TY - JOUR
T1 - Isolation, Characterization, and Synthesis of trans-Pilosine Stereoisomers Occurring in Nature. Circular Dichroism and Mass Spectral Studies
AU - Tedeschi, Enzo
AU - Kamionsky, Julia
AU - Zeider, Dov
AU - Packler, Simon
AU - Sarel, Shalom
AU - Usieli, Varda
AU - Deutsch, Joseph
PY - 1974/6/1
Y1 - 1974/6/1
N2 - “Pilosine” of [α]20+83.9° is shown to be a 1:1 mixture of pilosine and isopilosine. Data on pure pilosine are described. The isolation and assignment of structure of a new pilosine constituent in Pilocarpus jaborandi are herein presented. From circular dichroism measurements it is concluded that pilosine, isopilosine, and epiisopilosine are of 2R,3R,6S (1), 2S,3R,6S (4), and 2S,3R,6R configurations (3), respectively. Optimal conditions for the production of 3, 4, and the fluoro derivatives (3a and 3b), via aldol condensation between benzaldehyde, 2- and 4-fluorobenzaldehydes, and (3R)-pilosinine, in the presence of lithium methoxide, have been worked out. Effects of stereochemistry on trends of mass spectral fragmentations are discussed in terms of abundances of M- H2O and m/e 223 ions being higher in the spectrum of the cis (1) than in that of the trans (4) isomer and in terms of [M - 1]/[M] ratios.
AB - “Pilosine” of [α]20+83.9° is shown to be a 1:1 mixture of pilosine and isopilosine. Data on pure pilosine are described. The isolation and assignment of structure of a new pilosine constituent in Pilocarpus jaborandi are herein presented. From circular dichroism measurements it is concluded that pilosine, isopilosine, and epiisopilosine are of 2R,3R,6S (1), 2S,3R,6S (4), and 2S,3R,6R configurations (3), respectively. Optimal conditions for the production of 3, 4, and the fluoro derivatives (3a and 3b), via aldol condensation between benzaldehyde, 2- and 4-fluorobenzaldehydes, and (3R)-pilosinine, in the presence of lithium methoxide, have been worked out. Effects of stereochemistry on trends of mass spectral fragmentations are discussed in terms of abundances of M- H2O and m/e 223 ions being higher in the spectrum of the cis (1) than in that of the trans (4) isomer and in terms of [M - 1]/[M] ratios.
UR - http://www.scopus.com/inward/record.url?scp=0016146069&partnerID=8YFLogxK
U2 - 10.1021/jo00927a017
DO - 10.1021/jo00927a017
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AN - SCOPUS:0016146069
SN - 0022-3263
VL - 39
SP - 1864
EP - 1870
JO - Journal of Organic Chemistry
JF - Journal of Organic Chemistry
IS - 13
ER -