Reactivity of chloroacetylated β-enamino compounds. Synthesis of heterocycles

Tetrahedron Letters

Volumn 43, Issue 45, 2002, Pages 8079-8081

  Braibante, Mara E F ^a   Braibante, Hugo T S ^a   Costa, Carla C ^a   Martins, Demétrius B ^a  

^a FEDERAL UNIVERSITY OF SANTA MARIA   (Brazil)

Author keywords

[No Author keywords available]

Indexed keywords

ACETAMIDE DERIVATIVE; ACETIC ACID DERIVATIVE; CHLORIDE; CHLOROACETYLCHLORIDE; ESTER DERIVATIVE; ETHYL 3 CHLOROMETHYLCARBOXAMINO 2 BUTENOATE; HETEROCYCLIC COMPOUND; HYDRAZINE; HYDROXYLAMINE; KETONE; METHYL GROUP; N (1 METHYL 3 OXO 1 BUTENYL) 2 CHLOROACETAMIDE; UNCLASSIFIED DRUG;

ACETYLATION; ARTICLE; CHEMICAL REACTION; EVALUATION; NUCLEAR MAGNETIC RESONANCE; STEREOCHEMISTRY; SYNTHESIS;

STAPHYLOCOCCUS PHAGE 3A;

EID: 0037020620     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(02)01961-5     Document Type: Article

References (13)

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6. Braibante M.E.F., Braibante H.S., Valduga C.J., .Santis D.B. J. Heterocyclic Chem. 36:1999;505.
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11. General experimental procedure for the preparation of 2c-g and 3a,c: β-Enamino compounds 1a-g (9 mmol) were dissolved in chloroform (30 mL), cooled to -10°C and chloroacetyl chloride (21 mmol) was added dropwise. The solution was stirred at 0°C for 2-3 h, then neutralized with sodium carbonate, washed with water, dried over magnesium sulfate, filtered and the solvent was removed in vacuo to yield the crude products. Compounds 2d and 3a were purified by recrystallization from diisopropyl ether. Compounds 2e-g were purified by column chromatography on silica gel (Vetec, 70-230 mesh) using 1% dichloromethane/ethyl acetate as eluent, resulting in the following yields of products: 2e (10%), N-phenyl-2-chloroacetamide (60%), 2f (35%), and 2g (30%). The mixture of 2c and 3c was separated by filtration with hot hexane, affording solid 2c (15%). The solvent was then evaporated, resulting in the formation of 3c (45%).
12. Ethyl (E)-(3-amino substituted)-2-chloroacetyl-2-butenoates 2c or 2d (1 mmol) were mixed with phenyl hydrazine or hydrazine hydrochloride or hydroxylamine hydrochloride (2 mmol) in ethanol (2 mL). The mixture was refluxed for 24 h for to give 4, 16 h to give 5 and 4 h to give 6. These were extracted with ethyl acetate, then the organic layer was washed with water (3×10 mL), dried over magnesium sulfate, filtered and the solvent was removed in vacuo to yield the crude products. Product 4 was purified by recrystallization from diisopropyl ether, while compounds 5 and 6 were purified by column chromatography on silica gel (Vetec, 70-230 mesh) using 40% dichloromethane/ethyl acetate as eluent for 5 and 10% dichloromethane/ethyl acetate as eluent for 6.
13. 2), 109.72 (C-4), 159.79 (C-3), 160.87 (C=O), 170.95 (C-5).