Preparation and alkylation of regioisomeric tetrahydrophthalimide‐substituted indolin‐2(3H)‐ones

Abstract

A series of novel regioisomeric tetrahydrophthalimide‐substituted indolin‐2‐ones has been prepared via the Sommelet‐Hauser type cyclization of appropriately substituted anilines as potential herbicides. The resultant indolin‐2‐ones were then regioselectively alkylated at N‐1 and C‐3 to give 1,3,3‐trisubstituted indolin‐2‐ones. The most active series was also prepared by the bis‐nitration of m‐fluorophenylacetic acid followed by reduction and cyclization to give 6‐amino‐5‐fluoroindolin‐2‐one. Elaboration to the tetrahydrophthalimide‐substituted indolin‐2‐one was followed by C‐ and N‐alkylation to give the desired compounds.

Catalytic Thia-Sommelet−Hauser Rearrangement: Application to the Synthesis of Oxindoles

“…When a meta substituent is introduced to the aromatic ring attached to the nitrogen, the thia-Sommelet−Hauser rearrangement encounters regioselectivity problem. In Gassman’s synthesis of oxindole, generally low regioselectivity has been observed in the thia-Sommelet−Hauser rearrangement. , We also observed low regioselectivities in our catalytic reaction system for the reaction with m -F-, m -Cl-, and m,p -Cl 2 -substituted sulfenamides ( 1k , 1l and 1m , respectively), affording a mixture of ( 3p + 3p′ ), ( 3q + 3q′ ), and ( 3r + 3r′ ), respectively.…”

“…Recently, a plethora of new methods for the synthesis of oxindoles bearing quaternary carbon centers in the 3-position have been developed through transition-metal-catalyzed coupling reactions or various cyclization methods . In particular, the derivatives with a thio group at the 3-position have been widely investigated. , Among various approaches toward this type of oxindoles, − we noticed that Gassman and co-workers developed a useful method to synthesize (3-methylthio)oxindoles by the reaction of α-carboalkoxy sulfides and aniline derivatives through a thia-Sommelet−Hauser rearrangement (Scheme ) . The synthesis needs several steps, which include (a) formation of mono- N -chloroaniline; (b) generatation of azasulfonium salt; (c) the formation of sulfonium ylide A by treatment of the salt with base; (d) thia-Sommelet−Hauser-type rearrangement leading to imine B ; and (e) acid-promoted intramolecular attack of the amino group on the carbonyl group.…”

“…In Gassman’s synthesis, thia-Sommelet−Hauser rearrangement is the key step, which is a unique process involving a [2,3]-sigmatropic dearomatization with subsequent [1,3]-shift rearomatization. This unique rearrangement is a useful way for constructing a cyclic quaternary carbon center from aromatic rings , or making ortho -substituted aromatic compounds. , It is noteworthy that in classic thia-Sommelet−Hauser rearrangement, the formation of sulfonium ylides is achieved by the treatment of the corresponding sulfonium salts with stoichiomeric amount of base. − …”

Discovery of N‐benzyl‐6‐methylpicolinamide as a potential scaffold for bleaching herbicides

“…Briefly, the tested compounds were dissolved in dimethylsulfoxide (DMSO), and subsequently diluted with sterile water containing 0.1% Tween‐80 to achieve concentrations of 50, 10, 1.0, and 0.5 μg mL −1 , respectively. Ten germinated seeds were gently placed in a Petri dish (90‐mm diameter) and transferred to a light incubator set at a temperature of 25 °C under an illumination intensity of 3000 Lx under a 12 h:12 h, light:dark photoperiodh 12 . Commercial herbicide diflufenican was used as a positive control.…”

Novel non-peptidic neuropeptide Y Y 2 receptor antagonists

“…15 7-(N-Acetyl-tetrahydroquinolinyl) 10 a16 6-(2-oxoindoline) 30 a17 6-(N-acetyl-indolyl) 30 a n=1 for this compound.…”