Cyclisation of N-(3,4-dimethoxyphenylacetyl)tryptamine (4) with either phosphorus trichloride, or phosphoryl chloride, affords the spirocyclic indoline (12) together with small amounts of β-carboline derivatives, whereas with trifluoroacetic anhydride as reagent the spirocyclic indoline (13) is formed in quantitative yield.

K M BISWAS

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

&nbsp;

The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

&nbsp;

It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Journal of the Chemical Society, Chemical Communications

Reduction of the title compound (2) with diborane furnishes 1-trifluoroethyl-3-(2′-(trifluoroethylamino)ethyl)-3-vinylindoline (4), 1-hydroxy-trifluoroethyl-3-(2′-(trifluoroethylamino)-ethyl)indole (5), and 1-methyl-2-trifluoroethyl-1,2,3,4-tetrahydro-β-carboline (6). However, treatment of 2 with lithium aluminum hydride, H2/Pd on charcoal, and sodium borohydride affords hydroxyspiroindolenine 8, hydroxy-bis(trifluoroacetyl)enaminospiroindoline 9, and N-ethyltryptamine 7, respectively. The results are discussed and the mechanisms of the reactions leading to 4-8 are presented.

Monatshefte für Chemie - Chemical Monthly

Diborane as a reducing agent IX [1]: Reduction of a tris(trifluoroacetyl)enaminospiroindoline

Synthesis of spiropentacyclic indolines by cyclisation of 3,4-dimethoxyphenylacetyltryptamine

Treatment of N-acyltryptamines [3-(2-amidoethyl)indoles] with trifluoroacetic anhydride or pentafluoropropionic anhydride affords spirocyclic indolines from intermediate indolenines.

Journal	Journal of the Chemical Society, Chemical Communications
Publisher	-
ISSN	0022-4936