# US 5,344,936 A · Chalcogen-based chiral reagents for nuclear magnetic resonance detection of stereochemical assignments and enantiomeric ratios

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- Number: US 5,344,936 A
- Document ID: US5344936A
- Status: Granted
- Kind: A
- Application number: 08/027,552
- Filed: 1993-03-05
- Granted: 1994-09-06
- Earliest claimed: 1989-10-06
- Assignees: University of South Carolina
- Inventors: Louis A. Silks, III; R. Bruce Dunlap; Jerome D. Odom
- Web page: https://patentgrep.com/patent/US5344936A

## CPC

- C07D 263/16: with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
- G01R 33/281: {Means for the use of in vitro contrast agents (G01R33/282 takes precedence; involving use of a contrast agent in MR imaging G01R33/5601; in vivo contrast agents A61K49/0002)}
- Y10T 436/24: Nuclear magnetic resonance, electron spin resonance or other spin effects or mass spectrometry
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Selenium reagents when coupled to a compound containing an asymmetric carbon atom can be used in a highly sensitive method for determination of enantiomeric purity and for stereochemical assignment. Preferred reagents include a selenocarbonyl moiety (Se=C) and a reactive center for coupling to the compound of interest. Particularly preferred selenocarbonyls for use in the invention are chiral selenooxazolidinones of the formula ##STR1## wherein R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are selected from among hydrogen, alkyl of up to 10 carbons and aryl having up to 12 carbon atoms in the ring system. The substituent R.sup.1 is selected to facilitate the formation of a bond between the nitrogen atom of the selenooxazolidinone reagent and the compound of interest. Since the ability of the reagent to resolve enantiomers decreases as the number of bonds between the selenium and the asymmetric carbon increases, the reactive center is preferably located no more than three bonds from the selenium atom.

## Claims

### Claim 1

An optically pure chiral compound of the formula ##STR10## wherein R.sup.1 is H, ##STR11## and X is a halogen, R.sup.2 is an alkyl group of up to 10 carbon atoms;
R.sup.3 is an aryl group of up to 12 carbon atoms in the ring system;
R.sup.4 and R.sup.5 are selected from hydrogen, alkyl group of up to 10 carbon atoms and aryl groups of up to 12 carbon atoms in the ring system, or the enantiomer thereof, with the proviso the R.sup.2 and R.sup.4 are not the same.

### Claim 2 (depends on 1)

The compound of claim 1, wherein R.sup.1 is H.

### Claim 3

An optically pure chiral compound of the formula ##STR12## wherein R.sup.1 is H, ##STR13## and X is a halogen R.sup.2 is 2-propyl and R.sup.3, R.sup.4 and R.sup.5 are H or R.sup.4 is 2-propyl and R.sup.2, R.sup.3 and R.sup.5 are H.

### Claim 4 (depends on 3)

The compound of claim 3, wherein R.sup.1 is H.

### Claim 5

An optically pure chiral compound of the formula ##STR14## wherein R.sup.1 is H, ##STR15## and X is a halogen R.sup.2 is benzyl and R.sup.3, R.sup.4 and R.sup.5 are H or R.sup.4 is benzyl and R.sup.2, R.sup.3 and R.sup.5 are H.

### Claim 6 (depends on 5)

The compound of claim 5 wherein R.sup.1 is H.

### Claim 7

An optically pure chiral compound of the formula ##STR16## wherein R.sup.1 is H, ##STR17## and X is a halogen, R.sup.2 is methyl, R.sup.3 is phenyl and R.sup.4 and R.sup.5 are H, or the enantiomer thereof.