阅读说明：本技术 环戊烯酮的合成 (Synthesis of cyclopentenones ) 是由 A·I·帕迪利亚-阿塞韦多 于 2019-09-11 设计创作，主要内容包括：一种包括合成取代的环戊烯酮化合物的方法,其经由在五氧化二磷/甲磺酸试剂存在下使取代的丙烯酸环烷酯反应以制备所述取代的环戊烯酮化合物来实现。(A process comprising synthesizing a substituted cyclopentenone compound via reacting a substituted cycloalkyl acrylate in the presence of a phosphorus pentoxide/methanesulfonic acid reagent to produce the substituted cyclopentenone compound.)

1. A method of synthesizing a substituted cyclopentenone compound, comprising (a) reacting a compound of formula (1) ("compound (1)"):wherein subscript n is 1,2, 3, or 4; and each of the groups R1, R2, R3 and R4 is independently H or (C)₁-C₄) Alkyl, or any two adjacent R1 to R3 groups are bonded together to form (C)₁-C₄) Alkylene and the remainder of R1 to R3 being H or (C)₁-C₄) Alkyl with an effective amount of phosphorus pentoxide/methane sulfonic acid reagent (P)₂O₅/H₃CSO₃Reagent H), under reaction conditions sufficient to produce a compound of formula (2) ("compound (2)"):wherein the subscript n and the groups R1 to R4 are as defined above; and with the proviso that the contacting step (a) does not contain added polyphosphoric acid (PPA).

2. The method of claim 1, wherein for preparing the P₂O₅/H₃CSO₃P of H reagent₂O₅And H₃CSO₃The ratio of H is from 0.05/1 to 1/1 (weight/weight).

3. The process according to claim 1 or 2, wherein for the preparation of said P₂O₅/H₃CSO₃P of H reagent₂O₅And H₃CSO₃The ratio of H is 0.1/1(weight/weight).

4. A method according to any one of claims 1 to 3, characterized by limiting any one of (i) to (xxi): (i) wherein at least one of R1 to R3 is (C)₁-C₄) Alkyl or R4 is H; (ii) wherein each of R1 to R4 is H; (iii) wherein each of R1 to R3 is H and R4 is methyl; (iv) wherein each of R1 and R2 is H and each of R3 and R4 is methyl; (v) wherein R1 and/or R2 are methyl and R3 is H; (vi) wherein R1 is methyl, R2 is 1-methylethyl, and R3 is H; (vii) wherein R1 is 1-methylethyl, R2 is methyl, and R3 is H; (viii) wherein R1 and R2 are independently (C)₁-C₄) Alkyl, R3 is H, and the stereochemistry of the carbon atom bound to R1 is (R) and the stereochemistry of the carbon atom bound to R2 is (S); (ix) wherein R1 and R2 are independently (C)₁-C₄) Alkyl, R3 is H and the stereochemistry of the carbon atom bound to R1 is (S) and the stereochemistry of the carbon atom bound to R2 is (R); (x) (vi) both (vi) and (viii); (xi) (vi) both (ix); (xii) (vii) both (vii) and (viii); (xiii) (vii) both (vii) and (ix); (xiv) Wherein R5 is H; (xv) Wherein R5 is methyl; (xvi) (ii) both (i) and (xiv) or (xv); (xvii) (ii) both with (xiv) or (xv); (xviii) (iii) both with (xiv) or (xv); (xix) (iv) both with (xiv) or (xv); (xx) (v) and both (xiv) or (xv); and (xxi) any two adjacent R1 to R3 groups are bonded together to form (C)₁-C₄) Alkylene and the remainder of R1 to R3 being H or (C)₁-C₄) An alkyl group.

5. The method according to any one of claims 1 to 4, wherein the compound (2) is selected from the group consisting of any one of compounds (2a) to (2 e):

compound (2a)2,3,4,5,6, 7-hexahydro-3-methyl-1H-inden-1-one having the structure (2 a):

compound (2b) bicyclo [3.3.0]-1(5) -octen-2-one having the structure (2 b):

compound (2c) 4-methyl-bicyclo [3.3.0]-1(5) -octen-2-one having the structure (2 c):

compound (2d) 10-methyl-bicyclo [5.3.0] -1(7) -decen-8-one; and

the compound (2e)2,4,6, 11-tetramethyl-bicyclo [6.3.0] -1(8) -undecen-9-one.

Technical Field

Synthesizing cyclopentenone.

Background

Uemichi, Yoshio; kanoh, Hisao, "research report on technical meeting of the glass industry of the glass of Asahi glass (Kenkyu Hokoku-Asahi Garasu Kogyo Gijutsu Shoreikai), vol 49, pp 225-30, 1986. CODEN AGKGAA. ISSN 0365-2599 reported a powerful source of platinum degradation, particularly of polyethylene. Uemichi, Yoshio; makino, Yutaka; kanazuka, Takaji, Degradation of polyethylene to aromatics over metal-supported activated carbon catalysts (Degradation of polyethylene to aromatic hydrocarbons over metal-supported activated carbon catalysts), Journal of Analytical and Applied Pyrolysis (1989),14(4), 331-44.

