Aminobenzenethiol

Amino-77/-dibenz[/),t/]azepin-7-ones, e.g. 7, prepared either by successive bromination, aminodebromination, and dehydrogenation of 5-tosyl-5A/-dihydro 7>,t/]azepin-7(6//)-ones, or by the oxidation of 6-ethoxy-6,7-dihydro-5//-dibenz 7>,r/]azepincs with lead(IV) acetate followed by aminodemethoxylation, on treatment with a bidentate nucleophile (e.g.. benzene-1,2-diamine or 2-aminobenzenethiol) yield the pentacyclic systems 8 and 9, respectively.27... 

The reaction of diketene with 2-aminobenzenethiol was reported to yield 4-methyl-l,5-benzo-thiazepin-2(3//)-one (1A),52 which exists in tautomeric equilibrium with the hydroxy form IB.53... 

Aminobenzenethiol undergoes a Michael reaction with methyl 5,5-dimethyl-2-oxo-2,5-dihyd-rofuran-3-carboXylate (4) to give the adduct 5, which cyclizes to the tricyclic benzothiazepinone 6 under the influence of triethylamine hydrochloride.426... 

An unexpected cleavage has also been described for the coordinated Schiff base of 2-aminobenzenethiol in alkaline solution. Instead of neutral complexes of the Schiff bases, anionic 1 2 Tc(V) oxo complexes are formed the donor groups are now the thiol and generated amino groups [206]. 

NIR region (see Chapter 9.13), complexes of 1,2-dithiolene (DT) and related ligands have attracted considerable attention for their (largely cubic) NLO properties. The complex (156) (a.k.a. BDN) is a highly photochemically stable, saturable absorber and has hence found extensive applications in laser Q-switching. The cubic NLO properties of (156) have been studied by DFWM148,403-407 and more recently, Z-scan.408 Time-resolved DFWM has been applied to square planar Co, Ni, Cu, or Pt complexes of 1,2-benzenedithiolate (BDT) or 1,2-aminobenzenethiolate ligands by Lindle and co-workers.409,410... 

The most common method for the preparation of 1,2,3-benzothiadiazoles is the diazotization of 2-aminobenzenethiol. This method was discussed and exemplified in CHEC-II(1996). The method has been extended in recent years to include heterocyclic derivatives. The 2-aminothiophene 79 can be converted into the thienothiadiazole 82 on treatment with sodium nitrite in HC1 but in poor yield (16%). The bis(BOC)-protected derivative 80 or the mono(BOC)-protected derivative 81 when reacted under similar conditions afford product 82 in much higher yields (BOC = /-butoxycarbonyl Scheme 9). The increase in yield is explained in terms of hard and soft electrophilic character. The intermediate in the BOC-protected examples has a soft character allowing attack by sulfur to proceed more easily <1999JHC761>. 

When aqueous ethanolic solutions of 2-aminobenzenethiol (abt) and chromium(II) chloride are mixed, the green suspension first formed turns light blue within one hour. The blue product... 

Generally, two strong tt bases are required to stabilize Os(VI), hence its chemistry is dominated by octahedral complexes with the trans-dioxo moiety. However, a complex containing three doubly depro-tonated 2-aminobenzenethiol ligands, [Os(abt)3], has been characterized (24). In addition, a growing number of five-coordinate complexes... 

The buff-coloured bis chelate formed by 2-aminobenzenethiol (334) can be oxidized in alkaline solution to a blue-coloured complex of nickel(II) which contains the ligand in an oxidized form (Scheme 34).2422,2462 Complex (334) reacts with Mel in acetone affording the six-coordinate complex NiL containing the S-methylated ligand.2452... 

The initial reactions of this type were used to produce copper(II) complexes of salicylaldimines, where additional coordination support is provided by the phenolic oxygen atoms (equation l).10 11 Similar use can be made of pyridine-2-carbaldehyde in the formation of imine chelates. For example, the combination of pyridine-2-carbaldehyde and 2-aminobenzenethiol in the presence of metal ions yields tridentate complexes (Scheme l).12 If the reaction is carried out in the absence of the metal ion, the benzothiazolidine (1) is isolated. Thus the metal ion is essential for the formation of the imine product in this case. Metal complexes of the related tridentate ligands (2),13 (3),14 (4)li and (5)16 can be prepared similarly. 

Before completing the discussion of linear chelate systems related to compounds (17), it is noteworthy that a range of quinquedentate chelates can be obtained by means of condensation of the dialdehyde with 4-aminoethylimidazole (equation 5)45 and 2-aminobenzenethiol (Scheme 3).46 47 In the latter case, the metal exerts an effect on the equilibrium between the cyclic and diimine structures. 

Keywords 2-aminobenzenethiol, /i-kctocstcr, /Ldiketone, basic alumina, micro-wave irradiation, 4H-1,4-benzothiazin... 

Appropriate 2-aminobenzenethiol 1 (2 mmol) and /(-kctocstcr or /(-di ketone 2 (2 mmol) were introduced in a beaker (100 mL) and dissolved in chloroform (5 mL). Basic alumina (S.D. Fine Chemicals Pvt. Ltd., 5 g) was then added and swirled for a while followed by removal of solvent under gentle vacuum. The dry powder thus obtained was irradiated in a microwave oven at power output of 520 W for an appropriate time (monitored by TLC). The inorganic support (which can be reused 3-4 times without any loss of activity) was separated by filtration after eluting the product with acetone (5x20 mL). The filtrate was dried over sodium sulfate and the product, obtained after removal of solvent, was recrystallized from methanol as colored crystals in good yields. 

An assortment of other mixed donor ligand complexes of oxo-rhenium(V) are also known but these are not particularly well characterized and, generally speaking, their structures are uncertain. These data include the complexation of Rev by such ligands as 2-aminobenzenethiol,372 thiosemi-carbazides,373 l-methyl-2-mercaptoimidazole374 and 2-mercaptobenzothiazole.345 Recently, the pyr-azolylborate complex ReOCl2[HB(pz)3] has been prepared.572... 

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