Benzothiadiazole structure

In parallel, Mullen and co-workers [106] and Zhu et al. [107] reported new copolymers based on an alternating cyclopentadithiophene-benzothiadiazole structure (entries 33 and 34, Table 3.1). These donor-acceptor polymers have shown excellent OFET and OPV device characteristics. The octadecyl... 

The molecular structure of both 1,2,5-thiadiazole 1 and 2,1,3-benzothiadiazole 2 were described in CHEC(1984) <1984CHEC(6)513>. Since the publication of CHEC-II(1996) <1996CHEC-II(4)355>, a large number of single crystal X-ray structures have been published for various monocyclic, fused, and related thiadiazoles. 

Fig. 4 Chemical structure of a family of PAEs developed independently by the groups of Bunz [57] and Yamamoto [52]. The polymers feature electron-poor 2,1,3-benzothiadiazole and electron-rich 2,5-dialkoxybenzene moieties in an alternating fashion...

The product of the reaction between bis(S-aminodithionitrito)nickel(ii), NH3, HCHO, and MeOH has the structure (179). Complexes of 2,1,3-benzothiadiazole, 2,1,3-benzoselenadiazole, isothiazole, 2-methylbenzo-... 

The x-ray structure of 1,2,3-benzothiadiazole complexed with AsFj (9) shows that the arsenic binds at N3 <86CJC849>. When Fe2(CO)9 reacted with (10) one of the products was (11), for which x-ray diffraction revealed the unusual feature of the nitrogen and sulfur joined by an iron atom (Equation (2)) <890M296l>. The mesoionic structure (13) is formed by methylation of 1,2,3-thiadiazole (12). It can best be described as a resonance hybrid of structures (13a) and (13b) and this was corroborated by the x-ray data (Scheme 1) <91jhC477>. 

The naphthalene-like, aromatic structure of 1,2,3-benzothiadiazole imparts stability to the system which survives exposure to 20% potassium hydroxide at 150°C or 27% sulfuric acid at 200°C. It is not oxidized by potassium permanganate, potassium ferricyanide, chromic acid and dilute nitric acid . Electrophilic substitution occurs in the benzo ring, predominantly at the 4-position. Chlorine in the 6-position is displaced by a variety of nucleophiles <75SST670>. 

Fig. 3 TFB F8BT structures (slightly tilted forward) showing two different orientations of the polymer constituents. In each, the FBT (top chain) consists of 3 fluorene (F) units and 3 benzothiadiazole (BT) units while the TFB (bottom chain) consists of 3 F units and 2 triarylamine (TB) units. These co-monomer units are labeled with indices. The eclipsed orientation (panel a) has the middle F units (F12 and F22) of both chains 7r-stacked while the staggered orientation (panel b) has the middle BT of FBT (BT2) and the middle F of TFB (F22) 7r-stacked, see Eqs. (l)-(2). Reprinted with permission from Ref. [41]. Copyright 2007, American Institute of Physics.

Wittig and Hoffmann (1961) obtained benzyne from a compound of somewhat similar structure, 1,2,3-benzothiadiazole 1,1-dioxide, at 0°. 

An X-ray diffraction study, when possible, is the ultimate structure proof. Bond lengths are known for certainty to 0.001 A and bond angles to 0. T. Although the literature abounds with X-ray data for heterocycles there are no X-ray spectra for a 4,5-dialkyl substituted, nonionic 1,2,3-thiadiazole. However, an X-ray structure has been reported for a 1,2,3-benzothiadiazole (5), and the bond lengths and bond angles are listed in Table 1 (79AX(B)3114>. 

In some cases, single component representation is unsuitable. Figure 14.4 shows a simple sequence of structure standardization executed by a compound registration system including structure correction of the benzothiadiazole, salt/addend stripping and neutralization to depict the canonical parent structure representation. Any alternative salt form or structure representation of this compound will be standardized into the same parent structure and thus recognized as identical (at that level). 

Freis and Reitz, using potassium nitrate in sulfuric acid on heating, have obtained two mononitrated products and assigned to them the structures of 4- and 7-nitro isomers [212], Later, this structure has been proved by a secondary synthesis [213], and the other isomer turned out to be 5-nitro-l,2,3-benzothiadiazole [214, 215], On a more careful study all three isomers were found among the reaction products, as shown in Scheme 2.18 [216],... 

The synthesis, structure, and superoxide dismutase mimetic activity in vitro and the protection against reactive oxygen species in vivo of mononuclear copper complexes with 2-(4-methylphenylsulfamoyl)-6-nitrobenzothiazole have been reported [602], Like 1,2,3-benzoxadiazoles, nitroderivatives of 1,2,3-benzothiadiazoles were obtained on diazotization of the corresponding or/Zzo-aminothiophcnolcs [213, 218, 583], The initial or/Zzo-thiophcnols for this reaction were synthesized by nucleophilic substitution of halogen in ort/zo-halogenoanilines. It turned out that 4-nitro- and... 

A large body of information on the methods of synthesis, application, structure, and properties of all known five-membered nitroazoles - pyrazoles, imidazoles, triazoles, tetrazoles, oxazoles, isoxazoles, oxadiazoles, thiazoles, isothiazoles, thiadiazoles, selenazoles, selenadiazoles, and their benzo analogs - indazoles, benzimidazoles, benzoxazoles, benzisoxazoles, benzoxadiazoles, benzothiazoles, benzoisothiazoles, benzothiadiazoles, benzotriazoles, benzoselenazoles, and ben-zoselenadiazoles has been systematized, summarized, and critically discussed in this monograph. 

Other sulfur-bonding adducts of the Rh4+ core have been reported for thiols,338 thioethers,305,335 alkyl sulfides,291 293,336 thiourea derivatives,339-341 and benzothiadiazole.342 Reaction ofNCX- (X = S, Se) with [Rh2(02CMe)4] is reported to lead to the anionic 1 1 adduct [Rh2(02CMe)4(NCX)]-, 343 A structure has not been reported, but based on analytical data, one-dimensional chains with bridging NCX- anions were proposed.343... 

Benzoselenadiazole (128) behaves as a heterodiene toward dimethyl acetylenedicarboxylate, with which it gives the quinoxaline 124 and selenium. But 128 reacts differently with benzyne (generated from 4 or from 9) to give the 1,2-benzisoselenazole derivative 132 (88%) and a small amount of a cis,trans stereoisomer of 132.82 The analogous adduct 131 is obtained in lower yield from benzyne and 2,1,3-benzothiadiazole (127). The structure of these benzyne adducts is strikingly reminiscent of 135, which is obtained from a photochemical addition of dimethyl acetylenedicarboxylate to 126 via a nitrile oxide intermediate.84 However, for reasons given elsewhere,82 a nitrile selenide is unlikely to be an intermediate in the formation of 132, which is better explained by the mechanism outlined in Scheme 16. As in the case of thiophen (Section V,B), this is a 1,3-cycloaddition (in one or two steps) of benzyne to the heterocycle, enabled by the use of d orbitals on the sulfur or selenium atom. 

Fig. 1. Salicylic acid and its synthetic functional analogs. Salicylic acid and its derivative acetyl salicylic acid (aspirin) induce expression of the PR genes and enhance resistance to pathogens. The two synthetic compounds, 2,6-dichloroisonicotinic acid (INA) and benzothiadiazole S-methyl ester (BTH) show structural similarities to salicylic acid and like salicylic acid induce expression of the PR genes and enhance resistance to pathogens.

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