Synthesis of cannabidiol and analogs thereof, and related compounds, formulations, and methods of use

Abstract

Methods are provided for the synthesis of cannabinoids, including cannabidiol (CBD), cannabinol (CBN), cannabichromene (CBC), cannabidiolic acid (CBDA), cannabigerol (CBG), cannabigerolic acid (CBGA), cannabidivarin (CBDV), cannabidibutol (CBD-C4), dihydrocannabidiol (DCBD), tetrahydrocannabivarin (THCV), analogs thereof, and precursors to the foregoing. One method employs phloroglucinol or a phloroglucinol analog as a starting material. The syntheses are stereospecific, efficient, selective, and cost-effective, with little or no potential for generation of THC ((-)-trans-Δ 9 -tetrahydro-cannabinol) or any other psychoactive side product. Telescoped syntheses are also provided, as are new cannabinoids, pharmaceutical formulations, and methods of use.

1 . A method for synthesizing a cannabinoid, wherein the method comprises: 
 reacting a compound having the structure of formula (AA-1)
                     
 with an electron-withdrawing hydroxyl-protecting reagent under conditions effective to provide a hydroxyl-protected intermediate having the structure of formula (AA-2) 
                     
 in which PR represents an electron-withdrawing hydroxyl protecting group; 
   (b) effecting a cross-coupling reaction between the hydroxyl-protected intermediate (AA-2) and a reactant R 1 -M in the presence of a catalyst that facilitates the cross-coupling reaction, wherein M comprises a metallic element, to provide a compound having the structure of formula (AA-3)
                     
   (c) hydrolyzing the compound of (AA-3) to remove the hydroxyl protecting groups and provide a reaction product composition comprising compound (AA)
                     
 wherein m is zero or 1; n is zero, 1, or 2; R 
 1  is selected from C 1 -C 12  hydrocarbyl, substituted C 1 -C 12  hydrocarbyl, heteroatom-containing C 1 -C 12  hydrocarbyl, and substituted heteroatom-containing C 1 -C 12  hydrocarbyl; and R 2  is selected from C 1 -C 12  hydrocarbyl, substituted C 1 -C 12  hydrocarbyl, heteroatom-containing C 1 -C 12  hydrocarbyl, substituted heteroatom-containing C 1 -C 12  hydrocarbyl, and functional groups, and when n is 2, the R 2  may be the same or different, and any R 2  on adjacent carbon atoms may be linked to form a cyclic structure   (d) contacting (AA) with a second reactant having the structure of formula (CC-1)
                     
 wherein R 
 5  is H, carboxyl, C 2 -C 6  acyloxy, C 2 -C 6  alkoxycarbonyl, C 1 -C 6  alkyl, or C 1 -C 6  alkyl substituted with hydroxyl, carboxyl, or halo; R 6  and R 7  are independently selected from C 1 -C 12  hydrocarbyl, substituted C 1 -C 12  hydrocarbyl, heteroatom-containing C 1 -C 12  hydrocarbyl, substituted heteroatom-containing C 1 -C 12  hydrocarbyl, and functional groups; R 8  is methyl, hydroxymethyl, or halomethyl; and L is a leaving group, in the presence of a Lewis acid catalyst under reaction conditions effective to result in cross-coupling of reactants (AA) and (CC-1) and thereby provide a reaction product composition comprising a cannabinoid having the structure of formula (CC)
                     
 . 
   
     
     
         2 . The method of  claim 1 , wherein: 
 m is 1, n is zero, and (AA-1) is phloroglucinol;   R 5  and R 8  are methyl; and   R 6  and R 7  are H,   so that the cannabinoid (CC) in the reaction product composition has the structure of formula (CC-3)
                     
 . 
   
     
     
         3 . The method of  claim 1 , wherein the reaction conditions comprise contacting the first reactant with the second reactant in a solvent at an elevated temperature in the presence anhydrous alumina and MgSO 4 . 
     
     
         4 . The method of  claim 1 , wherein the Lewis acid catalyst comprises BF 3 . 
     
     
         5 . The method of  claim 1 , wherein R 1  is n-pentyl, and (CC-3) comprises CBD. 
     
