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The oxidative rearrangement of furan-2-carboximidamides: preparation and properties of 2-acylaminofurans

The oxidative rearrangement of furan-2-carboximidamides: preparation and properties of 2-acylaminofurans
The oxidative rearrangement of furan-2-carboximidamides: preparation and properties of 2-acylaminofurans
Oxidation of furan-2-carboximidamides 8 by (dicarboxyiodo)benzenes gives N-1-acyl-N-1-(2-furyl)ureas 9 via rearrangement to a carbodiimide. Thermolysis of eleven ureas 9 gave the corresponding 2-acylaminofurans 10, which cannot be made from the free amines owing to their high instability. When oxidation of the corresponding benzo[b]furan derivatives 12 was investigated a new type of product was isolated, in addition to the expected ureas 14, and these were shown to be benzo[4,5]furo[2,3-d]pyrimidine derivatives 15. The mechanism of formation of these products must involve reaction of the carbodiimide intermediate with the amidine precursor and cyclisation of the resulting guanidine derivatives 19. The corresponding tetraphenylguanidine 21 was prepared and underwent thermal cyclisation but the quinazoline derivative formed 23 was shown to occur via an alternative cyclisation mechanism. The structures of cyclisation products 15 and 23 were confirmed by X-ray crystallography. N-(2-Furyl)acetamide 10a readily undergoes cycloaddition reactions with electron-deficient alkynes to give phenols after spontaneous ring opening. Observed regioselectivity is in agreement with the results of AM1 molecular orbital calculations. Reaction of the amide 10a with Lawesson's reagent gave the thioamide 26.
diels-alder reaction, cycloaddition, furans, construction, cyclization, alkaloids, sequence, anilines
0300-922X
680-689
Bobošíková, Mária
ee415658-dbe9-416c-b3e9-ae9880fbc39a
Clegg, William
5b1994af-8799-4402-9c01-8479959de00b
Coles, Simon J.
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Dandárová, Miloslava
682cda3a-5bcc-4afd-a960-4220cd45be8a
Hursthouse, Michael B.
57a2ddf9-b1b3-4f38-bfe9-ef2f526388da
Kiss, Tibor
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Krutošíková, Alžbeta
0b8d1a32-224a-474c-a38a-afef96b40e54
Liptaj, Tibor
aa01584a-c8fc-4648-9731-908d9eb4e413
Prónayová, Nad'a
6aba32fb-c63a-4aea-89e2-312c7c74d5c6
Ramsden, Christopher A.
6369fadb-e248-41e8-b4f3-af7d6fbfbb6e
Bobošíková, Mária
ee415658-dbe9-416c-b3e9-ae9880fbc39a
Clegg, William
5b1994af-8799-4402-9c01-8479959de00b
Coles, Simon J.
3116f58b-c30c-48cf-bdd5-397d1c1fecf8
Dandárová, Miloslava
682cda3a-5bcc-4afd-a960-4220cd45be8a
Hursthouse, Michael B.
57a2ddf9-b1b3-4f38-bfe9-ef2f526388da
Kiss, Tibor
8e4261f9-1752-4032-8d82-9c732c76fa74
Krutošíková, Alžbeta
0b8d1a32-224a-474c-a38a-afef96b40e54
Liptaj, Tibor
aa01584a-c8fc-4648-9731-908d9eb4e413
Prónayová, Nad'a
6aba32fb-c63a-4aea-89e2-312c7c74d5c6
Ramsden, Christopher A.
6369fadb-e248-41e8-b4f3-af7d6fbfbb6e

Bobošíková, Mária, Clegg, William, Coles, Simon J., Dandárová, Miloslava, Hursthouse, Michael B., Kiss, Tibor, Krutošíková, Alžbeta, Liptaj, Tibor, Prónayová, Nad'a and Ramsden, Christopher A. (2001) The oxidative rearrangement of furan-2-carboximidamides: preparation and properties of 2-acylaminofurans. Journal of the Chemical Society, Perkin Transactions 1, (7), 680-689.

Record type: Article

Abstract

Oxidation of furan-2-carboximidamides 8 by (dicarboxyiodo)benzenes gives N-1-acyl-N-1-(2-furyl)ureas 9 via rearrangement to a carbodiimide. Thermolysis of eleven ureas 9 gave the corresponding 2-acylaminofurans 10, which cannot be made from the free amines owing to their high instability. When oxidation of the corresponding benzo[b]furan derivatives 12 was investigated a new type of product was isolated, in addition to the expected ureas 14, and these were shown to be benzo[4,5]furo[2,3-d]pyrimidine derivatives 15. The mechanism of formation of these products must involve reaction of the carbodiimide intermediate with the amidine precursor and cyclisation of the resulting guanidine derivatives 19. The corresponding tetraphenylguanidine 21 was prepared and underwent thermal cyclisation but the quinazoline derivative formed 23 was shown to occur via an alternative cyclisation mechanism. The structures of cyclisation products 15 and 23 were confirmed by X-ray crystallography. N-(2-Furyl)acetamide 10a readily undergoes cycloaddition reactions with electron-deficient alkynes to give phenols after spontaneous ring opening. Observed regioselectivity is in agreement with the results of AM1 molecular orbital calculations. Reaction of the amide 10a with Lawesson's reagent gave the thioamide 26.

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More information

Published date: 2001
Keywords: diels-alder reaction, cycloaddition, furans, construction, cyclization, alkaloids, sequence, anilines

Identifiers

Local EPrints ID: 19413
URI: https://eprints.soton.ac.uk/id/eprint/19413
ISSN: 0300-922X
PURE UUID: 4f08f4f8-e86d-41a6-90de-b65b3b31795b
ORCID for Simon J. Coles: ORCID iD orcid.org/0000-0001-8414-9272

Catalogue record

Date deposited: 14 Feb 2006
Last modified: 06 Jun 2018 12:54

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Contributors

Author: Mária Bobošíková
Author: William Clegg
Author: Simon J. Coles ORCID iD
Author: Miloslava Dandárová
Author: Tibor Kiss
Author: Alžbeta Krutošíková
Author: Tibor Liptaj
Author: Nad'a Prónayová
Author: Christopher A. Ramsden

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