A kind of preparation method of shellfish cholic acid difficult to understand
Technical field
The present invention relates to a kind of preparation method of shellfish cholic acid difficult to understand.
Background technology
Shellfish cholic acid (shown in formula I) difficult to understand is a kind of semi-synthetic chenodeoxycholic acid derivatives, and for treating, portal blood pressure is too high and liver diseases, including PBC, bile acid diarrhoea, nonalcoholic fatty liver disease.Shellfish cholic acid difficult to understand is played a role by activating FXR acceptors, and FXR is a kind of nuclear receptor, is mainly expressed in liver, intestines, kidney, and it can be adjusted and bile acid, the expression of fat and sugar metabolism related gene, moreover it is possible to adjust immune response.Activation FXR can suppress bile acid biosynthesis, and prevention bile acid builds up caused toxic reaction.
WO2002072598 makes public for the first time the preparation method (as follows) of shellfish cholic acid difficult to understand; this method obtains compound VII with iodoethane direct alkylation under strongly alkaline conditions by compound VI, and shellfish cholic acid difficult to understand is made by reduction and carboxyl deprotection in compound VII.But due to, the building-up process difficult to realize amplification synthesis too low with the poor selectivity and yield of iodoethane direct alkylation.
Shellfish cholic acid synthetic method (WO2002072598) difficult to understand
WO2006122977 is improved (as follows) above synthesis technique; compound IX by being converted into the enolization compound X that silicon substrate is protected by this method; compound X after acetaldehyde condensation dehydration with obtaining compound Vb; compound Vb obtains compound XI by palladium carbon hydrogenating reduction in the basic conditions, and Austria's shellfish cholic acid is made in compound XI after carbonyl reduction.
Shellfish cholic acid synthetic method (WO2006122977) difficult to understand
Although the synthesis technique can realize amplification synthesis; but; substantial amounts of accessory substance is produced during compound Vb under strongly alkaline conditions palladium carbon hydrogenating reduction and strong basicity high-temperature process prepare compound XI; so as to which the separation yield for causing the step to be reacted is relatively low (about 60%), the low yield of step reaction is probably to be caused because the side reactions such as dehydration occur under the conditions of strong basicity (30%NaOH) and high temperature (95-105 DEG C) for the unprotected hydroxyl in compound Vb and XI.
The content of the invention
Shortcoming present in synthetic method for existing shellfish cholic acid difficult to understand; inventor is by discovery of concentrating on studies; protected by the hydroxyl to compound V; it can avoid that the side reactions such as dehydration occur under strong basicity and hot conditions; the combined coefficient of shellfish cholic acid difficult to understand is substantially increased, thus it is few there is provided a kind of accessory substance, it is easy to operate; synthesize with low cost, the shellfish cholic acid preparation method difficult to understand suitable for large-scale production.
The invention provides a kind of new method for synthesizing shellfish cholic acid difficult to understand,
Wherein, R1For hydroxyl protecting group, R2For carboxyl-protecting group.
Specifically, the synthetic method comprises the following steps:
1) Formula V compound obtains the compound as shown in formula IV by hydroxyl protection;
2) compound as shown in formula III is made by palladium carbon catalytic hydrogenation reaction in the basic conditions in formula IV;
3) compound as shown in Formula II is made by reduction for formula III;
4) eliminating hydroxide protects the shellfish cholic acid difficult to understand being made shown in formula I to Formula II in acid condition.
Wherein, method synthesis of the compound V according to described in WO2006122977 is obtained.
In yet other embodiments, hydroxyl protecting group R1For MOM, carboxyl-protecting group R2For ethyl.
In presently preferred embodiment, hydroxyl protecting group R1For MOM, carboxyl-protecting group R2For methyl.
In an especially preferred embodiment, the synthetic route of present invention offer shellfish cholic acid difficult to understand is as follows:
Specifically, the synthetic method comprises the following steps:
1) Formula V a compounds react the compound obtained as shown in formula IV a with MOMCl;
2) compound as shown in formula III a is made by palladium carbon catalytic hydrogenation reaction in the basic conditions in formula IV a;
3) compound as shown in Formula II a is made by sodium borohydride reduction by formula III a;
4) Formula II a protects the shellfish cholic acid difficult to understand being made shown in formula I by hydrochloric acid water solution eliminating hydroxide.
Wherein, method synthesis of the compound Va according to described in WO2006122977 is obtained.
The present invention also provides a kind of compound as shown in formula IV,
Wherein, R1For hydroxyl protecting group, R2For carboxyl-protecting group.
In yet other embodiments, hydroxyl protecting group R1For MOM, carboxyl-protecting group R2For ethyl.
