OxiNDOLE, 3 ETHYL 1 METHYL

Further reaction of A -chloroaniline 6 with ethyl (methyl)thioacetate yields azasulfonium ion 7, which forms ylide 8 upon deprotonation with triethylamine. After the ylide undergoes a [2,3]-Sommelet-Hauser-like rearrangement, a proton transfer and subsequent rearomatization produces the intermediate aniline derivative 9, which upon cyclization forms a transient tetrahedral anion. Collapse of the anion with loss of ethoxide produces the stable oxindole derivative 2. Removal of the methyl thiol functionality with Raney nickel produces the final product 3. 

Knoevenagel adduct 239 of oxohomophthalimide 240 with malononitrile 27a in reactions with CH-acids behaves ambiguously (82CPB1215). Reactions of 239 with acetylacetone, ethyl esters of acetoacetic and ben-zoylacetic acids, as well as methyl pyruvate led to the formation of the desired spiropyrans 241. However, benzoylacetone, dibenzoylmethane, cyanacetamide, and oxindole always gave the same 242. Authors explain this feature in terms of a retro-cleavage of adducts of Michael product 239... 

The formation of cyclopropane derivatives by photolysis of diazoalkanes in the presence of alkenes is believed to occur by photolytic decomposition of the diazoalkane to yield the carbene, followed by addition of this carbene to the alkene. Cycloaddition of this type has been reported in furan, dihydrofuran, and thiophene.198 Thus, photolysis of ethyl diazoacetate in thiophene yields the bicyclic sulfur heterocycle (215). Alternatively, photolysis of 3-diazo-l-methyl-oxindole (216) in cyclohexene leads to the formation of two isomers which are thought to have the spirocyclopropyl structure (217) photolysis in ethanol yields 3-ethoxy-1-methyloxindole.194... 

Two ° independent and different degradations have been carried out to establish the absolute stereochemistry, and in each case the final compound contained only the C(3a) asymmetric centre. One approach was to degrade the alkaloid to the oxindole (10), the enantiomorph of which was then synthesised starting from (R)-( — )-2-methyl-2-phenylbutyric acid. In the second approach the molecule was broken down to an amino-acid (11) which was characterised as its 2,4-dinitrophenyl derivative. Its enantiomer was synthesised from 3-ethyl-3-methoxycarbonyl-3-methylpropionic acid of known absolute configuration. 

Two representatives of this class of compounds, one with a free NH— benzopyrano[2,3-b]indole(VIII)—and the other, an V-methyl derivative (IX) were prepared by the condensation of oxindoles with ethyl salicylate in the presence of sodium hydride, followed by ring closure with hydrochloric acid (Scheme 1) [6]. The products were identified by elemental analyses as well as by their spectra (u.v., i.r., n.m.r. and mass). Methylation of (VIII) also gave (IX) in 77 per cent yield. 

Ozone bubbled briefly into an ice-cooled soln. of 3-cyano-4-ethyl-4-methyl-l-tosyl-l,4-dihydroquinoline in methylene diloride, and the resulting ozonide refluxed briefly with methanol containing 5%-HCl 3-ethyl-3-methyl-l-tosyl-oxindole. Y ca. 100%. F. e. s. M. Natsume and I. Utsunomiya, Chem. Pharm. Bull. 20, 1595 (1972). 

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