Gatterman reagent

When unsubstituted, C-5 reacts with electrophilic reagents. Thus phosphorus pentachloride chlorinates the ring (36, 235). A hydroxy group in the 2-position activates the ring towards this reaction. 4-Methylthiazole does not react with bromine in chloroform (201, 236), whereas under the same conditions the 2-hydroxy analog reacts (55. 237-239. 557). Activation of C-5 works also for sulfonation (201. 236), nitration (201. 236. 237), Friede 1-Crafts reactions (201, 236, 237, 240-242), and acylation (243). However, iodination fails (201. 236). and the Gatterman or Reimer-Tieman reactions yield only small amounts of 4-methyl-5-carboxy-A-4-thiazoline-2-one. Recent kinetic investigations show that 2-thiazolones are nitrated via a free base mechanism. A 2-oxo substituent increases the rate of nitration at the 5-position by a factor of 9 log... 

Arenes can be formylated by generating the active intermediate, CfeC—H, from reagents other than HCOCl. The Gatterman-Koch reaction uses a high-pressure gaseous mixture of CO and HCl. 

Gattermann Reaction (Gatterman Aldehyde Synthesis) /Gattermann Reagent... 

Triazine may be used in the Gatterman aldehyde synthesis in place of hydrogen cyanide (Scheme 15) (67AG(E)940>. On treatment of 1,3,5-triazine with aryl Grignard reagents, the aryl aldehyde is formed (Scheme 16) (63MI22000). 

The reaction apparently involves free-radical mechanism, but arylcopper compounds take a part, at least under certain reaction conditions, as clearly demonstrated through Cohen s concise results [99,100]. The reaction was discovered as a side-reaction during probes of the Gatterman synthesis of aryl halides from diazonium salts and copper(l) halides. Probably the most known example is very practical preparation of diphenic acid (57) starting from anthranilic acid (58). The reaction is usually conducted by adding an aqueous diazotized anthranilic acid solution (diazonium salt 59) to the copper(l) reagent, in situ obtained by reduction of CUSO4 with an equimolar amount of hydroxylaminc in aqueous sodium hydroxide solution, to produce diphenic acid with a 80-90% yield [99,100], Scheme 25. 

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