Syntheses of Oxazolo [4,5-<i>b</i>]pyridines and [4,5-<i>d</i>]pyrimidines

Doise, M.; Blondeau, D.; Sliwa, H.

doi:10.1080/00397919208021112

Cited by 12 publications

(5 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Oxazolo [4,5-d]pyrimidines by annulation of oxazole rings. [3,4] Besides thioimidates and orthoesters, a carboxylic acid can also be used as a source of the C(2) carbon atom of the oxazolopyrimidine scaffold. [3] In later work, a thiobenzyl imidate proved a suitable alternative to an orthoester.…”

Section: Scaffold Construction Starting From a Functionalized Pyrimidinementioning

confidence: 99%

“…No yields were reported for the latter approach. [4] Scheme 3. Condensation of an aminopyrimidinol with excess orthoester or a thiobenzyl imidate as reported by Doise and co-workers.…”

Section: Scaffold Construction Starting From a Functionalized Pyrimidinementioning

confidence: 99%

“…Condensation of an aminopyrimidinol with excess orthoester or a thiobenzyl imidate as reported by Doise and co-workers. [3,4] Besides thioimidates and orthoesters, a carboxylic acid can also be used as a source of the C(2) carbon atom of the oxazolopyrimidine scaffold. When 4-aminopyrimidin-5-ol 3 was treated with 3-hydroxybenzoic acid under harsh reaction conditions, oxazolopyrimidine scaffold 13 was obtained in low yield (Scheme 4).…”

Section: Scaffold Construction Starting From a Functionalized Pyrimidinementioning

confidence: 99%

See 2 more Smart Citations

Synthesis and Biological Activity of Oxazolopyrimidines

et al. 2018

View full text Add to dashboard Cite

In this work, the synthesis of oxazolo[4,5‐d]pyrimidines and oxazolo[5,4‐d]pyrimidines is reviewed. The review is focused on the construction of the scaffold rather than on its further modification. Nevertheless, selected examples illustrate some of the most common modifications of these scaffolds. The synthetic part is complemented by an overview of their biological activity. This review covers literature and patents from 1967 until the present.

show abstract

Section: Scaffold Construction Starting From a Functionalized Pyrimidinementioning

confidence: 99%

“…No yields were reported for the latter approach. [4] Scheme 3. Condensation of an aminopyrimidinol with excess orthoester or a thiobenzyl imidate as reported by Doise and co-workers.…”

Section: Scaffold Construction Starting From a Functionalized Pyrimidinementioning

confidence: 99%

Section: Scaffold Construction Starting From a Functionalized Pyrimidinementioning

confidence: 99%

See 1 more Smart Citation

Synthesis and Biological Activity of Oxazolopyrimidines

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Amidinates are of interest as structural units with wide utility in drug design and as synthons for the synthesis of heterocyclic compounds . Several synthetic strategies have been developed 3,4 in which the nucleophilic addition of amine to nitrile is the most convenient and atom-economic method …”

mentioning

confidence: 99%

Addition of Amines to Nitriles Catalyzed by Ytterbium Amides: An Efficient One-Step Synthesis of Monosubstituted N-Arylamidines

et al. 2008

View full text Add to dashboard Cite

show abstract

“…[1][2][3][4][5][6][7][8][9] Figure 1 [1,3]Oxazolo [5,4-d]-and [1,3]oxazolo[4, 5-d]pyrimidines In contrast, the isomeric [1,3]oxazolo[4, 5-d]pyrimidines II ( Figure 1) are poorly studied. Some have been obtained from 4-amino-5-hydroxypyrimidine and its derivatives by condensations with ortho esters 10,11 and benzoic anhydrides. 12 These methods are obviously unsuitable for the introduction of functional substituents at position 7 of the [1,3]oxazolo[4,5-d]pyrimidine system.…”

