Category: 185815-59-2

With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.185815-59-2,4-Isobutyldihydro-2H-pyran-2,6(3H)-dione,as a common compound, the synthetic route is as follows.

EXAMPLE 1 Synthesis of 3-hydrazinocarbonylmethyl-5-methyl-hexanoic acid (III)A 100 ml three-necked round-bottom flask, under nitrogen atmosphere, is added with 98% hydrazine hydrate (19.5 g, 0.382 mols), sodium hydroxide (12.4 g, 0.309 mol) in water (150 ml) and the solution is cooled to a temperature of -5 C. A solution of 3-isobutyl-glutaric anhydride (50.0 g, 0.294 mol) in toluene (200 ml) is dropped therein in about 1-2 h, keeping the temperature below 0-5 C. The mixture is reacted for about 1 h, then the phases are separated, the aqueous phase is concentrated to small volume, thereby obtaining a white solid which is taken up into isopropanol (100 ml) and filtered. The solid is dried under vacuum at a temperature of 30-35 C. for 16-18 hours. 56.7 g of product are obtained, in an 86% yield.1H-NMR (300 MHz, D2O, 28 C.): delta 2.20-1.90 (m, 5H); 1.50 (m, 1H); 1.05 (m, 2H); 0.75 (d, 6H)., 185815-59-2

185815-59-2 4-Isobutyldihydro-2H-pyran-2,6(3H)-dione 11480690, aTetrahydropyrans compound, is more and more widely used in various fields.

Reference£º
Patent; Dipharma Francis S.r.l.; US2009/143615; (2009); A1;,
Tetrahydropyran – Wikipedia
Tetrahydropyran – an overview | ScienceDirect Topics

With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.185815-59-2,4-Isobutyldihydro-2H-pyran-2,6(3H)-dione,as a common compound, the synthetic route is as follows.

In a 100mL three-necked flask, under nitrogen, was added thereto 3-isobutylglutaric anhydride (1.70g, 0.01mol), (S)-2-(3-(3,5-bis(trifluoromethyl)phenyl)thioureido)-N,N,4-trimethyl-N-(4-nitrobenzyl) pentan-1-ylammonium chloride (590mg, 1.0mmol), and 50mL methyl tert-butyl ether to dissolve solids. At -10C, was added with stirring benzyl mercaptan (1.50g, 0.012mol). It was stirred for 16h. The solvent was removed under reduced pressure to give the thiol ester 2.84g, yield 96%, ee value of 95%.

185815-59-2, 185815-59-2 4-Isobutyldihydro-2H-pyran-2,6(3H)-dione 11480690, aTetrahydropyrans compound, is more and more widely used in various fields.

Reference£º
Patent; Shenzhen Huaxian Pharmaceutical Tech Co., Ltd.; Lan, Wenlong; (9 pag.)CN105753726; (2016); A;,
Tetrahydropyran – Wikipedia
Tetrahydropyran – an overview | ScienceDirect Topics

185815-59-2, 4-Isobutyldihydro-2H-pyran-2,6(3H)-dione is a Tetrahydropyrans compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated

