A New Synthesis of Unsaturated Acids. IV. Further Aspects of the Scope and Mechanism of the Conversion of Halopyrazolones to α,β-Acetylenic and Olefinic Acids<sup>1</sup>

Carpino, Louis A.; Terry, Paul H.; Thatte, S. D.

doi:10.1021/jo01347a031

Cited by 33 publications

(4 citation statements)

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“…The mother liquor was chromatographed (silica gel, ether/hexane) to give 43 mg (21%) more. The material was identical in all respects with material prepared previously:10 mass spectrum ( + 1)+ 344; [a]D -64.91°(c 2.20, CHC13); IR (CHClg) 3430, 2940,1680,1500, and 1160 cm"1; NMR (CDClg) 0.8-1.85 (m, 15 ), 0.88 (d, 3 H, J = 7 Hz), 0.94 (d, 3 H, J = 7 Hz), 1.46 (s, 9 ), 1.93 (m, 1 H), 3.2 (br d, 1 H, J =8 Hz), 3.33 (m, 1 H), 4.04 (m, 1 H), 4.25 (br, 1 H), 4.58 (br d, 1 H, J = 9 Hz). The below data were obtained in CDgCN: 0.8-1.95 (m, 16 ), 0.84 (d, 3 H, =7 = 7 Hz), 0.92 (d, 3 H, J = 7 Hz), 1.42 (s, 9 H), 2.84 (d, 1 H, J = 7 Hz), 3.02 (m, 1 H), 3.22 (m, 1 H), 3.89 (m, 1 ), 4.04 (d, 1 H, J = 4 Hz), 5.23 (d, 1 H, J = 10 Hz), when D20 was added, the 2.84, 4.04, and 5.23 ppm resonances exchanged out.…”

Section: Methodsmentioning

confidence: 87%

“…Drying (MgS04), filtering, and evaporating provided the desired product (1.39 g, 99%), which was used directly in the next step. The following chemical shifts for 13a were derived from a spectrum of the crude mixture, which showed 1:8 14a (NH, 4.85 ppm): 13a (NH, 4.52 ppm): NMR (CDC13) 0.93, 0.94 (2 d, 3 H each, J = 7, 7 Hz), 1.39 (s, 9 H), 0.85-1.95 (several m), 2.18 (m, 1 ), 2.41 (dd, 1 H, J = 7,17 Hz), 2.66 (dd, 1 H, J = 7, 17 Hz), 3.8 (br, 1 H), 4.04 (br s, 1 ), 4.30 (m, 1 H), 4.52 (br d, 1 H, J = 10 Hz).…”

Section: Methodsmentioning

confidence: 99%

“…After being stirred overnight, 11a (R' = H, 2R/2S = -8/1, 9.77 g, 63%) was collected by filtration as a white solid: mp 110-113 °C; NMR (500 MHz, CDClg) for 11a (R' = H, 2R): 6 0.85-0.92 (m, 1 ), 0.97-1.05 (m, 1 ) 1.10-1.30 (m, 3 H), I. 32-1.43 (m, 2 ), 1.60-1.80 (m, 6 ), 1.95 (s, 9 H), 3.82 (br s, 1 H), 4.57 (br s,l H), 4.64 (br s, 1 H) and 4.73 (d, J = 7.5 Hz, 1 H); for 11a (R' = H, 2S): 0.85-0.92 (m, 1 ), 0.97-1.05 (m, 1 ), 1.10-1.30 (m, 3 ), 1.32-1.43 (m, 2 ), 1.60-1.80 (m, 6 H), 1.98 (s, 9 H), 4.10 (m, 1 H), 4.35 (br s, 1 H), 4.46 (d, J = 5 Hz, 1 H), and 5.05 (br s, 1 H); IR (CHClg) 3450,1690,1500, and 1160 cm"1; mass spectrum, m/e ( + 1) 283. Anal.…”

Section: Methodsmentioning

confidence: 99%

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A convenient stereoselective synthesis of 1,2,3-aminodiols from .alpha.-amino acids

Luly¹,

Hsiao²,

Bamaung³

et al. 1988

J. Org. Chem.

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6109nylsulfonyl)ethylene9 ( l l b ) (191 mg, 0.6 mmol) in xylene (5 mL) was heated under reflux for 30 min. The cooled solution was diluted with ether, and the white adduct 12b-15b (277 mg, 92.5%) was collected by filtration: 'H NMR (CDC13) 6 2.27 (m, 2 H), 3.68-4.05 (m, 2 H), 4.10 (m, 2 H), 4.90 (m, 2 H), 6.65 (m, 2 H), 7.00-8.05 (m, 18 H).Sodium Amalgam Reduction of Adducts 12b-15b. A mixture of adducts 12b-15b (272 mg, 0.45 mmol) was taken up in dry tetrahydrofuran (5 mL) and methanol (10 mL), containing sodium dihydrogen phosphate (1.2 g), and purged with nitrogen. With efficient stirring, 3% sodium amalgam (ca. 2.5 g) was added in small portions. After 16 h, the mixture was filtered through a Celite pad and poured onto brine (20 mL). The solvent was evaporated off on the rotary evaporator, and the aqueous residues were extracted with dichloromethane (4 X 20 mL). The combined organic layer was washed with water (2 X 20 mL) and brine (20 mL), dried (Na2S04), and evaporated to give 16-19 as a light yellow solid (140 mg, 97.8%). GC-MS analysis of this mixture showed it to be an isomeric mixture of four components, in the approximate ratio of 2:1:2:7 (column used: 12 m X 0.32 mm (i.d.), packed with fused silica-BPI type, column temperature 250 OC, isothermal conditions), all with the m / e (M+) of 318: IR (film, NaCl plate) 3054,

