Thiazolo indoles

The methine chain is obtained by reacting ethyl o-formate (method A ) or ethylisoformanilide (method B) with a bis quaternary salt of bis-(2-thiazolyllbutane. Concerning dyes with fused thiazolo rings pyrrolo[2. lb]thiazoIe. thiazolo[2.3a]indole. thiazolo[2.3c]1.4-benzox-azine. the a carbon directly linked to the carbon 2 of the thiazoJe ring is also responsible for the classical syntheses giving trimethine or penta-methine dyes. 

Thiazolo] 2,3fl) indole, in synthesis of chain-bridged thiazolocyanines, 58 Thiazolosemicyanines, tables of, 119 Thiazolostyryl dyes, tables of, 107 Thieno [ 2,3d ] thiazole. 30 2-[2-Thienyl) selenazole, formylation in 5-position, 239... 

Cyclocondensation of isatin hydrazones 620 with 621 in strong acid gave thiazolo[3, 4 2,3][l,2,4]triazino[5,6-6]indoles 622, which underwent conventional reaction with 2-methyl-3-ethylbenzothiazolium perchlorate 623 to form unsymmetrical cyanines 624 (83URP1054350 85KGS211). The spectral properties of a series of polymethine dyes were examined (88KGS1547). 

Fused 2-substituted thiazoles are most conveniently synthesized by condensing an a-haloketone with a thiono-amide. Thiazolo[5,4- ]indoles 118 were prepared via the Gunch reaction using bromindoxyl 117 and primary thionoamides of phenylacetic acid, phenylpropionic acid, and cyanoacetic acid affording the products as either... 

P. Tardieu, R. Dubest, J. Aubard, A. Kellmann, F. Tfibel, A. Samat, and R. Guglielmetti, Synthesis Mid photochromic characteristics of l,3-dihydrospiro[2fir-indole-2,3 -[3 /7]pyrimido[5,4-/7[l,4]benzoxa-zines] and 1,3-dihydrospiro[2/f-indole-2,7 -[7/f]thiazolo[5,4-/][l,4]benzoxazines], Helv. Chim. 

A straightforward synthesis of this system involves the addition of mercaptoacetic acid or its ester across the double bond of the azomethine linkage. 3,3-Dimethyl-2-ethoxycarbonyl-l-indolene (245) reacts with appropriate mercaptocaids (or esters) to give the corresponding thiazolo[3,2- ]indol-3(2//)-ones (246) (74LA206) (Scheme 60). 

A synthesis of thiazolo[5,4-e]indoles from 5-aminoindoles was reported <05TL2865>. The key step was an NBS-mediated regioselective annulation of a 5-thiourea-substituted indole. 

Synthesis of thiazolo[3, 272,3]ll,2,4]triazino[5,6-i)]indoles has been reported <04IJC(B)1585>. Different functionalizations of l,2,4-triazino[5,6-f>]indoles have been carried out <04JCR(S)183>. Reaction of 3-diazopyrazolo[3,4-clpyridazine with reactive methylene compounds yielded condensed 1,2,4-triazine derivatives <04H1143>. 

Thiazolo[ 3,2-z indoles C3NS-C4N-C6. Treatment of the indole derivative (167) with thionyl chloride unexpectedly gave the thiazolo[3,2-a]indol-3(2//)-one (168), for which a possible mechanism has been suggested. ... 

A mixture of 2.7 g 8-(methylsulfanyl)-6,8-dihydro-7 f-[l,3]thiazolo[5,4-e]indol-7-one (11 mmol), 3.0 g activated zinc, 41 mL acetic acid, and 41 mL THF was heated at 60-65°C for 3.5 h. The gray-green mixture was filtered through a sintered glass funnel containing a 0.5-inch pad of Celite, and the pad was washed with 40 mL hot THF/acetic acid (1 1). Water (200 mL) was added to the filtrate, and the pale yellow mixture was stirred for 10 min. The resulting solid was isolated by filtration, washed with 25 mL water, and dried under vacuum at 70°C to furnish 1.05 g 6,8-dihydro-7Ff-[l,3]thiazolo[5,4-e]indol-7-one as a pale yellow solid, in a yield of 49%. 

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