See also below. TabatabaenianK.; mamghani, m.; neshat, a.; masjedi, M. a newly substituted binuclear-synthesis and spectroscopic analysis studies of 4,5,6, 7-tetrahydroindenyl ruthenium complex. Journal of Russian Coordination Chemistry 2003,29,7, 501. Austin, r.n.; clark, t.j.; dickson, t.e.; killian, c.m.; nile, t.a.; shaker, d.j.; synthesis and characterization of McPhail, t.a. novel substituted 4,5,6, 7-tetrahydroindenes and selected metal complexes. Journal of Organometallic Chemistry 1995 (Journal of Organometallic Chemistry), 491, 11. Conia, j.m.; lerivend, M.L. Tetrahedron Letters 1968,17.2101(Conia et al). Rand and r.j.dolinski, journal of organic chemistry (j. org. Chem.),1966,31,3063 and l.rand and r.j.dolinski, journal of organic chemistry, 1966,31,4061 (collectively "Rand and Dolinski"). Yokota, k.; kohsaka, t.; ito, k.; ishihara, N.investigation of the Mechanism of Styrene/Ethylene Copolymerization using a Half-metallocene titanium catalyst (Consideration of Mechanism of Styrene/Ethylene Copolymerization with Half-Titanocene Catalysts.) Journal of Polymer Science (Journal of Polymer Science) 2005,43, 5041. Tetsuya, i., et al, Brancaccio g.; letteri, g.; monforte, p.; larizza, JP10316694A, Farmaco, Edizone scientific, 1983,9, 702-8. Eaton, p.e.; carlson, g.r.; lee, j.t. phosphorus pentoxide methanesulfonic acid. A convenient polyphosphoric acid substitute. Journal of organic chemistry 1978,38, 4071. Pattette, l.a.; stevens, k.e., 1984,62,2415, journal of chemistry in canada (can.j.chem.). Pattette, l.a.; cheney, d.l., journal of organic chemistry, 1989,54, 3334. Journal of organic chemistry 1966,3065.

Conia et al reported that reacting cyclohexene with crotonic acid in the Presence of Polyphosphoric Acid (PPA) produced only 2,3,4,5,6, 7-hexahydro-3-methyl-1H-inden-1-one (Structure 1 in Conia et al) as the only product. Conia et al reported that reacting cyclopentyl crotonate or cyclohexyl crotonate in the presence of PPA gave 3-methyl-bicyclo [3.3.0] -2-octen-1-one (40% yield, Table 1 in Conia et al) or 2,3,4,5,6, 7-hexahydro-3-methyl-1H-inden-1-one (60% yield, Table 2 in Conia et al), respectively.

Rand and Dolinski reported the use of polyphosphoric acid (PPA) or phosphorus pentoxide (P)₂O₅Or P₄O₁₀) The mixture with PPA catalyzes the reaction of cycloheptene, cyclohexene or cyclopentene with an α, β -unsaturated carboxylic acid (e.g., acrylic acid or crotonic acid) to produce a reaction mixture with or without an ester by-product (e.g., cycloheptyl crotonate, cyclohexyl crotonate or cyclopentyl crotonate). It is stated that how much ester by-product is produced is dependent on the amount of PPA or P used in the mixture with PPA or relative to the amount of cycloolefins₂O₅Amount of PPA mixture.

Disclosure of Invention

The present invention includes a method for cyclizing an α, β -unsaturated carboxylic acid cycloalkane ester compound in the presence of a phosphorus pentoxide/methanesulfonic acid reagent (e.g., eaton's reagent) to produce a substituted cyclopentenone compound. The synthesis can be carried out at lower temperatures but with higher yields than the previous PPA-based synthesis by Conia et al.

The substituted cyclopentenone compounds prepared by the method can be used as intermediates in the synthesis of compounds useful as pharmaceuticals, herbicides, pesticides, or catalysts such as olefin polymerization catalysts, e.g., substituted metallocene compounds.

Detailed Description

The summary and abstract are incorporated herein by reference.

Certain embodiments of the invention are described below in the form of numbered aspects that are readily cross-referenced. Additional embodiments are described elsewhere herein.

Aspect 1. a method of synthesizing a substituted cyclopentenone compound, the method comprising (a) reacting a compound of formula (1) ("compound (1)"):wherein subscript n is 1,2, 3, or 4; and each of the groups R1, R2, R3 and R4 is independently H or (C)₁-C₄) Alkyl, or any two adjacent R1 to R3 groupsBonded together to form (C)₁-C₄) Alkylene and the remainder of R1 to R3 being H or (C)₁-C₄) Alkyl with an effective amount of phosphorus pentoxide/methane sulfonic acid reagent (P)₂O₅/H₃CSO₃Reagent H), under reaction conditions sufficient to produce a compound of formula (2) ("compound (2)"):wherein the subscript n and the groups R1 to R4 are as defined above; and with the proviso that contacting step (a) does not contain polyphosphoric acid (PPA). Reaction conditions sufficient to prepare compound (2) include an anhydrous environment and a temperature of-80 ℃ to 30 ℃. Step (a) may be PPA-free.

Aspect 2 the method according to aspect 1, wherein for the preparation of P₂O₅/H₃CSO₃P of H reagent₂O₅And H₃CSO₃The ratio of H is from 0.05/1 to 1/1 (weight/weight).

Aspect 3 the process according to aspect 1 or 2, wherein for the preparation of P₂O₅/H₃CSO₃P of H reagent₂O₅And H₃CSO₃The ratio of H was 0.1/1 (weight/weight). Known as the eaton reagent.

