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Volumn 8, Issue 1, 2006, Pages 85-94

Synthesis of spirohydantoins and spiro-2,5-diketopiperazines via resin-bound cyclic α,α-disubstituted α-amino esters

Author keywords

[No Author keywords available]

Indexed keywords

AMINO ACID; ESTER; HYDANTOIN DERIVATIVE; PIPERAZINE DERIVATIVE; RESIN; SPIRO COMPOUND;

EID: 31544447509     PISSN: 15204766     EISSN: None     Source Type: Journal    
DOI: 10.1021/cc050072s     Document Type: Article
Times cited : (41)

References (61)
  • 6
    • 0036036249 scopus 로고    scopus 로고
    • (e) Najera, C. Synlett 2002, 1388-1403.
    • (2002) Synlett , pp. 1388-1403
    • Najera, C.1
  • 43
    • 31544444903 scopus 로고    scopus 로고
    • note
    • In this study, 2,3-dimethylbutadiene was selected as a (symmetric) model diene. Application of other (asymmetric) dienes is currently part of our research.
  • 46
    • 31544463988 scopus 로고    scopus 로고
    • note
    • -1, in agreement with the spectral properties of methyl (Z/E)-2-nitro-3-phenylprop-2-enoate.
  • 47
    • 31544475346 scopus 로고    scopus 로고
    • note
    • Although this cycloaddition can be carried out at atmospheric pressure in refluxing toluene, the use of high pressure was preferred in view of shorter reaction times, higher yields, avoiding high temperatures, stirring, and the use of large excesses of 2,3-dimethylbutadiene. Comparison of high pressure versus reflux conditions: 4-methoxybenzyl (E/Z)-2-nitro-3-phenyl-2-propenoate reacted with 2,3-dimethylbutadiene and yielded 73% of the cycloadduct after 48 h of reflux in toluene. At 15 kbar, the same cycloadduct was obtained in 86% after 16 h at room temperature.
  • 49
    • 31544466457 scopus 로고    scopus 로고
    • note
    • Cyclization attempts with triethylamine (in tetrahydrofuran or ethylene glycol dimethyl ether) or sodium hydride in tetrahydrofuran failed. The stereochemistry of one of the diastereomers of hydantoin 18 was confirmed with X-ray analysis.
  • 50
    • 31544440072 scopus 로고    scopus 로고
    • note
    • The reported yield is after six reaction steps and is based on an initial loading of the hydroxymethylene resin of 1.0-2.0 mmol/g.
  • 51
    • 31544462542 scopus 로고    scopus 로고
    • note
    • In principle, this matrix might be extended into a third dimension by application of a series of dienes; however, for the synthesis of the library as described in this report, just one diene was used.
  • 52
    • 31544473335 scopus 로고    scopus 로고
    • note
    • 1 position were unsuccessful. There are indications that the Knoevenagel reaction merely failed using imines with these substituents (according to IR and gravimetrical analysis).
  • 53
    • 31544453538 scopus 로고    scopus 로고
    • note
    • + signal of the Boc-deprotected derivative was dominant in the LC/MS analysis.
  • 54
    • 31544462001 scopus 로고    scopus 로고
    • note
    • 6.
  • 55
    • 31544455182 scopus 로고    scopus 로고
    • note
    • Derivatives with 2′-, 3′-, or 4′-pyridyl substituents either were not formed or were formed in very low yields and purities when following the described synthetic route; unpublished results.
  • 58
    • 85010450312 scopus 로고
    • For a review on synthesis and application of nitroacetic acid and its esters, see: Shipchandler, M. T. Synthesis 1979, 666-682.
    • (1979) Synthesis , pp. 666-682
    • Shipchandler, M.T.1
  • 59
    • 31544460877 scopus 로고    scopus 로고
    • note
    • Acts as a radical scavenger to avoid diene polymerization.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.