Unexpected Dealkylation During Nucleophilic Substitution: Synthesis of 2-N,N-Dialkylamino Benzoxazoles and Benzothiazoles

A.I. Khalaf, R.G. Alvarez, C.J. Suckling, R.D. Waigh

Research output: Contribution to journal › Article

24 Citations (Scopus)

Abstract

Mild reaction conditions are described for the preparation of a number of 2-alkyl- and 2-arylaminobenzoxazoles and benzothiazoles from 2-chlorobenzoxazole and 2-chlorobenzothiazole and N-methyl or other simple N-alkyl tertiary amines. The reaction proceeds neat or in THF solution and involves dealkylation of the amine reactant by nucleophilic substitution by chloride. In the case of N-methylpyrrolidine and N-methylpiperidine demethylation was not observed and the major product was formed by ring opening to give chlorobutyl- and chloropentyl-methylamino substituted benzoxazoles and benzothiazoles. Treatment of the chlorobutyl derivative with iodide in acetone afforded the new 1H,2H,3H,4H,5H-[1,3]diazepino[2,1-b][1,3]benzoxazol-6-ium ring system.
LanguageEnglish
Pages8567-8571
Number of pages4
JournalTetrahedron
Volume56
Issue number43
DOIs
Publication statusPublished - 20 Oct 2000

Fingerprint

Benzothiazoles
Benzoxazoles
Dealkylation
Amines
Substitution reactions
Iodides
Acetone
Chlorides
Derivatives

Keywords

  • 2-arylaminobenzoxazoles
  • 2-chlorobenzoxazole
  • 2-chlorobenzothiazole
  • dealkylation
  • [1
  • 3]diazepino[2
  • 1-b][1
  • 3]benzazoles

Cite this

Khalaf, A.I. ; Alvarez, R.G. ; Suckling, C.J. ; Waigh, R.D. / Unexpected Dealkylation During Nucleophilic Substitution: Synthesis of 2-N,N-Dialkylamino Benzoxazoles and Benzothiazoles. In: Tetrahedron. 2000 ; Vol. 56, No. 43. pp. 8567-8571.
@article{0d40fc04e63d43239eb9c21c8af3b0c9,
title = "Unexpected Dealkylation During Nucleophilic Substitution: Synthesis of 2-N,N-Dialkylamino Benzoxazoles and Benzothiazoles",
abstract = "Mild reaction conditions are described for the preparation of a number of 2-alkyl- and 2-arylaminobenzoxazoles and benzothiazoles from 2-chlorobenzoxazole and 2-chlorobenzothiazole and N-methyl or other simple N-alkyl tertiary amines. The reaction proceeds neat or in THF solution and involves dealkylation of the amine reactant by nucleophilic substitution by chloride. In the case of N-methylpyrrolidine and N-methylpiperidine demethylation was not observed and the major product was formed by ring opening to give chlorobutyl- and chloropentyl-methylamino substituted benzoxazoles and benzothiazoles. Treatment of the chlorobutyl derivative with iodide in acetone afforded the new 1H,2H,3H,4H,5H-[1,3]diazepino[2,1-b][1,3]benzoxazol-6-ium ring system.",
keywords = "2-arylaminobenzoxazoles, 2-chlorobenzoxazole, 2-chlorobenzothiazole, dealkylation, [1, 3]diazepino[2, 1-b][1, 3]benzazoles",
author = "A.I. Khalaf and R.G. Alvarez and C.J. Suckling and R.D. Waigh",
year = "2000",
month = "10",
day = "20",
doi = "10.1016/S0040-4020(00)00802-4",
language = "English",
volume = "56",
pages = "8567--8571",
journal = "Tetrahedron",
issn = "0040-4020",
number = "43",

}

Khalaf, AI, Alvarez, RG, Suckling, CJ & Waigh, RD 2000, 'Unexpected Dealkylation During Nucleophilic Substitution: Synthesis of 2-N,N-Dialkylamino Benzoxazoles and Benzothiazoles' Tetrahedron, vol. 56, no. 43, pp. 8567-8571. https://doi.org/10.1016/S0040-4020(00)00802-4

Unexpected Dealkylation During Nucleophilic Substitution: Synthesis of 2-N,N-Dialkylamino Benzoxazoles and Benzothiazoles. / Khalaf, A.I.; Alvarez, R.G.; Suckling, C.J.; Waigh, R.D.

In: Tetrahedron, Vol. 56, No. 43, 20.10.2000, p. 8567-8571.

Research output: Contribution to journal › Article

TY - JOUR

T1 - Unexpected Dealkylation During Nucleophilic Substitution: Synthesis of 2-N,N-Dialkylamino Benzoxazoles and Benzothiazoles

AU - Khalaf, A.I.

AU - Alvarez, R.G.

AU - Suckling, C.J.

AU - Waigh, R.D.

PY - 2000/10/20

Y1 - 2000/10/20

N2 - Mild reaction conditions are described for the preparation of a number of 2-alkyl- and 2-arylaminobenzoxazoles and benzothiazoles from 2-chlorobenzoxazole and 2-chlorobenzothiazole and N-methyl or other simple N-alkyl tertiary amines. The reaction proceeds neat or in THF solution and involves dealkylation of the amine reactant by nucleophilic substitution by chloride. In the case of N-methylpyrrolidine and N-methylpiperidine demethylation was not observed and the major product was formed by ring opening to give chlorobutyl- and chloropentyl-methylamino substituted benzoxazoles and benzothiazoles. Treatment of the chlorobutyl derivative with iodide in acetone afforded the new 1H,2H,3H,4H,5H-[1,3]diazepino[2,1-b][1,3]benzoxazol-6-ium ring system.

AB - Mild reaction conditions are described for the preparation of a number of 2-alkyl- and 2-arylaminobenzoxazoles and benzothiazoles from 2-chlorobenzoxazole and 2-chlorobenzothiazole and N-methyl or other simple N-alkyl tertiary amines. The reaction proceeds neat or in THF solution and involves dealkylation of the amine reactant by nucleophilic substitution by chloride. In the case of N-methylpyrrolidine and N-methylpiperidine demethylation was not observed and the major product was formed by ring opening to give chlorobutyl- and chloropentyl-methylamino substituted benzoxazoles and benzothiazoles. Treatment of the chlorobutyl derivative with iodide in acetone afforded the new 1H,2H,3H,4H,5H-[1,3]diazepino[2,1-b][1,3]benzoxazol-6-ium ring system.

KW - 2-arylaminobenzoxazoles

KW - 2-chlorobenzoxazole

KW - 2-chlorobenzothiazole

KW - dealkylation

KW - [1

KW - 3]diazepino[2

KW - 1-b][1

KW - 3]benzazoles

UR - http://dx.doi.org/10.1016/S0040-4020(00)00802-4

U2 - 10.1016/S0040-4020(00)00802-4

DO - 10.1016/S0040-4020(00)00802-4

M3 - Article

VL - 56

SP - 8567

EP - 8571

JO - Tetrahedron

T2 - Tetrahedron

JF - Tetrahedron

SN - 0040-4020

IS - 43

ER -

Khalaf AI, Alvarez RG, Suckling CJ, Waigh RD. Unexpected Dealkylation During Nucleophilic Substitution: Synthesis of 2-N,N-Dialkylamino Benzoxazoles and Benzothiazoles. Tetrahedron. 2000 Oct 20;56(43):8567-8571. https://doi.org/10.1016/S0040-4020(00)00802-4

Access to Document