Cannabinoid deuterated analogs

A key feature of our quantitative procedures was the use of appropriate deuterated analogs of the cannabinoids under study as both carriers for the small quantity of cannabinoids expected to be present in many cases and as internal standards for quantitation by... 

Measurement of the ratio of concentrations of each cannabinoid and its deuterated analog is achieved using chemical ionization and the technique of selected ion monitoring as previously described. Because of the low carrier gas flow rate used for capillary columns, we can use virtually any carrier gas we want (helium, hydrogen, etc.) and simply introduce our reagent gas or gases into the ion course via the make-up gas inlet. 

When we first approached the study on the determination of the cannabinoids by mass spectrometry, we were somewhat intimidated by the large number of possible metabolites. We were also concerned about the requirement of deuterated analogs of the compounds for mass spectrometric determination. The difficulties involved in the synthesis of nonlabeled compounds, however, argued for an approach that did not require total synthesis of the deuterated analogs. 

Razdan and coworkers (10) have reported a modification of the Petrzilka (9) cannabinoid synthesis. Thus, condensation of olivetol with (-h)-cjs- or trans-p-mentha-2,8-dien-l-ol in the presence of boron trifluoride-etherate and anhydrous magnesium sulfate at 0°C yielded (-)-A -THC, and practically no A -iso-mer was formed (Scheme 2). This modification represents a useful direct route to (-)-A -THCs, (-)-A -tetrahydrocaimabivarins, and their regiospecifically deuterated analogs (22-24). It was recently reported that the synthesis of a (-)-A -THC derivative was accomplished without the presence of a drying agent by keeping the reaction temperature at 0°C (25). 

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