With 2-aminothiazoles

Acetic anhydride and sodium acetate when heated with 2-aminothiazole for 2 hr give 2-acetamidothiazole 105 (Scheme 72) (243). 

Maleic anhydride condenses with 2-aminothiazole-4-carboxylic acid giving the raaleimide 107 (269) another report claims, however, that the reaction of 2-amino-4-methylthiazole with this anhydride gives the N-substituted maleamic acid (108) (Scheme 73) (270). 

The reaction of propiolic acid or its esters with 2-aminothiazole yields 7H-thiazolo[3.2o]pyTimidine 7-one (109) (Scheme 74) (273), The reaction probably proceeds by initial nucleophilic attack of 2-aminothiazole on the sp C followed by intramolecular addition of ring nitrogen to spC. 

Esters react with 2-aminothiazole and derivatives in the presence of catalysts the reaction between 3-ketoesters and 2-aminothiazole is. for example, realized in acidic medium (278. 279) and yields 2-aceto-acetamidothiazole (114) (Scheme 771. No secondary products are... 

The 2-pyridyIformimidate (122) reacts with 2-aminothiazole. yielding 123 (Scheme 81) (283). 

Formamidinoyl isothiocyanates (157) combine with 2-aminothiazoles the ring nitrogen attacks the spC part of the electrophilic reagent (312) further reaction then yields aza-condensed thiazolo-s-triazines (158) (Scheme 99) (313). Mesoionic S-alkvlthiazolo[3.2-fl]-i-tria2ine-5,7-diones (159) are obtained when 2-alkylaminothiazoles react with phenoxycar-bonyl isocyanate (304). 

Condensation of (chloroformyl)-sulfur chloride with 2-aminOthiazole gives a product (170) whose structure was established by X-ray analysis (Scheme 108) (352-354). 

These compounds may be obtained by the Hantszch heterocyciization method (see Chapter II, Section 11.3). A -widely used two-step preparative method (Scheme 195) involves initial reaction of a 2-amiriothiazole -with 339 in pyridine (631-638) in aqueous sodium carbonate (639) or by fusion without solvent (640). The formed 340 is then hydrolyzed in acidic (641, 642, 1593) or alkaline medium (643-646). The direct reaction of 342 (Scheme 196) -with 2-aminothiazoles is less common and takes place in... 

A heterocyclic ring may be used in place of one of the benzene rings without loss of biologic activity. The first step in the synthesis of such an agent starts by Friedel-Crafts-like acylation rather than displacement. Thus, reaction of sulfenyl chloride, 222, with 2-aminothiazole (223) in the presence of acetic anhydride affords the sulfide, 224. The amine is then protected as the amide (225). Oxidation with hydrogen peroxide leads to the corresponding sulfone (226) hydrolysis followed by reduction of the nitro group then affords thiazosulfone (227). ... 

Reactions of 2-methylthio-4-oxo-3-phcnylpyrido[2,1 -/][l,2,4]triazinium iodide 73 with nucleophiles were carried out to obtain mesomeric betaines. Nucleophilic displacement of the methylthio group of 73 with 2-aminothiazole or 2-amino-l,3,4-thiadiazole afforded 74 (Equation 1) <1996T11349>. 

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>. 

Dinitrobenzofuroxan (DNBF) is known as a superelectrophile due to its high reactivity both as an electrophile and in its pericyclic addition reactions. NMR studies show that reaction with 2-aminothiazole and its 4-methyl derivative yield anionic carbon-bonded adducts such as (11) by reaction at the 5-position, whereas the 4,5-dimethyl derivative reacts via the exocyclic amino group. Kinetic studies of the first two compounds, both in acetonitrile and in 70 30 (v/v) water-DMSO, have been used to assess their carbon nucleophilicities and place them on the Mayr nucleophilicity scale.55 In a related study, the nucleophilic reactivity, in acetonitrile, of a series of indoles with both DNBF and with benzhydryl cations have been compared and used to determine nucleophilicity parameters for the indoles.56... 

Isopropanol, with aminothiazoles, 47 Isothiocyanates, 58 with 2-aminobenzothiazoles, 59 with 2-aminothiazoles, 65 with azirines, 15... 

Sulfonimidothiazolines, 317, 318 Sulfonyl halides, with 2-aminothiazoles, 69 Sulfur (Sg), in synthesis of, A-4-thiazoline-2-thione, 373 Sulfur compounds, 69 Sulfuric acid, with alcohols, 38, 47, 80, 90 in bromination, 77 dealkylation by, 39 deuterated, 92 diazotization with, 66 in nitrations, 72 rearrangements in, 73, 113 Sulfuryl chloride, 432 Symbiotic behavior, see HSAB theory Symmetry. C2v and C2p, 120 Synthetic fibers, 154... 

Chlorothioformic phenyl ester (103) reacts under mild conditions with 2-aminothiazole to give 104 (Scheme 71) (266). 

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