Photochemistry of fluorinated heterocyclic compounds. An expedient route for the synthesis of fluorinated 1,3,4-oxadiazoles and 1,2,4-triazoles

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Abstract

The photochemistry of some 3-N-alkylamino-5-perfluoroalkyl-1,2,4-oxadiazoles in the presence of nitrogen nucleophiles such as ammonia and primary and secondary aliphatic amines has been investigated. The primary photolytic intermediate from the cleavage of the ring O−N bond follows two distinct and competing pathways leading to (i) 5-perfluoroalkyl-1,3,4-oxadiazoles, through the ring contraction−ring expansion photoisomerization route favored by the presence of the base or (ii) 5-perfluoroalkyl-1,2,4-triazoles, through the intervention, as an internal nucleophile, of the exocyclic N-alkylamino moiety of the oxadiazole followed by the attack of the external nitrogen nucleophile and subsequent heterocyclization. Some comments on the photoreactivity of fluorinated oxadiazoles and on the applications of these photoprocesses in the synthesis of target fluorinated structures are emphasized. In this context, irradiations of 3-perfluoroalkanoylamino-4-phenylfurazan in the presence of primary aliphatic amines are reconsidered as feasible one-pot synthetic methodologies toward fluorinated heterocycles. X-ray analysis of two representative products 1-methyl-3-methylamino-5-perfluoroheptyl-1,2,4-triazole and 2-methylamino-5-trifluoromethyl-1,3,4-oxadiazole confirmed the proposed structures and furnished interesting information on the crystal packing of these fluorinated five-membered heterocycles.
Lingua originaleEnglish
pagine (da-a)4108-4115
Numero di pagine8
RivistaJournal of Organic Chemistry
Volume69
Stato di pubblicazionePublished - 2004

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Oxadiazoles
Heterocyclic Compounds
Nucleophiles
Photochemical reactions
Amines
Nitrogen
Photoreactivity
Photoisomerization
X ray analysis
Ammonia
Irradiation
Crystals
1,2,4-triazole
1,3,4-oxadiazole

All Science Journal Classification (ASJC) codes

  • Organic Chemistry

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@article{c2431bbe6eeb4f3597f956dbc4ebd726,
title = "Photochemistry of fluorinated heterocyclic compounds. An expedient route for the synthesis of fluorinated 1,3,4-oxadiazoles and 1,2,4-triazoles",
abstract = "The photochemistry of some 3-N-alkylamino-5-perfluoroalkyl-1,2,4-oxadiazoles in the presence of nitrogen nucleophiles such as ammonia and primary and secondary aliphatic amines has been investigated. The primary photolytic intermediate from the cleavage of the ring O−N bond follows two distinct and competing pathways leading to (i) 5-perfluoroalkyl-1,3,4-oxadiazoles, through the ring contraction−ring expansion photoisomerization route favored by the presence of the base or (ii) 5-perfluoroalkyl-1,2,4-triazoles, through the intervention, as an internal nucleophile, of the exocyclic N-alkylamino moiety of the oxadiazole followed by the attack of the external nitrogen nucleophile and subsequent heterocyclization. Some comments on the photoreactivity of fluorinated oxadiazoles and on the applications of these photoprocesses in the synthesis of target fluorinated structures are emphasized. In this context, irradiations of 3-perfluoroalkanoylamino-4-phenylfurazan in the presence of primary aliphatic amines are reconsidered as feasible one-pot synthetic methodologies toward fluorinated heterocycles. X-ray analysis of two representative products 1-methyl-3-methylamino-5-perfluoroheptyl-1,2,4-triazole and 2-methylamino-5-trifluoromethyl-1,3,4-oxadiazole confirmed the proposed structures and furnished interesting information on the crystal packing of these fluorinated five-membered heterocycles.",
author = "Nicolo' Vivona and Silvestre Buscemi and Andrea Pace and Ivana Pibiri and Luciana Malpezzi",
year = "2004",
language = "English",
volume = "69",
pages = "4108--4115",
journal = "Journal of Organic Chemistry",
issn = "0022-3263",
publisher = "American Chemical Society",

}

TY - JOUR

T1 - Photochemistry of fluorinated heterocyclic compounds. An expedient route for the synthesis of fluorinated 1,3,4-oxadiazoles and 1,2,4-triazoles

AU - Vivona, Nicolo'

AU - Buscemi, Silvestre

AU - Pace, Andrea

AU - Pibiri, Ivana

AU - Malpezzi, Luciana

PY - 2004

Y1 - 2004

N2 - The photochemistry of some 3-N-alkylamino-5-perfluoroalkyl-1,2,4-oxadiazoles in the presence of nitrogen nucleophiles such as ammonia and primary and secondary aliphatic amines has been investigated. The primary photolytic intermediate from the cleavage of the ring O−N bond follows two distinct and competing pathways leading to (i) 5-perfluoroalkyl-1,3,4-oxadiazoles, through the ring contraction−ring expansion photoisomerization route favored by the presence of the base or (ii) 5-perfluoroalkyl-1,2,4-triazoles, through the intervention, as an internal nucleophile, of the exocyclic N-alkylamino moiety of the oxadiazole followed by the attack of the external nitrogen nucleophile and subsequent heterocyclization. Some comments on the photoreactivity of fluorinated oxadiazoles and on the applications of these photoprocesses in the synthesis of target fluorinated structures are emphasized. In this context, irradiations of 3-perfluoroalkanoylamino-4-phenylfurazan in the presence of primary aliphatic amines are reconsidered as feasible one-pot synthetic methodologies toward fluorinated heterocycles. X-ray analysis of two representative products 1-methyl-3-methylamino-5-perfluoroheptyl-1,2,4-triazole and 2-methylamino-5-trifluoromethyl-1,3,4-oxadiazole confirmed the proposed structures and furnished interesting information on the crystal packing of these fluorinated five-membered heterocycles.

AB - The photochemistry of some 3-N-alkylamino-5-perfluoroalkyl-1,2,4-oxadiazoles in the presence of nitrogen nucleophiles such as ammonia and primary and secondary aliphatic amines has been investigated. The primary photolytic intermediate from the cleavage of the ring O−N bond follows two distinct and competing pathways leading to (i) 5-perfluoroalkyl-1,3,4-oxadiazoles, through the ring contraction−ring expansion photoisomerization route favored by the presence of the base or (ii) 5-perfluoroalkyl-1,2,4-triazoles, through the intervention, as an internal nucleophile, of the exocyclic N-alkylamino moiety of the oxadiazole followed by the attack of the external nitrogen nucleophile and subsequent heterocyclization. Some comments on the photoreactivity of fluorinated oxadiazoles and on the applications of these photoprocesses in the synthesis of target fluorinated structures are emphasized. In this context, irradiations of 3-perfluoroalkanoylamino-4-phenylfurazan in the presence of primary aliphatic amines are reconsidered as feasible one-pot synthetic methodologies toward fluorinated heterocycles. X-ray analysis of two representative products 1-methyl-3-methylamino-5-perfluoroheptyl-1,2,4-triazole and 2-methylamino-5-trifluoromethyl-1,3,4-oxadiazole confirmed the proposed structures and furnished interesting information on the crystal packing of these fluorinated five-membered heterocycles.

UR - http://hdl.handle.net/10447/4339

M3 - Article

VL - 69

SP - 4108

EP - 4115

JO - Journal of Organic Chemistry

JF - Journal of Organic Chemistry

SN - 0022-3263

ER -