Aspect 4. the method according to any one of aspects 1 to 3, characterized by limiting any one of (i) to (xxi): (i) wherein at least one of R1 to R3 is (C)₁-C₄) Alkyl or R4 is H; (ii) wherein each of R1 to R4 is H; (iii) wherein each of R1 to R3 is H and R4 is methyl; (iv) wherein each of R1 and R2 is H and each of R3 and R4 is methyl; (v) wherein R1 and/or R2 are methyl and R3 is H; (vi) wherein R1 is methyl, R2 is 1-methylethyl (i.e., isopropyl), and R3 is H; (vii) wherein R1 is 1-methylethyl (i.e., isopropyl), R2 is methyl, and R3 is H; (viii) wherein R1 and R2 are independently (C)₁-C₄) Alkyl, R3 is H, and the stereochemistry of the carbon atom bound to R1 is (R) and the stereochemistry of the carbon atom bound to R2 is (S); (ix) wherein R1 and R2 are independently (C)₁-C₄) Alkyl, R3 is H and a bondThe stereochemistry of the carbon atom bound to R1 is (S) and the stereochemistry of the carbon atom bound to R2 is (R); (x) (vi) both (vi) and (viii); (xi) (vi) both (ix); (xii) (vii) both (vii) and (viii); (xiii) (vii) both (vii) and (ix); (xiv) Wherein R5 is H; (xv) Wherein R5 is methyl; (xvi) (ii) both (i) and (xiv) or (xv); (xvii) (ii) both with (xiv) or (xv); (xviii) (iii) both with (xiv) or (xv); (xix) (iv) both with (xiv) or (xv); (xx) (v) and both (xiv) or (xv); and (xxi) any two adjacent R1 to R3 groups are bonded together to form (C)₁-C₄) Alkylene and the remainder of R1 to R3 being H or (C)₁-C₄) An alkyl group.

Aspect 5. the method according to any one of aspects 1 to 4, wherein compound (2) is selected from the group consisting of any one of compounds (2a) to (2 e): compound (2a)2,3,4,5,6, 7-hexahydro-3-methyl-1H-inden-1-one having the structure (2 a):compound (2b) bicyclo [3.3.0]-1(5) -octen-2-one having the structure (2 b):compound (2c) 4-methyl-bicyclo [3.3.0]-1(5) -octen-2-one having the structure (2 c):compound (2d) 10-methyl-bicyclo [5.3.0]-1(7) -decen-8-one; and compound (2e)2,4,6, 11-tetramethyl-bicyclo [6.3.0]-1(8) -undecen-9-one.

The compound (2) may be free of platinum, palladium, nickel, rhodium and ruthenium. The compound (2) can be used as an intermediate for synthesizing a compound useful as a drug, a herbicide, a pesticide or a catalyst such as an olefin polymerization catalyst, such as a substituted metallocene compound. For example, the compound (2) may be converted into a substituted cyclopentadiene compound by reducing the carbonyl group (C ═ O) of the compound (2) to an alcohol and dehydrating the alcohol to obtain a substituted cyclopentadiene compound. The substituted cyclopentadienyl compound may be deprotonated with a strong base such as an alkyllithium to give a substituted cyclopentadienyl anion, one or both, or may be complexed with a transition metal such as a group 4 metal (e.g., Ti, Zr, or Hf) to give a substituted metallocene compound comprising a metal- (substituted cyclopentadienyl ligand) complex. Substituted metallocene compounds can be used as olefin polymerization catalysts or can be activated with an activator (e.g., a trialkylaluminum) to give substituted metallocene catalysts for polymerizing olefin monomers such as ethylene and α -olefins.

The term "free" means that no presence is detected.

Since the subscript n and groups R1 to R4 are defined for compound (1), they can be defined for compound (2).

Compound (1) can be obtained from commercial suppliers or synthesized from starting materials suitable for the preparation of cyclic alkyl α, β -unsaturated carboxylates. Examples of commercially available compounds (1) are (1a) cyclohexyl (2E) -2-butenoate; (1b) (2E) -2-butenoic acid cyclopentyl ester (CAS 1195328-04-1); (1c) (2E) -cycloheptyl 2-butenoate (CAS 10555-39-2); and (1d) cyclopentyl acrylate (CAS 16868-13-6). (2E) -2-butenoic acid is also known as (E) -crotonic acid. Unless otherwise indicated herein, "crotonic acid" refers to (2E) -2-butenoic acid. In some embodiments, compound (1) is any one of compounds (1a) to (1d), or compound (1) is selected from the group consisting of any three of compounds (1a) to (1 d); alternatively, compound (1) is compound (1a), or compound (1b), or compound (1c), or compound (1 d).

The compound (1) can be prepared by reacting a corresponding cycloalkanol of the formula (a):wherein the subscript n and the groups R1 to R3 are as defined for compound (1), with an α, β -unsaturated carboxylic acid of formula (b):wherein R4 is as defined for compound (1), is reacted to ease the synthesis. Suitable dehydration conditions include refluxing toluene, protic acids such as p-toluene sulfonic acid (pTsOH) and Didi for removing the water producedAn ampere-Stark trap (Dean-Stark trap) or a desiccant for sequestering the water produced. An example of a desiccant is 3 Angstrom TeronMolecular sieves and anhydrous sodium sulfate. Methods and conditions for the synthesis of carboxylic acid esters from the corresponding alcohols and carboxylic acids are well known and useful. Compound (1) can also be synthesized by reacting the cycloalkanol of formula (a) with the corresponding α, β -unsaturated carboxylic acid anhydride, which can be prepared by dehydrating two molar equivalents of compound (b).