mentioning

confidence: 99%

Original Approach to New Derivatives of [1,3]Oxazolo[4,5-d]pyrimidine

Sviripa¹,

Gakh²,

Brovarets³

et al. 2006

Synthesis

View full text Add to dashboard Cite

Based on the readily available 4-dichloromethylene-2-phenyl-1,3-oxazol-5(4H)-one, preparative methods for the synthesis of a set of functionalized derivatives of the poorly studied [1,3]oxazolo [4,5-d]pyrimidine system were elaborated.Annelation of azole moieties at the d-side of the pyrimidine nucleus leads to analogues structurally related to purine. Of these, derivatives of the [1,3]oxazolo[5,4-d]pyrimidine fused system I ( Figure 1) have been studied the most comprehensively, and various methods for their synthesis have been presented. 1-9 Figure 1 [1,3]Oxazolo[5,4-d]-and [1,3]oxazolo[4,5-d]pyrimidines In contrast, the isomeric [1,3]oxazolo[4,5-d]pyrimidines II ( Figure 1) are poorly studied. Some have been obtained from 4-amino-5-hydroxypyrimidine and its derivatives by condensations with ortho esters 10,11 and benzoic anhydrides. 12 These methods are obviously unsuitable for the introduction of functional substituents at position 7 of the [1,3]oxazolo[4,5-d]pyrimidine system. The formation of 2-phenyl-[1,3]oxazolo[4,5-d]pyrimidin-7-one by isomerization of its isooxazole analogue 13 under flash vacuum pyrolysis at 700°C is also more likely to be of scientific than preparative interest.We report here on the elaboration of a preparative method for the synthesis of a series of mono-and difunctionalized derivatives of fused system II based on readily available 4-dichloromethylene-2-phenyl-1,3-oxazol-5(4H)-one (1) 14 (Scheme 1).Treating 1,3-oxazol-5(4H)-one 1 with benzamidine hydrochloride (2a) or similar reagents 2b and c in the presence of triethylamine led to substituted imidazol-4(5)-ones 3a-c, which on heating in pyridine underwent cyclocondensation followed by recyclization affording the corresponding [1,3]oxazolo[4,5-d]pyrimidines 7a-c in 60-70% yields (Scheme 1). Since the structure of one of the intermediates 3a was reliably established earlier, 15 the structures of the similar compounds 3b and c were confirmed by 1 H NMR and IR spectroscopy ( Table 1). The structure of compound 10, the end product of the cascade transformation 1→3c→7c→10, was unequivocally solved by X-ray diffraction ( Figure 2 and Table 2).In the solid state there are two symmetrically independent molecules 10A and 10B with virtually the same geometry. The central oxazolo [4,5-d]pyrimidine system N(1-3)C(1-5)O(1) is planar within 0.03 Å. Notable is the quite strong 16 intramolecular hydrogen bond N(2)-H···O(3) 'assisted by resonance' 17 forming a six-membered ring O(3)C(12)N(4)C(5)N(2)H(2) as an interesting peculiarity of the molecular structure of compound 10.Since the presence of the [1,3]oxazolo[4,5-d]pyrimidine system in key compound 10 was reliably established, there are no doubts that the similar compounds 7a-c as well as 8a,b and 9a,b are also derivatives of this system. Furthermore, the melting points and spectral characteristics of compounds 7a, 8a, and 9a differ from those of the corresponding derivatives of the isomeric [1,3]oxazolo[5,4-d]pyrimidine system prepared by known methods. 6 This supports the correctness of the int...

show abstract

Syntheses of Oxazolo [4,5-b]pyridines and [4,5-d]pyrimidines

Cited by 12 publications

References 6 publications

Synthesis and Biological Activity of Oxazolopyrimidines

Synthesis and Biological Activity of Oxazolopyrimidines

Addition of Amines to Nitriles Catalyzed by Ytterbium Amides: An Efficient One-Step Synthesis of Monosubstituted N-Arylamidines

Original Approach to New Derivatives of [1,3]Oxazolo[4,5-d]pyrimidine

Contact Info

Product

Resources

About