Thiazole tetrahydro

Thiazole, 4-methyl-5-(2-hydroxyethyl)-in thiamine biosynthesis, 1, 97 Thiazole, 4-methyl-2-methylami nosynthesis, 6, 300 Thiazole, 4-methyl-2-phenyl-alkylation, 6, 256 mercuration, 6, 256 Thiazole, 2-(methylthio)-methylation, 6, 290 thermodynamic values, 6, 291 Thiazole, 2-methylthio-5-phenyl-synthesis, 5, 153 Thiazole, 4-methyl-5-vinyl-occurrence, 6, 327 Thiazole, 2-phenyl-acetylation, 6, 270-271 Conformation, 6, 237 synthesis, 5, 113, 6, 306 Thiazole, 4-phenyl-conformation, 6, 237 2,5-disubstituted synthesis, 6, 304 Thiazole, 5-phenyl-conformation, 6, 237 Thiazole, 2-phenyl-5-triphenylmethyl-synthesis, 6, 265 Thiazole, 2-(2-pyridyl)-metal complexes, 5, 51 6, 253 Thiazole, 4-(2-pyridyl)-metal complexes, S, 51 6, 253 Thiazole, tetrahydro-ring cleavage, 5, 80 Thiazole, 2,4,5-trimethyl-occurrence, 6, 327... 

Thiazolidine, 2,5-Dihydro- 1,3-thiazole, Tetrahydro-l,3-thiazine und 5,6-Dihydro- 1,3-thiazine werden durch Lithiumalanat6,7 und meist auch durch Natriumboranat7 zu den (w-Mercapto-aminen aufgespalten. 1,3-Thiazolidine lassen sich mit einem Lithi-umalanat-OberschuB ahnlich den 4,5-Dihydro-1,3-oxathiolanen zu Athylaminen wei-terreduzieren7,8 ... 

Thiazole, tetrahydro- 1,3,4-Thiadiazolidine, 2,2-dimethyl-4-phenyl- 248.4 — 245.9 226.9 74CR(ai279)717... 

Rhodacyanines possess two chromophoric systems. They are at the same time neutrocyanine derivatives, which involves position 5 of the ketomethylene, and methine cyanine, which involves position 2. Following lUPAC s standard nomenclature rules, structure 7 is named 3-ethyl-4-phenyl-2- 4-oxo-3-ethyl-5-[2-(3-ethy]-2,3-dihydro-benzo-l,3-thiazo-lylidene)ethylidene]-tetrahydro-l,3-thiazolylidene-methyl -1.3-thiazolium iodide (Scheme 5). It implies that the 4-phenyl thiazole ring having the... 

These compounds usually show the typical reactions of their aliphatic analogues. 1,3-Dioxolanes (316), tetrahydroimidazoles (313), tetrahydrooxazoles (314) and tetrahydro-thiazoles ( 317) are somewhat less easily ring-cleaved than their acyclic analogues (cf. previous section), but their properties are otherwise similar. 

Imidazo[2,l-6]thiazole, 2-phenyl-azo dyes from, 1, 325-326 Imidazo[2,l-6]thiazole, 2,3,5,6-tetrahydro-synthesis, 6, 993 Imidazo[2,l-6]thiazole,... 

Vilsmeier-Haack formylation of 2-(4-methyl-l-piperazinyl)-4//-pyrido-[l,2-n]pyrimidin-4-one with a mixture of POCI3 and DMF at 95°C gave a 3-formyl derivative (93FES1225) while ethyl 4-oxo-6,7,8, 9-tetrahydro-4//-pyrido[l,2-n]pyrimidine-2-acetate at 50 °C yielded a 9-dimethylaminomethylene-3-formyl derivative (01MI4). 3-Formyl-2-hydroxy-8-[2-(4-isopropyl-l,3-thiazol-2-yl)-l-ethenyl]-4//-pyrido[l,2-n]pyri-midin-4-one was obtained from the 3-unsubstituted derivative with oxalyl chloride-DMF reagent in CH2CI2 at room temperature for 3h (OlMIPl). 

