
TY  - JOUR
A1  - Philp, RP 
A1  - Robertson, AV 
T1  - Cyclic hydroxycarboxylic acids. III. Tosylation studies on Mono- and Di-hydroxycyclopentanecarboxylates and Mono- and Di-hydroxyprolines
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1977
VL  - 30
IS  - 1
SP  - 131
EP  - 140
KW  - 
UR  - https://doi.org/10.1071/CH9770131 
N2  - A large excess of reagent is needed for satisfactory ditosylation of methyl c-2,t-3- and t-2,c-3-di-hydroxycyclopentane-r-1-carboxylates using tosyl chloride-pyridine at 5&#176; overnight. With less reagent, mixtures are produced from which one monotosyl derivative of the t-2,c- 3-series was isolated and its structure proved. By contrast, the methyl cis- and trans-2-hydroxycyclopentanecarboxylates readily tosylate with normal molar ratios of reagent. In the proline series ditosylation of 2,3-trans- 3,4-cis-3,4-dihydroxy-N-tosylproline methyl ester occurs normally in tosyl chloride-pyridine, and so does tosylation of both cis- and trans-4-hydroxy-N-tosylproline methyl esters. On the other hand tosylation of the 3-hydroxy counterparts is very slow, although acetylation of these 3-hydroxyl groups proceeds normally. The O-tosylation results are striking for the lack of pattern. A comparison is also made of O-tosylation accompanying N-tosylation of the free amino acids cis- and trans-3-hydroxy-proline, cis- and trans- 4- hydroxyproline, and the two cis-glycols of 3,4-dihydroxyproline in the heterogeneous system tosyl chloride-ether-aqueous NaOH. Significant O- tosylation occurs in some cases but not in others. This correlation permits assignment of structure to a mono-O-tosyl derivative of a 3,4- dihydroxy-N-tosylproline obtained previously by us. 
ER  -

