Synthesis 2010(6): 1009-1013  
DOI: 10.1055/s-0029-1218641
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

Synthesis of Masked 2-Amino-3-furancarboxaldehydes

Alexander V. Denisenkoa, Anton V. Tverdokhlebov*b, Andrey A. Tolmacheva,b, Yulian M. Volovenkoa, Svitlana V. Shishkinac, Oleg V. Shishkinc
a Kiev National Taras Shevchenko University, Volodimirska str. 62, 01033 Kiev, Ukraine
b Enamine Ltd., Alexandra Matrosova str. 23, 01103 Kiev, Ukraine
Fax: +380(44)5373253; e-Mail: atver@univ.kiev.ua;
c STC Institute for Single Crystals, NAS of Ukraine, 60 Lenina ave., 61001 Kharkiv, Ukraine
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Publikationsverlauf

Received 13 October 2009
Publikationsdatum:
08. Januar 2010 (online)

Abstract

5′-Substituted 2-(2-amino-3-furanyl)-1,3-dimethyl-1H-benzimidazolium bromides were obtained in excellent yields upon heating (1,3-dimethyl-1,3-dihydro-2H-benzimidazol-2-ylidene)ace­tonitrile with α-bromo ketones in refluxing N,N-dimethylform­amide. Reduction of the prepared quaternary salts with sodium borohydride afforded 5-substituted 3-(1,3-dimethyl-2,3-dihydro-1H-benzimidazol-2-yl)-2-furanamines. The latter were shown to be masked amino aldehydes. Thus, the corresponding 2-amino-3-furancarboxaldehyde phenylhydrazones and semicarbazones were obtained upon treatment with phenylhydrazine and semicarbazide, respectively, whereas condensation with malononitrile yielded 2-substituted 6-aminofuro[2,3-b]pyridine-5-carbonitriles.