Lane, Uxbridg e, M idd lesexThe Friedel-Crafts acetylation and benzoylation of iodobenzene and the isomeric iodotoluenes have been investigated in a range of solvents and a t a range of temperatures. Under specific conditions good yields of p-iodoacetophenone or p-iodobenzophenone may be obtained. The reactivities of the iodotoluenes follow the sequence p -< o-< rn-. The main products formed in the acylation of o-iodotoluene are 3-iodo-4-methyl-and 4-iodo-3methyl-acetophenones (or -benzophenones). rn-lodotoluene generally affords acetophenones or benzophenones in the order 4-iodo-2-methyl-> 2-iodo-4-methyl-> 2-iodo-6-methyl. In acylations p-iodotoluene gives very-(3-1 1 %) or benzophenone (2-36%) proceeds essentially by this path. However, the molar ratios of di-iodobenzene to aceto-(or benzo-)phenone are near unity, as '
Syntheses of derivatives of the isomeric 4-amino-? ,3,4,5-tetrahydrobenz[cd]indol-5-ols (1) and (6) and the structurally similar 4-amino-2a,3,4,5-tetrahydroacenaphthen-5-ols ( 2 2 ) and (28), and of certain N-alkyl and NN-dimethyl derivatives are described. Preparation of the tetrahydrobenz[cd] indole series was made possible by the use of the tosyl group for protection of the indole imino-group.
The preparation of 3.4-dihydro-1 -(p-tolylsulphonyl) benz[cd]indol-5(1 H)-one (2) and its conversion to a wide variety of 5-substituted tetrahydrobenz[cd] indoles are described, thus demonstrating the value of the N-tosyl protecting group in indole chemistry. Several reactions were also possible with the corresponding 1 -acetyl derivative (3).
THE chemistry of 3,4-dihydrobenz[cd]indol-5( 1H)-one (1)is dominated by the inherent tendency of the molecule to undergo isomerisation to the more stable naphthalenoid system.2 Protection of the indole imino-group as its N-acetyl derivative overcomes this problem only to a limited extent since the protecting group is labile in alkaline media. A more promising protecting group should be the tosyl since the stability of N-tosylindole to mild alkali has already been reported by us ; removal of the protecting group may be easily achieved in reflux-
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