Indole-3-acetic acid continued

To 21.6 g phenylhydrazine dissolved in 300 ml 0.3N sulfuric acid, add 9.8 g concentrated sulfuric acid. Add dropwise with stirring and heating at 100°, 11.6 g methyl-beta-formyl-propionate in 300 ml 0.3 N sulfuric acid and continue heating six hours to get 14 g indole-3-acetic acid. Convert to the dialkyltryptamine as already described. 

Indole-3-Acetic Acid. Dissolve 21.6 g of phenylhydrazine in 300 ml 0.3 N sulfuric acid. To this solution add 9.8 g of coned sulfuric acid. With stirring and heating to 100°, add dropwise 11.6 g of methyl-beta-formyl-propionate in 300 ml of 0.3 N sulfuric acid. Continue the heating and gentle stirring for 6 hours to get about 14 g of indole-3-acetic acid. This is from CA, 72, 66815 (1970). 

SYNTHESIS To a 50 °C warmed mixture of 60 mL glacial acetic acid and IS mL acetic anhydride, there was added 66 g crystalline ammonium acetate, and stirring continued until solution was complete (20 min). To this there was added a solution of 87 g indole 3-carboxaldehyde (see under a-MT for preparation) and 300 mL nitropropane in 360 mL acetic acid. The mixture was held at reflux temperature for... 

A (Alternative) JCS 2834(1962). 4.8 g Mg turnings, 32 g ethyl iodide in 20 ml dry anisole. Cool to 0° and add dropwise 15.6 g indole in 20 ml anisole. Stir one-half hour at 20° eool to 0° and treat with 20 ml prop-2-yny 1-bromide in 10 ml anisole over 20 minutes. Continue stirring one hour at 0° and let stand at room temperature twelve hours. Cool to 0°, add 100 ml ether, 200 ml water, 12 ml glacial acetic acid, 100 ml water, and extract with 5X25 ml ether. Wash with NaHCOs and dry, evaporate in vacuum the extract to get 8 g oily material which precipitates on standing in refrigerator. Add V2g HgS04 to 100 ml 2N sulfuric acid stir and heat on steam bath and add 15 g of the precipitate in 100 ml ethanol. Stir and heat two hours and pour into water. Basify with NaHCOs to get 3 g (I) (recry stallize-benzene). 

Despite these other reduction methods—notably the excellent Cava variation [16]—the traditional iron/acetic acid and catalytic hydrogenation conditions continue to be preferred. Eor example, the indoles 9-22 were prepared using the iron/acetic acid conditions (Scheme 3 [19-32]). Indole 10 was converted to 5-hydroxytryptamine-4,7-dione, the neurocytotoxic product of 5,7-dihydroxy-tryptamine [20], and indoles 11 and 12 were recruited for... 

Alkaloids with polycyclic skdetal frameworks are, when it comes to their synthesis, excellent candidates for RCM. Illustrative are the indolizidines rhynchophylline (43) and its C(7)-epimer ixo-rhynchophylhne (44), both isolated from the plant Uncaria rhynchophytta (Rubiaceae) [26]. Deiters total synthesis of 43 and 44 started with the efficient construction of diallylamine 39 via amide formation between indole-3-acetic acid (38) and diallylamine (Scheme 2.10). One-pot RCM-carbomagnesation of 39 was smoothly achieved with only 1 mol% of [Ruj-I catalyst and 4 equiv. of EtMgCl to afford the 2-ethyl-3-butene-amine derivative in 71% yield. It appeared that the electron-withdrawing carbonyl moiety was critical to the success of the RCM-carbomagnesation steps. Amide reduction and subsequent treatment with acryloyl chloride dehvered the second metathesis precursor 40. Cyclization with [Ruj-I (5 mol%) then furnished the a,j8-unsaturated lactam 41 in a high yield of 91%. Continuation of the total synthesis of alkaloids 43 and 44 included a Bischler-Napieralski cychzation (42) and subsequent rearrangement into the oxindole framework. 

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