Gallium iodide/iodine as a versatile reagent for the aza-Prins cyclization: an expeditious synthesis of 4-iodopiperidines

Yadav, J. S.; Reddy, B. V. Subba; Chaya, Dudhmal N.; Kumar, G. G. K. S. Narayana; Subramanian, Aravind; Kunwar, A. C.; Madavi, C.

doi:10.1016/j.tetlet.2008.03.006

Cited by 46 publications

(15 citation statements)

References 21 publications

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“…109 Various secondary benzylic chlorides were converted to the cyclopropylated products in moderate to high yields (Table 30). [3][4][5][6][7][8][9][10] Chlorocyclohexene and β-chloroesters could also be transformed in this manner, albeit in more modest yields (entries 6 and 8).…”

Section: 13mentioning

confidence: 99%

Recent applications of gallium and gallium halides as reagents in organic synthesis

Gupta

O’Sullivan

2013

RSC Adv.

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Section: 13mentioning

confidence: 99%

Recent applications of gallium and gallium halides as reagents in organic synthesis

Gupta

O’Sullivan

2013

RSC Adv.

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“…H); other signals overlapped with the major diastereomer 13. C NMR (75 MHz, CDCl 3 ): δ (trans-3h) = 18.7, 21.3, 26.7, 28.0, 28.8, 45.9, 59.7, 122.5, 123.3, 126.7, 126.9, 127.4, 127.8, 129.1, 129.4, 129.8, 132.7, 133.3, 136.0, 137.4, 143.1, 145.1, 147.5; δ (cis-3h) = 18.5, 21.3, 26.2, 27.2, 27.6, 46.5, 60.2, 123.0, 123.7, 126.0, 126.7, 127.4, 128.4, 129.2, 129.9, 130.2, 132.6, 134.9, 135.8, 136.8, 143.7, 146.5, 147.7.…”

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confidence: 97%

“…1,2 Thus, preparations of piperidines and tetrahydropyridines by a wide range of protocols have been reported. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] However, aza-Prins reactions have been used less frequently in the construction of other ring systems. [19][20][21][22][23] In this context, we describe the synthesis under mild and metal-free conditions of a series of hexahydrobenzo[f]isoquinolines through an iodine-catalyzed aza-Prins cyclization.…”

mentioning

confidence: 99%

“…13 C NMR (75 MHz, CDCl 3 ): δ (trans-3c) = 14.3, 18.9, 19.3, 21.4, 27.4, 28.2, 28.4, 34.5, 46.2, 57.4, 122.2, 126.4, 126.5, 127.1, 127.5, 129.4, 131.0, 132.3, 133.5, 136.2, 139.2, 142.8; δ (cis-3c) = 13.7, 18.7, 19.9, 21.2, 25.3, 27.0, 28.1, 35.0, 45.8, 57.3, 122.7, 125.5, 125.9, 126.8, 129.0, 131.2, 133.2, 135.0, 136.0, 137.7, 143.0; other signals overlapped with the major diastereomer.…”

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Iodine-Catalyzed Aza-Prins Cyclization: Metal-Free Synthesis and Antiproliferative Activity of Hexahydrobenzo[f]isoquinolines

et al. 2013

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A series of hexahydrobenzo[f]isoquinolines were synthesized by an iodine-catalyzed aza-Prins cyclization under metalfree conditions. An aliphatic or an aromatic aldehyde can be used as the carbonyl component in this reaction, which can also be performed efficiently under solvent-free conditions. During this study, we discovered new compounds with moderate antitumor activities.Aza-Prins cyclization can be defined as the reaction of a homoallylic amine with a carbonyl compound in the presence of an acid (Lewis or Brønsted). This reaction provides a powerful method for the synthesis of Nheterocycles. 1,2 Thus, preparations of piperidines and tetrahydropyridines by a wide range of protocols have been reported. 3-18 However, aza-Prins reactions have been used less frequently in the construction of other ring systems. [19][20][21][22][23] In this context, we describe the synthesis under mild and metal-free conditions of a series of hexahydrobenzo[f]isoquinolines through an iodine-catalyzed aza-Prins cyclization. On the basis of the potential biological activity of the target compounds 24-26 and our continuing efforts to discover new antitumor entities, 27,28 we also examined the antiproliferative activities of the hexahydrobenzo[f]isoquinolines that we prepared. N- [2][3]propyl]-4-methylbenzenesulfonamide (1) was prepared from 1-tetralone in four steps: Reformatsky/dehydration reaction, reduction, Mitsunobu reaction, and hydrolysis of a tert-butoxycarbonyl group. 29-31 A series of commercially available aldehydes were used as the carbonyl components. On the basis of our previous works on Prins cyclization, 32,33 we performed the cyclizations by using 10 mol% of iodine as the catalyst in dichloromethane (Table 1). When an unhindered aliphatic aldehyde such as formaldehyde, acetaldehyde, or butanal was used as the carbonyl component, the reaction was complete within 1.5-3 hours (entries 1-3). For more-hindered aliphatic aldehydes, such as 2d-e, the reaction time increased to one to two days, and yields were lower, although still within the practical range (entries 4 and 5). We also performed the reaction with aromatic aldehydes, including aldehydes substituted with electron-withdrawing and or electron-donating groups, and the reaction times in these cases were as much as three days (entries 6-8). The nitro-substituted aldehyde 2h gave a low yield of the corresponding product (entry 8). We also investigated the behavior of cinnamaldehyde (2i) in the aza-Prins reaction with 1, and we found that it gave the desired product 3i in very good yield (entry 9).The reaction time for some of the reactions shown in Table 1 was relatively long (>24 hours). With solvent-free conditions and higher temperatures, it was possible to isolate the desired N-heterocyclic compounds in shorter reaction times and in comparable or higher yields (compare Table 2 with entries 7 and 8 in Table 1).The relative configurations of compounds 3b-i were assigned by NMR analysis, including NOESY experiments. The preferential formation of the trans-diastereo...

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“…Hence, it is a preferred replacement for toxic and expensive acid catalysts. The application of iodine has been reported in various organic strategies, such as the synthesis of a wide spectrum of heterocycles, 3 the iodination of organic compounds, 4 protection-deprotection of functional groups, 5 Michael additions, 6 Prins-related reactions, 7 and oxidation reactions. 8 Recently, iodine has attracted much attention as an expedient reagent for the synthesis of heterocyclic as well as acyclic compounds starting from isothiocyanates, thioamides, or dithiocarbamates through a desulfurization process.…”

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Iodine-Mediated Synthesis of Novel Pyrazole Derivatives

et al. 2016

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The reaction between N,2-diarylhydrazinecarbothioamide (generated from arylhydrazines and aryl isothiocyanates) and malononitrile in the presence of iodine/triethylamine in N,N-dimethylformamide at 80 °C afforded novel pyrazoles, 5-amino-1-aryl-3-(arylamino)-1H-pyrazole-4-carbonitriles, in good yields. In this strategy, iodine served as a versatile desulfurizing agent, efficiently promoting the cyclization reaction.

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Gallium iodide/iodine as a versatile reagent for the aza-Prins cyclization: an expeditious synthesis of 4-iodopiperidines

Cited by 46 publications

References 21 publications

Recent applications of gallium and gallium halides as reagents in organic synthesis

Recent applications of gallium and gallium halides as reagents in organic synthesis

Iodine-Catalyzed Aza-Prins Cyclization: Metal-Free Synthesis and Antiproliferative Activity of Hexahydrobenzo[f]isoquinolines

Iodine-Mediated Synthesis of Novel Pyrazole Derivatives

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