     
         6 . The method of  claim 1 , wherein R 1  is n-propyl. 
     
     
         7 . The method of  claim 6 , further including subjecting (CC-3) to cyclization conditions, thereby providing a reaction product composition comprising tetrahydrocannabivarin. 
     
     
         8 . The method of  claim 1 , wherein (AA) is not isolated or purified prior to step (d). 
     
     
         9 . The method of  claim 1 , wherein the hydroxyl-protected intermediate (AA-2) is not isolated or purified prior to the cross-coupling reaction of step (b). 
     
     
         10 . A cannabinoid having the structure of formula (EE)
                       q1 is zero or 1, and q2 is zero, 1, or 2;   R 11  is selected from C 1 -C 12  hydrocarbyl, substituted C 1 -C 12  hydrocarbyl, heteroatom-containing C 1 -C 12  hydrocarbyl, substituted heteroatom-containing C 1 -C 12  hydrocarbyl, and functional groups, and wherein when n is 2, the R 11  may be the same or different and any two R 11  bound to adjacent carbon atoms may be taken together to form a cyclic structure selected from a five-membered ring and a six-membered ring, optionally fused to an additional five-membered or six-membered ring, wherein the rings are aromatic, alicyclic, heteroaromatic, or heteroalicyclic, and have zero to 4 non-hydrogen substituents and zero to 3 heteroatoms;   R 12  is H, carboxyl, C 2 -C 6  acyloxy, C 2 -C 6  alkoxycarbonyl, C 1 -C 6  alkyl, or C 1 -C 6  alkyl substituted with hydroxyl, carboxyl, or halo;   R 13  and R 14  are independently selected from H, C 1 -C 12  hydrocarbyl, substituted C 1 -C 12  hydrocarbyl, heteroatom-containing C 1 -C 12  hydrocarbyl, substituted heteroatom-containing C 1 -C 12  hydrocarbyl, and functional groups;   R 15  is methyl, hydroxymethyl, or halomethyl; and   R 16  is C 1 -C 18  alkyl, C 2 -C 18  alkenyl, or C 2 -C 18  alkynyl, substituted with (a) -(CO)-NR 28 -R 29  wherein R 28  is H or C 1 -C 12  hydrocarbyl and R 29  is C 1 -C 12  hydrocarbyl, (b) -NR 30 -R 31  wherein R 30  is H or C 1 -C 12  hydrocarbyl and R 31  is C 6 -C 12  hydrocarbyl, C 1 -C 12  hydrocarbyl substituted with at least one functional group, C 1 -C 12  heterohydrocarbyl, or C 1 -C 12  heterohydrocarbyl substituted with at least one functional group, (c) -(SO 2 )-R 32  wherein R 32  is H or C 1 -C 12  heterohydrocarbyl, C 1 -C 12  hydrocarbyl substituted with at least one functional group, or C 1 -C 12  heterohydrocarbyl substituted with at least one functional group, (d) -(SO 2 )-NR 33 R 34  wherein R 33  is H or C 1 -C 12  hydrocarbyl and R 34  is H or C 1 -C 12  hydrocarbyl,                                                                     wherein L   1  is C 1 -C 6  alkyl, or wherein R 16  is C 1 -C 12  hydrocarbyloxy substituted with an additional C 1 -C 12  hydrocarbyloxy. 
     
     
         11 . The cannabinoid of  claim 10 , wherein:
 q1 is 1, q2 is zero, and the two hydroxyl groups are located meta to R 16 , R 12  and R 15  are C 1 -C 6  alkyl, R 13  and R 14  are H, and R 16  is C 1 -C 12  alkyl or C 2 -C 12  alkyl substituted with: 
 (a) -(CO)-NR 28 -R 29  wherein R 28  is H or C 1 -C 8  alkyl and R 29  is C 1 -C 8  alkyl; 
 (b) -NR 30 R 31  wherein R 30  is H or C 1 -C 8  alkyl and R 31  is C 6 -C 12  alkyl, C 1 -C 6  alkyl substituted with at least one functional group, C 1 -C 6  heteroalkyl, or C 1 -C 8  heteroalkyl substituted with at least one functional group; 
 (c) -(SO 2 )-R 32  wherein R 32  is C 1 -C 8  heteroalkyl, C 1 -C 6  alkyl substituted with at least one functional group, or C 1 -C 6  heteroalkyl substituted with at least one functional group; 
 (d) -(SO 2 )-NR 33 R 34  wherein R 33  is H or C 1 -C 8  alkyl and R 34  is H or C 1 -C 8  alkyl, wherein the C 1 -C 8  alkyl groups are either substituted or unsubstituted;
                     
                     
                     
 . 
 
