Thomas W. Whaley

Large-scale photosynthetic production of carbon-13 labeled sugars: The tobacco leaf system

Abstract A system is described for the production of carbon-13 uniformly labeled starch, glucose, fructose, and sucrose from kilogram quantities of tobacco leaves. Nearly 60% of the CO 2 administered (at 80 atom % carbon-13 or above) was found in these four compounds; the loss of enrichment between carbon-13 administered and isolated sugars was 3% or less. About 25 g 13 C-glucose can be produced in a 40-hr incubation from 1.2 kg of leaves. Label uniformity in the products was established by 13 C-nmr spectroscopy.

Improved synthesis of 4-ethylsulfonyl-1-naphthalenesulfonamide

4-Ethylsulfonyl-1-naphthalenesulfonamide (1,ENS), reported to promote experimental bladder carcinogenesis was prepared in a convenient, high-yield, five-step synthesis from 1-naphthalenethiol (2). After conversion of 2 to the ethylthioether (3) by a standard procedure, 3 was sulfonated using one equivalent of cholosulfonic acid to yield the sulfonic acid (4) which was isolated as the sodium salt (5). The acid chloride (6) was prepared from 5 by reaction with chlorosulfonic acid in anhydrous C HCl/sub 3/, and treatment of 6 with ammonia gave the thioether sulfonamide (7), which was converted to ENS by peroxide oxidation. Overall conversion yields were reported as 50--60 percent. (BLM)

A STEREOCHEMICAL APPROACH TO SELF QUENCHING STUDIES IN SOME BRIDGED p-QUATERPHENYL SYSTEMS*

Abstract The relative pulse height curves for two bridged p -quaterphenyls in both racemic and optically active forms have been measured. Examination of molecular models indicates that the optically active system could be more susceptible to self quenching due to preferential excimer formation. This effect has not been observed in the measurements made thus far. The synthesis of these compounds is also described.