Indoline substructure

This type of photocyclization strategy has also been utilized [80] to construct indoline substructures 157 and 159 by irradiating enamine derivatives bearing an electron-withdrawing substituent on the olefinic double bond, such as 156. This was produced as a mixture of cis and trans diastereomeric indolines, as shown in Scheme 8.45. The formation of diastereomers (157 and 159) is explained by... 

This chapter has illustrated the numerous advances made toward identifying selective PDE inhibitors. Despite the heterogeneity that may appear at first glance, several common structural features have become clear. The majority of compounds can be grouped into families of common substructures that address conserved features of the PDE active site. Most notably, the substrate-like cGMP-PDE5 inhibitors, the structurally unrelated indoline derivatives, and the cAMP-PDE4... 

Aniline derivatives have been used to synthesize the indoline system. A large variety of indoline alkaloid substructures are available in a very efficient way. Enamine derivatives such as 39 bearing electron withdrawing substituents on the olefinic double bond were transformed in high yields (Scheme 7). Two syn/anti isomers 41 and 42 were isolated. The isomeric ratio of the final products was influenced by a photostationary equilibrium between the substrates 39 and 40. The reaction was applied to the synthesis of a variety of derivatives of the alkaloid aspidospermidine." In this context, the cyclization products 43 were transformed into the polycyclic indole derivatives 44,45, and 46. Polycyclic indolone compounds 48 have been successfully produced by cyclization of enaminone derivatives 47 carrying a quinoline substituentIn these cases and contrary to the examples 41,42, and 43, the products 48 resulted from an oxidation of the cyclization product (also compare the formation of 30 in Scheme 5). 

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