   
     
     
         12 . The cannabinoid of  claim 11 , wherein R 12  and R 15  are methyl, such that the compound has the structure of formula (EE-1)
                     
 . 
 
     
     
         13 . A cannabinol (CBN) analog having the structure of formula (FF)
                       q3 is zero or 1, and q4 is zero, 1 or 2;   R 17  is selected from C 1 -C 12  hydrocarbyl, substituted C 1 -C 12  hydrocarbyl, heteroatom-containing C 1 -C 12  hydrocarbyl, substituted heteroatom-containing C 1 -C 12  hydrocarbyl, and functional groups, and wherein when n is 2, the R 17  may be the same or different and any two R 17  bound to adjacent carbon atoms may be taken together to form a cyclic structure selected from a five-membered ring and a six-membered ring, optionally fused to an additional five-membered or six-membered ring, wherein the rings are aromatic, alicyclic, heteroaromatic, or heteroalicyclic, and have zero to 4 non-hydrogen substituents and zero to 3 heteroatoms;   R 18  is H, carboxyl, C 2 -C 6  acyloxy, C 2 -C 6  alkoxycarbonyl, C 1 -C 6  alkyl, or C 1 -C 6  alkyl substituted with hydroxyl, carboxyl, or halo;   R 19  and R 20  are independently selected from H, C 1 -C 12  hydrocarbyl, substituted C 1 -C 12  hydrocarbyl, heteroatom-containing C 1 -C 12  hydrocarbyl, substituted heteroatom-containing C 1 -C 12  hydrocarbyl, and functional groups;   R 21  is methyl, hydroxymethyl, or halomethyl; and   R 22  is C 1 -C 18  alkyl, C 2 -C 18  alkenyl, or C 2 -C 18  alkynyl, substituted with (a) -(CO)-NR 35 -R 36  wherein R 35  is H or C 1 -C 12  hydrocarbyl and R 36  is C 1 -C 12  hydrocarbyl, (b) -NR 37 -R 38  wherein R 37  is H or C 1 -C 12     hydrocarbyl and R 38  is C 6 -C 12  hydrocarbyl, C 1 -C 12  hydrocarbyl substituted with at least one functional group, C 1 -C 12  heterohydrocarbyl, or C 1 -C 12  heterohydrocarbyl substituted with at least one functional group, (c) -(SO 2 )-R 39  wherein R 39  is H or C 1 -C 12  heterohydrocarbyl, C 1 -C 12  hydrocarbyl substituted with at least one functional group, or C 1 -C 12  heterohydrocarbyl substituted with at least one functional group, (d) -(SO 2 )-NR 40 R 41  wherein R 42  is H or C 1 -C 12  hydrocarbyl and R 43  is H or C 1 -C 12  hydrocarbyl,
                     
                     
                     
 
 wherein L 1  is C 1 -C 6  alkyl, or wherein R 22  is C 1 -C 12  hydrocarbyloxy substituted with an additional C 1 -C 12  hydrocarbyloxy. 
     
