- Organolead-mediated Arylation of Allyl β-Ketoesters: A Selective Synthesis of Isoflavanones and Isoflavones
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Arylation of A-ring substituted and unsabstituted 3-allyloxycarbonylchroman-4-ones with aryllead(IV) triacetates followed by selective catalytic deallyloxycarbonylation affords isoflavanones or isoflavones in high overall yields.The highest yield in the arylation step was observed in the reaction of 5,7-dimethoxychroman-4-one with the more hindered 2,4,6-trimethoxyphenyllead triacetate.
- Donnelly, Dervilla M.,Finet, Jean-Pierre,Rattigan, Bernard A.
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p. 1729 - 1736
(2007/10/02)
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- Some novel observations on ethoxymethylation of 2-hydroxy- and 2-methoxyphenyl benzyl ketones: Isolation of α-methylene- and α-hydroxymethyl derivatives
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Ethoxymethylation of benzyl 2-hydroxyphenyl ketones (6a, 6b and 6c) with two mol equivalents of ethoxymethyl chloride in the presence of K2CO3 and DMF affords directly the isoflavanones (8a, 8b, and 8c respectively) albeit in smaller yields than recorded earlier .In the case of 6a and 6b, α-methylene derivatives (7a and 9) are also formed.However, ethoxymethylation of benzyl-2-methoxyphenyl ketones (10a, 10b and 10c) with one mol equivalent of ethoxymethyl chloride under similar conditions gives invariably the α-methylene derivatives (11a, 11b and 11c respectively) and α-hydroxymethyl derivative (12).
- Jain, Amolak C.,Nayyar, Naresh K.,Paliwal, Poonam
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- A New General Synthesis of Hydroxy- and Methoxy-isoflavones
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A new general synthesis of hydroxy- (5e-h) and methoxy- (5e-d) isoflavones has been accomplished in overall yields of 47-73percent from the corresponding 2-hydroxydeoxybenzoins (1a-h).The first step involves reaction with appropriate amounts of ethoxymeth
- Jain, Amolak C.,Mehta, Anita
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p. 215 - 220
(2007/10/02)
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- Hydroxymethylation Studies of o-Hydroxyphenyl Benzyl Ketones with and without the use of Phase Transfer Catalyst: A Novel Synthesis of Isoflavanones
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o-Hydroxyphenyl benzyl ketones, having a resorcinol unit in ring-A, on treatment with formalin in chloroform-aq. potassium carbonate biphase system give the corresponding α-hydroxymethyl derivatives.This reaction when carried out in the presence of a phas
- Jain, P. K.,Makrandi, J. K.,Grover, S. K.
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- A New Synthesis of Isoflavanones
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7-Methoxy-(3a)- and 5,7-dimethoxy-(3b)-isoflavanones have been synthesised in good yields by reacting corresponding o-hydroxydesoxybenzoins (1) with ethoxymethyl chloride in the presence of boiling acetone and dry potassium carbonate, followed by refluxing with ethanolic 4 percent aq. sodium carbonate.The products of the first step have been isolated as α-hydroxymethyldesoxybenzoins (2) and explanation of their formation is provided.
- Jain, A. C.,Sharma, Anita
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p. 451 - 452
(2007/10/02)
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- SYNTHESIS OF METHOXYISOFLAVONONES FROM ARYLMETHYL o-HYDROXYARYL AND PARAFORMALDEHYDE
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Paraformaldehyde reacts with benzyl o-hydroxyphenyl ketones in the presence of diethylamine in methanolic solution to afford isoflavanones in excellent yields.
- Pinkey,Jain, Pramod K.,Grover, Surinder K.
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p. 355 - 358
(2007/10/02)
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- A Convenient Phase Transfer Catalysed Synthesis of Isoflavanones
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o-Hydroxyphenyl benzyl ketones (1, 4, 6, 8, 10, 12) on treatment with diiodomethane under phase transfer catalysed conditions in the presence of n-tetrabutylammonium iodide and sodium thiosulphate have been found to undergo smooth conversion into the corresponding isoflavanones (2, 5, 7, 9, 11, 13) in good yields (60-70percent).
- Singh, Harcharan,Jain, P. K.,Makrandi, J. K.,Grover, S. K.
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p. 547 - 548
(2007/10/02)
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