Facile syntheses of oxazolines and thiazolines with N-acylbenzotriazoles under microwave irradiation.
Microwave reactions of 2-amino-2-methyl-1-propanol (2) or 2-aminoethanethiol hydrochloride (4) with readily available N-acylbenzotriazoles 1a-j in the presence of SOCl(2) produced 2-substituted 2-oxazolines 3a-j in 84-98% yields and 2-substituted thiazolines 5a-i in 85-97% yields, respectively. With use of this method chiral oxazoline 6, bisoxazoline 7, bisthiazoline 8, and 5,6-dihydro-4H-1,3-oxazines 9 or 10 have also been prepared in 82-96% yields. These results demonstrate a new application of N-acylbenzotriazoles in the preparation of oxazolines and thiazolines under mild conditions and short reaction times with microwave irradiation.
Katritzky
Alan R
AR
Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, USA. katritzky@chem.ufl.edu
Cai
Chunming
C
Suzuki
Kazuyuki
K
Singh
Sandeep K
SK
D008872:Microwaves; D010080:Oxazoles / Q000138:chemical synthesis*; D013844:Thiazoles / Q000138:chemical synthesis*; D014230:Triazoles / Q000737:chemistry*
D010080:Oxazoles; D013844:Thiazoles; D014230:Triazoles; C012771:benzotriazole