Center for Molecular Modeling - N. Dieltiens

The Formation of trans-Fused Macrocycles from N3,N3′-Polymethylenebis(hydantoins) by Ring-Closing Metathesis

wim — Mon, 03 Oct 2011 08:31:01 +0000

D.D. Claeys, C.V. Stevens, N. Dieltiens

European Journal of Organic Chemistry

(1), 171–179

2008

Abstract

A straightforward ring transformation giving polymethylenebis(hydantoins) was extended, as these are HMBA analogues. Firstly, ethyl or allyl pyroglutamate was carbamoylated with a diisocyanate. Upon treatment with KOtBu in allyl alcohol the bis(carbamoyllactam) rearranged to give the hydantoin, which was followed by the ring-opening of the pyrrolidinone with formation of the allyl ester. These compounds were subsequently ring-closed in the presence of second-generation Grubbs' catalyst to form macrocycles containing the ester functionality in the ring. It was established by HSQC experiments with inverse detection that only the E isomers were formed in the cases of the 24- and 26-membered heterocycles. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

DOI

http://dx.doi.org/10.1002/ejoc.200700836

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08 eur. j. org. chem 1 171 claeys.pdf

Exploiting the regioselectivity of pyroglutamate alkylations for the synthesis of 6-azabicyclo[3.2.1]octanes and 4-azabicyclo[3.3.0]octanes

wim — Mon, 03 Oct 2011 07:20:21 +0000

K.G.R. Masschelein, C.V. Stevens, N. Dieltiens, D.D. Claeys

Tetrahedron

63 (22), 4712–4724

2007

Abstract

Depending on the N-protecting group of pyroglutamates, the reactivity can be directed to the formation of 6-azabicyclo[3.2.1]octanes or 4-azabicyclo[3.3.0]octanes, which are conformationally restricted glutamate analogues.

DOI

http://dx.doi.org/10.1016/j.tet.2007.03.084

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07 tetrahadron 22 7412 masschelein.pdf

The Pyroglutamate Hydantoin Rearrangement

wim — Fri, 30 Sep 2011 13:49:24 +0000

N. Dieltiens, D.D. Claeys, V.V. Zhdankin, V.N. Nemykin, B. Allaert, F. Verpoort, C.V. Stevens

European Journal of Organic Chemistry

2006 (11), 2649–2660

2006

Abstract

When a mixture of a pyroglutamate and an isocyanate in THF is treated with NaH, a ring transformation occurs leading to functionalised hydantoins. The novel reaction involves a ring-closing ring-opening sequence providing a new and straightforward access to an interesting class of heterocyclic compounds. Furthermore, starting from pyroglutamates allows the synthesis of highly substituted hydantoins under very mild conditions. This ring transformation in combination with ring-closing metathesis is used in a four-step reaction sequence for the synthesis of multi-functionalised bicyclic hydantoin derivatives.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

DOI

http://dx.doi.org/10.1002/ejoc.200600051

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06 eur. j. org. chem. 11 2649 dieltiens.pdf

Synthesis of N(3),N‘(3)-Polymethylene-bis-hydantoins and Their Macrocyclic Derivatives

wim — Fri, 30 Sep 2011 13:46:21 +0000

N. Dieltiens, D.D. Claeys, C.V. Stevens

Journal of Organic Chemistry

71(10), 3863–3868

2006

Abstract

An efficient and straightforward two-step approach toward N(3),N‘(3)-polymethylene-bis-hydantoins was developed. As a first step, a pyroglutamate is reacted with a diisocyanate to produce a bis-carbamoyllactam. The second step is a double-ring transformation by treatment of this bis-carbamoyllactam with KOtBu in ethanol. In this fashion N(3),N‘(3)-polymethylene-bis-hydantoins are produced in two quantitative steps and under very mild conditions. When properly derivatized, these compounds can be converted to their macrocyclic derivatives upon treatment with 5 mol % of second-generation Grubbs' catalyst. These macrocyclic derivatives are so far not described in the literature. It was proven that exclusively (E)-isomers are formed.