In presently preferred embodiment, hydroxyl protecting group R1For MOM, carboxyl-protecting group R2For methyl.
The present invention further provides a kind of preparation method of the compound as shown in formula IV, compound IV carries out being made after hydroxyl protection by compound shown as a formula V.
Wherein, R1For hydroxyl protecting group, R2For carboxyl-protecting group.
The present invention also provides a kind of compound as shown in formula III,
Wherein, R1For hydroxyl protecting group.
In yet other embodiments, hydroxyl protecting group R1For MOM.
The present invention further provides a kind of preparation method of the compound as shown in formula III, compound III is made by palladium carbon catalytic hydrogenation reaction in the basic conditions by the compound as shown in Formula IV,
Wherein, R1For hydroxyl protecting group.
In yet other embodiments, hydroxyl protecting group R1For MOM.
The present invention also provides a kind of compound as shown in Formula II,
Wherein, R1For hydroxyl protecting group.
In yet other embodiments, hydroxyl protecting group R1For MOM.
The present invention further provides a kind of preparation method of the compound as shown in Formula II, compound II is made by the compound as shown in formula III after reduction reaction,
Wherein, R1For hydroxyl protecting group.
In yet other embodiments, hydroxyl protecting group R1For MOM.
Term used in the present invention, in addition to having opposite statement, with following implication:
The hydroxyl protecting group of the present invention is the appropriate group for hydroxyl protection known in the art, referring to document (" Protective Groups in Organic Synthesis ", 5ThEd.T.W.Greene&P.G.M.Wuts the hydroxy-protective group in).As an example, preferably, described hydroxyl protecting group can be (C1-10Alkyl or aryl)3Silylation, for example:Triethyl group silicon substrate, triisopropylsilyl, t-Butyldimethylsilyl, tert-butyl diphenyl silicon substrate etc.;Can be C1-10Alkyl or substitution alkyl, preferably alkoxy or the alkyl of aryl substitution, more preferably C1-6The C of alkoxy substitution1-6The C of alkyl or phenyl substitution1-6Alkyl, most preferably C1-4The C of alkoxy substitution1-4Alkyl, for example:Methyl, the tert-butyl group, pi-allyl, benzyl, methoxy, ethoxyethyl group, 2- THP trtrahydropyranyls (THP) etc.;Can be (C1-10Alkyl or aromatic radical) acyl group, for example:Formoxyl, acetyl group, benzoyl etc.;Can be (C1-6Alkyl or C6-10Aryl) sulfonyl;Can also be (C1-6Alkoxy or C6-10Aryloxy) carbonyl.
" carboxylic acid protecting group " be it is known in the art it is appropriate be used for the group that carboxylic acid is protected, referring to document (" Protective Groups in Organic Synthesis ", 5Th Ed.T.W.Greene&P.G.M.Wuts)
In carboxylic acid protective group, as an example, preferably, described carboxylic acid protecting group can be substituted or non-substituted C1-10Straight or branched alkyl, substituted or non-substituted C2-10Straight or branched alkenyl or alkynyl, substituted or non-substituted C3-8Cyclic alkyl, substituted or non-substituted C5-10Aryl or heteroaryl or (C1-8Alkyl or aryl)3Silylation;It is preferred that C1-6Straight or branched alkyl, more preferably C1-4Straight or branched alkyl.
English abbreviation has following meaning employed in the present invention:
Abbreviation |
Full name |
MOMCl |
Chloromethyl methyl ether |
MOM |
Methoxy |
TMS |
Trimethyl silicon substrate |
Following table is the structural formula of involved compound in embodiment
Embodiment
The present invention is explained in detail below with reference to instantiation so that the present invention is more fully understood in those skilled in the art, instantiation is merely to illustrate technical scheme, the present invention is not limited in any way.
Embodiment 1:Prepare compound IVa
Compound Va (646 grams, the method in WO2006122977 is made) is dissolved in 7 liters of dichloromethane, 762 milliliters of diisopropylethylamines are added, it is cooled to 0 DEG C, 166 milliliters of MOMCl are added, reaction system is warming up to 20 DEG C, reacts 16 hours, add water and reaction is quenched, 10 liters of ethyl acetate extractions are added, organic phase, organic phase anhydrous sodium sulfate drying is separated, 696 g of compound IVa, yield 98% are obtained after filtering and concentrating.
1H NMR(400MHz,CDCl3)δ6.16(q,1H),4.76–4.59(m,2H),4.28–4.01(m,2H),3.70–3.48(m,1H),3.42–3.29(m,3H),2.56(dd,1H),2.46–2.14(m,4H),2.07–1.87(m,4H),1.87–1.68(m,5H),1.55–1.04(m,16H),1.00(s,3H),0.92(t,3H),0.78–0.62(m,3H).