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Section: Methodsmentioning

confidence: 87%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

A convenient stereoselective synthesis of 1,2,3-aminodiols from .alpha.-amino acids

Luly¹,

Hsiao²,

Bamaung³

et al. 1988

J. Org. Chem.

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“…These compounds were synthesized from the corresponding aldehydes via a (Z)-selective [5a] and an (E)-selective [12] Horner-Wadsworth-Emmons (HWE) reaction, respectively (Scheme 2). Each of the substrates was obtained with good (Z)-or (E)-selectivity, except for 1c and 1e which were obtained with low (Z)-selectivity ((E)/(Z) 44 : 56 for 1c and 22 : 78 for 1e) when hexamethyldisilazane potassium salt (KHMDS)/ [18]crown-6 was used as the base, while the standard method with NaH as the base [5a] afforded the (E)-product as the major isomer. Subsequently, the hydrolysis/desilylation reaction was studied.…”

Section: Introduction -The 2-[(trimethylsilyl)methyl]acrylate (¼ 2-[mentioning

confidence: 99%

Correlation of Hydrolysis and Desilylation of 2‐[(Trimethylsilyl)methyl]acrylate Derivatives in Aqueous Alkali Solutions

Kuroda

Sunakawa

Muguruma

2008

Helvetica Chimica Acta

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Hydrolysis and desilylation reaction of 2-[(trimethylsilyl)methyl]acrylate (¼ 2-[(trimethylsilyl)methyl]prop-2-enoate) derivatives were studied to evaluate the effect of the presence/absence of a further conjugating substituent (Schemes 3 and 4 and Tables 1 and 2). The substrates having a nonconjugating substituent at the acrylate moiety were stable to dilute alkali conditions, and afforded simple hydrolysis products under concentrated alkali conditions. In contrast, both hydrolysis and desilylation occurred from the substrates bearing conjugated substituents at the acrylate skeleton. The difference in reactivity can be explained in terms of the stabilization of the intermediate anion. During the course of these projects, we previously obtained a-methylene-g-lactones via a cyclization of 2-[(trimethylsilyl)methyl]pentadienoate or the corresponding carboxylic acid [9]. Moreover, ethyl (2Z,4E)-4-methyl-2-[(trimethylsilyl)methyl]hexa-2,4-dienoate (1a) and ethyl (2Z,4E)-3-(cyclohex-1-en-1-yl)-2-[(trimethylsilyl)methyl]-hexa-2,4-dienoate (1b) were hydrolyzed to the corresponding acids 2a and 2b via a typical hydrolysis reaction, i.e., in the presence of aqueous KOH solution in MeOH (Scheme 1). However, the yields of the hydrolysis products 2a and 2b were low (26% for 2a and 31% for 2b). Although not mentioned in the report, the major products were the desilylated acids 3a and 3b. Since direct desilylation from an allylsilane moiety does not occur under such weak-base conditions [10], the desilylation reaction proceeded presumably via an intramolecular assistance of the ester group or its hydrolyzed carboxylate. Indeed, intramolecular attack of an electron-rich anion or related species at the Si-atom as a Lewis base [11] is considered to facilitate protodesilylation. The aim of the present study is to clarify the generality and the substituent effect of this

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Methyl 2‐Alkynoates from 3‐Alkyl‐2‐Pyrazolin‐5‐ones: Methyl 2‐Hexynoate

et al. 2003

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A New Synthesis of Unsaturated Acids. IV. Further Aspects of the Scope and Mechanism of the Conversion of Halopyrazolones to α,β-Acetylenic and Olefinic Acids¹

Cited by 33 publications

References 2 publications

A convenient stereoselective synthesis of 1,2,3-aminodiols from .alpha.-amino acids

A convenient stereoselective synthesis of 1,2,3-aminodiols from .alpha.-amino acids

Correlation of Hydrolysis and Desilylation of 2‐[(Trimethylsilyl)methyl]acrylate Derivatives in Aqueous Alkali Solutions

Methyl 2‐Alkynoates from 3‐Alkyl‐2‐Pyrazolin‐5‐ones: Methyl 2‐Hexynoate

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A New Synthesis of Unsaturated Acids. IV. Further Aspects of the Scope and Mechanism of the Conversion of Halopyrazolones to α,β-Acetylenic and Olefinic Acids1

Cited by 33 publications

References 2 publications

A convenient stereoselective synthesis of 1,2,3-aminodiols from .alpha.-amino acids

A convenient stereoselective synthesis of 1,2,3-aminodiols from .alpha.-amino acids

Correlation of Hydrolysis and Desilylation of 2‐[(Trimethylsilyl)methyl]acrylate Derivatives in Aqueous Alkali Solutions

Methyl 2‐Alkynoates from 3‐Alkyl‐2‐Pyrazolin‐5‐ones: Methyl 2‐Hexynoate

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A New Synthesis of Unsaturated Acids. IV. Further Aspects of the Scope and Mechanism of the Conversion of Halopyrazolones to α,β-Acetylenic and Olefinic Acids¹