The cycloalkanol compound (a) may be obtained from commercial suppliers or synthesized by well-known methods for preparing alcohols. Examples of commercially available compounds (a) having a subscript n of 1 are (a1) cyclopentanol (CAS 96-41-3); (a2) 3-methyl-cyclopentanol (CAS 18729-48-1); (a3)3, 4-dimethyl-cyclopentanol (CAS 73316-51-5); and (a4)3, 3-dimethyl-cyclopentanol (CAS 60670-47-5). Examples of commercially available compounds (a) having subscript n of 2 are (a5) cyclohexanol (CAS 108-93-0); (a6) 2-methylcyclohexanol (either as a mixture of stereoisomers or as a single enantiomer); (a7) 4-methylcyclohexanol (CAS 589-91-3); (a8)2, 5-dimethylcyclohexanol (CAS 3809-32-3); and (a9) 5-methyl-2- (1-methylethyl) -cyclohexanol (e.g., as a mixture of stereoisomers or any enantiomer thereof, e.g., (1R,2S,5R) -menthol). Examples of commercially available compounds (a) having subscript n of 3 are (a10) cycloheptanol (CAS 502-41-0); (a11) 4-methylcycloheptanol (CAS 90200-61-6); and (a12)4, 4-dimethylcycloheptanol (CAS 35099-84-4). Examples of commercially available compounds (a) having subscript n of 4 are (a13) cyclooctanol (CAS 696-71-9); and (a14)3,5, 7-trimethylcyclooctanol (CAS 1823711-29-0). In some embodiments, compound (1) is prepared from the following compounds, and the alcohol-derived moiety containing R1-R3 corresponds to the following compounds: any one of compounds (a1) to (a14), or a compound selected from the group consisting of any thirteen of compounds (a1) to (a14), or compound (1), wherein subscript n is 1,2, or 3; or compound (1) wherein subscript n is 1 or 2; or compound (1) wherein subscript n is 1; or compound (1) wherein subscript n is 2; or compound (1) wherein subscript n is 3 or 4; or compound (1) wherein subscript n is 3; or compound (1) wherein subscript n is 4.

The α, β -unsaturated carboxylic acid compound (b) can be obtained from commercial suppliers or synthesized by well-known methods for preparing carboxylic acids. Examples of commercially available compounds (b) are (b1) acrylic acid (compound (b) wherein R4 is H); (b2) crotonic acid (compound (b) where R4 is methyl); (b3) 2-pentenoic acid (compound (b) wherein R4 is ethyl); and (b4) 2-hexenoic acid (compound (b), wherein R4 is propyl). In some embodiments, compound (1) is prepared from the following compound, and the moiety derived from a carboxylic acid comprising R4 corresponds to the following compound: any one of compounds (b1) to (b 4); or a compound selected from the group consisting of any three of compounds (b1) to (b 4); or compound (b1) or (b 2); or compound (b 1); or compound (b 2); or compound (b3) or (b 4); or compound (b 3); or compound (b 4).

Alkyl means an unsubstituted monovalent saturated acyclic hydrocarbon that is straight-chain (if 1 or more carbon atoms), branched (if 3 or more carbon atoms), or cyclic (if 3 or more carbon atoms). Each (C)₁-C₄) Alkyl is independently methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl or 1, 1-dimethylethyl. Or, each (C)₁-C₄) Alkyl is independently (C)₁-C₃) An alkyl group; or (C)₂-C₄) An alkyl group; or (C)₁-C₂) An alkyl group; or (C)₂-C₃) An alkyl group; or (C)₃-C₄) An alkyl group; or methyl or (C)₃) An alkyl group. In some aspects, each (C)₁-C₄) Alkyl is independently (C)₁-C₃) Alkyl and each (C)₁-C₃) Alkyl is independently methyl, ethyl, propyl or 1-methylethyl; or methyl, propyl or 1-methylethyl; or a methyl group; or an ethyl group; or a propyl group; or 1-methylethyl. Substituted alkyl is alkyl as defined above, except wherein one or more hydrogen atoms are replaced as substituents such as unsubstituted alkyl, halogen or alkyl carboxylateAnd (c) other than.

An alkylene group is an unsubstituted divalent saturated acyclic hydrocarbon that is straight-chain (1 or more carbon atoms), branched (if 3 or more carbon atoms), or cyclic (if 3 or more carbon atoms). Each (C)₁-C₄) Alkylene is independently methylene (CH)₂) Ethylene (CH)₂CH₂) Propylene (CH)₂CH₂CH₂) 1-methylethylidene (CH)₃)CH₂) Butylene ((CH)₂)₄) 1-methylpropylidene (CH)₃)CH₂CH₂) 2-methylpropylidene (CH)₂CH(CH₃)CH₂) Or 1, 1-dimethylethylene (C (CH)₃)₂CH₂. Substituted alkylene is alkylene as defined above, except that one or more hydrogen atoms are formally replaced by a substituent such as unsubstituted alkyl, halogen or alkyl carboxylate.

