A one‐step synthesis of 2‐methylthio‐6‐oxopyrimidine derivatives: Preparation of fused pyrimidinones

Hussain, S. M.; El‐Barbary, A. A.; Mansour, Said

doi:10.1002/jhet.5570220141

Cited by 30 publications

(13 citation statements)

References 5 publications

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“…Furthermore, the assignment of structure 6 to the products isolated from the studied reactions is also substantiated by the similarity of their carbonyl stretching frequencies ( = 1690-1710 cm -1 ) with those reported for pyrimidinones I. For example, pyrimidinones I exhibit their CO bands in the region 1680-1690 cm -1 whereas pyrimidinones II exhibit their CO bands in the region1640-1660 cm -1 [13].…”

Section: Resultsmentioning

confidence: 57%

“…An immediate distinction between these two structures was reached by comparison of the 13 C NMR and IR spectra with those of similar annelated pyrimidinones. Literature reports [12,13] have shown that the chemical shift for the carbonyl carbon in 4-pyrimidinone derivatives is markedly affected by the nature of the adjacent nitrogen (N3) (pyrrole type in our structure 6 and pyridine type as in structure 7). For example, the 13 C nmr spectra of 6Aa, 6Bb, 6Ca and 6Da, taken as typical examples of the series prepared, revealed the signals of the carbonyl carbon of the pyrimidinone ring residue at 168, 167.5, 167.7 and 167.8, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…1 H NMR spectra were recorded on a Joel JNM-EX 270 FT NMR spectrometer and a Bruker spectrometer model 250. 13 C NMR spectra were measured on a Joel 68.5 MHz instrument. Mass spectra were obtained with a 75 eV Kratos spectrometer.…”

Section: Methodsmentioning

confidence: 99%

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Facile entries for regioselective synthesis of [1,2,4]triazolo-[4,3-a]pyrimidin-5(1H)-ones from 2-thiouracil

Shawali

Abbas

Mahran

2004

JICS

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Three new alternative synthetic strategies based on reactions of hydrazonoyl halides 3 with 2-methylthiouracil 2 and treatment of either 2-pyrimidinyl thiohydrazonates 8 or the diazonium coupling products of active (pyrimidin-2-ylthio)methylene compounds 12 with sodium ethoxide in ethanol are described for the title compounds. The mechanisms and regiochemistry of the studied reactions are discussed.

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Section: Resultsmentioning

confidence: 57%

Section: Resultsmentioning

confidence: 99%

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Facile entries for regioselective synthesis of [1,2,4]triazolo-[4,3-a]pyrimidin-5(1H)-ones from 2-thiouracil

Shawali

Abbas

Mahran

2004

JICS

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“…T hey w ere p re p a red [28] by the nucleophilic dis placem ent of the SH or SR groups at C-2 of 1 -3 . The displacem ent from 2 and 3 was m ore facile th a n th at from 1.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Dimroth Rearrangement of 6-Cyano-l,2,4-triazolo- [4,3-a]pyrimidin-5- and 7-ones. A Novel Alkylation with Orthoesters and a New Participation of the Cyano Group in the Rearrangement

Ashry¹,

Kilany²,

Rashed³

et al. 1998

Zeitschrift Für Naturforschung B

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The cyclization products of 5-cyano-2-hydrazino-6-phenyl-3,4-dihydropyrimidin-4-one (6) with one carbon inserting agents have been confirmed to be of the l,2,4-triazolo[4,3-a]pyrimidin-5(8//)-ones type and not the respective 7-ones, by comparing their alkylated deriva tives 10a, 11a, 27 and 28 with the product from the cyclization of the 3-methyl and 3-benzyl derivatives of 6. A novel alkylation process was found when triethyl orthoformate was used as a cyclizing agent. Dimroth rearrangement of 8, 14, 15, 24, 34 and 36 with 2% ethanolic KOH gave the respective triazolo[l,5-a]pyrimidinone 13, 18, 19, 25, 38 and 40, respectively. Using 10% ethanolic KOH led to a novel participation of the cyano group in the rearrange ment whereby 8a gave 7-imino-5-phenyl-l,2,4-triazolo[l,5-a]pyrimidine 22.