Example 4; Asymmetric Ring Opening of IBG-Anhydride with Chiral Alkaloide; A three-neck-flask (0.25 L) is charged with quinidine (11 mmol), 3-isobutyl glutaric anhydride (10 mmol) and toluene (50 ml). The mixture is cooled at -55 C. Methanol (30 mmol) is added dropwise over a period of 10 min to the cooled suspension. The reaction is stirred at for 96 h. The solution is concentrated to dryness, and the resulting residue is dissolved in diethyl ether (65 ml). The solution is washed with HCl-2N, and the aqueous layer is back-extracted with ether. The combined organic layers are dried with MgSO4, and filtered. The filtrate is evaporated to dryness. Example 5; Asymmetric Ring Opening of IBG-Anhydride with Chiral Alkaloide; Methanol (6.2 ml, 153 mmol) was added to a flame-dried 250 ml single, round-bottomed flask equipped with magnetic stirrer and charged with Quinidine (7.14 g, 22 mmol), 3-isobutyl glutaric anhydride (3.28 g, 19.3 mmol) and Toluene (100 ml, 30.5 vol) at -75 C. The reaction was stirred for 21 hours. The solution was concentrated to dryness, and the resulting residue was dissolved in diethyl ether (125 ml). The solution was washed with HCl-2N (40 ml¡Á3), and the aqueous layer was back-extracted with ether. The combined organic layers were evaporated until dryness, to give 3.56 g of a yellow oil of S-hemiester ((S)-3-((methoxycarbonyl)methyl)-5-methylhexanoic acid) (Optical purity 90%, Yield -91%). Example 6; Asymmetric Ring Opening of IBG-Anhydride with Chiral Alkaloide; Methanol (6.2 ml, 153 mmol) was added to a 250 ml three-necked, round-bottomed flask equipped with magnetic stirrer and charged with Quinidine (7.14 g, 22 mmol), 3-isobutyl glutaric anhydride (3.28 g, 19.3 mmol) and Toluene (100 ml, 30.5 vol) at -50 C. The reaction was stirred for 2 hours. The slurry was washed with H2SO4-2N (40 ml¡Á3). The organic layer was evaporated until dryness, to have 3.7 g yellow oil of S-Hemiester (Optical purity 90% Yield -95%). Example 7; Asymmetric Ring Opening of IBG-Anhydride with Chiral Alkaloide; Methanol (6.2 ml, 153 mmol) was added to a 250 ml three-necked, round-bottomed flask equipped with magnetic stirrer and charged with Quinidine (12.5 g, 38.6 mmol), 3-isobutyl glutaric anhydride (3.28 g, 19.3 mmol) and Toluene (100 ml, 30.5 vol) at -78 C. The reaction was stirred for 22.5 hours. The slurry was washed with HCl-2N (40 ml¡Á3). The organic layer was evaporated until dryness, to have 3.63 g yellow oil of S-Hemiester (Optical purity 90%, Yield -93%). Example 8; Asymmetric Ring Opening of IBG-Anhydride with Chiral Alkaloide; Methanol (6.2 ml, 153 mmol) was added to a 250 ml three necked, round-bottomed flask equipped with magnetic stirrer and charged with Quinidine (7.14 g, 22 mmol), 3-isobutyl glutaric anhydride (3.28 g, 19.3 mmol) and Toluene (33 ml, 10 vol) at -78 C. The reaction was stirred for 19 hours. The solution was washed with HCl-2N (25 ml¡Á3). The organic layer was evaporated until dryness, to give 3.38 g yellow oil of S-Hemiester (Optical purity 90%, Yield -87%). Example 9; Asymmetric Ring Opening of IBG-Anhydride with Chiral Alkaloide; Methanol (6.2 ml, 153 mmol) was added to a 250 ml three-necked, round-bottomed flask equipped with magnetic stirrer and charged with Quinidine (7.14 g, 22 mmol), 3-isobutyl glutaric anhydride (3.28 g, 19.3 mmol) and Toluene (100 ml, 30 vol) at -78 C. The reaction was stirred for 2 hours. The slurry was washed with H2SO4-2N (40 ml¡Á3). The organic layer was evaporated until dryness, to give 3.4 g yellow oil of S-Hemiester (Optical purity 95%, Yield -93%). Example 10; Asymmetric Ring Opening of IBG-Anhydride with Chiral Alkaloide; To a stirred suspension of 3-isobutyl glutaric anhydride (88 mmol) and Quinidine (100 mmol) in Toluene (30 vol) at -50 C., Methanol (273 mmol) was added drop-wise. The reaction was stirred at -50 C. for 17 h. The solution was washed with H2SO4-2N. The organic layer was evaporated to dryness to obtain S-Hemiester. (Optical purity -94%, Yield -94%). Example 11; Asymmetric Ring Opening of IBG-Anhydride with Chiral Alkaloide; To a stirred suspension of 3-isobutyl glutaric anhydride (19.3 mmol) and Quinidine (22 mmol) in Toluene (20 vol) at -50 C., Methanol (59.8 mmol) was added drop-wise. The reaction was stirred at -50 C. for 17 hours. The solution was washed with H2SO4-2N. The organic layer was evaporated to dryness to obtain S-Hemiester. (Optical purity -95%, Yield -89%). Example 12; Asymmetric Ring Opening of IBG-Anhydride with Chiral Alkaloide; To a stirred suspension of 3-isobutyl glutaric anhydride (19.3 mmol) and Quinidine (22 mmol) in Toluene (10 vol) at -50 C., Methanol (59.8 mmol) was added drop-wise. The reaction was stirred at -50 C. for 4 hours. The solution was washed with H2SO4-2N. The organic layer was evaporated to dryness to obtain S-Hemiester. (Optical purity -94%, Yield -92%). Example 13; Asymmetric Ring Opening of IBG-Anhydride with Chiral Alkaloide; To a stirred suspension of 3-isobutyl glutaric anhydride (19.3 m…

