Indole Synthesis of indoles

Fischer indole synthesis One of the oldest and most reliable methods for synthesizing substituted indoles is the Fischer indole synthesis developed in 1883 by Emil Fischer. Although the synthesis of indole itself is problematic using the Fischer indole synthesis, it is often used to generate indoles substituted in the 2- and/or 3-positions.

Madelung synthesis     The Madelung synthesis is a chemical reaction that produces (substituted or unsubstituted) indoles by the intramolecular cyclization of N-phenylamides using strong base at high temperature. The Madelung synthesis is a chemical reaction that produces (substituted or unsubstituted) indoles by the intramolecular cyclization of N-phenylamides using strong base at high temperature.

Madelung synthesis

Chemical reactions of indole Nitrogen basicity بالرغم من أن ذرة النيتروجين الوحيدة في الاندول تحمل زوج حر من الالكترونات إلا أن الاندول ليس قاعدي مثل الأمينات الأليفاتية والعطرية . والسبب........

Electrophilic substitution The most reactive position on indole for electrophilic aromatic substitution is C-3, which is 1013 times more reactive than benzene. For example, Vilsmeier-Haack formylation of indole[10] will take place at room temperature exclusively at C-3.

وجود مركبات أيونية مثل KI, NaCl يؤدي إلى توجيه الاستبدال على ذرة النيتروجين وذلك في وجود المذيبات القطبية اللابروتونية مثل DMSO, DMF. بينما الأملاح التساهمية يوجة التفاعل إلى الموقع 3 على الاندول.في وجود مذيبات غير قطبية البنزين.

Oxidation of indole Due to the electron-rich nature of indole, it is easily oxidized. Simple oxidants such as N-bromosuccinimide will selectively oxidize indole 1 to oxindole (4 and 5).