A compound means a molecule or collection of molecules.

An effective amount is an amount sufficient to effect the production of a detectable amount of the desired product, e.g., compound (2). An effective amount of a phosphoric and/or sulfonic acid reagent is an amount sufficient to achieve a detectable amount of compound (2) produced. The detectable amount can be characterized by any suitable analytical method (e.g., 1H-nuclear magnetic resonance (1H-NMR), high performance liquid chromatography (HPLC, compared to known standards), gas chromatography (GC, compared to known standards), or mass spectrometry; typically 1H-NMR. the effective amount of phosphorus pentoxide/methanesulfonic acid reagent used in step (A) can vary depending on its composition, reaction conditions, and cost. An effective amount may be 50 to 95 wt%, or 50 to 80 wt%. Or, P is the number of moles of the compound (1)₂O₅/H₃CSO₃An effective amount of H reagent can be1 to 10 molar equivalents (mol quiv.), or 1 to 5 molar equivalents, or 1 to 3 molar equivalents. For example, if 1.0 mole of compound (1) is used in the contacting step (A), then P₂O₅/H₃CSO₃An effective amount of H reagent may be 1 to 10 moles, alternatively 1 to 5 moles, alternatively 1 to 3 moles.

Methanesulfonic acid is of formula H₃CSO₃H and CAS number 75-75-2, and are widely available from commercial suppliers.

Phosphorus pentoxide of the formula P₂O₅(also written as P)₄O₁₀) And CAS number 1314-56-3, and is widely available from commercial suppliers.

Phosphorus pentoxide and methanesulfonic acid reagent ('P')₂O₅/H₃CSO₃H reagent ", also written as P₄O₁₀/H₃CSO₃H reagent or P₂O₅/MeSO₃H reagent) is P₂O₅(also written as P4O10) and H₃CSO₃A physical blend of H or a reaction product thereof. In the reagent P₂O₅/H₃CSO₃The weight/weight ratio of H may be from 0.05/1 to 1/1, or from 0.1/1 to 1/1, or from 0.15/1 to 1/1, or from 0.2/1 to 1/1, or from 0.05/1 to 0.14/1, or 0.1/1. 0.1/1(wt/wt) P₂O₅/H₃CSO₃The H reagent is commercially available and may be referred to as the eaton reagent. P₂O₅And CH₃SO₃The agent of H may be formed in situ in the presence of compound (1), such as before or during contacting step (a). Alternatively, P may be preformed prior to the contacting step (A)₂O₅And CH₃SO₃H (in the absence of compound (1)). It is desirable to pre-form P prior to the contacting step (A)₂O₅/CH₃SO₃H reagent, and storing the resulting preformed reagent for subsequent use in embodiments of the contacting step (a). In some aspects, the method further comprises limiting (i) or (ii): (i) preforming P before the contacting step (A) and in the absence of compound (1)₂O₅/H₃CSO₃A step of H reagent; or (ii) wherein the contacting step further comprises contacting together phosphorus pentoxide and methanesulfonic acid in the presence of compound (1) to form P in situ₂O₅/H₃CSO₃And H, reagent.

The CAS number of polyphosphoric acid or PPA is 8017-16-1 and is typically of the formula HO- [ P (═ O) (OH)]_n-H, wherein the subscript n indicates the degree of polymerization. PPA consists of oxygen and phosphorus atoms and is free of sulfur and carbon atoms.

In some aspects, each reactant, reagent, solvent, or other material and its respective product used in the methods of the present invention is free of Pt, Ni, Pd, Rh, and Ru.

Conditions under the reaction sufficient for preparation include reaction temperature, reaction pressure, reaction atmosphere, reaction solvent (if any), reactant and reagent concentrations, molar ratios of reactants to each other and to reagents, and the absence of an eliminating compound (neutralizing compound). The reaction pressure is typically room pressure (e.g., 101 kilopascals (kPa)), except for higher for olefin polymerization reactions. If the desired reaction (e.g., step (A)) is carried out in a fume hood under a nitrogen atmosphere without the presence of molecular nitrogen or using Schlenk line technology (Schlenk line technique) and conditions.

The reaction temperature under reaction conditions sufficient for preparation may vary from step to step. For example, in step (a) (cyclization), conditions under the reaction sufficient to prepare compound (2) may include a reaction temperature of-78 ℃ to 30 ℃, alternatively-30 ℃ to 25 ℃, alternatively 0 ℃ to 25 ℃, alternatively-5 ℃ to 5 ℃.

