Multikilogram-Scale Synthesis of a Biphenyl Carboxylic Acid Derivative Using a Pd/C-Mediated Suzuki Coupling Approach
摘要:
Reaction of 4-bromo-3-methylanaine with 4-chlorobutyryl chloride/TEA and subsequent treatment of the resulting secondary amide intermediate with KOt-Bu gives 1-(4-bromo-3-methylphenyl)pyrrolidin-2-one in 65% yield, This procedure has been optimised (74-76% overall yield) and has been carried out on 41 molar scale. In a variation of this process, we have employed NaOH as the ring-closing base under phase-transfer conditions, NaOH is added to a mixture of 4-bromo-3-methylaniline, 4-chlorobutyryl chloride, and catalytic TBAC in THF/ H2O, A further 2 equiv of aqueous NaOH is added, and the mixture is heated at 40-45 degrees C, providing access to cyclised product In an improved 86% yield. 1-(4-Bromo-3-methylphenyl)pyrrolidin-2-one is subsequently coupled with 4-carboxyphenylboronic acid under standard Suzuki coupling conditions [Pd(PPh3)(4), Na2CO3, DME/H2O] to give 2'-methyl-4'-(2-oxo-1-pyrrolidinyl)biphenyl-4-carboxylic acid in 64% yield, contaminated with 40-80 ppm of residual Pd, In a modification of this process, we have used Pd/C as the catalyst, Reaction in MeOH/ H2O gives an improved yield of the biphenylcarboxyiic acid with residual Pd levels of <6 ppm, This process has been carried out on 24 molar scale, The synthesis of the arylpyrrolidinone and subsequent Suzuki coupling have been combined into a one-pot procedure, providing access to 2'-methyl-4'-(2-oxo-1-pyrrolidinyl)biphenyl-4-carboxylic acid in 82% overall yield from 4-bromo-3-methylaniline.
Tetracyclic spiro compounds as 5HT.sub.1B receptor antagonists
申请人:SmithKline Beecham p.l.c.
公开号:US06100272A1
公开(公告)日:2000-08-08
Compounds of formula(I) where B is oxygen or sulphur, D is nitrogen, R.sup.6 and R.sup.7 forms a ring, m is 2, R is a substituted latam ring of formula (i) ##STR1## where p is 1, P is a substituted or unsubstituted bicyclic ring containing one or two heteroatoms or P is an unsbustituted or substituted 5- to 7-memebered saturated ring containing one or two heteroatoms; X, Y, Z, E, G, R.sup.3, R.sup.4, R.sup.5, R.sup.8, R.sup.9, and R.sup.10 are as defined in the specification.