Isatin reaction with diazomethane

The most frequently reported oxidation reaction of isatins is the oxidation with alkaline hydrogen peroxide to give anthranilic acids. This procedure has been both as a proof of structure of isatins and as a method of synthesis of anthranilic acids. The oxidation has been applied to alkyl 8"10 11 23 33>38-40>46 49>50>118halo n.18.35.36-38-40.47.10 .11 . 119,136,240 alkoxy,26,a8 39,47,75.io7,ii8,i36 trifluoromethyl,33,38,137 and nitro8,120,217 isatins. Use of N-substituted isatins led to N-substituted anthranilic acids.66,71,125,158,169,243 In the oxidation of 5-bromo-l-(y-carbethoxypropyl)-7-ethylisatin, 60 was isolated after treatment with ethanol and acid.11 Oxidation of isatin derivatives 61 led, after treatment with diazomethane, to the acridine derivatives 62.67 Application of this oxidation method to 7-hydroxyisatins gave rise to benzoxazo-lones (63).2,41... 

Isatin and N-substituted isatins react with diazoalkanes to give a variety of products. Simple adducts of the type 181 have been obtained when N-substituted isatins react with methanol-free diazomethane and are reported to lose nitrogen and react further in methanol.505 Such adducts have also been reported in other cases.196,506-508 Ring enlargement to quinolones (182 R is the R in RCHN2 and R is usually OH but sometimes OMe from diazomethane) frequently occurs.123,196,506-509 Finally, epoxides of the type 183 have sometimes been obtained from the diazoalkane reaction.123,249,507,510 With diphenyldiazomethane, ring expansion does not take place and 183 (R = Ph) is the only... 

Thianaphtheneqiiinone - (109) and diazomethane give a different reaction from that found with isatin, A -methylisatin and coumarandione. In as far as crystalline products could be isolated, the ring expansion occurs here between the sulfur and the carbonyl group in the 2-position. Depending on the solvent, there are formed 3-hydroxy-thiochromone (110), its 0-methyl derivative (111), or (presumably by attack on the 3-keto group of the tautomeric 3,4-diketo form of 110), 3,3 -epoxy-3-methylthiochromone (108). 

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