185815-59-2, The synthetic route of 185815-59-2 has been constantly updated, and we look forward to future research findings.

Reference£º
Patent; Hedvati, Lilach; Gilboa, Eyal; Avhar-Maydan, Sharon; US2007/293694; (2007); A1;,
Tetrahydropyran – Wikipedia
Tetrahydropyran – an overview | ScienceDirect Topics

185815-59-2, 4-Isobutyldihydro-2H-pyran-2,6(3H)-dione is a Tetrahydropyrans compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated

KR of thiol 28 with simultaneous enantioselective synthesis of a ( ?)-Pregabalin precursor; [00120] A 20 mL reaction vial containing a stirring bar was charged with 3-isobutylglutaric anhydride (4) (102.1 mg, 0.60 mmol) and 1 8 (47.2 mg, 0.080 mmol). The reaction vial was flushed with argon and fitted with a septum. MTBE was then injected (4.0 mL, 0.2M) and the solution cooled to -30 C. 28 (0.30 mmol) was added dropwise via syringe and the resulting solution was stirred for 48 h. The mixture was the immediately loaded onto a column and the ‘slow reacting’ thiol enantiomer separated from the mixture by flash-chromatography (71 .0 mg, 0.39 mmol, 98.7% ee as determined by CSP-HPLC after derivatisation as per general procedure B). The hemithioester product (29) was suspended in aq. NH3 (3 mL) and stirred at room temperature for 4 h. The reaction was then diluted with CH2CI2 (10.0 mL) and H20 (5.0 mL) and transferred to a separating funnel. The organic and aqueous layers were separated and the aqueous layer was extracted with CH2CI2 (2 x 10.0 mL). The combined organic layers were then dried over MgS04 and the solvent removed under reduced pressure affording the ‘fast reacting’ (S)-thiol enantiomer (62.4 mg, 0.35 mmol, 95.5% ee as determined by CSP-HPLC after derivatisation as per general procedure B) after flash chromatography. Conversion = 50.8%, S Factor = 226.[00121 ] The aqueous layer was then acidified by addition of HCI (8 N) and extracted with EtOAc (5 x 15 mL). The combined organic phases were then dried over magnesium sulphate and the solvent was removed under reduced pressure to afford the desired hemiamide as a white solid (71 .2 mg, 0.38 mmol, 97.0% ee as determined by CSP-HPLC after transformation to the corresponding o-nitrophenoxy ester, as per the procedure reported below).[00122] 1H NMR spectrum of (S)-30 (400 MHz, DMSO-d6): delta 12.0 (br s, 1 H), 7.27 (s, 1 H), 6.74 (s, 1 H), 2.22-1 .91 (m, 5H), 1 .66-1 .51 (m, 1 H), 1 .09 (app t, J 6.6, 2H), 0.81 (d, J 6.6, 6H). 13C NMR (100 MHz, DMSO-d6): delta 174.3 (q), 173.9 (q), 43.6, 40.2, 39.2, 30.1 , 25.0, 23.2, 23.1. HRMS (m/z): [M+Na]+ calcd. for C9H17N03Na 210.1 106; found, 210.1 1 14.; Synthesis of Pregabalin [( ?)- 3-(aminomethyl)-5-methylhexanoic acid]; [0066] To demonstrate the potential utility of this methodology, the KR of thiol 28 (0.80 mmol) was carried out with catalyst 18 in the presence of achiral anhydride 4, which furnished (R)-28 (0.39 mmol, 99% ee) and the ring-opened product 29 (0.40 mmol) with excellent efficiency at 51 % conversion as shown in Figure 1 . Thioester 29 (as a mixture of diastereomers) was then treated with aqueous ammonia, resulting in its cleavage to afford the other thiol enantiomer (S)- 28 (96% ee, 0.35 mmol) and the aminolysed product (S)-30 (97% ee, 0.38 mmol), again with high efficiency. Hemiamide (S)-30 is a precursor which can be converted in a single step to the (R)-antipode of the anticonvulsive agent Pregabalin and thus this sequence – in addition to serving as a highly efficient KR of 28 – constitutes a rapid and convenient formal synthesis of the ‘blockbuster’ drug (marketed as ‘Lyrica’).