The use or non-use of a solvent and the type of solvent may vary depending on the procedure if used under reaction conditions sufficient for the preparation. Step (A) may be free of solvent or may employ a solvent. When the amount of methanesulfonic acid is sufficient to dissolve the reactants, the solvent may be omitted. Alternatively, polar aprotic solvents may be used. The polar aprotic solvent may be selected from sulfolane, 1, 2-dimethoxyethane, 1-methoxy-2- (2-methoxyethoxy) ethane, and mixtures of any two or more thereof. The amount of polar aprotic solvent employed is not particularly critical. The aforementioned polar aprotic solvent can be used to dissolve the compound (1) and/or P₂O₅/H₃CSO₃And H, reagent. The amount of solvent employed may be sufficient to prepare a compound in which P is₂O₅/H₃CSO₃The H reagent is a starting solution of 0.5 molar (M) to 5M, or 1M to 2.5M. The polar aprotic solvent may allow the contacting step (a) to be carried out at a lower temperature within the ranges given above. Use of polar aprotic solvents for P₂O₅/H₃CSO₃H reagent, since protic solvents would be expected to react with P₂O₅/H₃CSO₃H reagent (which is a powerful dehydrating agent) reacts improperly. The polar aprotic solvent may have an intermediate polarity so as to cause the compound (1) and P₂O₅/H₃CSO₃And H reagent co-dissolves. The polar aprotic solvent may be capable of producing a homogeneous solution of compound (1) at-25 ℃ to 25 ℃, alternatively at 10 ℃, alternatively at 0 ℃, alternatively at-10 ℃, alternatively at-25 ℃. At P₂O₅/H₃CSO₃The successful reaction of compound (1) in the presence of H reagent does not require a homogeneous solution.

The reaction atmosphere included under reaction conditions sufficient for preparation may be molecular nitrogen free or schlenk line conditions for step (a) (cyclization).

The reactant and reagent reaction concentrations included under reaction conditions sufficient for preparation may independently range from 0.1 to 1.4M, alternatively from 0.25 to 1 molar concentration (M), alternatively from 0.4 to 1M.

The molar ratios of the reactants to each other and to the reagents included under reaction conditions sufficient for preparation may vary, depending on the reactants and reagents used, from 0.25 to 1.5 times the theoretical reaction stoichiometry, or from 0.99 to 1.2 times the theoretical reaction stoichiometry, or from 1.0 to 1.1 times the theoretical reaction stoichiometry.

The elimination agent should not be included under reaction conditions sufficient for preparation. In step (A) (cyclization), the elimination agent may be an amount of a basic compound that will neutralize P₂O₅/H₃CSO₃The acidity of the H reagent renders it ineffective. For example, the purity of the compound (1) used in step (A) may beAt least 95%, or at least 98%, or at least 99%, or at least 99.5% by weight.

The compounds include all isotopes and naturally abundant and isotopically enriched forms thereof. The enriched form may have medical or anti-counterfeiting use.

In some aspects, any compound, composition, formulation, mixture, or reaction product herein may be free of any of the chemical elements selected from the group consisting of: H. li, Be, B, C, N, O, F, Na, Mg, Al, Si, P, S, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, I, Cs, Ba, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi, lanthanides and actinides; with the proviso that chemical elements required for the compound, composition, formulation, mixture or reaction product (e.g., C, H and O required for C and H or for alcohols required for polyolefins) are not excluded.

Unless otherwise indicated, the following applies. Or in advance of different embodiments. ASTM means the Standard organization, ASTM International (ASTM International, West Consho-hocken, Pennsylvania, USA) of West Conshohoken, West Farnia. Any comparative examples are used for illustration purposes only and should not be prior art. Absent or not means completely absent; or not detectable. The option may be given, but not necessarily essential. Operation means functionally enabled or effective. Optional (optionally) means absent (excluded), or present (included). The properties (e.g.viscosity: 23 ℃ C. and 101.3kPa) were measured using standard test methods and conditions for measurement. Ranges include endpoints, subranges, and all values and/or fractional values contained therein, except integer ranges that do not include fractional values. Room temperature: 23 ℃ plus or minus 1 ℃. Substituted when referring to a compound means up to and including one or more substituents in place of hydrogen per substitution. When there is any conflict between a structure and a name of a compound, the structure controls.

Examples of the invention

Unless otherwise indicated herein, the following preparations were usedAnd (6) line characterization. When indicated, the synthesis was performed in a glove box under an atmosphere of dry nitrogen. It is desirable to carry out the reaction under anhydrous conditions in a dry nitrogen atmosphere in a cooled, dried glass vessel under a flow of dry nitrogen. Anhydrous toluene, hexane, tetrahydrofuran, diethyl ether and 1, 2-dimethoxyethane were obtained from Sigma-Aldrich (Sigma-Aldrich). The solvent used for the experiments performed in a nitrogen-filled glove box was passed through a heated chamber at activated 4 angstromsStoring on molecular sieve and further drying. All other reagents were purchased from sigma-aldrich and used as received. For example, 0.1/1(wt/wt) P₂O₅/MeSO₃Reagent H is available from sigma aldrich, CAS No. 39394-84-8.

Residual protons in deuterated solvents were used as a reference, reported on the delta scale as parts per million (ppm) downfield relative to Tetramethylsilane (TMS)¹H-NMR (proton nuclear magnetic resonance spectroscopy) chemical shift data. In CDCl₃Of¹H-NMR chemical shift data referenced 7.26ppm in benzene-d 6 (C)₆D₆) The data measured in (A) was referenced 7.16ppm, and the data measured in tetrahydrofuran-d 8(THF-d8) was referenced 3.58 ppm.¹H-NMR chemical shift data are reported in the following format: chemical shifts in ppm (multiplicity, coupling constants and integral values in hertz (Hz). multiplicity is abbreviated as s (singlet), d (doublet), t (triplet), q (quartet), pent (quintet), m (multiplet) and br (broad).

