Phloroglucinols, reaction with ethyl

The Pechmann condensation served as a key ring-forming reaction in Xu and co-workers s synthesis of the HIV-1-selective nonnucleoside reverse transcriptase inhibitor calanolide A (39). In this work, phloroglucinol (35) and ethyl butyrylacetate (36) were condensed in sulfuric acid at 90 °C to provide 5,7-dihydroxy-4-propylcoumarin (37) in nearly quantitative yield on 150 g scale. Subsequent Friedel-Crafls acylation of 37 followed by condensation of the acylcoumarin product with 4,4-dimethoxy-2-methylbutan-2-ol provided pyranylcoumarin 38, which was converted to... 

Application of MW irradiation in the solid add-catalyzed reaction of resorcinol and phloroglucinol with ethyl acetoacetate and propenoic and propynoic acid resulted in the formation of corresponding hydroxy coumarins in very high yields, avoiding the acidic waste associated with aqueous and Lewis adds (De la Hoz et al. 1999). 

Ethyl a-bromobutyrate (58.5 g., 0.30 mole) (Note 1) is poured into a stirred mixture of 600 ml. of N,N-dimethylformamide (DMF) (Note 1), 36 g. of sodium nitrite (0.52 mole) (Note 1), and 40 g. of anhydrous phloroglucinol (0.32 mole) (Note 2) contained in a 1-1. three-necked flask equipped with a sealed stirrer. The flask is closed, except for a tube containing calcium chloride, and immersed in a water bath maintained at room temperature (Note 3). Stirring is continued for 2.5 hours (Note 4) then the reaction mixture is poured into 1.2 1. of ice water layered over with 300 ml. of diethyl ether (Note 5). After separation of the upper layer, the aqueous phase is extracted with four 100-ml. portions of ether. The combined extracts are washed with four 100-ml. portions of water and then dried over anhydrous magnesium sulfate. The magnesium sulfate is removed by suction filtration and washed with four 25-ml. portions of ether which are combined with the filtered extract. 

As a first step toward a dopamine-jS-hydroxylase mimic, basket-shaped receptor 17 was functionalized with two sets of bis-[2-(3,5-dimethyl-l-pyra-zolyl)ethyl]amine ligands to give compound 35 (see Scheme 5). Reaction of 35 with Cu(C104,)2-6H20 yielded complex 36 which was fully characterized [39], Ligand system 35 binds dopamine derivative 37 and phloroglucinol (1,3,5-trihydroxybenzene) with association constants of = 60 and 3500 respectively. The affinity of the Cu(I) analogon of 36 for 37 was very similar to that of 36 itself and amounted to Ka = 60 M L Resorcinol is bound in the cavity of the Cu(I) complex with a Xj-value of 2(XX) M". ... 

Ethyl-3-nitropentanoate, H8C.CH2.00C.CH2.CH(N02).CH2. CH8 mwl75.19,N8.00% liq, bp 105-10°(15mtn , contains 12% 3-bromo compd). Prepd from the reaction of NaN02 with the 3-bromo compd in the presence of phloroglucinol in dimethylformamide at 60°... 

Phloroglucinol heated 8.5 hrs. with excess ethyl benzoylacetate at 153°/15mm chrysin. Y 60%.—Performing the reaction in vacuo allows lower reaction temp, so that this method can be applied to heat-sensitive compounds. F. e. s. R. Teoule et al., Bl, 1961, 546. 

Preparation by reaction of benzonitrile with phloroglucinol in the presence of zinc chloride and hydrochloric acid in ethyl ether at r.t. for overnight, followed by hydrolysis of the ketimine salt formed with dilute sulfuric acid [370], (65%) [371] (Hoesch reaction). 

Preparation by reaction of benzoyl chloride with phloroglucinol in the presence of aluminium chloride in a ethyl ether/nitrobenzene mixture [372],... 

Preparation by reaction of p-acetami-dophenyl-acetonitrile with phloroglucinol in ethyl ether in the presence of zinc chloride under hydrogen chloride... 

Preparation by reaction of 3,4, 5-trimethoxyphenyl-acetonitrile with phloroglucinol in ethyl ether (63%) (Hoesch reaction) [5496],... 

Also obtained (by-product) by reaction of propionyl chloride with phloroglucinol trimethyl ether in the presence of aluminium chloride in ethyl ether [7405]. 

The reactivity of the amino group can be strongly influenced by the presence of negative substituents in the amine molecule. For example, trinitroaniline and trichloroaniline do not react. On the other hand, in addition to primary aliphatic amines, aromatic amines, and amino acids, substances with an active methylene group also react (3). A positive reaction was also observed with substances such as guanidine, semicarbazide, phenyl-hydrazine, ethyleneimine, piperidine, piperazine, benzylcyanide, cyano-acetylacetone, diethyl malonate, ethyl acetoacetate, dibenzoylmethane, rhodanin, indole, methylphenylpyrazolone, resorcinol, phloroglucinol, and quaternary heterocyclic bases and oxonium salts. 

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