185815-59-2, As the paragraph descriping shows that 185815-59-2 is playing an increasingly important role.

Reference£º
Patent; THE PROVOST, FELLOWS AND SCHOLARS OF THE COLLEGE OF THE HOLY AND UNDIVIDED TRINITY OF QUEEN ELIZABETH, NEAR DUBLIN; CONNON, Stephen Joseph; PESCHIULLI, Aldo; PROCURANTI, Barbara; WO2011/70028; (2011); A1;,
Tetrahydropyran – Wikipedia
Tetrahydropyran – an overview | ScienceDirect Topics

With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.185815-59-2,4-Isobutyldihydro-2H-pyran-2,6(3H)-dione,as a common compound, the synthetic route is as follows.

Experimental ProceduresDesymmetrisation of 3-/sobutylglutaric anhydride by thiolysis using catalyst C2 at ambient temperature:[0099] A 60 ml. reaction vial, charged with 3-/sobutylglutaric anhydride (102.1 mg, 0.60 mmol) and C2 (7.1 mg, 0.012 mmol), was fitted with a septum and flushed with argon. MTBE (40 ml.) was added followed by cyclohexyl mercaptan (368 mul_, 3.0 mmol) in a dropwise manner via syringe. After 72 h stirring at room temperature, volatiles were removed under reduced pressure and the desired product (Vl) obtained, after purification by flash chromatography, in 100% yield(164.0 mg) as a colourless oil. [alpha]D20 = -5.9 (c 1.64, acetone).[0100] deltaH (400 MHz, CDCI3): 0.92 (app. d, J 6.5, 6H), 1.18-1.34 (m, 3H), 1.36-1.50 (m, 4H),1.56-1.78 (m, 4H), 1.88-1.98 (m, 2H), 2.34-2.52 (m, 3H), 2.56-2.64 (m, 2H), 3.48-3.59 (m, 1 H). deltac (100 MHz, CDCI3): 22.0, 22.1 , 24.7, 25.0, 25.5, 30.0, 32.5, 32.6, 37.6, 41.9, 42.7, 47.5, 176.7,198.2. HRMS (ESI): Found 285.1522 (M – H+) Ci5H25O3S requires 285.1524., 185815-59-2

As the paragraph descriping shows that 185815-59-2 is playing an increasingly important role.

Reference£º
Patent; THE PROVOST, FELLOWS AND SCHOLARS OF THE COLLEGE OF THE HOLY AND UNDIVIDED TRINITY OF QUEEN ELIZABETH NEAR DUBLIN; CONNON, Stephen Joseph; PESCHIULLI, Aldo; MARKEY, Lyn; WO2010/86429; (2010); A2;,
Tetrahydropyran – Wikipedia
Tetrahydropyran – an overview | ScienceDirect Topics

With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.185815-59-2,4-Isobutyldihydro-2H-pyran-2,6(3H)-dione,as a common compound, the synthetic route is as follows.

