the hexane extract of hashish onflorisil or acid washed alumina using 15% ether in
pentane (Mechoulam and Gaoni 1967 ).
Verwey and Witte described the preparation ofD^9 -THC acid ( 2 ) from hashish by
precipitating the cannabinoid acids using the acid-base extraction process.D^9 -THC
was obtained with ether, evaporated then cleaned by preparative TLC (Verwey and
Witte 1972 ). Yamauchi et al. ( 1967 ) isolatedD^9 -THC–acid A ( 2 ) from the Mexican
hemp in 1967 using cellulose powder column eluted with a mixture ofn-hexane and
dimethylformamide then preparative thin layer chromatography. ElSohly and Ross
improved a method for obtainingD^9 -THC ( 1 ) andD^9 -THC–acid ( 2 ) from cannabis
plant material with a reduced cost of production by extraction of cannabis materials
followed by fractional distillation. They also used various types of stationary phases
such as silica, alumina and C18 silica to get pure THC with a high yield. They also
reported an efficient preparative C-18 HPLC method for the purification of THC
from distillate with purity more than 98% (Elsohly and Ross 2002 ).
D^9 -THC-acid B ( 3 ) was obtained from a hashish sole in 1969 by chromatog-
raphy on Silicic acid column eluted with a mixture of ether in petroleum ether
(Mechoulam et al. 1969 ). Roenqvist and Ottersen reported the crystal structure of
D^9 -THC–acid B in 1975 by slow evaporation of a chloroform solution (Rosenqvist
and Ottersen 1975 ).
(-)-D^9 - trans-tetrahydrocannabinol-C 4 (D^9 -THC-C4, 4 ) and (-)-D^9 - trans-tetra-
hydrocannabinolic acid A-C 4 (D^9 -THC-C 4 A, 5 ) were characterized by GC/MS of
the ethyl acetate extract of ten police confiscated cannabis resins, tinctures and
leaves. The extracts were prepared as silyl derivatives before GC analysis (Harvey
1976 ).
In 1971, Gill, E. W. isolatedD^9 - trans-tetrahydrocannabivarin (D^9 -THCV-C 3 , 6 )
from Cannabis tincture of a Pakistani origin. He used counter current distribution
technique to isolate THCV from the light petroleum ether extract (Gill 1971 ).
(-)-D^9 - trans-tetrahydrocannabivarinic acid (D^9 -THCV-C 3 A, 7 ) was reported in
1973 by Paris et al. from the fresh leaves ofC. sativafrom South Africa (Paris et al.
1973 ), but its chemical structure was determined in 1977 by Shoyama et al.
(Shoyama et al. 1977 ).
Turner et al. (1973a, b) identified (-)-D^9 - trans-tetrahydrocannabiorcol (D^9 -
THCO-C 1 , 8 ) in the light petroleum ether extract of Brazalian marihuana in 1973,
while (-)-D^9 - trans-tetrahydrocannabiorcolic acid (D^9 -THCOA-C 1 A, 9 ) was
detected by GC/MS in some confiscated samples in 1976 (Harvey 1976 ).
Ahmed et al. isolated eight new tetrahydrocannabinol type compounds shown in
Fig.7.1by using multiple chromatographic techniques, including vacuum liquid
chromatogarphy (VLC), C18 semi-preparative HPLC and semi-preparative enan-
tioselective chiral HPLC. These compounds were identified asb-fenchylD^9 -tetra-
hydrocannabinolate ( 10 ),a-fenchyl D^9 -tetrahydrocannabinolate ( 11 ),epi-bornyl
D^9 -tetrahydrocannabinolate ( 12 ), bornyl D^9 -tetrahydrocannabinolate ( 13 ),
a-terpenylD^9 -tetrahydrocannabinolate ( 14 ), 4-terpenylD^9 -tetrahydrocannabinolate
( 15 ), a-cadinyl D^9 -tetrahydro-cannabinolate ( 16 ), and c-eudesmyl D^9 -tetra-
hydrocannabinolate ( 17 ). The spectroscopic analysis including NMR and GC-MS
7 Natural Cannabinoids of Cannabis and Methods of Analysis 173