title: SYNTHESIS AND SPECTROSCOPIC DIFFERENTIATION OF 2- AND 4-ALKOXYTHIOTETRONIC ACIDS.
abstract: O-Alkylation of thiotetronic acids gives a mixture of 2- and 4-position enol ether products. Comparison of the physical data revealed that UV spectroscopy was the most reliable method of distinguishing between these related ethers. We have determined that 4-position ethers have a distinct absorption between 235-240 nm, while 2-position ethers have two absorbance peaks, one between 205-220 nm and the other between 305-310 nm. This report describes the synthesis and unambiguous characterization of 2- and 4-methoxy-3,5-dimethylthiotetronic acids. The UV absorption properties of several other pairs of thiotetronic acid ethers confirm that these differences are general features that provide a simple method for distinguishing between 2- and 4-substituted isomers.
authors.affiliation: Tuberculosis Research Section, National Institute of Allergy and Infectious Diseases, Rockville, MD 20852 USA; Email: cdowd@niaid.nih.gov.
authors.forename: Gautham
authors.initials: G
authors.lastname: Shenoy
authors.forename: Pilho
authors.initials: P
authors.lastname: Kim
authors.forename: Michael
authors.initials: M
authors.lastname: Goodwin
authors.forename: Quynh-Anh
authors.initials: QA
authors.lastname: Nguyen
authors.forename: Clifton E
authors.initials: CE
authors.lastname: Barry
authors.forename: Cynthia S
authors.initials: CS
authors.lastname: Dowd