185815-59-2, Example 4: Preparation of C3R)-5-methyl-3-(‘2-oxo-2(r(lRVl-phenylethvnamino>ethv? hexanoic acid compound (24); [0078] A three-necked flask equipped with an addition funnel, thermometer pocket, drying tube and a mechanical stirrer), was charged with tert-butyl methyl ether (100 ml), (R)-(+)-phenylethylamine (43.05 g, 0.355 mole) and 4-dimethylaminopyridine (0.258 g, 0.0021 mole). The mixture was cooled to a temperature of 0-5C, followed by addition of a solution of 3-isobutyl glutaric anhydride (40 g, 0.235 mole) in tert-butyl methyl ether (100 ml), over a period of 15-20 minutes, and stirring for additional 1.5-2 hours, at a temperature of 0-5C. The mixture was then extracted with 5 percent aqueous solution of NaHCO3 solution (700 ml), and the aqueous phase was washed with tert-butyl methyl ether (1 x 100 ml). The pH of the aqueous phase was adjusted to 2-2.5 by adding a 1-12N solution of hydrochloric acid. The aqueous phase was further extracted with ethyl acetate (I x 200 ml), followed by drying the combined ethyl acetates extracts over anhydrous sodium sulfate, and stripping off the solvents, to obtain a residue. The residue was crystallized from ethyl acetate and toluene mixture to get 44.5 g (70 percent yield) of a white solid of (3R)-5- EPO memyl-3-(2-oxo-2-{[(lR)-l-phenylethyl]amiho}ethyl)hexanoic acid with an optical purity of 99.19 percent, as measured by chiral HPLC.

As the paragraph descriping shows that 185815-59-2 is playing an increasingly important role.

Reference£º
Patent; TEVA PHARMACEUTICAL INDUSTRIES LTD.; TEVA PHARMACEUTICALS USA, INC.; WO2007/35789; (2007); A1;,
Tetrahydropyran – Wikipedia
Tetrahydropyran – an overview | ScienceDirect Topics

185815-59-2, 4-Isobutyldihydro-2H-pyran-2,6(3H)-dione is a Tetrahydropyrans compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated,185815-59-2

A 100 ml three-necked round-bottom flask, under nitrogen atmosphere, is added with 98% hydrazine hydrate (19.5 g, 0.382 mols), sodium hydroxide (12.4 g, 0.309 mol) in water (150 ml) and the solution is cooled to a temperature of -5C. A solution of 3-isobutyl-glutaric anhydride (50.0 g, 0.294 mol) in toluene (200 ml) is dropped therein in about 1-2 h, keeping the temperature below 0-5C. The mixture is reacted for about 1 h, then the phases are separated, the aqueous phase is concentrated to small volume, thereby obtaining a white solid which is taken up into isopropanol (100 ml) and filtered. The solid is dried under vacuum at a temperature of 30-35C for 16-18 hours. 56.7 g of product are obtained, in an 86% yield. 1H-NMR (300 MHz, D2O, 28C): delta 2.20-1.90 (m, 5H); 1.50 (m, 1H); 1.05 (m, 2H); 0.75 (d, 6H).

As the paragraph descriping shows that 185815-59-2 is playing an increasingly important role.

Reference£º
Patent; Dipharma Francis S.r.l.; EP2067768; (2009); A1;,
Tetrahydropyran – Wikipedia
Tetrahydropyran – an overview | ScienceDirect Topics

185815-59-2, 4-Isobutyldihydro-2H-pyran-2,6(3H)-dione is a Tetrahydropyrans compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated

Example 4(5)-3-(2-(Cinnamyloxy)-2-oxoethyl)-5-methylhexanoic acid (III) – (opposite enantiomer to Example 3)Quinidine (17.2g, 52.8mmol) was suspended in toluene (23OmL). Cinnamyl alcohol (9.3 g, 69mmol) was added and the reaction mixture was cooled to -35 0C. The solution of 3- isobutylglutaric anhydride (9.Og, 52.8mmol) in toluene (6mL) was added during 15 min and the reaction mixture was stirred at -38 C for 24 hours. Working up is carried out analogously to the preparation of the compound from Example 3. Combined extracts were warmed to 35 0C and (S)- alpha-phenylethylamine (5.8 g, 48mmol) was added, followed by seed crystals (10 mg). The mixture was stirred for 4 hours at 25C and filtered to obtain 14.6 g of (5)-alpha-phenylethylamine salt of (S)- 3-(2-(cinnamyloxy)-2-oxoethyl)-5-methylhexanoic acid. Salt was suspended in toluene (90 mL) and stirred with 3% HCl (600 mL) until clear solution was obtained. Aqueous acidic solution was separated and organic layer was washed once again with 3% HCl (2OmL). Evaporation of toluene afforded 10.2 g (65%) of monoester as viscous yellowish oil. HPLC analysis on Chiralpak AS column, hexane/EtOH/TFA=95/5/0.1 revealed 91.4 % ee.1H NMR (CDCl3), delta/ppm: 0.87 (d, 6H, J=6.5 Hz), 1.21-1.27 (m, 2H), 1.56-1.70 (m, IH), 2.38-2.48 (m, 5H), 4.73 (dd, 2H, Jy=6.5 Hz, J2=1.2 Hz), 6.27 (dt, IH J/=15.8 Hz, J2=6.5 Hz), 6.65 (d, IH, J=15.8 HZ), 7.22-7.40 (m, 2H).13C NMR (CDCl3), delta/ppm: 22.34, 25.07, 29.64, 38.30, 38.48, 43.26, 64.92, 122.95, 126.50, 127.96, 128.49, 134.18, 136.07, 172.26, 178.64., 185815-59-2

