Indoles 2-acylamino

The hydrolysis and alcoholysis reactions have been extended to the heterocyclic series. A systematic study has been published of the hydrolysis of unsaturated oxazolones derived from a selection of heterocyclic aldehydes. A detailed study of the synthesis and stereospecific hydrolysis and methanolysis of the (Z) and ( ) isomers of 2-methyl (or phenyl)-4-(thienylmethylene)-5(4F/)-oxazo-lones 435 and 437 has also been described (Scheme 7.144). The synthesis of 2-acylamino-3-(indol-3-yl or carbazol-3-yl)acryhc acid derivatives as potential antifertility agents via oxazolone hydrolysis has also been published. ... 

Indolo[ 1,2-a]quinazoline s (67) were prepared through the formation of their diazine rings, by cyclizing 2-acylamino-l-phenyl-indoles (66) with phosphoryl chloride (81KGS844). 

Indoles were prepared (80-95%) from o-acylamino-benzyltriphenylphosphoranes by intramolecular Wittig reaction. 

Fig. 14 Indole derivatives, with changes in the 5-methoxy and acylamino groups [134]...

The indole nitrogen of 9-(3-indolylvinyl)pyrrolo[2,l-a]quinazoline (367) was methylated with methyl iodide in the presence of sodium hydride in dimethylformamide under a nitrogen atmosphere at room temperature. The acylamino group of pyrrolo[2,l-6]quinazolinone was N-methylated with methyl iodide in the presence of sodium hydride. ... 

Miyashita, K., Kondoh, K., Tsuchiya, K., Miyabe, H., Imanishi, T. Novel indole-ring formation by thermolysis of 2-(N-acylamino)benzylphosphonium salts. Effective synthesis of 2-trifluoromethylindoles. J. Chem. Soc., Perkin Trans. 11996, 1261-1268. 

The heterocyclic double bond in simple indoles will take part in cycloaddition reactions with dipolar 4n components,and with electron-deficient dienes (i.e. inverse electron demand), in most reported cases, held close nsing a tetherf° a comparable effect is seen in the intermolecular cycloaddition of 2,3-cycloalkyl-indoles to ortfto-quinone generating a l,4-dioxane. ° The introduction of electron-withdrawing substituents enhances the tendency for cycloaddition to electron-rich dienes 3-acetyl-1-phenylsulfonylin-dole, for example, undergoes aluminium-chloride-catalysed cycloaddition with isoprene, " and 3-nitro-l-phenylsulfonylindole reacts with l-acylamino-buta-l,3-dienes without the need for a catalyst. Both 3- and 2-nitro-l-phenylsulfonyl-indoles undergo dipolar cycloadditions with azomethine ylides. ... 

Aminoindole exists mainly as the 3H-tautomer, presumably because of the energy advantage conveyed by amidine-type resonance. 3-Aminoindole is very unstable, and easily autoxidised. Both 2- and 3-acylamino-indoles are stable and can be obtained by catalytic reduction of nitro-precursors in the presence of anhydrides. 1-Amino-indoles can be prepared by direct amination of the indolyl anion. ... 

Al-tosyltryptamine with 2-methyl-5-oxazolecarbonyl chloride generated 1470a, which was cychzed to the C-D-E-F indole bis-oxazole model fragment 1471 via the A -acylamino ketone 1470b. Finally, the authors noted they were unable to effect an intramolecular Ullmann coupling of 1472 to prepare the B-C-D-F-G-H model fragment 1473. 

They first prepared the indole-oxazole C-D-E fragment 1506. The O-TBDPS protected glycolamide 1504 was readily prepared from 4-bromoindole in three steps and 69% overall yield. Oxidation of 1504 to the intermediate A-acylamino ketone (not shown) was best accomplished in two steps using DDQ followed by IBX, prepared in situ from oxone and 2-iodobenzoic acid. Following cyclization... 

Gribble and Pelkey adapted the Barton-Zard pyrrole synthesis [84] to 3-nitroindoles and ethyl isocyanoacetate (and tosylmethyl isocyanide) to give 2,4-dihydropyrrolo [3,4-T [indoles (Scheme 15, equation 1) [85, 86], In complementary work, Gribble and cowoikers synthesized pyrrolo[3,4-fc]indoles from the 1,3-dipolar cycloaddition of 2- and 3-nitroindoles with miinchnones (1,3-oxazo-lium-5 elates) (eqnations 2, 3) [87, 88]. The mesoionic miinchnones were generated in situ from the appropriate Af-benzyl-Af-acylamino acids. Gribble and Kishbaugh... 

Indoles from the intramolecular cyclization of 2-(acylamino)-toluenes using strong bases. 

A simple method for the synthesis of 2-acylamino-benzonitriles is based on the Beckmann fragmentation of 3-hydroxyimino-3 T-indoles. ... 

---