Conversion of conjugated p-tosylhydrazones to the corresponding ethers by sodium borohydride, sodium alkoxide, or potassium carbonate in alcohol solvents

Grandi, Romano; Marchesini, A.; Pagnoni, Ugo Maria; Trave, R.

doi:10.1021/jo00872a019

Cited by 27 publications

(9 citation statements)

References 7 publications

(14 reference statements)

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“…Interestingly, sugar derived carboxylic acids (entries 21-24) gave the highest yield of the products. Based on these experiences, it can be assumed that from the possible mechanistic pathways 25 (Scheme 3) protonation of either the intermediate diazo compound (path a) or the carbene (path b) is a 7f ¼ 4 in Table 1.…”

Section: Resultsmentioning

confidence: 99%

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Coupling of anhydro-aldose tosylhydrazones with hydroxy compounds and carboxylic acids: a new route for the synthesis of C-β-d-glycopyranosylmethyl ethers and esters

et al. 2017

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Cross couplings of O-peracylated 2,6-anhydro-aldose tosylhydrazones (C-(b-D-glycopyranosyl) formaldehyde tosylhydrazones) with alcohols, phenols, and carboxylic acids were studied under thermic or photolytic conditions in the presence of K 3 PO 4 or LiOtBu. The reactions failed with EtOH, BnOH, or tBuOH, however, (CF 3) 2 CHOH, electron poor phenols and carboxylic acids gave the corresponding C-b-D-glycopyranosylmethyl ethers and esters, respectively, representing a new access to these glycomimetic compounds.

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Section: Resultsmentioning

confidence: 99%

“…20,22,23 Insertion of carbenes into O-H bonds is a long known transformation. 24 Carbenes generated from tosylhydrazones were inserted into alcohols and phenols 5,6,[25][26][27][28][29][30] as well as into carboxylic acids 7,8 to give the corresponding ethers and esters, respectively.…”

Section: Introductionmentioning

confidence: 99%

Coupling of anhydro-aldose tosylhydrazones with hydroxy compounds and carboxylic acids: a new route for the synthesis of C-β-d-glycopyranosylmethyl ethers and esters

et al. 2017

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“…The first approach to synthesize the pyrazole derivatives (MW1) refers to the 1,3-cycloaddition of the corresponding tosylhydrazones of the carbonyl compounds selected, using a base in dry media (Scheme 2). Tosylhydrazones were prepared following the classical procedure (ketone plus tosylhydrazine in methanol at reflux) [12]. Scheme 2.…”

Section: Synthesismentioning

confidence: 99%

“…In a 40 mL Pyrex tube, the appropriate tosylhydrazone of the studied carbonyl compounds (10 mmol), previously prepared by a classical procedure [12], was mixed together with anhydrous K 2 CO 3 (20 mmol). A minimum amount of N,N-dimethylformamide (30 mg/mmol of organic substrate) was added in order to improve energy transfer [13].…”

Section: Microwave Mediated Synthesis Of Pyrazoles A-c (Mw1) Generalmentioning

confidence: 99%

New “Green” Approaches to the Synthesis of Pyrazole Derivatives

et al. 2007

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A novel approach to the synthesis of pyrazole derivatives from tosylhydrazones of α,β-unsaturated carbonyl compounds possessing a β-hydrogen is proposed, exploiting microwave (MW) activation coupled with solvent free reaction conditions. The cycloaddition was studied on three ketones (trans-4-phenyl-3-buten-2-one, β-ionone and trans-chalcone). The corresponding 3,5-disubstitued-1H-pyrazoles were obtained in high yields and after short reaction times. In order to simplify and point out the green chemistry features of the method, a further improvement was achieved under the same catalytic conditions with a "one pot" synthesis of these heterocyclic compounds, starting directly from their carbonyl precursors via tosylhydrazones generated in situ. For an exhaustive study, the dielectric properties of the solid reaction mixtures were also measured, in order to obtain input data for the numerical simulation of their heating behaviour in the single mode MW cavity which was used for experimental work. In order to supply a valid methodology and tool for measuring the environmental impact, a comparative study between the synthetic route proposed and the classical synthetic route has been carried out.

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“…110-112 ˚C (lit., 6 110-112 ˚C, MeOH); 1 H NMR (400 MHz, β-Phenyl-cinnamaldehyde tosyl hydrazone. 9 Colourless needles (90% yield); R f = 0.23 (EtOAc/petroleum ether 1:4); m.p.…”

Section: Characterisation Of Tosylhydrazonesmentioning

confidence: 99%

Diastereoselective Synthesis of Cyclopropane Amino Acids Using Diazo Compounds Generated in situ.

et al. 2004

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Diastereoselective Synthesis of Cyclopropane Amino Acids Using Diazo Compounds Generated in situ. -An efficient method for the diastereoselective synthesis of cyclopropane amino acids is presented, involving the reaction of dehydroamino acids (II), (VI) and (VIII) with in situ generated aryldiazomethanes (from tosylhydrazone salts). The diastereoselectivity can be directed by the reaction conditions. Thus, good to high trans-selectivity is achieved in the absence of metal catalysts [cf. (VII)], while good cis-selectivity is accessible in the presence of FeCl(tpp) catalyst [cf. (IX)]. The method is applied to the formal synthesis of dopa decarboxylase inhibitor (XVI) via trans-cyclopropane derivative (XI) and of coronamic acid (XVII) via cis-cyclopropane (XIV). -(ADAMS, L. A.; AGGARWAL*, V. K.; BONNERT, R. V.; BRESSEL, B.; COX, R. J.; SHEPHERD, J.; DE VICENTE, J.; WALTER, M.; WHITTINGHAM, W. G.; WINN, C. L.; J. Org. Chem. 68 (2003) 24, 9433-9440; Sch. Chem., Univ. Bristol, Cantock's Close, Bristol BS8 1TS, UK; Eng.) -Mischke 15-071 2004 Cyclopropane derivatives

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Conversion of conjugated p-tosylhydrazones to the corresponding ethers by sodium borohydride, sodium alkoxide, or potassium carbonate in alcohol solvents

Cited by 27 publications

References 7 publications

Coupling of anhydro-aldose tosylhydrazones with hydroxy compounds and carboxylic acids: a new route for the synthesis of C-β-d-glycopyranosylmethyl ethers and esters

Coupling of anhydro-aldose tosylhydrazones with hydroxy compounds and carboxylic acids: a new route for the synthesis of C-β-d-glycopyranosylmethyl ethers and esters

New “Green” Approaches to the Synthesis of Pyrazole Derivatives

Diastereoselective Synthesis of Cyclopropane Amino Acids Using Diazo Compounds Generated in situ.

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