Chemical Name L-2,3,5,6-Tetrahydro-6-phenylimidazo[2,1-b]thiazole hydrochloride Common Name L-Tetramisole hydrochloride Structural Formula ... 

Pyrrolo[l,2-A]thiazoles are aromatic compounds but only one fully conjugated derivative has been described. A few dihydro and tetrahydro derivatives have been prepared, mainly in connection with search for biologically active drugs. Saturated compounds are also known. 

With a-trifluoromethyl oxiranes. cr-Opening oxirane ring of the 2-benzenesulfonyl-2-trifluoromethyl-oxirane 374 by nucleophilic attack with 2-aminothiazole followed by Mannich cyclocondensation of the intermediate trifluoroketone gave the 6-trifluoromethyl-imidazo[2,l-A]thiazole 375 (Equation 168) <1995JFC83>. The same transformation was conducted with 2-isopropoxy-2-trifluoromethyl-3-phenyloxirane 376 and 2-imidazolidinethione and furnished the 2,3,5,6-tetrahydro-imidazo[2,l-A]thiazole 377 in good yield (Equation 169) <1999RJ0741>. 

With ketones. The 17/-imidazole-2(377)-thione 378 and 2-mercaptobenzoimidazole 380 reacted separately with cycloheptanone to form the tetrahydro-imidazo[2,l- ]thiazole 379 and the dihydro-thiazolo[3,2-tf]benzimidazole 381, respectively (Equations 170 and 171) <2000JHC943, 2001RJ0564>. 

With a.-bromo Michael acceptors. Condensation reaction of 2-aminothiazoline with a-bromo-a,/3-unsaturated compounds, commercially available or generated in situ, provided a route to functionalized 2,3,5,6-tetrahydro-imidazo[2,l-3]thiazoles 411 (Equation 187) <1994H(38)2593>. 

Lewis acid SnCLj-assisted reaction between the l,3-thiazole-5-thione 434 and /ra r-2,3-dimethyloxirane led to the m 4,5-dimethyl-l,3-oxathiolane 435 The same Lewis acid enabled a second addition of /ra/ -2,3-dimcthyloxirane onto the C—N bond of the 1,3-thiazole ting of 434, leading to the formation of the tetrahydro-2//-thiazolo[2,3- ]-oxazole adduct 436 (Equation 200) <2000HCA3163>. Condensation of 2,4-dinitroimidazole, 8-bromotheophylline, and 8-bromoadenine with substituted methyloxiranes involved sequential A -alkylation-r/wo-substitution and furnished a series of 2,3-dihydro-imidazo[2,l- ]oxazole derivatives 437, 438, and 439 (Equations 201-203) <2000CCC1126, 2000EJ03489, 2005TL3561, 2004JHC51>. 

In NRPS, the cyclization domain catalyzes cyclization of the side-chain nucleophile from a dipeptide moiety such as AA-Ser or AA-Cys (AA = amino acids) to form a tetrahedral intermediate, followed by dehydration to form oxazolines and thiazolines (Scheme 7.1) [20]. The synthesis of a 2-methyl oxazoline from threonine follows a similar mechanism. Once a heterocycle is formed, it can be further modified by reductase to form tetrahydro thiazolidine in the case of pyochelin biosynthesis. Conversely, oxidation of the dehydroheterocycles lead to heteroaro-mahc thiazoles or oxazoles as in the case of epothilone D (Figure 7.2) [21]. 

Table VII lists biological activities that have been found for some aromatic azapentalenes. Among these, imidazo[2,l-6]thiazoles have probably been most studied, and this has partly followed the discovery454 that a tetrahydro derivative 480 possessed marked anthelmintic activity. This compound is marketed as Tetramisole (or as the L-isomer, Levamisole) and is at present one of the most effective agents for the treatment of roundworm infestations. Anthelmintic activity has been found for aromatic imidazo[2,l-6]thiazoles (Table VII), and it has been suggested331 that a 6-aryl substituent is necessary for activity in this series.

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