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“…The spectrum showed the disappearance of the NH proton and the appearance of a diagnostic singlet signal at δH 3.61 ppm arising from the N-methyl protons. This shift is characteristic for a N-3-methyl group, which has been reported by Ram et al [28], and by others [29][30][31], to experience a further downfield shift to around δH ~ 3.5 ppm due to the additional deshielding effect of the adjacent carbonyl moiety. The remaining resonances were also observed at the expected frequencies (see Experimental section).…”

Section: Chemistrymentioning

confidence: 74%

Regioselective synthesis and antimicrobial studies of novel bridgehead nitrogen heterocycles containing the thienopyrimidinone skeleton

Gaber

Moussa

2011

Eur. J. Chem.

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KEYWORDSVersatile 2-(alkylthio)pyrimidine-type and 2-(phenacylamino)thiophene building blocks (4ad) and 16 were obtained based on an ortho functionalized thiophene derivative 1. A novel series of thieno[2,3-d]pyrimidin-4-one derivatives with annelated bridgehead nitrogen heterocycles was synthesized starting from precursors 4 and 16 through convenient methods. Cyclocondensation of 2-(phenacylthio)pyrimidinone derivative (4b) with sulfuric acid led to the tricyclic thiazole derivative 5. Initial hydrazinolysis of 3-(carbethoxymethyl)pyrimidinone derivative (4d) followed by nitrous acid deamination of the formed N-aminolactam (7) to obtain a N-protodeamino analogue 8a, which on further treatment with formaldehyde and piperidine yielded the respective Mannich-type base 8b. On the other hand, initial hydrazinolysis of 3-unsubstituted pyrimidinone derivative 4a and subsequent acetylation gave the condensed 3-methyltriazole derivative 12, whereas the condensed pyrrole derivative 19 was obtained by heterocyclization of 2-phenacylamine derivative 16 with malononitrile. All newly-obtained thienopyrimidinones with annelated bridgehead nitrogen were screened for their antimicrobial activity against strains of a representative panel of Gram-positive and Gram-negative bacteria as well as fungi together with reference drugs. The compounds under investigation displayed generally good in vitro antibacterial and antifungal activities, with compound 8b that has a N-piperidinylmethyl moiety showing essentially the highest inhibition in both assays. Despite promising antimicrobial activity of N-1-substituted imidazole derivative 8b, the corresponding N-1-unsubstituted analogue 8a displayed poor activity. The heteroannelation of a N-(piperidinylmethyl)imidazole or 3-methyltriazole moiety to the thienopyrimidinone scaffold could be considered as a potential strategy for the development of new therapeutic antimicrobial agents.Thienopyrimidinone Alkylation Cyclodehydration Hydrazinolysis Acetylation Antimicrobial activity

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A one‐step synthesis of 2‐methylthio‐6‐oxopyrimidine derivatives: Preparation of fused pyrimidinones

Cited by 30 publications

References 5 publications

Facile entries for regioselective synthesis of [1,2,4]triazolo-[4,3-a]pyrimidin-5(1H)-ones from 2-thiouracil

Facile entries for regioselective synthesis of [1,2,4]triazolo-[4,3-a]pyrimidin-5(1H)-ones from 2-thiouracil

Synthesis and Dimroth Rearrangement of 6-Cyano-l,2,4-triazolo- [4,3-a]pyrimidin-5- and 7-ones. A Novel Alkylation with Orthoesters and a New Participation of the Cyano Group in the Rearrangement

Regioselective synthesis and antimicrobial studies of novel bridgehead nitrogen heterocycles containing the thienopyrimidinone skeleton

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