Heterocyclic rearrangements. Part V. Transformations of 3,5-diacetyl-4-chloromethyl-1,4-dihydro-2,6-dimethylpyridine

Allgrove, R. C.; Cort, L. A.; Elvidge, J. A.

doi:10.1039/j39710000434

Cited by 7 publications

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“…This reaction also occurred when the dihydropyridine 1 was treated with sodium cyanide in DMSO (20°C, 16 h) and resulted in the formation of the azepine 3 in nearly quantitative yield [23,24]. The azepines 11 [25], 12 [23], and 13 [26,27] were synthesized in a similar way, using the dihydropyridines 4-6, respectively, as substrates.…”

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confidence: 99%

Synthesis of Nitrogen-containing Heterocyclic Compounds by Ring Enlargement Reactions through Bicyclic Cyclopropane Intermediates (Review)

Fesenko

Шуталев

2013

Chem Heterocycl Comp

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Papers on the synthesis of nitrogen-containing heterocyclic compounds by ring enlargement reactions based on the formation of an annelated cyclopropane ring by intramolecular alkylation followed by cleavage of the zero bridge in the obtained [n.1.0] bicyclic systems are reviewed.Ring enlargement is currently one of the most important and often the only tool for the synthesis of various carbocyclic and heterocyclic compounds [1-6]. A significant place among this type of transformations is occupied by reactions that proceed through small ring intermediates, in particular cyclopropanes [7][8][9][10][11][12][13]. Cyclopropanation of cyclic compounds followed by cleavage of the zero bridge in the obtained [n.1.0] bicyclic systems should be noted among the known synthetic strategies based on ring enlargement by one carbon atom. One of the methods for creating an annelated cyclopropane ring is intramolecular alkylation.This review is devoted to analysis of published data on the synthesis of nitrogen-containing heterocyclic compounds using the above-mentioned methodology. Synthesis of AzepinesThe most studied types of heterolytic cyclopropanation used for the construction of [n.1.0] bicyclic systems are intramolecular alkylation of enamines and related compounds of the X-(C=C) n -C-C-LG type, where X is an atom with a lone pair of electrons (e.g., N, N -, C -, etc.) and LG is a leaving group. Typical examples of these compounds are the readily available 1,4-dihydropyridines [14, 15] containing a halomethyl

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confidence: 99%

Synthesis of Nitrogen-containing Heterocyclic Compounds by Ring Enlargement Reactions through Bicyclic Cyclopropane Intermediates (Review)

Fesenko

Шуталев

2013

Chem Heterocycl Comp

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“…A reinvestigation of the action of cyanide ion on the diester l c revealed that ring expansion had taken place leading to a 4,5-dihydro-lH-azepine (4), and this was extended to the dicyano ( 5 ) and diacetyl compounds (6). Subsequent work has shown that the chloromethyl compounds may be used in the synthesis of azepines (7), pyrroles (4-7), fulvenes (8).…”

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The rearrangement of 4-chloromethyl-1,4-dihydropyridine derivatives to pyrrolo [1,2-c] pyrimidines

Bullock¹,

Thomas²

1977

Can. J. Chem.

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. When refluxed with urea in ethanol, certain 4-chloromethyl-1,4-dihydropyridines undergo reamangement to give 1,2,5,9-tetrahydro-l-oxopy1~olo [l,2-c]pyrimidines In good yield. The structures of the products are established by spectroscopic properties and by dehydrogenation, hydrolysis, anddecarboxylation to a 1,2-dihydro-1-oxopyrrolo[l,2-clpyrimidine. In contrast, the reaction between thiourea and the 4-chloromethyl-1,4-dihydropyridines occurs w~thout rearrangement and gives isothiouronium salts which were isolated as the picrates.ERIC BULLOCK, BRIAN GREGORY et M. THOMAS THOMAS. Can. J. Chem. 55, 693 (1977). Lorsque l'on porte certaines chloromethyl-4 dihydro-1,4 pyridines au reflux avec de I'uree dans I'ethanol, il se produit un rearrangement qui conduit aux tetrahydro-1,2,5,9 0x0-l pyrrolo[1.2-clpyrimidines avec de bon rendement. On a etabli les structures des produits par des methodes spectroscopiques et par deshydrogenation, hydrolyse et decarboxylation pour conduire a la dihydro-1,2 0x0-l pyrrolo[l,2-c,]pyrimidine. Par opposition, la reaction entre la thiouree et les chloromethyl-4 dihydro-1,4 pyridines se produit sans rearrangement et donne des sels d'isothiouronium qui ont pu Ctre isoles sous forme de picrates.[Traduit par le journal]4-Chloromethyl-l,4-dihydropyridines having electron-withdrawing substituents such as ethoxycarbonyl (I), acetyl (2), and cyano (3) groups at C, and C, were first synthesized by Benary who also reported some of their reactions with nucleophilic reagents. A reinvestigation of the action of cyanide ion on the diester l c revealed that ring expansion had taken place leading to a 4,5-dihydro-lH-azepine (4), and this was extended to the dicyano ( 5 ) and diacetyl compounds (6). Subsequent work has shown that the chloromethyl compounds may be used in the synthesis of azepines (7), pyrroles (4-7), fulvenes (8). 2,3-dihydrofurans (6), 2-aza-8-thiabicyclo-[3.2.l]oct-3-enes (9), and furo[2,3-blpyridines (10). We now report that the reaction of urea on the 4-chloromethyl compounds leads to pyrrolo[l,2-clpyrimidine derivatives in adequate yield.When the chloromethyl compound Pc was refluxed with urea in ethanol, the ultraviolet maxima at 231 and 349 nm (4) of the dihydropyridine chromophore were replaced, over the course of a few hours, by bands at 263 and 310 nm. Addition of water at this stage caused precipitation of a compound C,,H,,N,O,, M + 308 whose ultraviolet spectrum was incompatible with the presence of dihydropyridine, tetrahydropyridine, dihydroazepine, and pyrrole chromophores. The infrared spectrum revealed the presence of NH (v,,, 3415 cm-I) and ester group(s) (v,,, 1707 cm-I), while the mass spectrum was indicative of the presence of two ester groups (see below). The nmr spectrum showed signals due to methyl groups at 6 2.68 (t,' J -1 Hz) and 2.28 (d, J -1 Hz), which exhibit homollylic coupling to two and one protons respectively. The appearance of 1 : 1 : 1 : 1 quartets at 6

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1999

Chemistry of Heterocyclic Compounds: A Series of Monographs

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Heterocyclic rearrangements. Part V. Transformations of 3,5-diacetyl-4-chloromethyl-1,4-dihydro-2,6-dimethylpyridine

Cited by 7 publications

References 0 publications

Synthesis of Nitrogen-containing Heterocyclic Compounds by Ring Enlargement Reactions through Bicyclic Cyclopropane Intermediates (Review)

Synthesis of Nitrogen-containing Heterocyclic Compounds by Ring Enlargement Reactions through Bicyclic Cyclopropane Intermediates (Review)

The rearrangement of 4-chloromethyl-1,4-dihydropyridine derivatives to pyrrolo [1,2-c] pyrimidines

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