- Unusual reactions of 2-aryl-4-(N,N-dimethylaminomethylene)-2-oxazolin5-ones with O-nucleophiles: Synthesis of 2-aryl-4-hydi oxymethylene- 2-oxazolin-5-ones
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The reactions of 2-aryl-4-(N,N-dimethyIaminomethylene)-2- oxazolin-5-ones 2 with aqueous or ethanolic KOH and sodium ethoxide lead to the formation of 2-aryl-4-hydroxymethylene-2-oxazolin-5ones 4, 1,5-bond remaining unaffected. However, the reactions of 2 with aqueous or methanolic KOH afford methyl 2-acylamino-3-dimethylaminopropenoates 9 along with 4. These observations are explained by the hard-soft acid-base (HSAB) principle. Further, compounds 9 on treatment with POCl3 in pyridine and ethanolic KOH give the corresponding cyclized products 2 and 4, respectively.
- Singh, Kumar K.,Singh, Ram S.,Singh, Radhey M.
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p. 120 - 126
(2007/10/03)
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- Reaction of 4-substituted aminomethylene-2-phenyl-2-oxazolin-5-ones with primary amines
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The regioselective reactions of 4-(N,N-dimethyIaminbmethylene)-2-phenyl-2-oxa2olin-5-one 2b and 4-anilinomethylene-2-phenyl-2-oxazolin-5-one 2c with primary alkyl amines in acetonitrile afford the corresponding 4-alkylaminomethylene-2-oxazolin-5-ones 4 in excellent yields. Oxazolones 2b and 2c are resistant to aminolysis with primary aryl amines. However, compound 2c gives 3-anilino-2-benzoylaminoacrylanilide 9 with aniline in acetonitrile containing catalytic amount of acetic acid, via 1, 5-bond cleavage. The regioselectivity is explained by the hard-soft acid-base (HSAB) principle.
- Singh, Manoj K.,Singh, Kumar K.,Singh, Ram S.,Singh, Radhey M.
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p. 137 - 141
(2007/10/03)
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- Vilsmeier-Haack reagent: A facile synthesis of 4-heteromethylene-2-aryl-2-oxazolin-5-ones from N-acyl-α-amino acid esters
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4-(N,N-dimethylaminomethylene)-2-aryl-2-oxazolin-5-ones (5) have been synthesised from N-acyl-α-amino acid esters (3) by treating with Vilsmeier-Haack reagent, in good yield.The variable temperature-NMR study and a plausible mechanism have also been discu
- Singh, Kumar K,Singh, Radhey M
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p. 232 - 235
(2007/10/02)
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