Preparation 1: (1a) synthesis of (2E) -2-butenoic acid cyclohexyl esterCyclohexanol (30mL (mL), 283.9 mmol), crotonic acid (25.9g, 300.98mmol), p-toluenesulfonic acid (1.08g, 5.68mmol), and 40mL of toluene were placed in a 250mL round bottom flask in a fume hood. The flask was equipped with a dean-stark trap and a reflux condenser. The resulting reaction mixture was heated to reflux,and azeotropically removing the water produced. After refluxing for 18 h, the reaction mixture was cooled to ambient temperature and quenched with water (55 mL). The resulting organic layer was separated and saturated NaHCO was used₃Aqueous solution (2X 40mL), then brine (30mL), then dried over magnesium sulfate and filtered. The solvent was removed under reduced pressure to give compound (1a) (40.6g) as a pale yellow liquid in 85% yield.¹HNMR (400MHz, chloroform-d) delta 6.93(dq,1H),5.81(dq,1H), 4.84-4.73 (m,1H), 1.92-1.80 (m,4H), 1.77-1.64 (m,3H), 1.59-1.12 (m,6H) and GC/MS (EI) (mass experiment values of 168, 87, 69) are consistent with (2E) -cyclohexyl 2-butenoate.

Preparation 2 (prophetic): (1b) synthesis of 3,5, 7-trimethylcyclooctyl (1E) of (2E) -2-butenoic acid. Preparation 1 was repeated except that 284mmol of (a14)3,5, 7-trimethylcyclooctanol (CAS 1823711-29-0) was substituted for the cyclohexanol to give 3,5, 7-trimethylcyclooctyl (2E) -2-butenoate (1 b).

Preparation 3: (2E) synthesis of cyclopentyl (1c) 2-butenoateA50 mL round bottom flask equipped with a dean-Stark trap and reflux condenser was charged with cyclopentanol (2.1mL, 23.2mmol), crotonic acid (2.11g, 24.6mmol), p-toluenesulfonic acid (0.088g, 0.46mmol), and 5mL toluene in a fume hood. The resulting mixture was heated to reflux and the water produced was azeotropically removed. After refluxing for 18 hours, the reaction mixture was cooled to ambient temperature and quenched with water (10 mL). The resulting organic layer was separated and saturated NaHCO was used₃Aqueous solution (2X 10mL), then brine (20mL), and then dried over magnesium sulfate. Filtration and removal of the solvent from the filtrate under reduced pressure gave 2.8g (78% yield) of compound (1c) as a colorless liquid.¹HNMR and GC/MS (Mass Experimental value of 154) were consistent with cyclopentyl (2E) -2-butenoate. Compound (1c) was characterized by GC/ms (ei)154 (mass), 87, 69.¹H NMR (400MHz, chloroform-d) Δ 6.91(dq,1H),5.79(dq,1H),5.18(tt,1H), 1.94-1.79 (m,5H), 1.83-1.63 (m,4H), 1.67-1.48 (m, 2H).

Inventive example 1: synthesis of Compound (2a)2,3,4,5,6, 7-hexahydro-3-methyl-1H-inden-1-one(2a) (Compound (2) wherein the subscript n is 2, R1-R3 are H, and R4 is methyl). Compound (1a) (2E) -cyclohexyl 2-butenoate (3g, 17.8mmol) was added under a nitrogen atmosphere in a 250mL round bottom flask equipped with a stir bar. The ester was cooled to 0 ℃ in the flask. Then P was added dropwise at 0 deg.C₂O₅/H₃CSO₃H reagent (0.1/1)) (8.49mL, 53.5 mmol). The resulting reaction mixture was warmed to ambient temperature (23 ℃) with stirring and stirring was continued at ambient temperature for 72 hours. The crude product obtained is diluted with 20mL of water and then solid NaHCO is added in portions₃Until the bubbling subsided, a quenched mixture of pH 8 to pH 9 was obtained. The aqueous and organic layers of the quenched mixture were separated in a separatory funnel. The aqueous layer was extracted three times with ether (3X 20 mL). The organic layer and the three extracts were combined and the combination was washed with brine (30mL), dried over magnesium sulfate and filtered. The solvent was removed in vacuo to give 2.45g of compound (2a) as a light brown oily product (91.4% yield).¹HNMR (400MHz, chloroform-d) delta 2.77-2.67 (m,1H),2.61(ddd,1H), 2.48-2.34 (m,1H), 2.32-2.03 (m,3H), 2.03-1.47 (m,5H),1.14(d,3H) is consistent with (2a)2,3,4,5,6, 7-hexahydro-3-methyl-1H-inden-1-one.

Inventive example 2 (prophetic): compound (2b) bicyclo [3.3.0]Synthesis of (E) -1(5) -octen-2-one(Compound (2) wherein the subscript n is 1 and R1-R4 are H). Example 1 was repeated except that compound (1a) was substituted with 18mmol of cyclopentyl (1b) acrylate (CAS 16868-13-6) to give compound (2 b).

