Synthesis 2020; 52(09): 1444-1450
DOI: 10.1055/s-0039-1690821
paper
© Georg Thieme Verlag Stuttgart · New York

Cyclization of Active Methylene Isocyanides with α-Oxodithioesters Induced by Base: An Expedient Synthesis of 4-Methylthio/Ethoxycarbonyl-5-acylthiazoles

Kuppalli R. Kiran
a   Department of Studies in Chemistry, University of Mysore, Manasagangothri, Mysuru – 570 006, India   Email: mpsadashiva@gmail.com   Email: rangappaks@gmail.com
,
Toreshettahally R. Swaroop
b   Department of Studies in Organic Chemistry, University of Mysore, Manasagangothri, Mysuru – 570 006, India   Email: swarooptr@gmail.com
,
Narasimhamurthy Rajeev
a   Department of Studies in Chemistry, University of Mysore, Manasagangothri, Mysuru – 570 006, India   Email: mpsadashiva@gmail.com   Email: rangappaks@gmail.com
,
Seegehalli M. Anil
a   Department of Studies in Chemistry, University of Mysore, Manasagangothri, Mysuru – 570 006, India   Email: mpsadashiva@gmail.com   Email: rangappaks@gmail.com
,
Kanchugarakoppal S. Rangappa
a   Department of Studies in Chemistry, University of Mysore, Manasagangothri, Mysuru – 570 006, India   Email: mpsadashiva@gmail.com   Email: rangappaks@gmail.com
,
Maralinganadoddi P. Sadashiva
a   Department of Studies in Chemistry, University of Mysore, Manasagangothri, Mysuru – 570 006, India   Email: mpsadashiva@gmail.com   Email: rangappaks@gmail.com
› Author Affiliations
The authors are grateful to UGC-SAP DRS III for providing financial support and IOE for instrumentation facility.
Further Information

Publication History

Received: 10 January 2020

Accepted after revision: 23 January 2020

Publication Date:
17 February 2020 (online)


Abstract

Cyclization of tosylmethyl isocyanide with α-oxodithioesters in the presence of KOH is reported for the synthesis of 4-methylthio-5-acylthiazoles. Similarly, ethyl isocyanoacetate underwent cyclization with α-oxodithioesters to form 4-ethoxycarbonyl-5-acylthiazoles in the presence of DBU/EtOH. Mechanisms for the formation of thiazoles are proposed. These thiazoles can also be obtained by Takeda reaction, in which thiazole-4,5-anhydride is acylated with aromatic compounds followed by esterification; however, that approach requires two steps and suffers from the formation of a regioisomeric mixture of products.

Supporting Information