyryKurri perchlorate from a seven-fold amount of hot water, containing a few drops of perchloric add and some carbon blade, gives colorless crystals, m.p. 245-247° dec. However, the recrystallization of larger amounts in this way presents some hazard and is not recommended. Concentration of filtrates should be avoided (see Note 4). 

Bei 1 -Isopropyl- 5-methylazulen stellten F. Jung und Mitarbeiter (73) eine ausgepragte Darmwirksamkeit im Sinne einer Peristaltikforderung fest, die auch bei Guajazulen (28) beobachtet werden konnte. 

Methylazulen- 5-carbon-saure 170—171° violettgraue Kri-stalle TNB. 157—158° S-Benzylthiuronium-salz 167,5—168° (102) ... 

Methylazulen-6-carbon- saure 250—251° griine Nadeln Semi-TNB. 217—218° S-Benzylthiuronium-salz 181—182° (102) ... 

In calculations on proton addition complexes of azulene and methyl-azulenes by means of the HMO method, Heilbronner and Simonetta (1952) took the effect of methyl groups into aecount by adjustment of the a and j8 values, as had already been done by PuUmann and collaborators (1950) in calculating the spectra of the methylazulenes. These calculations correctly reproduce the effeet of a methyl group on the basicity of azulene. In contrast to the ease of naphthalene, the position of addition of the proton remains independent of the position of the methyl group ... 

Compound 36, X = Cl, leads to l,6-methano-[10]annulene (37), 4-methylazulene (38) and 39 on dehydrohalogenation with strong base, in the same way, 36, X = Br, leads to 37, a reduced amount of 38 and the monobromide 40". Each of the products arises by a distinct reaction pathway, though a 1,4-elimination to leading 41 is thought to be involved in the case of 37. 

Saturated groups such as the methyl group exert a small secondary effect which is, in general, bathochromic (some exceptions in methylazulenes). This effect is caused by the electron-donating properties of the alkyl groups, which are less electrophilic than hydrogen (see also p. 264). In the series methane, ethane, hexane the absorption band shifts from 1250 A to 1350 A and to 1530 A. This shift is exclusively due to differences in the resonance possibilities of the molecule in the very highly excited upper level where one electron is nearly ionized. 

Xu et al. [44] reported the microwave assisted synthesis and antifungal activity of 2,5-disubstituted-l,3,4-oxadiazoles containing azulene moiety. The 5-aryl-2-(3-methylazulen-l-yl)-l,3,4-oxadiazoles (Lv) were obtained by the microwave... 

In the same manner as acetophenones some other methyl compounds can also be transformed with salts (8) to the corresponding phenyl compounds. 2-Methyl-chromone (19), and likewise 2,6-dimethyl-4-pyrone by double conversion, lead to flavone (20) and 2,6-diphenyl-4-pyrone respectively36. Even the very weak acid methyl groups in methylphenylsulphone and in 6-methylazulene (21) may be smoothly transformed. A 100% excess of (<5) and added sodium methoxide in this... 

Although azulene-l-acetonitrile (146) and 6-methylazulene (121 a) can be condensed with (44) to corresponding colored aminonitriles, they fail to cyclize to azulenoazulenes as hoped. 

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