Inventive example 3: compound (2c) (4-methyl-bicyclo [ 3.3.0)]-synthesis of 1(5) -octen-2-one, compound (2), wherein subscript n is 1 and R1-R3 are H and R4 is methyl):in a fume hood, under nitrogen, in a 100mL round-bottom flask equipped with a stir bar, add preparation3 (1c) (2E) -cyclopentyl 2-butenoate (0.5g, 3.24 mmol). The ester in the flask was cooled to 0 ℃. Then dropwise adding P at 0 DEG C₂O₅/H₃CSO₃H reagent (0.1/1) (1.5mL, 9.73 mmol). The resulting reaction mixture was warmed to ambient temperature (23 ℃) with stirring and stirring was continued for 72 hours. The crude product obtained is diluted with 5mL of water and then solid NaHCO is added in portions₃Until the bubbling subsided, a quenched mixture of pH 8 to pH 9 was obtained. The aqueous and organic layers of the quenched mixture were separated in a separatory funnel. The aqueous layer was extracted three times with ether (3X 8 mL). The organic layer and the three extracts were combined and the combination was washed with brine (15mL), dried over magnesium sulfate and filtered. The solvent was removed in vacuo to give 0.42g (95% yield) of compound (2c) as an orange oil.¹H NMR (400MHz, chloroform-d) delta 3.05-2.89 (m,1H),2.81(dt,1H), 2.66-2.47 (m,1H), 2.47-2.26 (m,6H),1.19(d,3H) was consistent with Compound (2 c).

Inventive example 4 (prophetic): synthesis of compound (2d) 10-methyl-bicyclo [5.3.0] -1(7) -decen-8-one (compound (2) where subscript n is 3 and R1-R3 are H and R4 is methyl). Example 1 was repeated except that compound (1a) was substituted with 18mmol of (1c) (2E) -cycloheptyl 2-butenoate (CAS 10555-39-2) to give compound (2 d).

Inventive example 5 (prophetic): synthesis of compound (2e)2,4,6, 11-tetramethyl-bicyclo [6.3.0] -1(8) -undecen-9-one (compound (2) wherein subscript n is 4 and R1-R4 are methyl). Inventive example 1 was repeated except that compound (1a) was substituted with 18mmol of (1E) (2E) -2-butenoic acid 3,5, 7-trimethylcyclooctyl (preparation 2) to give compound (2E).

As previously discussed, Conia et al, Rand and Dolinski et al report the use of PPA or P₂O₅the/PPA mixture catalyzes the reaction of cycloheptene, cyclohexene or cyclopentene with an α, β -unsaturated carboxylic acid (e.g., acrylic acid or crotonic acid) to yield a reaction mixture containing an ester by-product (e.g., cycloheptyl crotonate, cyclohexyl crotonate or cyclopentyl crotonate, respectively). We have found that the use of phosphorus pentoxide/methane sulphonic acid reagents to catalyse the reaction of cycloheptene, cyclohexene or cyclopentene with an alpha, beta-unsaturated carboxylic acid (e.g. acrylic acid or crotonic acid) gives esters freeA reaction mixture of by-products (e.g., the reaction does not produce cycloheptyl, cyclohexyl, or cyclopentyl crotonate, respectively). We failed to show any ester by-product based on this study of the analysis of at least one of the reaction mixtures by gas chromatography-mass spectrometry (GC-MS). We also based on the results of this study, at P₂O₅/H₃CSO₃In the presence of a H reagent, the reaction ratio of cycloheptene, cyclohexene or cyclopentene with an alpha, beta-unsaturated carboxylic acid (e.g. acrylic acid or crotonic acid) is P₂O₅/H₃CSO₃In the presence of the H reagent, cycloheptyl crotonate, cyclohexyl crotonate or cyclopentyl crotonate react much faster respectively.

Without wishing to be bound by theory, we believe that P₂O₅/H₃CSO₃Reaction of H reagent with an α, β -unsaturated carboxylic acid (e.g. crotonic acid) to give in situ R4CH ═ CHC (═ O) -SO₂-CH₃A mixed anhydride of the formula R4CH ═ CHC, generated in situ⁺(═ O) acylcations (i.e., acylcarbonium) which undergo rapid Friedel-Crafts acylation of cycloolefins to yield in situ the formula R^a-C(＝O)-R^cOf (a) wherein R is^aIs R4CH ═ CH-and R^cBeing a cycloalken-1-yl, the ketone undergoes a cyclization reaction to give the corresponding cyclopentenone. For example, when the cyclic olefin is cyclohexene and the α, β -unsaturated carboxylic acid is crotonic acid, we consider P to be₂O₅/H₃CSO₃Reacting the H reagent with crotonic acid to obtain a general formula H in situ₃CCH＝CHC(＝O)-O-SO₂-CH₃The mixed anhydride of formula H, which is formed in situ₃CCH＝CHC⁺(═ O) acylcation (i.e., acylcarbonium) which rapidly undergoes friedel-crafts acylation of the cycloalkene to give in situ the formula R^a-C(＝O)-R^cOf (a) wherein R is^aIs H₃CCH ═ CH-and R^cBeing cyclohexen-1-yl, the ketone undergoes a cyclization reaction to give the corresponding cyclopentenone, i.e., 2,3,4,5,6, 7-hexahydro-3-methyl-1H-inden-1-one (i.e., 7-methyl-bicyclo [4.3.0 ]]-7-nonen-9-one). Thus, in cyclic olefins (e.g. cycloheptene, cyclohexene orCyclopentene) with an α, β -unsaturated carboxylic acid (e.g., acrylic acid or crotonic acid) without the production of ester by-products (e.g., cycloheptyl, cyclohexyl or cyclopentyl crotonate, respectively) by Conia et al, Rand and Dolinski et al using PPA or P₂O₅The PPA mixture is reported.