     
         14 . The CBN analog of  claim 13 , wherein:
 q3 and q4 are zero, and the hydroxyl group is located meta to R 22 ;   R 18  and R 21  are C 1 -C 6  alkyl, R 19  and R 20  are H, and R 22  is C 1 -C 12  alkyl or C 2 -C 12  alkenyl substituted with:   (a) -(CO)-NR 35 R 36  wherein R 35  is H or C 1 -C 8  alkyl and R 36  is C 1 -C 8  alkyl;   (b) -NR 37 R 38  wherein R 37  is H or C 1 -C 8  alkyl and R 38  is C 6 -C 12  alkyl, C 1 -C 6  alkyl substituted with at least one functional group, C 1 -C 6  heteroalkyl, or C 1 -C 8  heteroalkyl substituted with at least one functional group;   (c) -(SO 2 )-R 39  wherein R 39  is C 1 -C 8  heteroalkyl, C 1 -C 8  alkyl substituted with at least one functional group, or C 1 -C 6  heteroalkyl substituted with at least one functional group;   (d) -(SO 2 )-NR 40 R 41  wherein R 40  is H or C 1 -C 8  alkyl and R 41  is H or C 1 -C 8  alkyl, wherein the C 1 -C 8  alkyl groups are either substituted or unsubstituted;
                     
                     
                     
 . 
   
     
     
         15 . The CBN analog of  claim 13 , wherein R 18  and R 21  are methyl, such that the compound has the structure of formula (FF-1)
                     
 . 
 
     
     
         16 . A cannabichromene (CBC) analog having the structure of formula (GG)
                       wherein:   q5 is zero or 1, q6 is zero1, or 2, and the sum of q5 and q6 does not exceed 2;   R 23  is selected from C 1 -C 12  hydrocarbyl, substituted C 1 -C 12  hydrocarbyl, heteroatom-containing C 1 -C 12  hydrocarbyl, substituted heteroatom-containing C 1 -C 12  hydrocarbyl, and functional groups, and wherein when n is 2, the R 23  may be the same or different and any two R 23  bound to adjacent carbon atoms may be taken together to form a cyclic structure selected from a five-membered ring and a six-membered ring, optionally fused to an additional five-membered or six-membered ring, wherein the rings are aromatic, alicyclic, heteroaromatic, or heteroalicyclic, and have zero to 4 n3on-hydrogen substituents and zero to 3 heteroatoms;   R 24  is H, C 1 -C 6  alkyl, or C 1 -C 6  alkyl substituted with hydroxyl, carboxyl, or halo;   R 25  is H, C 1 -C 12  hydrocarbyl, substituted C 1 -C 12  hydrocarbyl, heteroatom-containing C 1 -C 12  hydrocarbyl, substituted heteroatom-containing C 1 -C 12  hydrocarbyl, or a functional group;   R 26  is methyl, hydroxymethyl, or halomethyl; and   R 27  is C 1 -C 18  alkyl or C 2 -C 18  alkenyl substituted with (a) -(CO)-NR 42 R 43  wherein R 42  is H or C 1 -C 12  hydrocarbyl and R 43  is C 1 -C 12  hydrocarbyl, (b) -NR 44 R 45  wherein R 44  is H or C 1 -C 12  hydrocarbyl and R 45  is C 6 -C 12  hydrocarbyl, C 1 -C 12  hydrocarbyl substituted with at least one functional group, C 1 -C 12  heterohydrocarbyl, or C 1 -C 12  heterohydrocarbyl substituted with at least one functional group, (c) -(SO 2 )-R 46  wherein R 46  is H or C 1 -C 12  heterohydrocarbyl, C 1 -C 12  hydrocarbyl substituted with at least one functional group, or C 1 -C 12  heterohydrocarbyl substituted with at least one functional group, (d), (SO 2 )-NR 47 R 48  wherein R 47  is H or C 1 -C 12  hydrocarbyl and R 48  is H or C 1 -C 12  hydrocarbyl,
                     
                     
                     
 
wherein L 1  is C 1 -C 6  alkyl, or wherein R 27  is C 1 -C 12  hydrocarbyloxy substituted with an additional C 1 -C 12  hydrocarbyloxy. 
     
     
         17 . A pharmaceutical formulation comprising an effective amount of the compound of  claim 10  in combination with a pharmaceutical excipient. 
     
     
         18 . A method for treating a subject affected by a condition, disorder, or disease responsive to administration of a cannabinoid, comprising administering to the subject, optionally within the context of an ongoing dosage regimen, an effective amount of the compound of  claim 10 . 
     
     
         19 . The method of  claim 18 , wherein the compound is in a pharmaceutical formulation additionally comprising an excipient.