Embodiment 2:Prepare compound IIIa
Compound IVa (696g) is dissolved in ethanol (7 liters), palladium carbon (76g, 10wt%) and 500 gram of 30% sodium hydrate aqueous solution is added, 16h is reacted at hydrogen (1.5 atmospheric pressure) and 20 DEG C, 95 DEG C are then warming up to, stirred 16 hours, it is cooled to after 20 DEG C, filters, the mother liquor after concentration is neutralized with 2N hydrochloric acid, plus 10 liters of ethyl acetate extractions, after extract is concentrated, crystallization, filtering, 606 g of compound IIIa, yield 92% are obtained after drying.
1H NMR(400MHz,CDCl3)δ4.74–4.55(m,2H),3.52–3.39(m,1H),3.38–3.30(m,3H),2.68(dd,1H),2.49–2.13(m,4H),2.02–1.65(m,9H),1.58–1.02(m,15H),0.95(dd,4H),0.86–0.77(m,3H),0.67(d,3H).
Embodiment 3:Prepare compound IIa
Compound IIIa (606 grams) is dissolved in 7 liters of ethanol, 0 DEG C is cooled to, 50 grams of sodium borohydrides is added, is warming up to 20 DEG C, reaction 8 hours, is slowly added dropwise phosphoric acid until pH=6, solid precipitation, filtering, solid is washed with water, and 584 g of compound IVa, yield 96% are obtained after drying.
1HNMR(400MHz,CDCl3)δ4.66(s,2H),3.72(m,2H),3.35(m,4H),2.25-1.07(m,28H),0.90(m,8H),0.65(s,3H).
Embodiment 4:Prepare shellfish cholic acid difficult to understand
Compound IIa (584 grams) is dissolved in 6 liters of tetrahydrofurans, 0 DEG C is cooled to, 5 liters of 4N aqueous hydrochloric acid solutions is added, is warming up to 20 DEG C, reaction 8 hours, plus 10 liters of ethyl acetate extractions, after extract is concentrated, crystallization, filtering, is dried to obtain 497 Ke Aobei cholic acid, yield 94%.
1HNMR(400MHz,CD3OD)δ3.65(m,1H),3.30(m,1H),2.32(m,1H),2.20(m,1H),2.03-1.65(m,8H),1.60-1.06(m,18H),0.90(m,9H),0.67(s,3H).
Embodiment 5:Prepare compound IVb
Compound Vb (500 grams, the method in WO2006122977 is made) is dissolved in 5 liters of dichloromethane, 650 milliliters of diisopropylethylamines are added, it is cooled to 0 DEG C, 147 milliliters of MOMCl are added, reaction system is gradually raised to 20 DEG C, reacts 16 hours, add water and reaction is quenched, 10 liters of ethyl acetate extractions are added, organic phase, organic phase anhydrous sodium sulfate drying is separated, 524 g of compound IVb, yield 95% are obtained after filtering and concentrating.
1HNMR(400MHz,CDCl3) δ 6.16 (m, 1H), 4.65 (s, 2H), 3.66 (s, 3H), 3.55 (m, 1H), 3.34 (s, 3H), 3.08 (m, 1H), 2.55 (m, 2H), 2.53 (m, 2H), 2.22 (m, 2H), 1.96 (m, 6H), 1.80 (m, 2H), 1.69 (m, 4H), 1.56-1.01 (m, 14H), 0.93 (m, 3H), 0.62 (s, 3H)
Embodiment 6:Prepare compound IIIa
Compound IVb (70g) is dissolved in ethanol (750 persons of outstanding talent rise), palladium carbon (8g, 10wt%) and 50 gram of 30% sodium hydrate aqueous solution is added, 10h is reacted at hydrogen (1.5 atmospheric pressure) and 20 DEG C, 100 DEG C are then warming up to, stirred 10 hours, it is cooled to after 20 DEG C, filters, the mother liquor after concentration is neutralized with 2N hydrochloric acid, plus 1 liter of ethyl acetate extraction, after extract is concentrated, crystallization, filtering, 65 g of compound IIIa, yield 95% are obtained after drying.
1H NMR(400MHz,CDCl3)δ4.62(m,2H),3.43(m,1H),3.34(m,3H),2.68(m,1H),2.25(m,4H),1.82(m,9H),1.58–1.02(m,15H),0.95(m,4H),0.80(m,3H),0.66(s,3H).
Due to describing the present invention according to its specific embodiment, some modifications and equivalent variations are obvious for those skilled in this art and are included within the scope of the invention.