PROCESSES FOR THE PREPARATION OF HALOGENATED DIHYDROXYBENZENE COMPOUNDS
The present disclosure relates to the preparation of halogenated dihydroxybenzene compounds with high yield, selectivity and purity. The compounds are useful, among other things, in the synthesis of cannabinoids and cannabinoid-type compounds.
1 . A method of preparing a compound of Formula I:
wherein,
R 1 is a branched or straight chain C 1-12 alkyl; and
R 2 and R 3 are each independently selected from a group consisting of halogen, —C(O)O—C 1-6 alkyl, and hydrogen, wherein at least one of R 2 and R 3 is halogen, the method comprising:
contacting a compound of Formula I′ having a structure:
wherein, R 1′ is a branched or straight chain C 1-12 alkyl; and
R 2′ and R 3′ are each independently selected from the group consisting of halogen, —C(O)O—C 1-6 alkyl, and hydrogen, wherein at least one of R 2′ and R 3′ is hydrogen;
with HX, wherein X is a halide, in the presence of an organic sulfoxide
wherein, the contacting is at a temperature from about 0° C. to about 100° C.; and
wherein, the compound of Formula I is prepared.
2 . The method of claim 1 , wherein HX is selected from HBr, HCl, HI, and HF.
3 .- 4 . (canceled)
5 . The method of claim 1 , wherein R 1 and R 1′ are the same and each is selected from the group consisting of straight or branched methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, t-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl.
6 . (canceled)
7 . The method of claim 1 , wherein R 1 and R 1′ are the same and each is selected from the group consisting of a branched chain C 1-12 alkyl having one, two, three, four, five, six, seven, eight, nine, ten, eleven, or twelve carbon atoms.
8 . The method of claim 1 , wherein the compound of Formula I is a compound having a structure:
wherein R 1 and R 1′ are the same.
9 . The method of claim 8 , wherein R 1 and R 1′ are each selected from the group consisting of straight or branched methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, t-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl.
10 .- 11 . (canceled)
12 . The method of claim 9 , wherein the compound of Formula I is a compound having a structure:
wherein said compound has a purity above about 93A % by HPLC.
13 .- 14 . (canceled)
15 . The method of claim 1 , wherein the compound of Formula I′ is selectively di-halogenated in the 4 and 6 positions.
16 . The method of claim 15 , wherein the 4,6-di-halogenated compound of Formula I, wherein each of R 1 and R 2 is halogen is prepared at a ratio of from about 25:1 to about 34:1 relative to the 2,4-dihalogenated impurity compound.
17 . The method of claim 1 , wherein prior to said contacting, the compound of Formula I′ is contacted with a first solvent to form a mixture.
18 . (canceled)
19 . The method of claim 17 , wherein the solvent is selected from the group consisting of ethyl acetate, isopropyl acetate, acetonitrile, and acetone.
20 . (canceled)
21 . The method of claim 17 , wherein the solvent is present from about 9.7 vol to about 16.1 vol.
22 . The method of claim 1 , wherein the organic sulfoxide is present in an amount of about 2.0 equiv to about 3.0 equiv.
23 . The method of claim 22 , wherein the HX is present in an amount from about 2.0 equiv to about 3.0 equiv.
24 .- 26 . (canceled)
27 . A method of preparing a compound of Formula I:
wherein,
R 1 is a branched or straight chain C 1-12 alkyl; and
R 2 and R 3 are each halogen,
the method comprising:
selectively halogenating at the 4- and 6-positions by contacting a compound of Formula I′ having a structure:
wherein, R 1′ is a branched or straight C 1-12 alkyl; and
R 2′ and R 3′ are each hydrogen;
with a first solvent to form a mixture,
contacting the mixture with HX, wherein X is a halide, in the presence of an organic sulfoxide;
wherein, the contacting is at a temperature from about 0° C. to about 100° C.; and
wherein, the compound of Formula I is prepared.
28 . The method of claim 27 , wherein the compound of Formula I is present at a ratio of at least 10:1 relative to a mono-halogenated, tri-halogenated or 2,4-dihalogenated compound.
29 .- 30 . (canceled)
31 . The method of claim 27 , wherein the halide is Br and HX is HBr.
32 .- 35 . (canceled)
36 . The method of claim 27 , wherein R 1′ is propyl or pentyl, and the compound of Formula I is selected from the group consisting of:
37 .- 39 . (canceled)
40 . A composition comprising 4,6-DBO; 4-MBO; 2,4-DBO and TBO in amounts of about 94%, about 3%, about 1%, and about 1%, respectively.
41 . The method of claim 1 or 27 , wherein said organic sulfoxide is of the general formula:
wherein, Ra and Rb are each independently selected from the group consisting of benzyl, phenyl, alkyl, aryl and allyl.
42 .- 43 . (canceled)