DOI

http://dx.doi.org/10.1021/jo060370r

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06 j. org. chem. 71(10)3863 dieltiens.pdf

Synthesis of 1,3-dioxo-hexahydropyrido[1,2-c][1,3]diazepine carboxylates, a new bicyclic skeleton formed by ring expansion–RCM methodology

wim — Fri, 30 Sep 2011 13:02:42 +0000

N. Dieltiens, D.D. Claeys, B. Allaert, F. Verpoort, C.V. Stevens

Chemical Communications

(35), 4477

2005

Abstract

A short and elegant synthetic pathway was developed for the synthesis of 1,3-dioxo-hexahydropyrido[1,2-c][1,3]diazepine carboxylates, a new 1,3-diazepan-2,4-dione containing bicyclic moiety, starting from pyroglutamate esters.

DOI

http://dx.doi.org/10.1039/B508663A

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05 chem. comm. 35 4477 dieltiens.pdf

Straightforward Ring Expansion of Pyroglutamates to Perhydro-1,3-diazepine-2,4-diones

wim — Fri, 30 Sep 2011 12:58:12 +0000

C.V. Stevens, N. Dieltiens, D.D. Claeys

Organic Letters

7 (6), 1117–1119

2005

Abstract

Perhydro-1,3-diazepine-2,4-diones are rare and can only be prepared, up to now, by special methods. A new one-step protocol was developed, comprising N-carbamoylation using an isocyanate followed by intramolecular ring expansion. This new methodology provides a straightforward access to this interesting seven-membered skeleton.

(Additions and corrections: Org. Lett., 2005, 7, 5347), 2005

DOI

http://dx.doi.org/

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05 org. lett. 7(6)1117 stevens.pdf

Synthesis of Functionalised Bicyclic Hydantoin Derivatives via a Ring Transformation-RCM Sequence

wim — Tue, 18 Oct 2011 08:25:34 +0000

N. Dieltiens, D.D. Claeys, C.V. Stevens

Poster

Conference / event / venue

Sigma-Aldrich Organic Synthesis Meeting

Sol Cress, Spa, Belgium

Thursday, 1 December, 2005 to Friday, 2 December, 2005

The Formation of Trans-Fused Macrocycles from N(3),N’(3)-Polymethylenebishydantoins Using Second-Generation Grubbs’ Catalyst

wim — Tue, 18 Oct 2011 07:47:09 +0000

D.D. Claeys, N. Dieltiens, C.V. Stevens, V. Van Speybroeck, M. Waroquier

Poster

Conference / event / venue

IXth Netherlands' Chemistry and Catalysis Conference (NCCC IX)

Noordwijkerhout, The Netherlands

Monday, 3 March, 2008 to Wednesday, 5 March, 2008

The Formation of Trans-Fused Macrocycles from N(3),N’(3)-Polymethylenebishydantoins Using Ring-Closing Metathesis

wim — Tue, 18 Oct 2011 07:32:30 +0000

D.D. Claeys, N. Dieltiens, C.V. Stevens, V. Van Speybroeck, M. Waroquier

Poster

Conference / event / venue

VJC Vlaams Jongerencongres voor de Chemie

UA, Antwerp, Belgium

Tuesday, 8 April, 2008

Use of ring-closing metathesis to form trans-fused macrocyclic bis(hydantoins): synthesis and theory

wim — Tue, 18 Oct 2011 07:26:15 +0000

D.D. Claeys, N. Dieltiens, C.V. Stevens, V. Van Speybroeck, M. Waroquier

Poster

Conference / event / venue

11th Belgian Organic Synthesis Symposium (BOSS XI)

Ghent University, Ghent, Belgium

Sunday, 13 July, 2008 to Friday, 18 July, 2008