Figure 3
Synthesis and UHPLC-HRMS identification of CBDH, CBDM, Δ9-THCH and Δ9-THCM, and in vivo activity of CBDH. (A) Scheme 1. Reagents and conditions: (a) triphenylphosphine (1.1 equiv.), toluene, reflux, 6 h, quant. yield; (b) valeraldehyde (1.5 equiv.), 0.1 M K2CO3 aq. (10 mL per mmol of 1), reflux, 5 h, 81% yield; (c) H-Cube ThalesNano H2-Pd/C, EtOH, 30 °C, 20 bar, 1 mL/min, 91% yield; (d) BBr3 1 M in DCM (2.2 eq.), anhydrous DCM, N2 atmosphere, − 15 °C → r.t, 24 h, quant. yield; (e) (1S,4R)-1-methyl-4-(prop-1-en-2-yl)cycloex-2-enol (0.9 equiv.), pTSA (0.1 equiv.), DCM, r.t., argon, 2 h, 17% yield for (−)-trans-CBDH and 20% yield for (−)-trans-Δ9-THCH. Scheme 2. Reagents and conditions: dimethylsulphate (0.5 equiv.), K2CO3 (1 equiv.), DMF, r.t. 62% yield for (−)-trans-CBDM and 57% yield for CBGM. Scheme 3. Reagents and conditions: p-TSA (0.1 equiv.), dry DCM, r.t., 1 h, 43% yield. (B) Superimposition of extracted UHPLC-HRMS ion chromatograms (EICs) of synthetic cannabinoid n-hexyl and monomethyl ether homologs. and relative fragmentation spectra, in positive ionization mode. EICs were chosen based on the exact mass calculated for C23H32O4. (C) Effects of CBDH (1, 2, 3, and 5 mg/kg, i.p.) or vehicle in the formalin test in mice. The total time of the nociceptive response was measured every 5 min and expressed in min (see “Experimental” section). Data are represented as means ± SEM (n = 5–6). +,+++indicate statistically significant differences versus veh/form, p < 0.05 and p < 0.001, respectively. 2-way ANOVA followed by Bonferroni’s post hoc tests was used for statistical analysis.