185815-59-2 4-Isobutyldihydro-2H-pyran-2,6(3H)-dione 11480690, aTetrahydropyrans compound, is more and more widely used in various fields.

Reference£º
Patent; PLIVA ISTRAZIVANJE I RAZVOJ D.O.O.; MCLEISH, Nicholas, Alistair, Maxwell; WO2008/9897; (2008); A1;,
Tetrahydropyran – Wikipedia
Tetrahydropyran – an overview | ScienceDirect Topics

185815-59-2, 4-Isobutyldihydro-2H-pyran-2,6(3H)-dione is a Tetrahydropyrans compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated

Example 3; Preparation and Isolation of (S), (R)-Mandelate Ester; A three-neck-flask (0.25 L) is charged with toluene (70 ml), S-mandelic acid (3.04 g) and NaH-60% (1.6 g). The mixture is heated to reflux and then cooled to room temperature. 3-isobutyl glutaric anhydride (3.4 g) is added drop-wise. The solution is stirred for 6 hours at room temperature. The solvent is evaporated, and the residue is crystallized from ethyl acetate and toluene mixture to get an off-white solid of (S)-4-(((S)-carboxy(phenyl)methoxy)carbonyl)-3-isobutylbutanoic acid (Mandelate ester). The solid is dried at 55 C. under vacuum., 185815-59-2

The synthetic route of 185815-59-2 has been constantly updated, and we look forward to future research findings.

Reference£º
Patent; Hedvati, Lilach; Gilboa, Eyal; Avhar-Maydan, Sharon; US2007/293694; (2007); A1;,
Tetrahydropyran – Wikipedia
Tetrahydropyran – an overview | ScienceDirect Topics

With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.185815-59-2,4-Isobutyldihydro-2H-pyran-2,6(3H)-dione,as a common compound, the synthetic route is as follows.

Example: 13a(17?, 3S )-1-(1′ -Napthyl)ethyl 3-(carboxylomethyl)-5- methylhexanoate VII and (1 ‘R, ZR )-1 -(1 ‘ -Napthyl)ethyl 3- (carboxylomethyl)-5- methylhexanoate Vila Imidazole (0.02 g, 0.29 mmole) was added to a solution of the enantiomeric ( ?)- (+)-a-methyl-1 -napthalenemethanol IX (0.25 g, 1 .45 mmole) in terf-butyl methyl ether (2 ml) at – 78 C under an atmosphere of nitrogen. A solution of the anhydride VIII (0.25 g, 1 .47 mmole) in terf-butyl methyl ether (1 ml) was added to it and the reaction mixture was stirred at this temperature until the reaction was complete as indicated from the TLC.An aqueous solution of citric acid was added to the reaction mixture and it was allowed to warm up to room temperature. The organic layer was washed with an aqueous solution of citric acid (2 x 2 ml), water (3 x 2 ml) and brine (3 x 3 ml), dried over sodium sulfate and concentrated to furnish a diastereomeric mixture of esters VII and Vila; yield: 0.5 g, quantitative.

185815-59-2, As the paragraph descriping shows that 185815-59-2 is playing an increasingly important role.

Reference£º
Patent; Dr. Braja Sundar Pradhan; WO2012/93411; (2012); A2;,
Tetrahydropyran – Wikipedia
Tetrahydropyran – an overview | ScienceDirect Topics