Spiro indolone

Likewise, upon reacting alkynoyl ortho-ioAo anilides 118 and propargylallyl ethers 116 under Cl conditions in a boiling mixture of butyronitrile and triethylamine (tetrahydroisobenzofuran) spiro-indolones 119 can be isolated in moderate to excellent yields (Scheme 63). 

Scheme 63 Insertion-CI-Diels-Alder domino reaction to spiro-indolones 119...

The chiroptieal properties of the benzodioxole 26 have been examined <03OBC391> and the photochromism of compound 27 has been studied <03ARK(xiii)147>. Anti-diabetic activity is claimed for compound 28 <03WOP2550> and the spiro indolone/dioxolanes 29 have monoamine oxidase inhibiting and psychostimulant properties <01RRC517>. 

JCS(P1)2451]. Attempts to prepare the analogous diazomethane 116 gave a mixture of the required product together with the zwitterionic spiro-indolone 117 [74JCS(P1)2451]. 

The base-catalyzed reaction of 4-hydroxycoumarin 184 with indolones 213 or with isatin and MN 27a on short heating leads to spiro pyrano-benzopyrans 220 (89JHC1097, 05RCB992, 08JCO741, 08RCB2373) (Scheme 82). 

Under analogous conditions, the 3-cyanomethylene-2-indolones 213 react with barbituric acid and its derivatives 191 with the formation of spiro-annulated pyranopyrimidines 223 (88JIC202, 90H(31)31)... 

N-Methyl-4-hydroxy-2-quinolone 183 in a three-component reaction gives spiro pyrano[3,2-c]qionoline-2-ones (02MI2), but indolones 213 with 4-hydroxy-6-methyl-2-pyridone 177 react in a complicated way (97BCJ1625). Ethoxycarbonyl-methylene indolone (Z = COOEt) forms pyrans 224, while dicyano analogs (Z = CN) yield substituted quinoline 225 (Scheme 85). 

N-Phenylpyrazolone 194a adds to indolones 213 to form spiro pyrano-pyrazoles 226, which possess herbicidal activity (88JIC277) (Scheme 86). 

The A-chloro compound 176, obtained from the corresponding meth-oxyamide with f-butyl hypochlorite, was cyclized to l-methoxy-2-indolone 163 by silver carbonate in trifluoroacetic acid (87% yield) (84JA5728), or by other silver or mercury salts (87T2577), and more conveniently by anhydrous zinc acetate in 1,2-dichloroethane (91% yield) (87CL1771). The reaction proceeds through the spiro intermediate 177, followed by both possible 1,2-shifts. 

We have studied the reaction of similar cyclic -substituted enaminones which yielded indolones when the reaction was carried out in acetic acid and the quinones had lower oxidation potential, thus preventing prior oxidation of the enaminones. Secondary aminomethylene derivatives of cyclopentanone, cyclohexanone and cycloheptanone reacted with the quinones to presumably form intermediate spiro compounds, as a consequence of normal enaminone chemistry. However, this was unexpectedly followed by rearrangement with ring expansion to indolones (equation 158). In this way carba-zoles, cycloheptindoles and cyclooctindoles can be obtained by a simple entry to this class of indoles, although partially in low yields222-224. Due to their bifunction-ality the produced indol-2-ones are versatile synthons for fused heterocycles (e.g. triazepino- and pyrazino-carbazoles) which become easily accessible225,226. 

Exposed to the daylight in ethanol solution in air, oxepino[3,2-/)]indolones (176) undergo ring transformation, through the spiro intermediates (177), to produce compounds (178) in moderate yield (Scheme 28) <83JCS(P1)2413>. 

The substrate scope of the reaction is shown in Scheme 10.2. Aliphatic and aromatic enals, branched enolizable aldehydes, and different substituted unsaturated 2-indolones could be used to afford the corresponding spirooxindoles in excellent yields and high stereoselectivity. Later, Chen and coworkers expanded the substrate scope of this reaction using maleimides and imines instead of enals to afford the spiro products in excellent yields and stereoselectivities [11]. 

The Pictet Spengler type cyclisation of isatins (258) and tryptamines (259) catalysed by chiral phosphoric acids (253, 261-262) provided spiro-2-indolones products (260) in excellent yields (up to 99%) and enantio-selectivity (up to 98 2 er) (Scheme 67). " ... 

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