Alkaloids of Sarcococca saligna

New Cholinesterase Inhibiting Steroidal Alkaloids from the Leaves of Sarcococca coriacea of Nepalese Origin.

“…This compound was earlier isolated from the leaves of Holarrhena febrifuga. 16) The stereochemical assignments of stereogenic centers in the compounds 1-4 were made on the basis of nuclear Overhauser effect spectroscopy (NOESY) interactions, chemical shifts comparisions with reported compounds [9][10][11][12][13][14][15][16][17][18] and biogenetic considerations keeping in view of the fact that all pregnane-type steroidal alkaloids are biosynthesized from cholesterol via pregnenolone. 19) The b-orientation of the C-20 methine proton in compounds 1-3, and equatorial position of the C-3 tigloyl group in compounds 1-2 were confirmed by comparing the spectral data with reported compounds.…”

“…19) The b-orientation of the C-20 methine proton in compounds 1-3, and equatorial position of the C-3 tigloyl group in compounds 1-2 were confirmed by comparing the spectral data with reported compounds. [9][10][11][12][13][14][15][16][17][18]25) In compounds 1 and 2, the cis configuration of tigloyl methyl groups at C-2Ј and C-3Ј were inferred from NOESY interactions between the C-3Ј olefinic proton with C-4Ј methyl protons.…”

“…6) We have previously reported a number of steroidal alkaloids from various species of Sarcococca. 8,14,[16][17][18] In our continuing studies on steroidal alkamines from this genus, we recently initiated work on S. coriacea (HOOK. f.) SWEET which is an evergreen shrub widely distributed in central Nepal.…”

Steroidal Alkaloids from Holarrhena antidysenterica (L.) WALL.

“…The attachment of hydroxyl group at amine center was further confirmed by the analysis of mass fragmentation data which showed the peaks at m/z 317 [MϩHϪCH 3 CONOH] ϩ (-C-N-bond cleavage), 289 reported compounds and biogenetic considerations. [9][10][11][12][13][14][15][16][17][18][19][20] Based on critical spectroscopic studies, the structure of compound 1 was established as (20S)-20-acetylhydroxylamino,3b -amino,13b -hydroxymethylenepregn-5-ene and was designated as holadysenterine.…”

“…Two wide multiplets at d 2.92 and 3.53 were assigned to H-3a-and H-20b-, respectively. The b-orientation of H-20 was deduced by comparing the spectral values with published data for steroidal alkaloids [9][10][11][12][13][14][15][16][17][18][19] and biogenetic considerations keeping in view of the fact that all pregnane-type steroidal alkloids are biosynthesized from cholesterol via pregnenolone. 10,20) The H-21 (3H, d, Jϭ 6.6 Hz) and H-19 (3H, s) methyl groups appeared at d 1.38 and 1.09, respectively.…”