- Preparation of alkyl-substituted indoles in the benzene portion. Part 7. Synthesis of (±)- and (S)-(-)-pindolol
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A new, short-step synthesis of a β-adrenergic blocking agent, pindolol, 1-(4-indolyloxy)-3-(2-propylamino)-2-propanol, is described. The acid-catalyzed indole cyclization reaction of 4-[1-(4-methylphenyl)sulfonyl-3-pyrrolyl]-4-oxobutanal (14) in the presence of (±)-3-chloro-1,2-propanediol (12) and (R)-1-O-[(4-methylphenyl)sulfonyl]glycerol (24) afforded (±)-1-chloro-3-[1-(4-methylphenyl)sulfonyl-4-indolyloxy]-2-propanol (15) and (R)-(-)-3-[1-(4-methylphenyl)sulfonyl-4-indolyloxy]-1-[(4-methylphenyl sulfonyloxy]-2-propanol (25). Reaction of these with isopropylamine and removal of the protecting group at the indole nitrogen gave (±)- and (S)-(-)-pindolol (3 and 4), thus constituting an efficient three-step synthesis of 3 and 4 from the readily available aldehyde (14).
- Fuji,Muratake,Akiyama,Natsume
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p. 2353 - 2357
(2007/10/02)
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- Process for preparing indoles
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Convenient intermediates for preparing 3-substituted-2-hydroxypropyl aryl ether β-blockers, a reaction to the intermediates of the following formula and a conversion to obtain the said β-blockers are disclosed. STR1 (wherein X is hydrogen or halogen; Y is halogen, hydroxy, lower acyloxy, amino, lower alkylamino, lower aralkylamino, lower acylamino, di-lower alkylamino, lower alkyleneamino, N-lower alkyl-N-lower aralkylamino, di-lower acylamino, N-lower alkyl-N-lower acylamino or N-tri-lower alkylsilylamino; one of P and R combined together with Q represents lower alkylene or alkenylene optionally interrupted by O, N or S and optionally substituted by lower alkyl, lower aralkyl, lower carboxylic acyl, carboxy, protected carboxy; hydroxy, lower alkoxy, lower acyloxy, oxo; amino, lower alkylamino, lower acylamino, nitro, nitroso, lower alkylthio, lower sulfonic acyl or halogen; and the remaining R or P is hydrogen or halogen; and dotted line represents the presence of one or two double bonds).
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- SELECTIVE CLEAVAGE OF UNSYMMETRICAL 2,2-SPIRO-1,3-DIOXOLANES. II. CLEAVAGE OF KETAL RING Of 5'-BROMO-6',7'-DIHYDRO-4-ISOPROPYLAMINOMETHYL-1'-p-TOLUENESULFONYL-SPIRO AND ITS ANALOGS
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The bromodioxolane and its analogs (1-5) were treated with organic base (DBU, DBN, or morpholine), acid (p-toluenesulfonic acid or Lewis acid), or Lewis acid/tertiary amine, and yielded 4-alkoxyindoles (6-17).Reaction of 1 with organic base gave two isome
- Sakai, Makiko
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p. 1269 - 1275
(2007/10/02)
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